MSU LIBRARIES “ RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. If?“ ,w&=;:xa. -..-:, v.- Lit o‘ 5 =3 P3 . , . '29 6. y fi .4 3 a" DEC 1 3 1999 COMPARATIVE ANALYSIS OF COLLEMBOLA ASSOCIATED WITH ORGANIC AND CONVENTIONAL AGROECOSYSTEMS By Patricia 5. Michalak A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology I984 ABSTRACT COMPARATIVE ANALYSIS OF COLLEMBOLA ASSOCIATED WITH ORGANIC AND CONVENTIONAL AGROECOSYSTEMS By Patricia 5. Michalak Soil populations of Coliembola (Pseudosinella violenta, Entomobg/a unostri- gata, Isotoma notabilis, Isotoma viridis, Isotomiella minor, Isotomurus tricolor, Folsomides americanus, Proisotoma minuta, Onychiurus encarpatus, TullbergLia mg) were monitored in organic and conventional sweet corn agroecosystems in 1982 and 1983, at the Rodaie Research Center in Kutztown, Pennsylvania. The research site was under organic management for ten years previous. Agroecosystems differed with respect to weed management (cultivation, or atrazine and Lasso) and nitrogen source (bloodmeal, compost, or ammonium nitrate). Soil population density, species composition, extraction efficiency, horizontal distribution, vertical distribution, and population dynamics were evaluated. Conversion from organic to conventional management significantly reduced Coliembola soil population densities. Bloodmeal-nitrogen significantly increased densities of most Coliembola species, and ammonium nitrate significantly decreased densities. Most species were aggregated horizontally and vertically. Population dynamics varied with species. Key words: Coliembola, organic agroecosystem, conventional agroecosystem, cultivation, atrazine, Lasso, bloodmeal, compost, ammonium nitrate. DEDICATION This thesis is dedicated to Justin Thomas Cummings. ii ACKNOWLEDGMENTS My sincere thanks are extended to: Dr. George Bird and Dr. Tom Edens for their special contributions as co-chairmen of my guidance committee; Committee members Dr. James Bath, Dr. Stuart Gage, Dr. Richard Harwood, and Dr. Herman Koenig for their sincere interest and support; Staff and students at the Rodale Research Center, Pennsylvania, and the Department of Entomology "and Nematology", MSU, for their generous time, facilities and friendship; Dr. Richard Snider, for patiently and humorously introducing me to the Coliembola; Dr. George Ayers, Alice Silverthorn, and Helen and Nelson Stark, for seven years of encouragement; My parents, Vincent and Virginia Michalak, family and friends in Michigan, Pennsylvania, and New England for contributions that are evident in the essence of this thesis; The Regenerative Agriculture Association for their financial support. My greatest appreciation is extended to Spitzenberg's Cholmondeley for his unique contribution to this research. iii TABLE OF CONTENTS Page Introduction . . . . . .................................................. 1 Literature Review .................................................. 2 Biology of Soil Coliembola ....................................... 2 Soil Moisture and Temperature .............................. 3 Soil pH ... ..................... . ......................... 4 Spatial Distribution . . ...................... . ............... 5 Population Dynamics. . . . . . ................................. 6 Coliembola Associated with Sweet Corn in Berks Co., PA ............ 7 Isotoma (Desoria) notabilis Schaffer (Isotomidae) .............. 7 Isotomiella minor (Schaffer) (Isotomidae) ..................... 8 T ullbergia yosiii Rusek (Onychiuridae) . . . ..................... 8 Pseudosinella violenta (Folsom) (Entomobryidae) ............... 9 Entomobrya (Entomobrya) unostrigata Stach (Entomobryidae) . . . . 9 Impact of Agricultural Practices on Coliembola ..................... 10 Soil Tillage ............................................... 10 Crop Nutrition ............................................ ll Weed Management ........................................ 13 Recovery of Coliembola from Soil ................................ 14 Role of Coliembola in Nutrient Cycling ............................ 15 Alternative Farming Systems .................................... 17 Management System Inputs ...................................... 20 iv Page Nitrogen Fertilizers ....................................... 20 Herbicides ................................................ 24 Materials and Methods ..... - ......................................... 2 5 Research Site Description ....................................... 25 Quantification of Coliembola Soil Populations ...................... 33 Extraction Efficiency~ . . . ................................... 34 Standardization Procedure ...... . ........................... 35 Spatial Distribution and Population Dynamics ...................... 35 Coliembola Species Associated with Compost ...................... 38 Environmental Monitoring ....................................... 38 Agroecosystem Analysis . ........................................ 39 Orthogonal Comparisons .................................... 39 Results ........................................................... 42 Quantification of Coliembola Soil Populations ...................... 42 Extraction Efficiency ...................................... 42 Standardization Procedure ............. . .................... 44 Spatial Distribution and Population Dynamics ---------------------- 53 Coliembola Associated with Compost .............................. 67 Agroecosystem Analysis ......................................... 75 Orthogonal Comparisons .................................... 75 Discussion ...... . ...... . . . . . ....................................... 97 Quantification of Coliembola Soil Populations ---------------------- 97 Spatial Distribution and Population Dynamics ----------------------- 109 Agroecosystem Analysis ......................................... lll Summary............... Recommendations , , O 0 O OOOOOOOOOOOOOOOOO O OOOOOOOOOOOOOOOOOOOOOOOOO 115 References . .. ............. . ....................... . ............... 117 Appendices o o o o o o o ooooooooooooooooooooooo o o oooooooooooooooooooooo 126 vi LIST OF TABLES Table l. 10. 11. 12. Nutritional analysis of nitrogen fertilizers applied to sweet Corn. 0 O O O O ...... O OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO Percent nitrogen, and rate of application to sweet corn, of bloodmeal, compost and ammonium nitrate fertilizers . . . . . ...... Schedule of field operations and soil sampling in sweet corn (1982).. . . . . ............................................... (Sched)ule of field operations and soil sampling in sweet corn I983 . . . . . . ................................ . .............. Orthogonal comparisons utililized for separation of Coliembola soil population densities in sweet corn agroeco- systems .................................................. Extraction efficiency of Tullgren funnels for the determina- tion of Coliembola soil population densities .................... Influence of soil sample storage, and length of Tullgren extraction, on determination of Coliembola soil population density.. ....... . ..... ..................... Regression equations for soil population densities of Coliembola extracted by Tullgren funnels, compared with hours of extraction and sample storage ........................ Seasonal horizontal soil distribution of I. notabilis in clover, and clover-oats, to a soil depth of 15.24 cm .................... Seasonal horizontal soil distribution of 1. minor in clover, and clover-oats, to a soil depth of 15.24 cm. ....................... Seasonal horizontal soil distribution of I. yosiii in clover, and in clover-oats, to a soil depth of 15.24 cm ...................... Seasonal vertical distribution of _I_. notabilis in clover, and sudax, to a soil depth of 15.24 cm ............................ vii Page 21 30 31 32 41 43 52 54 55 57 68 Table Page 13. Seasonal vertical distribution of 1. minor in clover, and sudax, toasoildepth of 15.24 cm 69 14. Seasonal vertical distribution of I. yosiii in clover, and sudax, toasoildepthof1524cm 7O 15. Population densities of Collembola species associated with compost............................ ......... ..... 74 16. Variation in population densities of seven Collembola taxa associated with seasonal trends and agroecosystem treatmentOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 76 17. Influence of organic and conventional agroecosystems on Collembola soil populations densities in sweet corn, in the absenceofanitrogen'mput................. ..... ..... 77 18. Influence of organic and conventional agroecosyste ms on Entomobryidae soil population densities in sweet corn, in the absenceofanitrogeninput ...... .. ....... 78 19. Influence of organic and conventional agroecosystems on soil population density of Isotomidae, _I_. notabilis, E. americanus, and 1. minor in sweet corn in the absence of a nitrogen input . . . . . 79 20. Influence of organic and conventional agroecosystems on I. yosiii soil population densities in sweet corn, in the absence ofanitrogeninput...... ...... ...... ..... 80 21. Influence of organic agroecosystem nitrogen source on soil population densities of Collembola in sweet corn . . ............. 82 22. Influence of organic agroecosystem nitrogen source on soil population densities of Entomobryidae in sweet corn . . . . . ....... 83 23. Influence of organic agroecosystem nitrogen source on soil population densities of Isotomidae, _I_. notabilis, E. americanus, and _1_. minor in sweet corn . . . . . . . . ...... . . . . . . . . . . 84 24. Influence of organic agroecosystem nitrogen source on soil population densities of I. yosiii in sweet corn .................. 85 25. Influence of conventional agroecosystem nitrogen source on soil population densities of Collembola in sweet corn . . .......... 86 26. Influence of conventional agroecosystem nitrogen source on soil population densities of Entomobryidae in sweet corn. ........ 87 viii Table 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. Influence of conventional agroecosystem nitrogen source on soil population densities of Isotomidae, _I_. notabilis, 1_=_. americanusandi. minor in sweetcorn......................... Influence of conventional agroecosystem nitrogen source on soil population densities of I. yosiii in sweet corn, . . . . . . . . . . . . . . Influence of organic and conventional agroecosystem nitrogen sources on soil population densities of Collembola in sweet cornOOOOOOOOOOOOOOOOOOOIOOI ..... 0....OCOOOOOOOOOOOOCOOOOO Influence of organic and conventional agroecosystem nitrogen sources on soil population densities of Entomobryidae in sweetcorn‘...‘0.0.0.0...COO...OOIOOIOOOOOOOOOOOOOIO...I... Influence of organic and conventional agroecosystem nitrogen sources on soil population densities of Isotomidae, I. notabilis, E. americanus and _I_. minor in sweet corn. . . . . . . . . . . . . . Influence of organic and conventional agroecosystem nitrogen sources on soil population densitities of _T_. yosiii in sweet corn.0.0.0.0....OOOOOOOOI...OOOOOOOOOOOOIOOOOOOOOOOO ...... Influence of nitrogen input on soil population densities of Collembolainsweetcorn...................... ....... . ..... Influence of nitrogen input on soil population densities of Entomobryidae in sweet corn................ ........ . ........ Influence of nitrogen input on soil population densities of Isotomidae, I. notabilis, E. americanus and _I_. minor in sweet corn............ ..... .0.IOOOOOOOOOOOOOOOOOOOOOOOIOOOIOOOOO Influence of nitrogen input on soil population densities of :. yosiiiinsweetcorn.......... ..... ................. Influence of organic agroecosystem treatment randomization on soil population densities of Collembola in sweet corn. . . . . . . . . . Influence of organic agroecosystem treatment randomization 88 89 9O 91 92 95 99 on soil population densities of Entomobryidae in sweet corn. ....... 100 Influence of organic agroecosystem treatment randomization on soil population densities of Isotomidae, _I_. notabilis, 1:. americanus and _I_. minor in sweet corn . . . . . . ................... 101 Influence of organic agroecosystem treatment randomization on soil population densities of I. yosiii in sweet corn. ............ 102 Table 41. 42. 43. 4“. Influence of conventional agroecosystem treatment randomi- zation on soil population densities of Collembola in sweet cornCO.COCOOOO0.0.00.00.00.00.IOOIOIOOOIOOOOO...0.000.... Influence of conventional agroecosystem treatment randomi- zation on soil population densities of Entomobryidae in sweet corn.’OOOOOCOOIOOOOOOOOOOOOO0....I...OOOOOOOOOOOOOOOOOOOOI Influence of conventional agroecosystem treatment randomi- zation of soil population densities on Isotomidae, _I_. notabilis, Page . 103 104 §.americanusand_l_.minorinsweetcorn...................... 105 Influence of conventional agroecosystem treatment randomi- zation on soil population densities of I. yosiii in sweet corn . . . . . 106 LIST OF FIGURES Figure Page 1. Location of the Rodale Research Center in Berks County, Pennsylvania .................................... . . . . . ..... 26 2. Rodale Research Center research fields in which soil popula- tions of Collembola were monitored .......................... 27 3. Experimental design of the vegetable rotation study at the Rodale Research Center, and selected rotation sequences utilized for this M-S. research ............ . . . . . . . ....... . . . . . 28 4. Sampling design for the determination of Collembola spatial distribution in soil (1983) ....................... . ........... 37 5. Extraction rate of Collembolla from fresh and stored soil samples in Tullgren funnels ................................. 46 6. Extraction rate of I. notabilis from fresh and stored soil samples in Tullgren funnels. ..... . ........................... 47 7. Extraction rate of 1. minor from fresh and stored soil samples in Tullgren funnels ......... . ............................... 48 8. Extraction rate of I. yosiii from fresh and stored soil samples in Tullgren funnels ......................................... 49 9. Extraction rate of P. violenta from fresh and stored soil samples in Tullgren funnels. . . ............................... 50 10. Extraction rate of E. americanus from fresh and stored soil samples in Tullgren funnels ................................. 51 11. Horizontal soil population distribution of _I_. notabilis in clover on March 24, 1983, at two sampling densities: (A) 25 samples/ M2, and (B) 1 sample/M2 (Replication I) ....................... 58 12. Horizontal soil population distribution of _I_. notabilis in clover on March 24, 1983, at two sampling densities: (A) 25 samples/ M2, and (B) 1 sample/M2 (Replication n). ...................... 59 13. Horizontal soil population distribution of I. notabilis in clover on March 24, 1983, at two sampling densities: (A) 25 samples/ M2, and (B) l samplte/M2 (Replication III) ...................... 60 xi Figure Page 14. Horizontal soil population distribution of I_. minor in clover on March 24, 1983, at two sampling densities: (A) 25 samples/ M2, and (B) 1 sample/M2 (Replication I) ....................... 61 15. Horizontal soil population distribution of I_. minor in clover on March 24, 1983, at two sampling densities: (A) 25 samples/ M2, and (B) 1 sample/M2 (Replication II) ...................... 62 16. Horizontal soil population distribution of _I_. minor in clover on March 24, 1983, at two sampling densities: (A) 25 samples/ M2, and (B) 1 sample/ M (Replication 111) ...................... 63 I7. Horizontal soil population distribution of T. osiii in clover on March 24,1983 at two sampling densities: (A) 25 samples/M2 , and (B) 1 sample/M2 (Replication I) ........................... 64 18. Horizontal soil population distribution of T. osiii in clover on March 24,1983 at two sampling densities 7A samples/ M and (B) l sample/M2 (Replication II) .......................... 65 19. Horizontal soil population distribution of T. osiii in clover ozn March 24,1983 at two sampling densities: _(A) 25 samples/M2, and (B) 1 sample/ M (Replication III) .......................... 66 20. Seasonal vertical soil distribution of I. notabilis in clover and irrigated sudax ............................................ 71 21. Seasonal vertical soil distribution of 1. minor in clover and irrigated sudax ............................................ 72 22. Seasonal vertical soil distribution of _T_. yosiii in clover and irrigated sudax ............................................ 73 xii LIST OF APPENDICES Appendix Page 1. Log of Collembola species recovered from soil and compost at the Rodale Research Center, Berks County, Pennsylvania. ..... 127 2. Summary of literature concerning the agricultural impact on soil populations of Collembola ........................... . . . . . 128 3. Sources of information used for the preparation of Appendix 2 ......................................................... 131 4. Minimum and maximum air temperature at the Rodale Research Center, Berks County, Pennsylvania (1982) ....... . . . . . 133 5. Minimum and maximum air temperature at the Rodale Research Center, Berks County, Pennsylvania (1983) ............ 134 6. Soil moisture and temperature in sweet corn at the Rodale Research Center, Berks County, Pennsylvania (1983) . . . ........ 135 7. Soil moisture and temperature in clover at the Rodale Research Center, Berks County, Pennsylvania (1983) ............ 136 8. Weekly precipitation at the Rodale Research Center, Berks County, Pennsylvania (1982) ................................. 137 9. Weekly precipitation at the Rodale Research Center, Berks County, Pennsylvania (1983) ................................. 138 10. Pre-plant and post-harvest soil nutrient analysis in organic and conventional agroecosystems (1982) ....................... 139 11. Seasonal prominence and relative prominence values of soil Collembola in clover, and clover-oats, to a soil depth of 15.24 cm (1983) ................................................. 140 12. Seasonal prominence and relative prominence values of Collembola in clover and sudax, at 5.08 cm soil depths, to a total depth of 15.24 cm (1983) ............................... 143 xiii INTRODUCTION Farm-level agroecosystems are specialized units of biological organization, consisting of a community and its physical support system. Community interactions with the physical environment lead to characteristic trophic struc- ture and nutrient cycles. Agroecosystems are dependent on grower-manipulated processes that effect biological and mineral utilization rates and relationships within the system (Loucks 1977). Organic agriculture is designed to maximize intrinsic components and processes of the existing ecosystem. These components and processes are dependent on biological interactions within plant-nutrient cycles, and result in crop yield. In contrast, conventional agriculture maximizes extrinsic compon- ents that may deleteriously alter soil biological interactions. Examples of synthetic inputs include soluble fertilizers, pesticides and growth regulators. Soil mesofauna and microfauna are important components of soil agroeco- systems. With bacteria and fungi, they are responsible for nutrient cycling and humification of soil organic matter (Wallwork 1983). Soil animal population dynamics and, therefore, nutrient cycles, are a function of management practices in both conventional and organic agroecosystems. Agronomic practices such as tillage, rotations, and applications of manure, fertilizer, and pesticides, affect community ecology changes in biomass and species diversity. Organically managed farms may support a more stable and diverse community of soil organisms. As production system inputs common to conventional agriculture become more costly and biologically limiting, methods common to organic farming systems should be investigated. The objectives of this research were to conduct a comparative analysis of biomass and species diversity of soil Collembola in an organic agroecosystem, and in a conventional system previously managed with organic methods. Other objectives were to determine the effect of agroecosystem management on their species occurence, distribution, and abundance. Collembola were selected because of their great soil abundance. This research is a prerequisite for determining the qualitative and quantitative role of Collembola and other soil fauna in agroecosystem humification of organic matter. LITERATURE REVIEW The Collembola are a diverse and abundant group of insects within the soil ecosystem. Fluctuating population parameters are a result of interactions between biological and environmental factors. These factors include food, predator relationships, and soil micro-climate and structure. Significant factors influencing Collembola soil populations will be discussed in following sections. Biology of Soil Collembola Collembola are small soil insects often associated with decaying organic matter in soil. Their mean population density is approximately 100,000 per cubic meter of soil, with a mean biomass of 6 grams per cubic meter. Christiansen (1964) reported a maximum density of 100,000,000 per square meter in an agricultural soil. Most estimates place soil Collembola densities at slightly less than or comparable to densities of soil Acarina. Collembola are characterized by unique physiological and morphological criteria. These include the presence of a collophore and a furcula. Body length of most species is less than 1.0 mm, with a maximum length of 11.0 mm (Snider, pers. com.). The integument is often granulated, with characteristic setal patterns or covered with flattened scales. Eyes are absent, or consist of up to eight ocelli in a patch. Pigment is absent to distinct, with a range of colors and patterns. The diet of Collembola consists of a variety of materials, including decaying plant residues, fungi, bacteria, arthropod feces, pollen, and algae. Specialists occur, but many species encountered in agricultural environments are ubiquitous. Collembola reproduction is sexual or parthenogenic. Most sexual reproduc- tion occurs indirectly; females pick up spermatophores deposited by males. Eggs are laid singly or in clumps, and require 5-10 days to hatch under optimal conditions (Schaller 1970). Periodic molting continues throughout life, with sexual activity often restricted to alternate instars. Number of instars ranges from two to greater than fifty. Development can be interrupted by cold or dry conditions. Life span varies with species and environment from four months to over one and one-half years (Schaller 1970). _SgiL Moisture and Temperature—Soil temperature and moisture are among the (most important environmental factors influencing the biology of soil Collembola. Effects of temperature and moisture are complex. They may be direct or indirect, and are probably interrelated (Christiansen 1964; Butcher gt a_l. 1971). A wide range of temperature preferences have been reported for different species. Collembola are relatively resistant to low temperatures; however, this varies greatly. Temperature regulates rate of development, and spatial distribu- tion in soil. High temperatures during development may result in changes in form and histological structure, known as ecomorphosis (Christiansen 1964). Most Collembola require relative humidities greater than 89% (Christiansen 1964). Many species fail to survive in culture at humidities less than 10096, but this depends on the life stage and physiological state. Butcher gt a_l_. (1971) summarized the effects of low humidity. Responses included migra- tion, greater mortality, decrease in rate of reproduction, construction of protective cells, inactivity, ecomorphosis, and phenotype changes. They also stressed that there exists an optimal unknown combination of temperature and humidity. Somme (1976) described cold-hardiness of Isotoma hiemalis Schott, Entomobrya nivalis (L.) and Hypogastrura sogags (Uzel) from a coniferous forest in Norway. Mean chill-coma temperatures of these species were -7.1, -3.4, and - 8.6 C, respectively. Supercooling points were between -25 and -16 C, depending on the presence of food in the gut. Supercooling points were greater than those common for other winter-active insects, and it was concluded that Collembola survive temperature extremes by migrating to below the snow cover. M—Soil pH can influence populations of Collembola. Hale (1967) stated that although there are some pH preferences, most species are probably generalists, and a wide tolerance range exists. Butcher gt al. (1971) defined a general pH tolerance range of 6.0 - 7.8, and stated that pH may affect reproduction. Christiansen (1964) reviewed this subject, and concluded that pH is probably more indicative of soil type, and is therefore indirectly associated with different Collembola species. Spatial Distribution—Population densities of Collembola are most often concen- trated in the uppermost soil horizons, where organic matter concentrations and pore space are maximal (Hale 1966; Kevan 1962). Morphological criteria have been used to predict vertical stratification of Collembola species in the soil profile. Generally, large darkly-pigmented species are most abundant in upper layers or at the surface, and small light-colored species are concentrated in the lower layers (Christiansen 1964; Bellinger 1954; Kevan 1962). Large concentra- tions of Collembola have been found to a soil depth of 20 cm (Christiansen 1964). Vertical migration may occur daily or seasonally in response to changes in soil moisture and temperature (Hale 1966; Christiansen 1964). Poole (1961) monitored the vertical distribution of Collembola in a coniferous forest soil in North Wales, and estimated densities in soil, humus, and litter. Soil population densities were measured to a depth of 3.8 cm from the top of the mineral horizon, while the depths of the organic layers varied. Each family was found to have a characteristic vertical distribution. In this study, the Entomobryidae (Entomobrya spp., Lepidocrytus spp.) were concentrated in the litter. Percent distribution in soil, humus, and litter layers was approximatley 15:15:70. Most species of Isotomidae were concentrated above the soil layer (9596) and were recognized as either humus or litter forms. At uncompacted sites, however, many Isotomidae were found below 7.5 cm in the mineral soil layer. Onychiuridae were concentrated in humus (50%) and soil (3596), and were recovered from depths of 7.5 cm at uncompacted sites. Collembola exhibit an aggregated distribution pattern within and at the soil surface. The tendency to aggregate is attributed to many biological and environmental factors, including time of day, season, soil structure, organic matter concentration, soil moisture, humidity, food concentration, microflora concentration, vegetation type, eg batch size, molting, and reproduction (Christiansen 1964; Butcher gt at. 1971; Usher 1969; Joose and Verhoef 1974). Egg batch size has been suggested as a factor of aggregation. Poole (1961) concluded otherwise, and Hale (1966) was unable to prove that it was a major contributing factor. Joose and Verhoef (1974) concluded that aggregation is an important survival tool, especially during critical life stages. Usher (1969) conducted an extensive study to determine the spatial distribution characteristics of Collembola species in a pine forest. He determined densities in sixteen 4cm X 4cm X 3cm soil samples, within a 16cm X 16cm block; each soil sample was vertically stratified to three l-cm depth subsamples. In this way, distribution was subjectively analysed. Most species were found in aggregations of various size, but uniform and random distributions were also common. Different age classes and different color types of a species were'found to have dissimilar distributions. Random, uniform or aggregated distributions occurred in favorable and unfavorable niches. Population DynamicsuMany Collembola species are active throughout the year. They have seasonal fluctuations in population density reflecting reproductive cycles, mortality and migration. Trends in population dynamics are often masked by environmental conditions (Christiansen 1964). Hale (1967) provided a summary of seasonal population fluctuations of Collembola as a group. Most Collembola are included in one of two major categories: 1) species with population peaks in autumn and spring, and population declines in summer and winter; and 2) species with a summer or winter peak (Hale 1967; Christiansen 1964). Takeda (1979) studied the life cycles and population dynamics of surface active Collembola species. He concluded that seasonal fluctuations in population densities were closely related to the length of life cycle and number of generations per year. These seasonal changes reflect reproductive cycles and mortality as influenced by the environment. Solem and Sendstad (1978) monitored diel periodicity of surface-active Collembola in Norway with pitfall traps. Daily activity varied between two sampling years, although certain species were consistantly rythmic or arythmic each year. Temperature and rainfall were determined to be the most important factors influencing population dynamics. Colleabola Associated With Sweet Corn in Berks Co., PA Seven Collembola families were recognized taxonomically (Christiansen and Bellinger 1980). Thirteen species from four families were collected from sweet corn in Berks County, Pennsylvania (Appendix 1). Most species were members of the family Isotomidae. Only one species of Onychiuridae was collected with sufficient regularity for statistical evaluation. Occurance of species from the family Entomobryidae was seasonal. Sminthuridae were rarely collected. Certain Collembola species will be discussed in this section to introduce readers to species variability. Isotoma (Desoria) notabilis Schaffer (Isotomidae)-- t. notabilis is a moderately sized, pigmented Collembola; body color is pale to medium grey-blue. Eye patches are dark, but not well developed. The furcula is well developed, and maximum body length is 1.0 mm (Christiansen and Bellinger 1980). This species is most likely parthenogenic, but sexual dimorphism is difficult to detect. Under controlled laboratory conditions the life cycle is completed in one month or less, at greater than 14 C (Sharma and Kevan 1963). Field conditions probably support one generation per season (Loring 1979). t. notabilis is probably the most common member of its genus in North America. This species prefers a moist habitat, and is most often found in soil litter, or in greenhouse soil. Soil flora, nematodes, and organic debris are part of the diet (Christiansen and Bellinger 1980). The mandibular plate is well-developed, indicating herbivory, although carnivory has also been reported (Sharma and Kevan I963). Isotomiella minor (Schaffer) (Isotomidae)—_I_. m is a white, eyeless litter species. A distinct taxonomic characteristic is the lack of a post-antennal organ. The furcula is well-developed; maximum body length is 1.1 mm. This is the only Nearctic species (Christiansen and Bellinger 1980). Van der Drift (1959) reported that this species has a wide ecological tolerance. The diet includes fungi and plant debris (Poole 1959). Tullbergia (Tullbergia) mill Rusek (OnLchiuridae)-—I. 2.9%). is a small, elongate euedaphic species with a maximum body length of 0.7 mm. Both furcula and pigment are absent. This uncommon species has been found in soils of the Central and Eastern United States. Males have not been reported (Christiansen and Bellinger 1980). Species biology has not been summarized. Tullbergia krausbaueri (Borner), a closely related species, is commonly used in laboratory studies. I. krausbaueri is a slow-moving, widely distributed euedaphic species. Milne (1960) assumed a sex ratio of 1:1, but lack of sexual dimorphism prevented confirmation. Peterson (1971) collected eggs from isolated females, indicating parthenogenesis. In culture, a complete life cycle of I. krausbaueri lasts seven to nine weeks, and adults survive for more than six months (Milne 1960). Diet has not been reported; however, this author has successfully raised individuals of _T_. yggiit with brewers yeast. Field conditions probably result in one generation of I. y_o_s_ig per season. P§eudosinella violenta Folsom (Entomobryidae)--§. violenta is a large, active and aggresive species with a well-developed furcula. The body is scaled and without pigment or eyes. This species is widely distributed in the United States. Christiansen and Bellinger (1980) report maximum body length in cave and soil forms of 2.1 and 1.6 mm, respectively. 5011 forms are active at the surface and favor high humidity. This species is commonly found under rocks, rotting leaves, in ant nests and in greenhouse soil (Davis and Harris 1936). Laboratory culture has been successful with a diet of plant roots, corn grain and leaves, peanuts, and wheat. Extensive damage to sugar cane has resulted from root grazing by this species (Davis and Harris 1936). Reproduction is assumed to be sexual. Davis and Harris observed a female:male sex ratio of 65:35. At laboratory tempera- tures of 25-37 C, sexual maturity was reached in 16 to 22 days after hatching. Entomobrya (Entomobrya) unostrigta Stach (Entomobgidae)--E_. unostrigata is a large, pigmented species; maximum body length is 2.5 mm. Its body color ranges from white to orange-yellow or pale green. A dark-colored dorsal stripe is usually present. The furcula is well-developed. Individuals are reported from California and Michigan. This species was introduced to California and has been spreading east since 1938 (Christiansen and Bellinger 1980). 10 Impact of Agricultural Practice: on Collembola Soil Tillage—Effects of soil mixing on populations of soil animals can be beneficial or detrimental. A common result is an initial reduction in densities, followed by recolonization and altered species composition. These changes are attributed to alteration of environmental conditions resulting from soil disturbance. Abrasive forces of cultivation implements and destruction of habitats by compaction contribute to mortality of Collembola and other soil animals (Edwards and Lofty 1975; Wallwork 1976; Critchley _et a_l. 1979; Aritajat _t gt. 1977). Soil microclimate is less stable after cultivation, and extremes in soil moisture and temperature result from changes in soil structure and ground cover (Wallwork 1976; Critchley gt gt. 1979). Species balance is often altered after cultivation. Certain species may be eliminated and others significantly increased due to altered physical habitat and predator-prey relationships (Critchley gt a_l_. 1979; Edwards and Lofty 1969). Surface-dwelling species of Collembola are usually more negatively influenced than edaphic species (Edwards and Lofty 1976; Moore, gt _a_l_. 1983). Recolonization of soil animals after cultivation results when organic matter is redistributed evenly within a more aerated horizon. The homogeneous soil profile allows deeper penetration of Collembola. Increased pore space provides a more suitable habitat (Edwards and Lofty 1975; Wallwork 1976; Christiansen 1964). Aritajat gt a_l_. (1977) evaluated the impact of soil compaction on popula- tions of Collembola in silt loam and clay soils. Initial densities were greatest in the silt loam. After two weeks, Collembola densities in silt loam were significantly less than when the soil was disturbed. Densities were not 11 significantly different during a 1 - 6 month period after disturbance. Nine months after manipulation, compacted soil supported a significantly lower density of Collembola than the undisturbed sites. Soil compaction in clay soil resulted in highly significant reductions of Collembola populations for three months. Six months after compaction, no differences were found in populations associated with the different soil types. Sheals (1956) and Andren and Lagerlof (1980) reported similar population recovery rates in agroecosystems after cultivation. Crop NutritionuThe addition of crop nutrients or pesticides to soil ecosystems often disturbs populations of fauna and flora, including Collembola. Disturbance enhances or suppresses population characteristics of Collembola through the following modes of action: 1. Direct toxic, repellent or attractant properties of the amendment, 2. Alteration of plant cover (crop and weed species, and productivity), 3. Alteration of soil physical or chemical properties, 4. Addition of Collembola, predators or prey to the site with the amendment. Reactions to a variety of agricultural materials have been summarized (Appendix 2 and 3). These relationships’are often species or habitat specific and are difficult to generalize. Fertilizer application often results in increased soil population densities of Collembola. Enhancement of soil population densities of Collembola has been attributed to organic matter accumulation in soil (Behan g_t_ a_l. 1978). This is a result of greater plant productivity. Soil organic matter provides a food source for Collembola, and improves soil physical and chemical properties. 12 Edwards and Lofty (1969) reported slight increases in soil densities of Collembola after application of fertilizer containing nitrogen, phosphorous and potassium. In contrast, Collembola soil populations did not appear to respond to four years of ammonium sulfate, superphosphate, and potassium chloride applica- tion to fallow, corn and wheat treatments (Artemjeva and Gatilova 1975). Behan gt a_l. (1978) studied the effects of urea application in a Quebec black spruce humus, on soil populations of Collembola and other fauna. Densities of Collembola and related taxa decreased immediately after urea application. The relative abundance of species, however, remained constant. After treat- ment, Collembola migrated to deeper soil horizons. Three hypotheses were offered to explain the vertical migration: 1. Urea was toxic to Collembola, 2. Urea killed the original moss cover, causing greater temperature fluctuations in upper soil layers, 3. MicrOphytophagous Collembola were attracted to greater densities of ureolytic organisms in lower layers that resulted from urea applications. Relatively few studies are concerned with direct effects of fertilizer constituents on soil fauna. Moursi (1962a) reported that Onychiurus armatus Tullberg, a soil species, was attracted to a current of nitrogen gas (less than 4.1 ml/hour) passed through a humus substrate. Greater dosages repelled this species. Moursi (1962b) evaluated the toxicity of hydrogen sulfide and ammonia gases to several species of Collembola from different habitats. Ammonia was toxic to Omchiurus granulosus Stach, a soil species, and less toxic to Isotoma thermophila Axelson, a manure inhabitant. Hydrogen sulfide was toxic to the soil 13 species 9. granulosus, and less toxic to the compost species Hypogastrura bengtssoni (Agren). Results indicated that ammonia and hydrogen sulfide can be highly toxic but specific reactions depended on species habitat. The addition of manure or composted organic materials to soil often results in enhancement of Collembola density and species diversity (Chernova gt §_l_. 1971; Atlavinyte 1971; Edwards and Lofty 1969; Artemjeva and Gatilova 1975; Weil and Kroonjte 1979; Aleinikova and Utrobina 1975; Morris 1927; Davidson 1979). Manure or compost may result in an increased food supply for Collembola as well as increasing species diversity and establishing other arthropods at the site. Weil and Kroontje (1979) observed that applications of poultry manure to agricultural soil significantly increased Collembola density but did not alter seasonal variation. They reported a significant positive correlation of soil organic matter content with densities of Entomobryidae and Hypogastruridae, but not Isotomidae. Weed MgnagementuHerbicides are used to manage weeds in most conventional agroecosystems. Atrazine has been shown to significantly influence soil populations of Collembola. Fox (1964) observed reductions in Collembola soil density in grassland soil after applicatioin of atrazine. A decrease in population growth rate was directly attributed to toxicity, and indirectly to reduction of plant cover. Soil populations of Collembola, in corn treated with atrazine, were monitored by Popovici gt g1. (1977). Atrazine was applied to soil at two rates: 5 kg ai/ha and 8 kg ai/ha. Densities were evaluated in the upper 10 cm of soil. At the lower rate, Collembola densities were reduced 8096 one month after treatment, and 5996 after four months. At the higher application rate, densities were 95% lower after one month, and 80% reduced after four months. 14 Isotomidae, the most dominant and most frequently recovered taxon, was found to be most resistant to atrazine. Subajga and Snider (1981) cultured Folsomia m (Willem) and Tullbergia granulata Mills with diets of brewers yeast treated with atrazine at approximate field concentration. Mortality and length of instar duration were significantly increased. Egg production was significantly reduced, but egg viability was not affected. Recovery of Collembola from Soil Assessment of soil mesoarthropod populations, particularly Collembola, most often relies on dynamic extraction methods that depend on active responses of the animal to some stimuli. In contrast, mechanical methods of extraction depend on characteristic properties of the insect and sampling medium, with the animal playing a passive role. Dynamic methods of Collembola extraction from soil samples include Berlese (1905) and Tullgren (1918) funnels. Berlese funnels rely on dessication as a stimulus, whereas Tullgren funnels commonly rely on a lightbulb or other heat source to provide temperature and light stimuli. Murphy (1962) provides a detailed description of funnel modifications and mechanical methods of extraction. Extraction efficiency by Tullgren funnels depends on modifications made by the investigator, and also varies with soil type, sample size and bulk density. Efficiency is often less than 5096 of the mesoarthropods contained in the sample (Murphy 1962). Peterson (1978) determined extraction efficiency using various methods. High-gradient funnel and cannister extractors were found to be 80-90% efficient for Collembola in ten days of extraction, with initial and final soil temperatures 15 of 20 C and 40 C. Other efficiencies reported were as follows: Isotoma notabilis 90-10096; Isotomiella minor < 9096; Lepidocrytus _I_ignorum 7596; Onychiurus spp. 8596; and Tullbergia sp. < 5096. Tamura (1976), however, determined that Tullgren funnels were only 696 efficient for Collembola, in 42 hours of extraction. I Of total mesoarthrOpods, Peterson (1978) found that Collembola migrate from samples most quickly, with 5096 of total extraction occurring before the third day of extraction. In contrast, Block (1966) reported 5896 of the Collembola extracted occurred during the initial 24-36 hours of extraction from a mineral soil. Loring gt gt. (1981) reported efficiencies of 396 and 8296 extraction for Tullbergia granulata and the Isotomidae, respectively, from funnels similar to those used in this research. Samples were extracted for approximately three days, or the time required for thorough sample drying to occur. Role of Collembola in Nutrient Cycling Soil arthropods play an important role in the decomposition of soil organic matter and subsequent release of plant nutrients in forest ecosystems (Wallwork 1983). Only recently has research focused on the role of mesoarthropods in agroecosystems (Atlavinyte 1971; Chemova gt gt. 1971; Golebiowska and Ryszkowski 1977; Ghilarov 1978; Stinner and Crossley 1980). In 1954, Bellinger described mesoarthropod activity to be of significance in determining "the character and fertility of organic constituents of soil". A recent summary of Canadian research needs concluded that soil fauna are important in agricultural systems. This justification was based upon the role of soil fauna in nutrient cycling (Marshall gt gt. 1982). 16 Soil mesoarthropods are direct or indirect catalysts of organic matter decomposition (Crossley I977; Reichle 1977; Macfadyen 1963). Litter decom- poses and nutrients are mineralized at a rate directly related to the density of soil invertebrates (Edwards gt gt. 1970; Addison and Parkinson 1978). This is a result of increased organic matter surface area made available for microbial decomposers. Estimates of the direct effects of Collembola on organic matter decompostion are reported as percent litter consumption or breakdown. In a Central Sweden pine forest, Persson (1983) estimated that soil animals mineralized or excreted about 3096 of the annual net mineralization of nitrogen in soil. In oak leaf litter, Anderson gt gt. (1983) reported that Collembola were responsible for enhancement of mineral nitrogen losses. Loss of ammonia- nitrogen was significantly correlated with animal fresh weight, and Collembola were found to have a greater effect than most other mesofauna. Collembola and other soil fauna indirectly regulate rate of organic matter decomposition by grazing on microflora, resulting in a more controlled linear nutrient release throughout the growing season (Reichle 1977). Nutrient release from organic matter, however, may not be a function of grazing activity (Anderson gt gt. 1983). Soil animals may disrupt microbial immobilization and amplify existing variations in soil organic matter and litter (Anderson gt gt. 1983). This may account for the enhancement of metabolic activity in soil that is observed when Collembola are present, and microenvironment abiotic factors are not limiting (Addison and Parkinson 1978). Other indirect effects of Collembola feeding activities include the dissemi- nation of fungal spores and the elimination of mycostasis and bateriostasis, production of feces and complex humic substances, and substrate-soil mixing. 17 Person (1983) suggested that microbial-feeding animals control microbial bio- mass and thus control nitrogen availability. Anderson _e_t_ gt. (1983) described this as a disruption of the normal time course of nitrogen mineralization by microorganisms. Nitrogen is transferred to Collembola biomass with a more rapid turnover than that of other mesoarthropods. Collembola influence microbial colonizing ability by selective grazing on microbial species (Parkinson and Visser 1979; Hanlon and Anderson 1979). Nutrient assimilation by Collembola may reduce nutrient losses by leaching during transfer from one nutrient pool to another (Hanlon and Anderson 1979). Collembola may therefore influence species composition of microflora, and either increase or decrease rates of decomposition and mineral release. Alternative Farming Methods Increased production costs associated with present-day conventional agriculture have resulted in a renewed interest in alternative farming methods, especially regarding plant nutrient cycles and pest management. A diversity of European-based farming systems have been developed during this century. Boeringa (1980) described six commercial alternative methods of farming: 1. Arbeitsgemeinschaft fur naturgemassen Qualitatsanbau von Obst und Gemuse (ANOG); 2. Biodynamic; 3. Lemaire-Boucher; 4. Macrobiotic; 5. Organic-biological; and 6 Howard-Balfou r. 18 Each method has a unique philosophy regarding practices of cultivation, plant nutrient source and handling, and emphasizes certain soil chemical properties and reactions. A philosophy of maximization of biological processes and minimal system disruption is a common characteristic of most alternative methods. ANOG (Working Party for the Natural Cultivation of Fruit and Vegetables) is a type of agriculture founded in Germany in 1962 (Boeringa 1980). The objective of this Party is the production of agricultural products with high biological value. Biological value emphasizes nutritional quality, and is achieved with "Bodenruhe" (soil rest). Tillage is minimal and the soil is covered by a green manure crop or organic matter. The use of organic fertilizers and certain pesticides is permitted. Biodynamic agriculture is practiced by commercial growers in Western, Central and Northern Europe, and in North America. Steiner (1958) introduced the concept of Anthroposophy, which links grower and crop with cosmic forces; this philosophy is the foundation of biodynamic agriculture. Unique fertilizer preparations are utilized, and lunar rythyms are observed (Boeringa 1980). Lemaire-Boucher agriculture is practiced in France and Belgium. Calmagol, compost, organic fertilizers and legumes are incorporated to maintain a "balanced soil". Calmagol is a unique product that contains the coral algae Lithothamnizfl calcareum, and is applied to soil as a catalyst for elemental transmutations. Elemental transmutations are microbiological processes that respond to the nutritional requirements of the crop (Boeringa 1980). Macrobiotic agriculture is practiced in Western, Central and Northern Europe, and was founded in Germany in the early 1900's by Kraft (Boeringa 1980). Very briefly, this system of crop production relies on the synchronization 19 of macro-element (e.g. N, P, K) and trace-element supply with crop species and cosmic forces. Unique compost preparations are required (Boeringa 1980). Organic-biological agriculture is commercially practiced in Switzerland, Belgium, the Netherlands and West Germany. This method was developed by Rusch in 1955 (Boeringa 1980), and stresses the microbiological relationships between plants, herbivores and the soil. Fertilizers or pesticides that disturb these relationships are avoided. Howard-Balfour agriculture is practiced in England and in North America on a commercial scale. Howard (1943) and Balfour (1943) introduced this method, emphasizing the use of manure, compost, crop rotation, and crop- mycorrhizal interactions for yield and nutritional maintenance (Boeringa 1980). Organic farming in North American is derived from this method (Harwood 1982). In 1980, USDA defined current North American alternative farming systems as organic farming: a production system which avoids or largely excludes the use of synthetically compounded fertilizers, pesticides, growth regulators, and livestock feed additives. To the maximum extent feasible, organic farming systems rely upon crop rotations, crop residues, animal manures, legumes, green manure, off-farm organic wastes, mechanical cultivation, mineral-bearing rocks, and aspects of biological pest control to maintain soil productivity and tilth, to supply plant nutrients and to control insects, weeds and other pests. Harwood (1983) reviewed the development of organic farming in this country, and outlined philosophies associated with the development of regenerative agriculture. Regenerative agriculture encompasses most philosophies that unite alternative farming systems, but also stresses "the intimate connection between soil fertility, the health and growth of crops and the health of both animals and people who consume those crops." The concept of decentralized national agricultural systems is also stressed. 20 Management System Inputs Nitrogen Fertilizers-oThe nitrogen cycle consists of a well-known series of reactions. Soil nitrogen is in a continuous biological and chemical cycle of mineralization and immobilization between organic and inorganic soil nitrogen fractions. Inorganic soil nitrogen includes the soluble mineral forms N03, NH4, and N2. Organic soil nitrogen exists as insoluble, low molecular weight (amino acids, amides, amines) and high molecular weight compounds (proteins, nucleic acids) (Mengel and Kirkby 1982). Organic nitrogen fertilizers, such as bloodmeal and compost, are mineralized to NH3 and N03 after application to soil. In contrast, soluble inorganic nitrogen fertilizers, such as ammonium nitrate, do not require mineralization, and provide an available supply of NH3 and N03. These mineral forms of nitrogen are removed from the soil solution by plant uptake, or are often incorporated into soil organic matter or leached from the site. Discussion of nitrogen fertilizers will be limited to bloodmeal, compost, and ammonium nitrate. Bloodmeal was one of many organic ammoniates popular with growers in the early 1900's. Bloodmeal is a slaughterhouse by-product. It is dried and pulverized to a powder for use in animal feeds or as fertilizer. F\loodmeal is currently popular with home gardeners, but high cost restricts its use in large agricultural operations. In 1983, approximately 5,556 tons of bloodmeal were applied to agricultural crops in the United States (USDA 1983). Bloodmeal is approximately 1396 nitrogen, but analysis varies with source (Table 1). Approximately 9796 of the total nitrogen in bloodmeal is water insoluble, due to a high content (8996) of crude protein (Rubins and Bear 1942). 21 Table l. Nutritional analysis of nitrogen fertilizers applied to sweet corn. Fertilizer analysis 1 1 2 Plant nutrient Bloodmeal Compost ’ NH4NO3 N 13.23% 1.75% 33.5%3 P 1.74% 0.97% K 0.79% 0.60% S 0.43% Mg 0.14% Ca 2.00% Na 0 B 3 ppm4 Zn 46 ppm Mn 7 ppm Fe 2080 ppm Cu 9 ppm A1 140 ppm NH4 0.35% N03 0.12% 78.07:.5 NH3 22.07.5 lPrivate laboratory analysis 2Analysisof compost applied to sweet corn in 1982 3Manufacturer's analysis 4Parts per million 5Percent by weight 22 Bloodmeal application results in increased soil auxin concentration (Hamence 1948), but other side affects from its application are not known. In 1938 (USDA), agriculturalists considered bloodmeal a readily available source of nitrogen. Bloodmeal was a preferred nitrogen fertilizer in greenhouses for its quick and noninjurious action, and ease of distribution. A demand for bloodmeal as livestock feed caused prices to increase at that time. In 1950, Owen g gt. determined that the nitrification rate of bloodmeal was comparable to other slaughterhouse-derived nitrogen sources, such as bone- and hoof-and- horn-meal. They reported a nitrification rate of 6896 in 65 days for bloodmeal in a laboratory study. Mineralization after 65 days appeared to stop. At this time, most of the remaining nitrogen became incorporated in soil humus, and decomposition continued at a reduced rate. Rubins and Bear (1942) also studied nitrification rates of bloodmeal. Sixty percent of bloodmeal-N was converted to NO3 in 20 days, and 6696 was mineralized in 40 days. In contrast, urea (CO(NH2)2), a conventional nitrogen source, was 8796 mineralized in 20 days, and 8896 minerlized in 40 days. Compost is a mixture of variable ratios of plant and animal wastes, that has been mixed together, aerated, and partially decomposed in order to increase nutrient availability and reduce bulk. Composting originated in India as a method of utilizing human wastes for crop fertilizers; many technique modifications exist (Howard 1943). Most composting in this country is utilized as a method of sewage disposal, or by home gardeners and commercial growers for fertilizer (Gouleke 1972). In 1983, approximatley 23,915 tons of compost were used in the United States (USDA 1983). 23 Compost used in this M.S. research was composed of turkey, chicken, and horse manure with bedding, and leaves from a nearby city. At application, this compost contained approximately 1.75% nitrogen in 1982, and 1.0096 nitrogen in 1983 (Table 1). Less than 0.50% of the nitrogen was immediately available. Nitrogen in manure and compost is mineralized at a general rate of 20 to 5096 2096 and 1096 respectively, in the first three years following application to soil (Harmsen and Van Schreven 1955; Mengel and Kirkby 1982). Decomposition rate is dependent on source, environment, and proportion of non-hydrolyzable substances in the materials. Soil flora and fauna are responsible for decomposition of residues and release of plant nutrients in the composting process. Nishio (1983) hypothesized that greater that 3096 of the nitrogen release from compost might have passed through the microbial biomass. Nishio also observed significant fluctuations of microbial biomass in soil after compost application. Compost is an excellent medium for Collembola providing near-optimal moisture and food requirements. Each stage of decomposition is distinquished by a change in Collembola species predominance. Chernova (1963) described Collembola succession during the leaf- composting process in surface and deeper layers. Early stages of decomposition in the surface, during spring, were dominated by Isotomg olivgc_eg Tullberg. After partial decomposition, Proisotoma minuta Tullberg was most dominant, and was replaced in riper compost by Isotomg notabilis and later Onychiurus armatus. In deeper layers, decomposition began with P. m, and then followed the same succession of species. Chernova et gt. (1971) later noted changes in rate of oxygen—uptake of Collembola dependent upon stage of compost decay. 24 Gisin (1952) studied Collembola of leaf compost at three sites. Each site was composed of a unique array of Collembola species in succession with decay stage. Attempts to innoculate different compost sites with species from another site were not successful, indicating that each site represented a distinct habitat and that the Collembola species were habitat-specific. Ammonium nitrate is a soluble nitrogen fertilizer. Approximately 2,170,000 tons were used in conventional agroecosytems in the United States in 1983 (USDA 1983). Ammonium nitrate contains approximately 3596 nitrogen (Table 1), and is a source of readily available nitrate and ammonium ions. Plant uptake of nitrate is often greater than uptake of ammonium under field conditions. Ammonium may be partially adsorbed on soil colloids before plant uptake. Herbicides—Herbicides are used to manage weeds in most conventional agroecosystems. Atrazine is a selective herbicide used to control broadleaf and grassy weeds in corn, sorghum, and other crops. Selective weed control is achieved with rates of 2.24-4.48 kg/ha. Atrazine is absorbed through roots and foliage, and accumulates in apical meristems and leaves, acting as a photosynthetic inhibitor. Limited studies have shown some minor fungicidal and nematocidal activity. Atazine is readily adsorbed on organic matter and clay; leaching is limited. Most decomposition occurs by microbial organisms which may utilize it as a source of energy and nitrogen. Residues may persist in soil longer than 12 months, where soil adsorptive capacities are high (WSSA 1983). Alachlor (Lasso) is an herbicide used to control annual grasses and certain broadleaf weeds and yellow nutsedge. It is absorbed mainly by germinating plant 25 shoots and secondarily by roots, and is translocated throughout the plant, inhibiting protein synthesis. Alachlor is adsorbed by soil colloids, and is broken down mainly by microbial organisms. Other biocidal properties are not reported. Average persistence from recommended rates is approximately 6-10 weeks, depending on site conditions (WSSA 1983). MATERIALS AND METHODS Research Site Description A research site at the Rodale Research Center in east-central Pennsylvania was used to monitor the influence of agroecosystem management on 5011 population densities of Collembola associated with sweet corn in 1982 and 1983. This Center is near Kutztown, in Maxatawny Township, Berks County (Figure l). The site was part of a five-year vegetable rotation study (VRS), initiated in 1982 in a field that had been under organic management for ten years, and was considered a stable organic system (Figure 2). The objective of the study is to determine nitrogen contribution of a legume sod in organic and conventional agroecosystems. Agroecosystem was the main factor in a randomized split-split plot design. Systems were further divided into eight crop rotation sequences (Figure 3). Crop rotation sequences were unique with respect to nitrogen source, which was sub-divided to four rates of application. Rotations incorporated leguminous crops, or the nitrogen fertilizers bloodmeal, compost, or ammonium nitrate. Application rates were zero, low, moderate and high. The zero-rate units served as agroecosystem controls. Some rotations incorporated double- 26 .ofico>H>mccum .hucsoo exuum ca uuucoo couoomum mancom ecu mo coqunooq «Nadir ‘ '\ ‘5 ammo?» . H 0.3me 27 .pmHOuacoe one: mHonEoHHoo mo mcoauodsooo Haom :uwc3 :fi mcfiofiu noucoo consumed oamcox .N muswam @ ouua usuuuomaoo 1 n ouqa xavau unannoun< 1 c N“ on“: ua61uo>o~u ouaeuouu< 1 n uu>o~o 5 3360300 mo sown-.33.: .P z duouuuo> can aquacuauo: new ouun xenon 1 N Am¢>v aeaua coaueuou own-uouo> 1 a V 28 ALTERNATIVE . couvennouu l ALTERNATIVE | convent-10:11: Tl svsreu . system I svsreu | svsreu l '1— i‘ \ \{3 / BLOCK 9 ' BLOCK 1:: t m l BLOCK BLOCK II ' I S .313; L. _______ 1. ________ L ________ ALTERNATIVE SYSTEM CONVENTIONAL SYSTEM 'atooo HEAL _cowosr m "N303 - coweosr _CONI’ROL CONTROL m CONTROL CONTROL Figure 3. Experimental design of the vegetable rotation study at the Rodale Research Center, and selected rotation sequenc this M.S. research. es utilized for 29 cropping with Chinese cabbage. Each experimental unit (5m X 10m) was replicated four times in two adjacent research fields. This soil is a Fogelsville silt loam, but clay differences are apparent across replications. The site is directly south of a 8-10% slope, on a Berks shaley silt loam. Small grains were planted on the slope. Organic and conventional agroecosystems differed with respect to method of weed control, and nitrogen source. The organic agroecosystem used cultivation for weed control, and the conventional system recieved applications of the herbicides atrazine (1983) or atrazine and Lasso (1982). Atrazine was applied at a rate of 0.49 kg ai/ha in 1983, and 1.22 kg ai/ha in 1982. Lasso was applied at a rate of 4.8 liters/ha in 1982 only. Two rotation sequences in each agroecosystem at zero- and moderate- nitrogen fertilization rates, were selected as experimental units for this research (Figure 3). These rotations included a Chinese cabbage double-crop which was transplanted after sweet corn harvest. The organic system rotations used the nitrogen sources bloodmeal (1396) or compost ($93 1.5096). Conventional system nitrogen sources were compost or ammonium nitrate (33.596). Fertilizers were applied at a moderate rate of 80 kg N/ha. The volume of fertilizer applied was dependent on nitrogen content of the material (Table 2). Sweet corn (cv Merit) was seeded on May 19, 1982. Row spacing was 75.0 cm; equivalent plant population was 44,000/hectare. Each experimental unit consisted of six 10 M rows; data collection was confined to center rows. Rainfall prevented 1983 seeding until June 2; a short-season cultivar, Stardust, was planted. Chinese cabbage (cv Hikoshima Spring) was double-cropped after sweet corn harvest each season. Field operations were performed as timely as possible (Table 3 and 4). Table 2. 30 bloodmeal, compost, and NH4N03 fertilizers. Per cent nitrogen, and rate of application to sweet corn, of Nitrogen Application Fertilizer (kg) Fertilizer N (%) kg/ha Plot Hectare Compost 19321 1.75 80 54.0 12,000 191332 1.00 80 80.6 17,900 Bloodmeal 13.00 80 3.3 738 NHANO3 33.50 80 1.3 285 154% moisture 256% moisture 31 Table 3. Schedule of field operations and soil sampling in sweet corn (1982). Date Julian date Operation April 24 114 Entire field moldboard plowed May 1 121 Entire field disk plowed and culti- packed May 6 126 Compost applied in organic system May 10 130 Compost incorporated May 19-20 139 Sweet corn seeded May 26-27 146 Atrazine and Lasso applied to con- ventional system June 9 160 Bloodmeal applied (sidedress) in organic system; applied NHANO (1/2 rate) in conventional sygtem June 10 161 Bloodmeal incorporated June 24 175 Cultivated all plots; remaining NH4N03 applied to conventional system. July 1 I82 Collembola soil populations sampled July 1—2 182 Organic system sweet corn weeded July 7-8 188 Sweet corn hilled, both systems July 21 202 Collembola soil populations sampled July 24-27 205 Irrigated entire field (2.54 cm) August 3 215 Collembola soil populations sampled August 16-19 228 Sweet corn harvested 32 Table 4. Schedule of field operations and soil sampling in sweet corn (1983). Date Julian date Operation March 17 76 Collembola soil papulation sampled May 6 126 Entire field mowed and moldboard plowed May 12 132 Entire field disked May 14 134 ‘ Entire field disked June 1 151 All nitrogen fertilizers applied (NH4N03 at 1/2 rate) June 1 151 Entire field harrowed June 2 152 Entire field cultivated; corn seeded June 9 159 Atrazine applied to conventional system June 11 161 Rotary hoed all plots June 13 163 Rotary hoed organic system June 23 173 Collembola soil population sampled June 27 177 Cultivated organic system July 1 182 NHaNO applied (sidedress at 1/2 rate) in conventional system; cul- tivate organic system July 6-9 187 Entire field irrigated (2.54 cm) July 11 192 Collembola soil pOpulation sampled July 12 193 Cultivated organic system July 12-15 193 Entire field irrigated (2.54 cm) July 19-22 200 Entire field irrigated (2.54 cm) August 1-4 213 Entire field irrigated (2.54 cm) August 2 214 Collembola soil population sampled August 9 221 Began sweet corn harvest August 15 225 Collembola soil population sampled 33 Quantification of Collembola Soil Populations Collembola populations were sampled on four dates in 1982 (July 1, July 21, August 3, September 5), and five times in 1983 (March 17, June 23, July 11, August 2, August 15). Sampling was completed prior to sweet corn harvest and cabbage transplanting, except on September 5, 1982. On most sampling dates, soil sampling began in the early morning and was completed before 12:00 noon. Five in-row soil cores, 5.08 X 15.24 cm, were taken from alternate middle rows within each experimental unit. A stainless-steel corer was rotated into the soil between plants, to a depth of 15.24 cm. Diameter of the corer gradually increased over a short length, in order to relieve soil compression. Samples were inverted into plastic quart containers, and a lid was placed on each container. Samples were stored in the field for a short length of time in Styrofoam coolers. On each sampling date, 160 cores were collected. Eighty Tullgren funnels were available for extraction, therefore, two replications of 40 cores each were stored at 4 C for 24 hours before extraction. The remaining 80 soil cores were extracted immediately for 24 hours. Extraction and storage time was increased to 48 hours on March 17, 1983, only. Soil samples were inverted and uniformly spread onto squares of window- screening in each funnel. A four-ounce collection jar, filled with 196 glycerin- 9596 ethanol, was placed directly beneath each funnel. Hooded 25-watt light bulbs were lowered over each funnel, and soil temperature was maintained at a maximum of 27 C with a rheostat. Collection jars were capped and removed after 24 hours, and dried soil cores were discarded. This process was repeated with stored samples. 34 Alcohol—specimens were rough-sorted to major taxa using a dissecting microscope at low power. After an initial period of identifying slide-mounted specimens with a phase-contrast microscope, most species were recognizable in alcohol with a high—power dissecting microscope. Specimens were frequently slide-mounted, however, to verify identification. Collembola were identified to family (Onychiuridae, Isotomidae, Entomobryidae and Sminthuridae) on the first sampling date in 1982, and to species on subsequent dates, according to Christiansen and Bellinger (1980) (Appendix 1). Other Collembola families were not collected from this site. Soil population densities of Collembola were extremely low on September 5, 1983, after sweet corn harvest, field preparation, cabbage transplanting and irrigation. These samples were not sorted due to time restrictions. Certain experimental procedures were standard throughout this research. 5011 densities of Collembola are reported as the mean number per cm3 x 10'2, unless otherwise stated. Soil samples were taken to a depth of 15.24 cm, with a diameter of 5.08 cm. Other sampling procedures and the use of Tullgren funnels were standard throughout this investigation. Extraction Efficiency—Tullgren funnel efficiency was determined in 1982 and in 1983, for both stored and immediately extracted samples. On August 23, 1982, eight soil cores were taken from an untreated sweet corn plot in the vegetable rotation study (Figure 3). Four cores were extracted immediately and four cores were stored at 4 C for 24 hours before extraction. Tullgren funnel collection jars were changed at 6-and 24-hour intervals. After 72 hours of extraction, dry soil cores were mixed with saturated sugar solution, to collect soil-trapped Collembola, and determine extraction efficiency. Collembola remaining in the 35 soil sample floated to the top of the sugar solution, and were collected with a 400-mesh sieve. On this date, only families were identified. On August 15, 1983, twelve soil cores were taken from the same untreated sweet corn plot. Movement of Collembola from soil samples was monitored for 72 hours at lZ-hour intervals. Collembola were extracted from fresh soil cores, and from cores stored at 4 C for 24-and 48-hours. Numbers extracted per 12- hour period were recorded, but efficiency was not determined. Data were analyzed factorially. Standardization Procedure-Soil population density estimates obtained from stored soil samples or from samples extracted 48 hours (March 17, 1983), were adjusted to approximate densities achieved with 24 hours of extraction of fresh samples. The cumulative per cent Collembola extracted from soil cores in 72 hours, at 12-hour intervals, was plotted with extraction time. Treatments were fresh extraction, 24-and 48-hours of storage. Correlation coefficients and line equations were determined for each common species. A unique constant was obtained, from regression statistics, for each species extraction rate. Soil population densities of Collembola that were determined from stored samples, or from samples extracted for 48 hours, were multiplied by the respective species constant. This procedure standardized soil densities between replications and dates, and reduced variation caused by dissimilarities in replication handling. Spatial Distribution and Population Dynamics A field test conducted at the Rodale Research Center was used to evaluate horizontal, vertical, and seasonal distribution of soil Collembola. Soil samples were taken at approximately 2-week intervals from March 24 to August 25, 1983, in a non-irrigated weedy clover field (Figure 2). This site was plowed and 36 reseeded in early June, necessitating relocation of the sampling area. Beginning June 16, therefore, samples were taken from a different research field that was seeded with a mixture of clover and oats earlier in the season (Figure 2). Horizontal and vertical distribution of soil Collembola was initially determined March 24. On this date, soil samples were taken at two sampling densities: 1 core/M2 (25 cores/25M2) and l core/0.04 M2 (25 cores/1M2) (Figure 4). Three 5M X 5M grid areas were randomly marked in the field, and one soil core was taken per square meter. One square meter within each 5M X 5M grid 2 each) and one core was taken from was further divided into 25 sub-units (0.04 M each sub-unit. Nine cores in the upper left corner of each replicate were vertically stratified to 5.08 cm segments, and extracted individually to determine vertical distribution of Collembola. On remaining sampling dates, a 3 M X 3 M area was randomly selected in the field. One core was taken from each square meter, to monitor horizontal and seasonal distribution. On the last two sampling dates, limited soil moisture in the clover-oats field necessitated sprinkling the area with water prior to sampling. Soil samples were taken one hour after this irrigation. Low soil moisture content at the clover-oats site also prevented accurate stratification of soil cores for estimation of vertical distribution. Separate soil cores were collected, therefore, from an alternate site. Cores were taken from a nearby irrigated and untreated sudax plot within the vegetable rotation study (Figure 2), and stratified to 5.08 cm layers before extraction. Although this site was irrigated, plant cover was similar to the clover-oat site. - one soil core iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 38 Goodness of fit tests were utilized for distribution determination. Prominence values and relative prominence values were calculated for each species on each sampling date as follows: Eq. 1. Prominence value = AD x 1/A—Fz PV Eq. 2. Absolute density = absolute numbers per unit sample = AD Eq. 3. Absolute frequency = (ni/nt) x 100 = AF - where, ni = number of samples containing a species n t = number of samples collected. Soil temperature and gravimetric soil moisture to a depth of 15.24 cm were recorded each sampling date. Collembola Associated with Compost On March 23, 1983, compost samples were taken from an undisturbed pile at the Rodale Research Center, to identify the number and population density of Collembola species present in compost (Figure 2). On June 22, populations were sampled again at the same site. On this date, cores were taken at 15.2 and 30.5 cm depths from the perimeter, at approximately mid-pile height. Collembola were extracted immediately in Tullgren funnels, and species were determined. Environmental Monitoring Daily minimim and maximum air temperature at the Rodale Research Center were recorded in 1982 and 1983 (Appendix 4 and 5). In 1983, soil temperature and moisture to a depth of 15.24 cm was monitored weekly in the clover-oat and irrigated sweet corn sites (Appendix 6 and 7). Precipitation was monitored both seasons (Appendix 8 and 9). Soil nutrient status was determined prior to initial cultivation and after harvest in 1982 only (Appendix 10). 39 Agroecosystem Analysis Two-way analysis of variance was used to detect differences in soil population densities among sampling dates and treatments. This analysis was performed with the sum of soil Collembola densities on all dates in 1982 and 1983. Analysis of variance was performed on densities of the most prominent Collembola groups. Soil densities of Entomobryidae, Isotomidae, Isotoma notabilis, Isotomiella minor, Folsomides americanus Denis, and Tullbergia yosiii were analysed independently. Treatment means were separated with orthogonal comparisons. Orthogonal Comparisons-Orthogonal comparisons provide investigators with a statistical method for answering specific questions concerning a set of data. This analysis partitions the degrees of freedom and sums of squares for treatment effects into pertinent single degrees of freedom. Advantages of orthogonal comparisons for the purpose of separating treatment means are: 1. Sensitivity is great, 2. Specific questions that are designed into the treatments can be examined. Three rules must be met in order for planned comparisons to be considered orthogonal, or independent: 1. Coefficients within each comparison set must sum to zero ( c1 1 = 0), 2. The sum of the products of the corresponding coefficients of any two comparisons must sum to zero ( cuciz = 0), 3. There are exactly (t - 1) comparisons in one complete orthogonal table, 40 where, c1; = coefficients of a comparison t = number of treatments. A table of orthogonal coefficients may be constructed by asking planned questions, or stating hypotheses, regarding relationships and interactions of the data. Treatments are arranged horizontally as a table heading, as in Table 5. Each comparison, or hypothesis, appears as a different line in the table, and consists of positive or negative coefficients that contrast, or separate, treatment totals. Each comparison has one degree of freedom. In this investigation, a table of orthogonal comparisons was constructed that meets all rules of the analysis (Table 5). Questions regarding agroecosystem effects in 1982 and 1983 were: 1. In the absence of a nitrogen input, were soil population densities of Collembola significantly different in organic and conventional agroecosystems?, 2. Were soil population densities of Collembola influenced by organic system nitrogen input?, 3. Were soil population densities of Collembola influenced by conventional system nitrogen input?, 4. In the presence of nitrogen input, were soil population densities of Collembola significantly different in organic and conventional agroecosystems?, 5. Disregarding agroecosystem, were soil populations of Collembola influenced by nitrogen input?, 6. Was treatment randomization effective in reducing population differences caused by experimental design in the organic system?, 41 11 11 11 11 11 H1 11 fi+ c #1 H+ #1 H+ #1 ~+ #1 H+ m H1 11 #1 11 ~+ 11 ~+ 11 a ~1 11 ~+ 11 11 11 11 11 m 11 11 11 11 #1 11 ~+ 11 N 11 H1 11 H1 11 ~+ 11 ~+ a umooaoo Houucoo mozqmz Houucoo umooaoo Houucoo HmoEeooam Houucoo somfiumoaoo Hmsoaucu>coo oqcmwuo Euum%mouoouwm CHOU umm3m .maoummmouoouwm choc nouzm :« mofiuqmsom some coaumasooo masoEmHHOHVwo cowumumoom new eonaafiu: mcomfiumoeou HmcowOSuuo .m manna 42 7. Was treatment randomization effective in reducing population differences caused by experimental design in the conventional system? Sums of squares were calculated for each comparison: Eq. 1. $5 = (ciYi,)2/r eiZ where, c1 = comparison coefficients (Table 5), Y1. = treatment totals, r = number of replications. Mean squares are equal to each sum of squares, since each comparison has only one degree of freedom. An F-test was conducted by dividing each mean square by the mean square error, and using a common table of the F distribution for significance determination (Steel and Torrie 1980). RESULTS Quantification of Collembola Soil Populations Extraction EfficiencyuThe portion of the Collembola population recovered from soil cores in Tullgren funnels increased with time in the 1982 test (Table 6). The mean extraction efficiency for Collembola, from fresh soil samples, was 4296 after 24 hours. Extraction for 48 hours resulted in recovery of 7996 of the population. After 78 hours of extraction, 8396 were recovered. Sample storage at 4 C for 24 hours resulted in increases of 5596, 1096, and 1096 of the number of Collembola recovered from samples extracted for 24, 48 and 78 hours respec- tively. Extraction efficiency varied among Collembola families (Table 6). In this experiment, _Ii. americanus was mistakenly identified and included in data for the Onychiuridae. 43 Table 6. Extraction efficiency of Tullgren funnels for the determina- tion of<3011embola soil population densities. Collembola recovered (%)1 Stored @ 4° c Immediate extraction (hrs) 24 hours (hrs) T 24 48 78 24 48 78 axon Onychiuridae2 31 67 74 55 83 88 Isotomidae3 69 97 100 81 100 100 Entomobryidae 53 93 93 92 96 97 Total collembola 42 79 83 65 87 91 1August 16, 1982 2Includes Folsomides americanus (Isotomidae) 3Excludes E, americanus 44 The rate of extraction of Collembola with the Tullgren funnel varied with storage conditions and species in 1983. Storage of soil samples did not significantly alter extraction rates of most Collembola taxa. Significant (P=0.05) differences in extraction rate due to storage were observed for t. [DIEM (Table 7). Greater densities of this species were obtained from soil cores stored at 4 C for 24 hours before extraction. Densities were 2.5 and 3.3 times greater from stored samples when compared with fresh samples, after 12- and 48-hours of extraction, respectively. The length of the extraction period significantly (P=0.06) influenced density estimates of most species (Table 7). Collembola extraction efficiency was greatest in samples stored at 4 C for 24—hours (Figure 5). Storage at this temperature for 48-hours, however, lowered population density estimates. Extraction rate of _I_. notabilis fluctuated with hours of extraction (Figure 6). After 48 hours of extraction, densities were greatest from samples stored 24 hours. This trend reversed after 60 hours of extraction, however, when fresh extraction yielded greatest densities of this species. Optimal extraction rates for t. _m_tr_1_c_1_r_, I_. w, and P. violenta were achieved after 24-hours of sample storage at 4 C (Figures 7, 8, and 9). Sample storage, however, depressed the extraction rate of F. americanus; greatest population densities of this species were obtained with fresh extraction (Figure 10). Standardization Procedures-«The number of Collembola extracted from soil cores in Tullgren funnels increased with extraction hours. This positive correlation was significant (P = 0.06) for most species (Table 8). When soil populations were low, or if individuals were extracted only during the initial 12 45 Table 7. Influence of soil sample storage, and length of Tullgren extrac- tion, on determination of Collembola soil population density. Sample storage (df=2) Extraction (hrs) (df=5) Taxon F-statistic Significance F-statistic Significance g. violenta 0.95 N81 10.24 0.01 Isotomidae 0.25 NS 9.25 0.01 t, notabilis 0.07 NS 1.40 NS 3, Egggt_ 3.92 0.05 2.16 NS ‘E. americanus 0.71 NS 7.77 0.01 I, yggttt 2.57 NS 1.57 NS 1Level of significance is greater than 0.05. 46 ID 8 .1 . 0 III Fresh extractlon O Stored 24—hours (4°C) , a A Stored 48-hours (4°C) u :4 O to 35 I: a Q S 8 s 0 2 9.. t3 c: u _1 C) o - 1 g _. 2 ID 0 I; D U c; r 1 T 1 r 1 0 12 24 36 48 60 72 HOURS OF EXTRACTION Figure 5. Extraction rate of Collembola from fresh and stored soil samples in Tullgren funnels. 47 0.0015 11'! Fresh extraction (9 Stored 24-hours (4°C) A Stored 48—hours (4°C) —1 0.0005 0.0007 0.0010 0.0012 L4, MEAN I. window's/01,1a SOIL 0.0002 0.0000 0 1 1 1 1 1 1 12 24 38 4B 80 72 HOURS OF EXTRACTION Figure 6. Extraction rate of t. notabilis from fresh and stored soil samples in Tullgren funnels. 48 0.0040 7E] Fresh extraction 0 Stored 24—hours (4°C) A Stored 48—hours (4°C) 0.0030 MEAN I. minor/CW son. 0:0020 S Q o.— D O D D D c; 1 1 r r T 1 0 12 24 36 48 60 72 HOURS OF EXTRACTION Figure 7. Extraction rate of E. minor from fresh and stored soil samples in Tullgren funnels. 49 D LO Q 9- D E] Fresh extraction 0 Stored 24-hours (4°C) A Stored 48—hours (4°C) p (7) D 0.- D MEAN T. yosi'ii/CW SOIL 0.0025 N S ‘3- O c: Ara’TTAA—__-AF_—_—£r””A§—_——TA O O D c', I 1 1 1 1 T 0 12 24 36 48 60 72 HOURS OF EXTRACTION Figure 8. Extraction rate of g. yosiii from fresh and stored soil samples in Tullgren funnels. 50 In N D 0. °I III Fresh extraction 0 Stored 24—hours (4°C) 2: A Stored 48—hours (4°C) 8 =1 (5" 8 n 2 R 3 9‘. g c we :3. .§ 0 1:1; '3' (D 2 8 5’4 O O O D D c', 1 r 1 1 1 1 0 12 24 38 48 60 72 HOURS OF EXTRACTION Figure 9. Extraction rate of g. violenta from fresh and stored soil samples in Tullgren funnels. 51 ID to D c.’ D- _, 23 6 8 (n Cr ”2 O E 8 s: .0 o ‘3- g. a . ti. 2! as O c',‘ III Fresh extraction 0 Stored 24—hours (4°C) A Stored 48—hours (4°C) 0 8 D c', 1 I r 1 r 1 0 12 24 36 48 60 72 HOURS OF EXTRACTION Figure 10. Extraction rate of E. americanus from fresh and stored soil samples in Tullgren funnels. 52 Table 8. Regression equations for 3011 population densities of Collembola extracted by Tullgren funnels, and compared with hours of extraction and sample storage. Storage Regressron K1 (hrs)2 Iaxon at 4° C equation R 24 48 Entomobryidae o r - 0.57 + 0 01 t 0.3693 0.76 24 Y - 1 50 + 3 03 x 0.929.0 0.39 48 Y - 2 42 - 0 01 x 0.655 0 31 pg. violenta 0 Y - 0 5: 1 0.01 c 0.5653 0.39 0.76 24 t - 1.50 ~ 0.03 1 o.929° 0.39 48 Y - 2.50 + 0.01 x 0 655 0.29 Isotomidae o 1 - 5.22 - o 08 x 0 983° 0.79 24 1 - 3.88 1 0.15 t 0.954b 0 98 .8 T - 6 99 . 0.07 t 0.3613 0 39 t. notabilis 0 Y - -0.12 . 0.03 r 0.3923 0.45 :4 r - -0.03 - 0.05 x 0.9395 0.98 45d _3. americanus 0 Y - 3.17 2 0.03 ' .975b 0.35 24 r - 0.39 - 3.03 r 0.351a 2.30 48 Y - 1 60 + 0.02 v 0.331a 1 5‘ t. gtggt 0 Y - 0.33 + 0.02 t 0.9083 0.66 24 Y - 1.32 + 0.07 2 0.937b 0 24 48 Y - 0.58 + 0.03 1 0.953b 0.34 E- Egtttt 0 Y - 0 33 s a 07 r 0 9293 0 54 2. Y - 0 as + 0.07 t 0.923b 0.82 .3 r - 0 23 + o 31 r 0.217.3 3.45 Total Collembola 0 T - 6.37 + 3 17 V 0.973 0.‘2 24 v - 6... + 0.24 x 0.9565 0.34 48 2 - 9 95 + 0.30 x 0 5563 0.73 I ‘Multiplicative constant for standardization of Collembola sorl densities. K is utilized to obtain a Collembola soil density that approximates fresh extraction for 24 hours, if the soil sample was stored for 24 or 48 hours, or if the sample was extracced for 48 hours. , 'Eours of extraction a? . 0.05 P - '3001 3? - 0.001 U‘ 0. . . . . . . . . LRdl‘ldUdls were not tailectea atter 12 nears o: extraction. 53 hours of extraction, a relationship between estimated soil density and extraction rate was not noticeable. For these reasons, a significant relationship between extraction rate and hours was not observed for E. violenta and _I_. notabilis (Table 8). Spatial Distribution and Population Dynamics . Soil population densities of L. notabilis, l. m and Tullbergia yosiii associated with clover fit a negative binomial distribution (P=0.05) on most sampling dates, at both sampling densities. Poisson distributions (P=0.05) were common when soil densities were low. Soil densities and prominence values associated with these species fluctuated seasonally. Population densities of l. notabilis were greatest on June 1 (Table 9). This species made up the greatest proportion of the Collembola population on this date, when relative prominence and soil density were 38.07 and 5.87 respectively (Appendix 11). Densities declined when the sampling site was relocated to a drier clover-oats field on June 16. The horizontal distribution of l. notabilis was random 50% of the season and clumped on remaining sample dates (P=0.05). Random distribution was most prominent late in the season (Table 9). l. notabilis was the second most prominent species encountered in clover in the 1983 season (Appendix 10). Soil densities of _I_. mi_no_r_ peaked on June 1, at a density of 0.92, however, soil densities fluctuated greatly during the sampling period (Table 10). Relative prominence of this species on June 1 was 36.8, and most often ranked greater than third place (Appendix ll). Soil populations of this species fit a negative binomial distribution (P=0.05) on all dates except July 1 and July 28. On these dates the distribution was random (P=0.05, Table 10). 54 comwom n Ham ”Howeocfin m>Humwmz u 220 AN ouswfimv ouum monouuo>oaoo mo.oumo AN musmfimv mufim uo>oao humozv mwmao «oz amoo.o Ho.o oo.o ozem~v mm omawno zoo oooo.o No.o ~o.o mammmv Ho omsose ooz oaoo.o mo.o oo.o ozaomv om zone oz wooo.o mo.o Ho.o ozomov no zosz oz memo.o mo.o oo.o mzmmov o zone “oz moso.o No.o No.0 ozmoov oz «one oz mmmo.o om.o oo.o zzmmov o mesa oz mooo.o o~.o mm.o ezmmov No so: ooz Nomw.o No.o mo.o ozooov om onuao oz oooo.o mo.o mo.o zzeav a oooa< oz “soo.o N~.o mN.o zzmmv om ouoaz UGOfiu—aflfiuuwfifl UHumHuwum >OGHfiEm Nm mac NIOH K H Amuwv DNfiHSHv |>ouowoeqox pom mHHHnmuoc .H mmumc wcwaaamm .I .50 o~.mo mo ooamz HHom m Cu .wDQOIum>oao can .um>o~u :H mHHHamuo: .H mo :owuanwuumfic Hwom Houcoufiuo: Hoaommmw .a «Home 55 :omoom a zoo “Hassoooo m>oomwmz u ozU AN muswumv moan muoOIuo>oaoo mo.onmn AN ouowamv oufim uo>oao madman mwaao oz oooo.o ao.o mo.o mzemmv mm omawso o c mammmv Ha umows< Hem ocoo.o Ho.o Ho.o oAmomv mm zash o o ozoaov mo zone Hoe oooo.o oo.o Ho.o mzmoov o zone 0 o mAmoHv ea wash :2 mmNH.o mm.~ No.0 vammav H ocsm oz ommo.o wo.o mo.o ozmmov No so: 92 homo.o om.o NN.o UAcHHV cm Hfium< o o canav m kua< oz homo.o oo.o «H.o camwv om soup: coaunnfiuumfio nofiuwfiumum >ochfiam mm map NIoH x H Amuov :ofiaonv I>ouowOEHox you mmmflm..m. nounc mafiaaaom HHom o Cu .muooluo>oao can .uo>oao ca pocHE .m.mo oowusnwuumac Hmuooufiuon Hooomomm .au o~.no mo ooaoz .oa wanme 56 I. yo_si_i_i was the most prominent species in clover during the sampling period (Appendix 11). Relative prominence peaked at 78.8 on April 7. Soil densities were greatest on March 24, when the density was 1.21, and then declined during the sampling period (Table 11). I. M soil densities were aggregated (P=0.05) on all dates except August 11, when distribution was random (P=0.05). On March 24, soil population densites of _I_. notabilis, _I_. 92199 and I. y_o§ii_i were aggregatelly distributed for both of the sampling densities (Figures 11 - 19). Population density fluctuations within the sampling area form distinct aggrega- tions. Other Collembola species were commonly collected at low densities, or only infrequently from the clover sites (Appendix 11). Sminthuridae were collected infrequently, but more often than from the cultivated sweet com site. Soil Entomobyidae densities were low initially, but this was often the only Collembola group collected later in the season. A diversity of Isotomidae were collected on most dates. Population distribution of l. notabilis, 1. minor, and _‘I_'. yc_>§_i_i_i_ were aggreated (P=0.05) at soil depths of 0-5.08, 5.08-10.16, and 10.16-15.24 cm. When low population densities were recovered, vertical distribution most often trended towards randomness. 1. notabilis population densities were greatest at the soil surface on March 24, and at 10.16-15.24 and 5.08-10.16 cm on June 22 and July 25, respectively. Individuals were collected from the surface layer only on September 1 (Table 12). This species had the greatest relative prominence at 5.08-15.24 cm on June 22, at O-lO.l6 cm on July 26, and at 0-5.08 cm on September 1 (Appendix 12). 57 :omHom 0 H00 "HoHEocHn o>Huowoz n :20 AN oustmv muHm monouuo>0Huo m0.0umn Am oustmv ouHm uo>0Ho acomzv mmmHo oz 0H00.0 no.0 H0.0 oAzmmv mm umswo< Hem 0000.0 H0.0 H0.0 oAmNNV HH um=w=< oz o~oo.o Ho.o oo.o ozmomv om zozz nz 00NH.0 m0.0 m0.0 macaHv mH szw oz 000H.0 0~.0 «H.0 oAmmHv H szz oz ~0m0.0 50.0 «0.0 oAmch 0H 0:20 oz caHH.0 no.0 0H.0 vANmHV H 0:30 oz 0q00.0 mm.m 00.0 vfimmHv NH xx: 02 «H00.0 m~.0 00.0 cfioHHv 0N HHH0< oz 00NH.0 o0.m no.0 vfizmv n HHH0< oz Nooo.o oo.mo H~.o zzmwv om ooomz :oHuanHuumHn noHumHuoum >oouHEm mm mao N..0H x H Aouop :oHstv I>ouoonHoM pom HHHmON «M moumv wcHHasmw HHom m cu .muoOIuo>0Ho can .um>oHo :H HHHwON .H.wo :oHuanuumHv HmucouHuo: Hmoommmm .20 e~.nH to ooamo .HH mHnoB 58 (A) X11! \“l (B) Figure 11. Horizontal soil p0pulation distribution of l. notabilis in clover on March 24, 1983, at two sampling den- sities: (A) 25 samples/M2, and (B) l sample/M2 (Replication I). 59 (B) OI WJX Figure 12. Horizontal soil population distribution of I. notabilis in clover on March 24, 1983, at two sampling densities: (A) 25 samples/M2, and (B) l sample/M2 (Replica- tion II). 6O \ Alfi.,{fl!> ‘!Hh§’{3* 4;. ,hts‘!“\=§s§?: «! 1 "23;. \\ ’i;""\“§:§7II.‘\("I;III’&\\\tz:3. "=34" ' ‘ \k’: b 't ”I 0 \ ‘ ...0.0‘ \\ . \o ’ “ t ‘ ‘ V \’I be 'll ‘§",‘ ‘flfl’j' wallhp(p ‘fib “22222410;.\\§\‘§§§:: ° MEfi'Oolitzzztgse” ' GU _l E 4.1 111111 0! Figure 13. Horizontal soil pOpulation distribution of I, notabilis in clover on March 24, 1983, at two sampling densities: (A) 25 samples/M2, and (B) l sample/M2 (Replication III). 61 I: .\ O o. (5‘: 9‘ 3 ' g “ ‘3 4:010 o '0 e .0 0.3 «w I) ‘\\\§..222§22§2;:;:::2;2; ‘A’ ‘7 77lll ‘ \fiéiéiéizizéz 2;; ’1’] 'A‘\\\ ‘\:::.::::. " ‘ "0”, “e\\g‘.¢:.::::::.o O» 5 ME T598 ‘.._o b w 0 (B) ,. 5 5 .25 5 «$9 0 Figure 14. Horizontal soil population distribution of I. minor in clover on March 24, 1983, at two sampling densi- ties: (A) 25 samples/Mz, and (B) l sample/M2 (Replication I). 62 (B) Figure 15. Horizontal soil population distribution of I, minor in clover on March 24, 1983, at two sampling densities: (A) 25 samples/M2, and (B) l sample/M2 (Replication II). 63 9” e 6 ’0 9 ‘0’0 ’0’. '0” 9.0 o o O 0’ (.0 0.. O O 9 w i Q I .9 .o o ’9 o O O o O.) u w l )0 MO 1 O f 9 Pl ’4’» N" .u.o o \‘ W0 ~m H M 0» MM o M (NH (Will) .0.“ N u we Q ‘30“ ‘~‘~ a" 0.3.. 00 4 M W ’4 o u 0 m. I .9 .0 .0 N M \ ~ ~ Q § 9. 'M "I ’M’ ’M N" 0 0 MN m m W0. 0.0.§~ I. 90 (A) ’o n :9 O M (9.6. 0’ \‘5 Q \i d) E) l 5 Q 0 v Q is Q ‘§ \% O (B) Figure 16 . Horizontal soil population distribution of _I_. minor in clover on March 24, 1983, at two sampling densities: (A) 25 samples/142, and (B) 1 sample/M2 (Replication III). 64 (A) Figure 17. Horizontal soil population distribution of g. xosiii in clover on March 24, 1983, at two sampling densities: (A) 25 samples/M2, and (B) l sample/M2 (Replication I). 65 (A) Figure 18. Horizontal soil population distribution of g. zosiii in clover on March 24, 1983, at two sampling densities: (A) 25 samples/M2, and (B) 1 sample/M2 (Replication II). 66 .;i;;§i§:’§:$§33§iz 9 II \\ at“ Ii: R““‘§W§ O» .. o I [5&3 0.. ’III 'I Figure 19. Horizontal soil population distribution of 2. zosiii in clover on March 24, 1983 at two sampling densi- ties: (A) 25 samples/M2, and (B) l sample/M2 (Replication III) 67 Soil population densities of _I_. _r_n_i_1_1_o_r were greatest at a soil depth of 10.16- 15.24 cm on March 24, and at the surface on June 22 and July 25 (Table13). Individuals were not collected on September 1. _I_. £13211 was often the third most prominent species at each soil depth (Appendix 12). Soil population densities of 1. Egg were concentrated at a soil depth of 5.08-10.16 cm on March 24 and June 22 (Table 14). On July 26, however, densities were greatest at a soil depth of 10.16-15.24 cm. On September 1, a low population density was recovered from the surface only. This species was most prominent at all depths on March 24, at the soil surface on June 22, and at the 10.16-15.24 cm depth on July 26 (Appendix 12). Fluctuations in vertical distribution of_I_. notabilis, _I_. M and 1. 1921.1 were apparent during the season (Figures 20 - 22). Collembola Associated With Compost Compost samples were collected on March 28 and June 22 (Table 15). E. violenta, g. unostrigata and Lepidocrytus pallidus Reuter were recovered from compost samples on both sampling dates. 3. violenta, the most common Entomobryidae in the Rodale Research Center sweet corn research plots, was found at the greatest density on June 22, at a compost depth of 15.24-30.48 cm. In contrast, this species was not recovered from sudax plots on the same date. The low density on March 28 corresponds to a season low in sweet corn on March 17. l. notabilis and E. _m_in_u_ta were recovered from compost on both sampling dates. _I_. vim—Ls and _I_. m were detected on June 22 only, and _I_. M on March 28 only. I. notabilis, the most common isotomid associated with sweet corn plots, was concentrated in the compost surface on June 22; density at the 15.24-30.48 cm layer on this date was 0.50. This corresponds to the greatest 68 comHom 0 H00 “HmHEocHo o>Homwoz u ozu AN onstzv oUHm xmoom oooowHuuHo 00.0nzo AN muomeV ouHm Hm>oHo 000030 000Hm 0 «0.0H 0H.0H 0 0H.0H 00.0 ooz $36 85 86 meg o 03.5 o .0an oz 00NH.0 0H.0 00.0 «0.0H 0H.0H oz 0000.0 00.0 0H.0 0H.0H 00.0 Ba £25 3.0 86 mod o 0303 mm .33. oz 0NNH.0 00.0QH om.H 00.0H 0H.0H Hom «000.0 HH.0 0H.0 0H.0H 00.0 Hom 0000.0 00.0 no.0 00.0 0 mfimmHv mm 0:30 oz 0H00.0 00.0 H0.0 «0.0H 0H.0H oz 00q0.0 0H.0 00.0 0H.0H 00.0 oz 0000.0 00.0 00.0 00.0 0 0A00v om zoom: ocoHuonpomHo oooomHuoum >ocuHEm mm 08o N 0H x H AEov ooaoo Avon: ooHstv u>ouoonHox 0" you mHHHoouo: .H HHom poooo wcHHaemm mo oummo HHom o co .xmoom one .um>oHu :H mHHHonuoc .M.wo :OHusoHuumHo HmoHuuo> Hocommom .Eo «0.0H .NH oHomH 69 somHom 0 H00 momHeocHo o>Homwmz u ozu AN ouomev ouHm xooom omumeuuHo 00.0umo Am ouoszv ouHm uo>oHo 000030 000Hm 0 om.0H 0H.0H 0 0H.0H 00.0 o mo.m c ozmowv o .oaom oz 000H.0 NH.0 00.0 o~.mH oH.0H Hom 00n0.0 00.0 00.0 0H.0H 00.0 . oz mooH.o ~m.o mH.o mo.m o azooNv mm so:- oz 000H.0 00.0 HH.0 «0.0H 0H.0H oz 000H.0 0H.0 00.0 0H.0H 00.0 oz 000H.0 00.0 00.0 00.0 0 ozmsz mm 0::0 oz 0H00.0 0H.0 00.0 om.0H 0H.0H oz 0000.0 00.0 «0.0 0H.0H 00.0 oz 0000.0 00.0 00.0 00.0 0 oAm0V om ooze: ocoHusoHuomHo ooHumHomum >ocuHEm mm Eu N30H x H Asov ooaoo zoom: coostv l>ouoonHox Hon uooHe .m. HHom moomo wcHHeeom .Eo «0.0H mo oummo HHom o co .xnoam pom .uo>oHo :H uooHE 2N 00 :OHuooHuumHo HooHuuo> Hooommom .0H oHome 70 u Hom momososoo 0>oumuuz u ozu Am 0030000 00am x0030 00000000HJ 00.0u0o AN 0uswwmv 0uHm u0>o~0 >000: m0oo0 0 0N.mo 0o.0o o oo.oo mo.m oz nmmH.o 00.0 no.0 00.m o mzmqmv _ .0000 #00 0000.0 HH.0 0H.0 0N.mo 0o.0o oz ~50N.0 00.0 0H.0 0o.0~ 00.0 000 mm~o.o No.o No.o wo.m o «AOONV mm xozm oz H000.0 00.0 00.0 q~.ma 0H.0o Hon 05HH.0 00.0 00.0 0o.0~ 00.0 oz mm0~.0 H0.m «0.0 00.0 0 0Ammav mm 0:20 oz 00~0.0 00.0 00.0 q~.ma 0o.0o oz 000H.0 00.0 00.0 0H.0H 00.0 oz 0000.0 0H.q H0.0 00.0 0 0Am0v 0m ovum: ucoHuzoopumwn ouwumwumum >ocuwsm mm Eu too x a A600 o0000 A0000 :0Ho20v |>ouoonHox “flame H000 00000 0cwanmm .80 0N.0H mo £0000 Hwom 0 cu .x00am 0:0 .u0>oHo :H fiafimow .M.uo coauaowuuma0 H00Huh0> Hmcomm00 .qH 0Homa 71 W0 0 . ”0;“ ¢ .530 o O .‘ ”QM ~ « \ «WM ‘ q M ”W W. o‘ 9 N o Wo’o o‘o’o’o'm’: 93’ W956" I ’6 1 I 4 III, 1! I, 4» 2: 4f NW ”NW” .- NWO“— «me-e N . — WW .1 mm W.”- W“- H”- OH- ’o’i‘u' 4" I ’l O or - Q ~: Figure 20. Seasonal vertical soil distribution of I. notabilis in clover and irrigated sudax. 72 .xmwsm 0wummauua . . 0:0 H0>OH0 :H .l . HOCHE H 00 coflusofiuuma0 HHOm omoauu0> . . . H0c00000 .Hm 0H50 Hm 73 .x00Sm 00000HHHH 0:0 H0>0Ho :H MMflmo> .H 00 :oflusoflnumfl0 HHOm H00fl0h0> H0:00000 .mm 0H50flm a 0:0 am EN. 0 000 Amm, 030.: 6,3 6 a «N N 03. on? 444 r 444444 Table 15. Population densities of Collembola species associa- ted with compost. 74 Collembola per 1 x 10- 2 3 cm compost Sampling depth (cm) March 28 June 22 Taxon 0 - 15.24 0 - 15.24 15.24 - 30.48 Entomobryidae g. violenta 0.05 1.31 3.90 E. unostrigata 0.03 0.03 0 E. pallidus 0.11 0.03 0.03 Isotomidae 1. notabilis 0.36 1.68 0.52 g. americanus 0 g. minuta 0.42 0.08 0.10 1. viridis 0.03 1. minor 0.37 0.41 1. uniens 0.28 0 Onychiuridae g. encarpatus O 1.08 0.23 g. zosiii 0.07 O 0 Hypogastruridae 0.15 0.08 0.53 75 density in sweet corn on June 23. The surface density in compost on March 28 was GAO. Q. encarpatus was collected from compost on June 22 only. Population density of Q. encarpatus was 1.08 at the compost surface, and 0.23 at the 15.24- 30.l+8 cm compost depth. 1. 1%, the most common Collembola associated with sweet corn, was only collected from compost on March 28. Population density at the compost surface was 0.07. This species was collected in greatest numbers from sweet corn on March 17. Hypogastruridae were collected from compost on both dates. The greatest population density occurred on June 22 at a compost depth of 15.24-30.08 cm; density at this depth was 0.50. Density at the surface was 0.15 on this date. Agroecosystem Analysis Seasonal population fluctuations resulted in significant differences in soil densities among sampling dates (Table 16). Sweet corn agroecosystem manage- ment significantly influenced soil population densities of Collembola (P=0.001); the families Entomobryidae (P=0.02) and Isotomidae (P=0.001); and the species 1. notabilis (P=0.001) and I. M05031). These population differences are the result of agricultural inputs unique to organic and conventional systems, and will be described in the following section. Orthogonal Comparisons-«In the absence of a nitrogen input, total soil population densities of Collembola were significantly (P=0.005) greater in the organic than in the conventional agroecosystem (Table 17). Population densities were also significantly (P=0.001) greater in the organic than in the conventional agroecosystem for Entomobryidae (Table 18); Isotomidae (P=0.01), l. notabilis (P=0.001, Table 19); and 1.105111 (P=0.05, Table 20). 76 Table 16. Variation in population densities of seven Collembola taxa associated with seasonal trends and agroecosystem treatment. Anova table1 Sample date2 Agroecosystem treatment3 F Significance F Significance Taxon statistic level statistic level Entomobryidae 13.29 0.001 2.54 0.02 Isotomidae 3.19 0.01 4.75 0.001 I, notabilis 8.04 0.001 9.38 0.001 .E' americanus 4.38 0.001 1.13 0.34 1, minor 1.03 0.40 1.15 0.33 .2. zosiii 25.54 0.001 3.16 0.01 Total Collembola 11.27 0.001 4.91 0.001 lTwo-way randomized 2df=6 3df=7 block design 77 Table 17. Influence of organic and conventional agroecosystems oniiollembola soil popula- tion densities in sweet corn, in the absence of a nitrogen input. ’) Soil population density“ Orthogonall Treatment Coefficients Total Mean Alternative agroecosystem Bloodmeal Control +1 203 6.4 Treatment -— -— -- Compost Control +1 152 4.7 Treatment -— -— -—- Conventional agroecosystemq Ammonium nitrate Control -1 87 2.7 Treatment -— -—— -.. Compost Control -1 107 3.3 Treatment - -— -- 1Orthogonal comparison 1 (Table 5) F n 8.2 P - 0.005 1 - ”Sum of all sampling dates in 1982 and 1983, per 1 x 10 2 cm3 soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. I “weed o ulations mana ed by herbicide a olication. P P 8 _ . 78 Table 18. Influence of organic and conventional agroecosystems on Entomobryidae soil population densities in sweet corn, in the absence of a nitrogen input. Soil population density2 Orthogonal1 Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control +1 22 0.7 Treatment - -- -- Compost Control +1 15 0.5 Treatment -— -—— __. Conventional agroecosystemd Ammonium nitrate Control -1 8 0.3 Treatment - -- -- Compost Control -1 7 0.2 Treatment - -- -- lOrthogonal comparison 1 (Table 5) F - 12.7 P - 0.001 ZSum of all sampling dates in 1982 and 1983. per 1 x 10‘2 3Weed populations managed by cultivation. / ‘Weed populations managed by herbicide application. cm3 soil. to a depth of 15.24 cm. 79 Table 19. Influence of organic and conventional agroecosystem management on soil population density of Isotomidae. ‘I. notabilis. E, americanus, and I. minor in sweet corn in the absence of a nitrogen input. Soil population density2 7 Orthogonal‘ Total Mean Treatment Coefficients ISO IIN IPA IIM ISO IIN IFA IIM Organic Agroecosystem3 Bloodmeal Control +1 72 27 16 4 2.6 1.0 0.6 0.1 Treatment - -- -—- -— -— .._ ... .__ ._. Compost Control +1 60 20 18 4 2.1 0.7 0.6 0.1 Treatment -— -—— -- -— ——- .._ ._. .._ ._- Conventional Agroecosystem]I Ammonium nitrate Control -1 28 8 8 2 1.0 0.3 0.3 0.1 Treatment - -- —-— -— ——— -- -- -- -- Compost Control -1 42 8 22 3 1 5 0.3 0.8 0.1 Treatment - -- --— -— -—- -- -- -—- -—- lOrthogonal comparison 1 (Table 5) Isotomidae (ISO): F - 6 2 P a 0.01 ‘I. notabilis (IIN): F a 10.5 P - 0.001 ‘E. americanus (IPA): - 0.01 P a 1 3 ‘1. minor (TIM): F a 1.25 P . 0.26 2 . . . -2 3 . . - - ”Summation of 1982 and 1983 5011 denSities per 1 x 10 cm 5011, to a 5011 depth or 15.24 3. . . . . Jeed populations were managed by cultivation. 3.. . . . k. .4 «QEd populations were managed with nersiCiues. 80 Table 20. Influence of organic and conventional agroecosystems on I. vosiii soil popula- tion densities in sweet corn. in the absence of a nitrogen input. , Soil population density“ Orthogonal , Treatment Coefficients” Total Mean 3 Alternative agroecosystem Bloodmeal Control 11 Treatment -- Compost Control +1 Treatment - Conventional agroecosystem“ Ammonium nitrate Control -1 Treatment ._ Compost Control -1 Treatment - 27 1.0 41 1.5 22 0.8 19 0.7 lOrthogonal comparison 1 (Table 5) P - 3.79 P - 0.05 2Sum of all sampling dates in 1982 and 1983, 3Weed populations managed by cultivation. I Tweed populations managed by herbicide applic -7 per 1 x 10 ' cm3 soil. to a depth of 15.24 cm. ation. 81 In the organic agroecosystem, populations of Collembola were significantly (P=0.007) greater in soil recieving bloodmeal-nitrogen than in soil recieving compost-nitrogen (Table 21). This trend was also apparent (Tables 22, 23, and 24) with Entomobryidae (P=0.50); Isotomidae (P=0.02), _T_. notabilis (P=0.001), E. americanus (P=0.20); and I. grill; (P=0.01). For the conventional agroecosys- tem, population densities of Collembola were greater (P=0.lZ) in soil with compost input than with ammonium nitrate input (Table 25). This trend was also observed (Tables 26, 27 and 28) with Entomobryidae (P=0.58); Isotomidae (P=0.33), l. m (P=0.45); and _T_. Loiifl (P=0.ll). Soil populations of l. notabilis and _E. americanus were almost equal in response to these nitrogen sources (Table 27). In the presence of nitrogen input, soil population densities of Collembola were significantly (P=0.001) greater in the organic than in the conventional agroecosystem (Table 29). This soil population difference was also observed (Tables 30, 31 and 32) with Entomobryidae (P=0.23); Isotomidae (P=0.001), l. notabilis (P=0.001), E. americanus (P=0.06), 1. {PM (P=0.45); and I. M (P=0.02). Disregarding agroecosystem weed management, soil population densities of Collembola were not significantly (P=0.32) influenced by nitrogen input (Table 33). This trend was observed (Tables 34, 35 and 36) for Entomobryidae (P=0.60); Isotomidae (P=l.0), _E. americanus (P=0.29), l. m (P=0.24); and 1. mg; (P=0.44). Soil populations of _I_. notabilis were significatly (P=0.06) greatest in soil recieving nitrogen input, when compared to soil populations in the absence of nitrogen input (Table 35). 232 Table 21. Influence of organic agroecosystem nitrogen source on soil population densities of Collembola in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem Bloodmeal Control -— -- -- Treatment +1 262 8.2 Compost Control - -- -- Treatment -1 154 4.8 Conventional agroecosystem‘ Ammonium nitrate Control Treatment Compost Control Treatment 1 ‘Orthogonal comparison 2 (Table F - 7.3 P - 0.007 6 a _ . . . Sum or all sampling dates in 1982 and 1983, per 1 x 10-2 cm3 soil, to a depth of 15.24 cm. 3 Weed populations managed by cultivation. i Need populations managed by herbicide application. 823 Table 22. Influence of organic agroecosystem nitrogen source on soil population densities of Entomobryidae in sweet corn. 7 Soil population density” Orthogonal Treatment Coefficients Total Mean . . 3 Alternative agroecosystem Bloodmeal Control - -- -— Treatment +1 18 0.6 Compost Control -— -- -- Treatment -1 15 0.5 Conventional agroecosystem‘ Ammonium nitrate Control - -- -- Treatment - -- -- Compost Control ‘ - -- -- Treatment -— -- -—- lOrthogonal comparison 2 (Table 5) P . 0.50 P a 0.50 o _ ’Sum of all sampling dates in 1982 and 1983. per 1 x 10 ‘ cm3 soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. I ‘Weed populations managed by herbicide application. 84. Table 23. Influence of organic agroecosystem nitrogen source on soil population density of Isotomidae, I notabilis,‘£. americanus. and 1. minor in sweet corn. Soil population density2 Orthogonal Total Mean Treatment Coefficients ISO IIN IPA IIM ISO TIN IPA IIM Organic 3 Agroecosystem Bloodmeal Control - -- -- .-— ... -.. ... _._ ... Treatment +1 95 49 37 4 3.4 1.7 1.3 0.1 Compost Control - -- -—- -— ——— ... .._ ... _._ Treatment -1 59 25 22 3 2.1 0.9 0.8 0.1 Conventional Agroecosystem“ Ammonium nitrate Control - -- -- ——- ——- .—- .._ ... ... Treatment -+ -- -.- -—- -— ... ... ... ... Compost Control - -- -.. ——- -_- -.. ... ... ..- Treatment - -- -- .—— ——— ... ..- ... ... lOrthogonal comparison 2 (Table 5) Isotomidae (ISO): P . 5.6 P a 0.02 ' notabilis (IIN): P t 1 ‘:. 2.2 P - 0.001 E, americanus (IPA): P a 1.70 P a 0.20 .L. minor (IIM): P a 0.59 P - 0.45 9n . 0 a . - . -2 3 -q . .- °5ummation or 1982 and 1983 5011 denSities per 1 x 10 cm 5011, to a sail depth of 15.24 3Weed populations were managed by cultivation. 5‘" g . . y u . . seed popu1ations were managed with nerbicides. 85 Table 24. Influence of organic agroecosystem nitrogen source on soil population densities of I, vosii in sweet corn. 9 Soil population density“ Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control - -—— -- Treatment +1 52 1.9 Compost Control - -—- -- Treatment -1 27 1.0 Conventional agroecosystem‘ Ammonium nitrate Control —— —- +- Treatment - -- --- Compost Control - -- -- Treatment - -._ -.. lOrthogonal comparison 2 (Table 5) F - 7.1 P . 0.01 I) - 3 - _ 2Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth or 15.24 cm. 3“ . . . . need populations managed by cultivation. /. Tweed populations managed by herbicide application. 86 Table 25. Influence of conventional agroecosystem nitrogen source on soil population densities of Collembola in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean 3 Alternative agroecosystem Bloodmeal Control - ._. ._. Treatment -— -- -- Compost Control -— -- -- Treatment -— -—- -- 4 Conventional agroecosystem Ammonium nitrate Control - -- -- Treatment +1 74 2.3 Compost Control -— ._. .._ Treatment -1 137 4.3 1Orthogonal comparison 3 (Table 5) P - 2.49 P a 0.12 2Sum of all sampling dates in 1982 and 1983, per 1 x 10"2 7. . . . "deed populations managed by cultivation. 7Weed populations managed by herbicide application. 3 . . - cm 5011, to a depth or 15.24 cm. 87 Table 26. Influence of conventional agroecosystem nitrogen source on soil population densities of Entomobryidae in sweet corn. ’) Soil population density' Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem loodmeal Control - -- -- Treatment -— -- -- Compost Control - -—— ._. Treatment - -—- -- Conventional agroecosystem“ Ammonium nitrate Control - -- -- Treatment +1 11 0.4 Compost Control -— -- -—- Treatment -1 14 0.4 l Orthogonal comparison 3 (Table 5) P - 0.31 P a 0.58 2Sum of all sampling dates in 1982 and 1983, per 1 x 10'2 cm3 soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. I “Need populations managed by herbicide application. 88 Table 27. Influence of conventional agroecosystem nitrogen source on soil population density of Isotomidae,.T. notabilis, E. americanus. and I. minor in sweet corn. Soil population density2 Orthogonal Total Mean Treatment Coefficients ISO TIN IPA TIM ISO TIN IPA TIM Organic 3 Agroecosystem Bloodmeal Control -— -— -—- -—- -- -—- -- -- -—- Treatment -— -- -- -—- .._ .._ ... ... ._. Compost Control -— -—— -—— -—- -- -- -- -- -—- Treatment -— ~—- -- -— -- -- -- -- -—— Conventional Agroecosystem Ammonium nitrate Control - -- -- -—- -- —- -—- -- -— Treatment +1 25 7 13 0.6 0.9 0.2 0.5 0.02 Compost Control -— -- -- -- -—— -— -—- -- -- Treatment -1 40 9 15 2 1.4 0.3 0.5 0.1 1Orthogonal comparison 3 (Table 5) Isotomidae (ISO): P a 0.98 P - 0.33 notabilis (TIN): P a 0.06 P - 1.00 americanus (IPA): P . 0.03 P a 1.00 . minor (TIM): F n 0.57 P c 0.45 lH|flilH 1 ‘2 3 . 0' “Summation of 1982 and 1983 soil densities per 1 x 10 cm soil, to a 5011 depth of 15.24 1. . . . need populations were managed by cultivation. I 4,. . . . V . . need populations were managed with nerbiCioes. 89 Table 28. Influence of conventional agroecosystem nitrogen source on soil population denSities of T vosiii in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean . 3 Alternative agroecosystem Bloodmeal Control -— -—- -—- Treatment - -—- -—- Compost Control -— -- --— Treatment -— -- -- 4 Conventional agroecosystem ammonium nitrate Treatment +1 15 0.5 Compost Treatment -1 31 1.1 , ‘Orthogonal comparison 3 (Table 5) P - 2.55 P - 0.11 i -2 3 'Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth of 15.24 cm. 3'x'eed populations managed by cultivation. 3. . . . . . heed populations managed by herbiCide application. 90 Table 29. Influence of organic and conventional agroecosystem nitrogen sources on soil population densities of Collembola in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control - —-— -- Treatment +1 262 8.2 Compost Control -— -- ——- Treatment +1 155 4.8 . ‘ ‘5‘ Conventional agroecosystem Ammonium nitrate Control - -- -- Treatment -1 74 2.3 Compost Control - -— -- Treatment -1 137 4.3 lOrthogonal comparison 4 (Table 5) P . 13.4 P a 0.001 Sum of all sampling dates in 1982 and 1983, per 1 x 10.2 cm3 soil. to a depth of 15.24 cm. 3 Weed populations managed by cultivation. aWeed populations managed by herbicide application. 91. Table 30. Influence of organic and conventional agroecosystem nitrogen sources on soil population densities of Entomobryidae in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 loodmeal Control -— -—- -- Treatment +1 18 0.6 Compost Control - -- -—- Treatment +1 15 0.5 Conventional agroecosystem7 Ammonium nitrate Control —- -—- -- Treatment -1 11 0.4 Compost Control - -- -- Treatment -1 14 0.4 lOrthogonal comparison 4 (Table 5) F . 1.40 P s 0.23 2Sum of all sampling dates in 1982 and 1983, per 1 x 10'2 cm3 soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. I *Weed populations managed by herbicide application. 92 Table 31. Influence of organic and conventional agroecosystem nitrogen inputs on soil population densities of Isotomidae, I. notabilis, E, americanus, and‘T. minor in sweet corn . " "— _— Soil population density2 Orthogonal Total Mean Treatment Coefficients ISO TIM IPA TIM ISO TIN IPA TIM Organic 3 Agroecosystem Bloodmeal Control -— -- -—- -- -- -— -- -—- -+ Treatment +1 95 49 37 3.4 1.7 1.3 0.1 ‘\ Compost Control -—- -—- -- —- -—- -—- -—- -—- -- Treatment +1 60 25 22 3 2.1 0.9 0.8 0.1 Conventional 4 Agroecosystem Ammonium nitrate Control - -- -- -- -- -—- -- -— -- Treatment -1 25 7 13 0.6 0.9 0.2 0.5 0.02 Compost Control - ——- -- -- -- -—+ -- -—- -- Treatment -1 40 8 15 2 1.4 0.3 0.5 0.1 I . ,m . -\ Orthogonal comparison ~ (Table 5; Isotomidae (ISO): P a 17.5 P a 0.001 ‘I. notabilis (TIN): P n 38.4 P a 0.001 E, americanus (IPA): P - 3.36 P n 0.06 ., minor (TIM): P a 0.60 P a 0.45 C v - - N -2 a , - Summation of 1982 and 1983 soil densities per 1 x 10 cm soil. to a $011 depth of 15.24 IJ ‘. “Weed populations were managed by cultivation. Peed populations were managed with herbicides. 93 Table 32. Influence of organic and conventional agroecosystem nitrogen sources on soil population densities of _I_'_. [osiii in sweet corn. ‘7 Soil population density' Orthogonal Treatment Coefficients Total Mean . 3 Alternative agroecosystem Bloodmeal Control -— -- -- Treatment +1 52 1.9 Compost Control - ~—— -- Treatment +1 27 1.0 Conventional agroecosystem4 Ammonium nitrate Control —- -- -- Treatment -1 15 0.5 Compost Control -— -- -- Treatment -1 31 1.1 1 Orthogonal comparison 4 (Table 5) F.. 5.80 P a 0.02 2 3 Sum of all sampling dates in 1982 and 1983, per 1 x 10"2 cm soil. to a depth of 15.24 cm. 3 y e . . . deed popUIations managed by cultivation. 4 . . . . . Weed populations managed by herbiCide application. 94 Table 33. Influence of nitrogen input on soil pepulation densities of Collembola in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control +1 203 6.4 Treatment -1 262 8.2 Compost Control +1 152 4.7 Treatment -1 154 4.8 Conventional agroecosystema Ammonium nitrate Control +1 87 2.7 Treatment -1 74 2.3 Compost Control +1 107 3.3 Treatment -1 137 4.3 lOrthogonal comparison 5 (Table 5) P II 0.99 P a 0.32 -7 2Sum of all sampling dates in 1982 and 1983, per 1 x 10 ° cm3 soil, to a depth of 15.24 cm. 3“ . . . . weed populations managed by cultivation. 4“ - . . . . . weed populations managed by herbiCide application. 95 Table 34. Influence of nitrogen input on soil population densities of Entomobryidae in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control +1 22 0.7 Treatment -1 18 0.6 Compost Control +1 15 0.5 Treatment -1 15 0.5 A Conventional agroecosystem Ammonium nitrate Control +1 8 0.3 Treatment -1 11 0.4 Compost Control +1 7 0.2 Treatment -1 14 0.4 l Orthogonal comparison 5 (Table 5) P . 0.27 P . 0.60 ‘ -2 3 2Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. 4'? I I v v . - ‘ o . weed populations managed by herbiCide application. 96 Table 35. Influence of nitrogen input on soil population densities of Isotomidae, I, notabilis, E. americanus, and I, minor in sweet corn. Soil population density2 Orthogonal Total Mean Treatment Coefficients ISO TIN IPA TIM ISO TIN IPA TIM Organic Agroecosysrem3 Bloodmeal Control +1 72 27 16 4 3.0 1.0 0.6 0.1 Treatment -1 95 49 37 4 3.0 1.7 1.3 0.1 Compost Control +1 60 20 18 4 2.0 0.7 0.6 0.1 Treatment -1 60 25 22 3 2.0 0.9 0.8 0.1 Conventional Agroecosystem; Ammonium nitrate Control +1 28 8 8 2 1.0 0.3 0.3 0.1 Treatment -1 25 7 13 0.6 0.9 0.2 0.5 0.02 Compost Control +1 42 8 22 3 1.5 0.3 0.8 0.1 Treatment -1 40 8 15 2 1.4 0.3 0.5 0.1 1Orthogonal comparison 3 (Table 5) Isotomidae (ISO): P - 0.08 P s 1.00 . notabilis (TIN): P - 3.52 P a 0.06 americanus (IPA): P a 1.51 P a 0.29 . minor (TIM): P - 1.44 P - 0.24 hernhe 7 -2 3 'Summation of 1982 and 1983 soil densities per 1 x 10 cm soil, to a soil depth of 15.24 3“ , . . . weed populations were managed by cultivation. “Weed populations were managed with herbicides. 97 Randomization of sweet corn research plots in the organic system did not limit density differences between control treatments. Population density differ- ences were apparent (Tables 37, 38, 39 and 40) for Collembola (P=0.20); Entomobryidae (P=0.lO); Isotomidae (P=0.4l), l. notabilis (P=0.30), _I_. m (P=0.l5); and I. M (P=0.l5). 1:. americanus densities in control treatments were equal (P=l.00, Table 39). Treatment randomization in the conventional agroecosystem limited varia- tion of most Collembola soil population densities attributable to experimental design. Soil population densities of Collembola were similar (P=0.60) in control treatments (Table 41). Densities were alike (Tables 42, 43 and 44) for Entomobryidae (P=l.00); _I_. notabilis (P=l.0), I. M (P=0.44); and I. ”in (P=l.00). Randomization was not as effective for _I_. notabilis (P=0.l3) and F americanus (P=0.22, Table 43). DISCUSSION Quantification of Collembola Soil Populations Extraction efficiency for most Collembola taxa was comparable to other investigations. Soil densities of Collembola represented 42% of actual soil densities. Sampling efficiency can be influenced by rate of sample drying, soil temperature gradient, and length of extraction. Extraction was least efficient when samples were refrigerated 48 hours prior to extraction, or extracted for only 24 hours. Efficiency for Onychiuridae was high (74%) when the extraction period was extended to 78 hours. In contrast, Loring g3 a_l. (1981) recovered 3% of I. granulata in similar Tullgren funnels after circa three days of extraction. They 98 Table 36. Influence of nitrogen input on soil population densities of I, vosiii in sweet corn. Soil population density2 Orthogonal 1 Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control +1 27 1.0 Treatment -1 52 1.9 Compost Control +1 41 1.5 Treatment -1 27 1.0 Conventional agroecosystem“ Ammonium nitrate Control +1 23 0.8 Treatment -1 15 0.5 Compost Control +1 19 0.7 Treatment -1 31 1.1 lOrthogonal comparison 5 (Table 5) P - 0.62 P . 0.44 2- - -2 3 Sum or all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth of 15.24 cm. Need populations managed by cultivation. IWeed populations managed by herbicide application. 99 Table 37. Influence of organic agroecosyscem treatment randomization on soil population densities of Collembola in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean 3 Alternative agroecosystem Bloodmeal Control +1 203 6.4 Treatment - -—- -- Compost Control -1 152 4.7 Treatment —- -- -- / Conventional agroecosystemI Ammonium nitrate Control -— -- -- Treatment - -- -- Compost Control - -- -- Treatment - -- -- lOrthogonal comparison 6 (Table 5) P - 1.70 P - 0.20 2Sum of all sampling dates in 1982 and 1983, per 1 x 10.2 cm3 soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. need populations managed by nerbiCide application. 1130 Table 38. Influence of organic agroecosystem treatment randomization on soil population densities of Entomobryidae in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control +1 22 0.7 Treatment -— -- —-- Compost Control —1 15 0.5 Treatment - -—- ——- Conventional agroecosystem“ Ammonium nitrate Control - -.. ... Treatment —- -—- --- Compost Control -— -— -- Treatment - -- -- LOrthogonal comparison 6 (Table 5) F I 2.60 P a 0.10 ‘5 o. -2 3 Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth of 15.24 cm. 3'N'eed populations managed by cultivation. “Weed populations managed by herbicide application. 101 Table 39. Influence of organic agroecosystem treatment randomization on soil population densities of Isotomidae,.I. notabilis, E. americanus, and I, minor in sweet corn. Soil population density2 Orthogonal Total Mean Treatment Coefficients ISO TIN IPA IIM ISO TIN IPA TIM Organic 3 Agroecosystem Bloodmeal Control +1 72 27 16 4 2.6 1.0 0.6 0.1 Treatment —- -—— -- -. ... -._ ._. .._ .._ Compost Control -1 60 20 18 4 2.1 0.7 0.6 0.1 Treatment +1 --— --- --- --- --- --- ..-.. --- Conventional Agroecosyscema Ammonium nitrate Control - -- -—- -—- -- -- -- -—- -- Treatment - -—— -—- -- -—- -- —-— -—- -- Compost Control -— -- -. ——- ..- -.. ... ..- ... Treatment - -- -—- -— -— ... ._. ._. ..- lOrthogonal comparison 6 (Table 5) Isotomidae (ISO): P - 0.70 P a 0.41 .£° notabilis (TIN): P - 1.10 P - 0.20 .E- americanus (IPA): P a 0 P - 1.00 ‘1. minor (TIM): P . 2.1 P - 0.15 2 . - .. . . . -2 3 . . .. Summation or 1982 and 1983 scii denSities per i x 10 cm SOiI, to a 3011 depth of 15.24 3" - t P. . Need populations were managed by cultivation. .1 I - . . 1 1 . . heed populations were managed with nerbiCides. 102 Table 40. Influence of organic agroecosystem treatment randomization on soil population densities of T. yosiii in sweet corn. Soil population density2 Orthogonal 1 Treatment Coefficients‘ Total Mean Alternative agroecosystem3 Bloodmeal Control +1 27 1.0 Treatment - ... ..- Compost _ Control —1 41 1.5 Treatment - ——— ... Conventional agroecosystemL Ammonium nitrate Control - ..- --- Treatment -— .-— ... Compost Control -— ... ... Treatment - -—— .__ lOrthogonal comparison 6 (Table 5) P a 2.10 P - 0.15 ' -2 3 2Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. ‘Weed populations managed by herbicide application. 103 Table 41. Influence of conventional agroecosystem treatment randomization on soil population densities of Collembola in sweet corn. Soil population density2 Orthogonal Treatment Coefficients Total Mean 3 Alternative agroecosystem Bloodmeal Control ._ ... ___ Treatment - -- -- Compost Control - ——- -- Treatment -— -- -- Conventional agroecosystem* Ammonium nitrate Control +1 87 2.7 Treatment - -- -- Compost Control —1 107 3.3 Treatment - -- -- l Orthogonal comparison 7 (Table 3) F c 0.25 P - 0.62 ° - 3 ”Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil. to a depth of 15.24 cm. Weed populations managed by cultivation. I; Need populations managed by herbicide application. 1134 Table 42. Influence of conventional agroecosystem treatment randomization on soil population densities of Entomobryidae in sweet corn. ’3 Soil population density“ Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control —- —.- ._. Treatment - -- -—— Compost Control -— -—- -— Treatment - -- -- , 4 Conventional agroecosvStem Ammonium nitrate Control +1 8 0.3 Treatment - -- .- Compost Control -1 7 0.2 Treatment - -—- -- lOrthogonal comparison 7 (Table 5) F - 0.04 P . 1.00 -2 3 2Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm soil, to a depth of 15.24 cm. 3Weed populations managed by cultivation. I ‘Weed populations managed by herbiCide application. 1135 Table 43. Influence of conventional agroecosystem treatment randomization on soil popula— tion densities of Isotomidae. I. notabilis, E, americanus, and E. minor in sweet corn. Soil population density2 Orthogonal Total Mean Treatment Coefficients ISO IIN IPA TIM ISO TIN IPA IIM Organic Agroecosystem‘ Bloodmeal Control -— -— -—- -- ——- .._ ... ... ... Treatment -— -—- -- -—— .-— .._ ... ... ... Compost Control -— -—- -—- -- -. ... ... -.. ... Treatment -— -—- -- -- -— .__ ... .__ .._ Conventional l. Agroecosystem Ammonium nitrate Control +1 28 8 8 2 1.0 0.3 0.3 0.7 Compost I H ‘\ k) u) I“) N U H O U! Control 0.3 0.8 0.1 Treatment - -- -—- -—- .—— ... ... ... ..- lOrthogonal comparison 7 (Table 5) Isotomidae (ISO): P 3.33 P - 0.13 I. notabilis (IIN): - O P a 1.00 ‘g. americanus (IPA): P . 1.50 P - 0.22 ‘l. minor (IIH): P a 0.60 P = 0.&4 a ,— I‘ “I 7 . -3 3 . , . . - . summation of 1992 and 1983 soil denSities per 1 x 10 cm scil, to a SOll deptn or 15.a4 1 Need populations were managed by cultivation. '3" 1 . . . . . . need populations were managed with nerbiCides. 106 Table 44. Influence of conventional agroecosyStem treatment randomization on soil popula- tion densities of I. yosiii in sweet corn. ‘) Soil population density“ Orthogonal Treatment Coefficients Total Mean Alternative agroecosystem3 Bloodmeal Control -— ... ..- Treatment —- ——- -—- Compost Control -— -- -- Treatment -— -— -- Conventional agroecosystem‘ Ammonium nitrate Control +1 23 0.3 Treatment -— -- -- CompOSt Control -1 19 0.7 Treatment - -- ——- l - Orthogonal comparison 7 (Table 3) P a 0.17 P a 1.00 2 —2 3 . Sum of all sampling dates in 1982 and 1983, per 1 x 10 cm 5011, to a depth of 15.24 cm. 3. . . . . . deed populations managed by cultivation. 4. . . .. . deed populations managed by herbiCide application. 107 allowed soil samples to remain in the funnels until they were completely dry, and used the sugar-flotation method as a measure of extraction efficiency. 1. granulata is closely related to I. los_iii, a species that predominated in sweet corn in this research. Peterson (1978) also extracted Tullbergia spp. less efficiently, recovering less than 5096 with a high-gradient extracter in ten days. The Onychiuridae are typically small and slow-moving, causing density estimates based on Tullgren extraction to be much less than actual soil densities. One-hundred percent of the Isotomidae were extracted from fresh samples in 78 hours. Loring e_t a1. (1981) extracted 8296 in three days, and Peterson (1978) extracted approximately 95% in ten days. Isotomidae are typically litter- dwelling, with longer legs than the Onychiuridae; however, this depends upon species. This may account for the greater extraction efficiency observed for isotomids. Soil Isotomidae may be more tolerant of low-moisture and high- temperature than onychiurids (Schaller 1970). Entomobryidae were 93% extracted in 78 hours. Peterson (1978) obtained similar results for Lepidocgtus liggorum (Fabricius). Peterson extracted 7596 of this species from soil samples in ten days of extraction. Members of this genus are typically active surface-dwellers, with a clothing of body scales that may enhance tolerance to low moisture and high temperatures. Species from this family were found at highest densities in sweet corn research plots late in the season, when soil moisture was low and temperature high. This resistance to adverse conditions may enhance extraction efficiency. Measurement of extraction efficiency in this M.S. research may have been biased positively due to the inefficiency of the sugar-flotation method. This method is not as accurate as hand-sorting, for efficiency determination (Edwards 108 and Fletcher 1970). Insect exuviae, or Collembola that were dead before sampling, are not easily distinquished from recently killed individuals, and may be erroneously identified. This method is also less efficient for high-clay soil types typical of this research site. Estimates of soil densities based on Tullgren extraction are biased as a result of variable species reactions to the extraction process. Species most tolerant of dessication, and those that are fast-moving, are most efficiently extracted (Tamura 1976). A steep temperature gradient within the soil sample during extraction improves efficiency (Macfadyen 1953). This gradient is maintained by a cooling device on lower portions of the sample, while a light source heats the sample from above. In this investigation, a temperature gradient in Tullgren funnels was difficult to maintain, especially when room temperature was high late in the season. Greatest temperature gradients, and greatest extraction efficiency, occurred when samples were placed in funnels after storage at 4 C. Soil population density estimates were most accurate with increasing extraction time. Soil density estimates could have doubled if extraction time had been increased to 48 hours. Minimal extraction rates that were observed after #8 hours of sample refrigeration may have been the result of Collembola mortaility during storage. Sminthuridae are particularly susceptible to high carbon dioxide concentrations that occur in soil samples during storage (Snider, pers. comm.). Predation may also have been a factor during storage, but this factor was not investigated in this research. A population increase during storage due to egg-hatching is not likely to influence densities, as newly-hatched individuals are slow-moving and less tolerant of adverse soil moisture and temperature, and are not extracted as efficiently as adults. 109 Spatial Distribution and Population Dynamics Fluctuations in soil densities of _I_. notabilis in clover suggest that two generations occurred in this season. Densities were high in March, and peaked again on May 12. Loring (1979) observed the same pattern for this species in Michigan field corn. The population density increase was not maintained after relocation to the clover-oats site on June 16. This discrepancy suggests that _I_. notabilis populations at these clover sites were not following similar patterns in dynamics. Seasonal Collembola population trends at these clover sites should not be regarded as representative of one population, but as two discontinuous populations of the same species. This gap in population dynamics information applies to all Collembola species reported here. Soil populations of _I_. M reacted in a similar way: a population increase was observed for this species just before relocation. Seasonal dynamics of I. y_g_si_ii suggest that one generation occured in 1983 in clover. Densities were greatest on the first sampling date and declined afterwards. A population decrease was noted after site relocation. The same pattern of decline was observed in sweet corn. Aggregated and random distributions observed for Collembola in this research have been reported by other investigators. Farrar and Crossley (1982) and Usher (1969) determined that soil microarthropods, including Collembola, were aggregately distributed in soybeans and in a coniferous soil, respectively. Random or less-highly aggregated distributions were observed in this and other studies when soil densities were low. 110 Usher (1969) hypothesized that soil aggregations occur in response to environmental niche distribution in soil. He observed that as soil densities increased, the number of aggregations increased with the number of individuals forming an aggregation. This implies that declining soil densities would result in fewer and smaller aggregations, leading to the random distribution pattern that was observed in clover at the Rodale Research Center late in the season when soil densities were low. This population decline may have been in response to unfavorable soil environmental conditions of increasing soil temperature and decreasing moisture. Collembola response to these unfavorable factors may have been increased mortality, decreased fecundity, or migration to a more favorable soil horizon. The fact that Collembola were aggregated or randomly distributed in the clover ecosystem does not imply that the same pattern existed in the tilled sweet corn system. Farrar and Crossley (1982) found that microarthropod aggregations in tilled soybeans were smaller and less variable in area, in comparison to no-till beans. They suggested that tillage homogenized the soil and destroyed the environmental gradients that would give rise to aggregations. Reformation of aggregations in soil would depend on the recolonizing abilities of Collembola species, formation of new environmental gradients, and the impact of any further disturbance. Cultivation and hilling operations performed in sweet corn may have favored aggregations within rows where samples were taken, influencing density estimation of species. Vertical distribution of soil Collembola in clover and sudax fluctuated seasonally. Surface densities of l. notabilis were greatest during the first half of the season. Poole (1961) observed that this species was concentrated in the lll litter layer of a coniferous forest soil in Wales. He reported high litter densities in the spring, with a gradual decline to a minimum density in July. Surface densities increased again in the fall. Vertical fluctuations observed in this research imply that this species migrated out of the sampling zone. Migration have been in response to less favorable soil moisture and temperature at the soil surface. I. M was concentrated in the clover surface at high densities early in the season, and steadily declined in sudax. Sampling did not detect vertical migration. In contrast, Poole (1961) reported that _‘i_'. krausbaueri maintained a fairly constant vertical distribution during the season in a coniferous forest soil. This forest population, however, was not disturbed by cultivation, and environ- mental changes were buffered by the litter layer. Loring (1979) reported that the vertical distribution of I. granulata in Michigan field corn fluctuated seasonally. High surface densities in the spring declined after seeding and field preparation, then gradually increased to a peak in late September. At a soil depth of 5.08-10.16 cm, densities followed the same pattern. At a soil depth of 10.16-15.24 cm, densities remained fairly constant during the sampling period. Agroecosystem Management Soil insects respond to agroecosystem management. Dritschilo and Wanner (1980) observed greater ground beetle densities and species diversity in organic field corn in comparison to conventional corn. Collembola soil density and species prominence are influenced by crop rotation (Clemen and Pedigo 1970), and method of tillage (Loring gt a1. 1981). Soil aggregations of Collembola are smaller and less variable in tilled than in no~till soybeans (Farrar and Crossley 1982). 112 Agroecosystem management influenced soil Collembola species in sweet corn at the Rodale Research Center. Collembola populaions were altered by unique weed management and nitrogen fertilizers in the organic and conventional systems. Soil Collembola may serve as indicators of soil "health", or productivity potential. Disturbance of soil Collembola may indirectly influence crop nutrient cycles and crop response. Weed management influences soil Collembola. Soil cultivation and atra- zine decrease Collembola densities (Edwards and Lofty 1975; Critchley gt a_l_. 1979; Aritajat e_t_ §_l_. 1977; Popovici 91 _al. 1977; Subajga and Snider 1981). A favorable microhabitat and lack of herbicide residues, in this organic agroecosys- tem, contributed to a greater density of soil Collembola. Greater in-row weed populations were evident in the organic system. This may have buffered soil temperature and moisture fluctuations, creating a favorable habitat for Collem- bola. Atrazine and Lasso were applied to conventional sweet corn. Toxic effects of the herbicide and the absence of a weed cover contributed to low soil densities in conventional system soil. The application of nitrogen-rich organic materials to agricultural soil enhances soil flora and fauna. Compost fertilizer increases soil microbial biomass (Nishio 1983), contributing to Collembola food source. Manure applica- tion increases soil densities of Collembola and other fauna (Well and Kroontje 1979). Greater Collembola densities in the organic system in the presence of nitrogen were, therefore, expected. Soil populations of Collembola were greatest in the presence of bloodmeal-nitrogen. Bloodmeal is a concentrated source of proteinaceous nitrogen, providing a substrate for microorganisms. Compost also serves as a microbial substrate, innoculates the site with Collem- 113 bola, and improves soil structure. These beneficial effects of organic nitrogen positively influenced soil Collembola. Soil Collembola populations in the conventional system reflect the applica- tion of herbicides and soluble fertilizers, and interactions occurring between these factors. Behan g; g1. (1978) hypothesized that urea may be toxic to Collembola, or cause a downward migration in soil; ammonium nitrate may have influenced Collembola in this manner. Soil Collembola densities were least in the presence of this fertilizer in the conventional system, implying a negative relationship between this conventional nitrogen input and soil Collembola. Collembola response to compost in both systems was similar. Atrazine, however, is temporarily adsorbed on negatively-charged organic matter. Compost applica- tion in the conventional system may provide adsorption sites for the herbicide, temporarily concentrating the herbicide at potential Collembola feeding sites. This may negatively influence Collembola. Disregarding agroecosystem differences, nitrogen input did not influence soil Collembola. This is contrary to results observed with nitrogen input within systems. The opposite impact of organic and conventional nitrogen sources may have contributed to this lack of statistical difference. Soil Collembola may be indicators of soil productivity. In the absence of soluble nitrogen fertilizers, soil flora and fauna are important agents of nitrogen mineralization. Environmental factors that are beneficial to these organisms also provide optimal crop growth potential. Optimal soil structure, moisture, organic matter content and chemical prOperties that are necessary for crop yield maintenance, have been positively correlated with Collembola population abun- dance (Weil and Kroontje 1979). 114 Soil Collembola enhance nitrogen mineralization (Anderson g5 91. 1983). High soil densities of Collembola, as observed in this organic system, may have enhanced nitrogen release from bloodmeal and compost, and indirectly influenced crop yield. Insoluble organic matter must be decomposed before nitrogen mineralization. Soil Collembola have a catalytic role in this process (Reichle 1977, Macfadyen 1963). A lesser soil density of Collembola or other organisms important to this process, may have limited nitrogen supply and crop yield. In contrast, the conventional ammonium nitrate fertilizer supplied a readily available source of crop nitrogen; soil Collembola were not necessary agents of nitrogen release in this system. If the supply of soluble nitrogen fertilizers is limited, enhancement of decomposer organisms may contribute to crop yield maintenance. An agricul- tural system that is self—sustaining, and not dependent on conventional inputs, may also support abundant and diverse soil organism populations, which may be indicative of soil productivity and crop yield. SUMMARY Forty-two per cent of the soil Collembola were extracted from fresh soil samples in 24 hours, with Tullgren funnels. Extraction efficiency increased 55% when samples were stored at 4 C for 24 hours before extraction. Extraction efficiency varied with Collembola species. Rate of Collembola movement from soil samples in Tullgren funnels was positively correlated with length of extraction period. Soil populations of Collembola in clover were aggregately distributed in the surface 15.24 cm, at normal to high densities. Distribution was random when soil 115 populations were low. Collembola were aggregately distributed in 5.08 cm vertical soil layers, to a depth of 15.24 cm. Tullbergia yosiii was the most prominent Collembola species in clover, followed by Isotoma notabilis and Isotomiella minor. Species prominence, however, varied seasonally. Compost piles and sweet corn research plots supported common Collembola species. Hypogastruridae were numerous in compost, but absent in soil samples. Soil population densities of Collembola in sweet corn varied seasonally. Fluctuations in soil density on each sampling date were apparent. Agroecosys- tem management influenced soil populations of Collembola. Population densities in the organic system were greater than the conventional system. Within the organic system, densities were greater in the presence of bloodmeal-nitrogen than compost-nitrogen. Wid'iin the conventional system, densities were greater in the presence of compost-nitrogen, than ammonium nitrate. Randomization of research treatments limited population variation among plots in the conventional agroecosystem, but not in the organic system, however, this varied with species. RECOMMENDATIONS This research generated questions concerning the importance of soil Collembola in agroecosystems. These questions should be investigated in future research: In an organic agroecosystem, 1. What percentage of organic matter decomposition is attributable to Collembola activity? 2. Do soil Collembola directly or indirectly influence crop yield? 3. Do soil Collembola influence the rate of nitrogen release from bloodmeal and compost? 116 Are soil Collembola indicators of crop yield, and what is the comparable role of other soil fauna? During conversion from a conventional to an organic system, do initially low soil densities of Collembola limit crop yield?. LIST OF REFERENCES LIST OF REFERNCES Addison, J. A. and D. Parkinson. 1978. Influence of Collembolan feeding activities on soil metabolism at a high arctic site. Oikos 30:529-538. Aleinikova, M. and N. Utrobina. 1975. Changes in the structure of animal populations in soil under the influence of farm crops, pp. l$29-$35. In: Progress in Soil Zoology (J. Vanek, ed.), Academia, Praque. Anderson, J. M., P. Ineson, and S. A. Huisch. 1983. The effects of animal feeding activities on element release from deciduous forest litter and soil organic matter, pp. 87-100. In: New Trends in Soil Biology (Ph. Lebrun, H. Andre, A. De Medts, C. Gregoire-Wibo, G. Wauthy, eds.), Proc. VIII. Intl. Coll. Soil Zool. Louvain-la-Neuve (Belgium), 1982. Imprimeur Dieu-Brichart, Ottigines-Louvain-la-Neuve. Andren, O. and J. Lagerlof. 1980. The abundance of soil animals (Microarthropoda, Enchytraeidae, Nematoda) in a crop rotation dominated by ley and in a rotation with varied crops. In: Soil Biology as Related to Land Use Practice (D. Dindal, ed.), Office of Pesticides and Toxic Substances, EPA, Washington, D.C. Aritajat, V., D. S. Madge and P. Gooderham. 1977. The effects of compaction of agricultural soils on soil fauna. 1. Field investigations. Pedobio. 17:262- 282. Artemjeva, T. I. and F. G. Gatilova. 1975. Soil microfauna changes under the influence of various fertilizers, pp. l163-468. In: Progress in Soil Zoology (J. Vanek, ed.), Academia, Praque. 117 118 Atlavinyte, O. 1971. The activity of Lumbricidae, Acarina, and Collembola in the straw humification process. Pedobio. 11:107-115. Balfour, E. 1943. The Living Soil. Faber and Faber, London. 246 pp. Behan, V. M., S. B. Hill and D. K. McE. Kevan. 1978. Effects of nitrogen fertilizers, as urea, on Acarina and other arthropods in Quebec black spruce humus. Pedobio. 18:249-263. Bellinger, P. F. 1954. Studies of soil fauna with special reference to the Collembola. Conn. Agric. Expt. Sta. Bull. 583. Berlese, A. 1905. Apparecchio per raccaglierre presto ed in gran numero piccoli artropodi. Redia 2:85-89. Block, W. 1966. Some characteristics of the Macfadyen high gradient extractor for soil micro-arthropods. Oikos 17:1-9. Boeringa, R. (ed). 1980. Alternative Methods of Agriculture. Elsevier Sci. Pub. Co., Amsterdam. 199 pp. Butcher, J. W., R. Snider and R. J. Snider. 1971. Bioecology of edaphic Collembola and Acarina. Ann. Rev. Ent. 16:249-288. Chernova, N. M. 1963. Population dynamics of Collembola (Insecta) in compost made from fallen leaves. Soils Fertil. 28:160. Chernova, N. M., J. B. Byzova and A. I. Chernova. 1971. Relationship of number, biomass and gaseous exchange rate indices in microarthropods in substrates with various organic matter contents. Pedobio. 11:306-314. Christiansen, K. 1964. Bionomics of Collembola. Ann. Rev. Ent. 9:147-178. Christiansen, K. and P. Bellinger. 1980. The Collembola of North America North of the Rio Grande. A taxonomic analysis. Grinnell College, Iowa. 7,042 pp. 119 Clemen, R. B. and L. P. Pedigo. 1970. Collembola populations from selected arable fields. Proc. N. Central Branch, Ent. Soc. Am. 25(2):115-119. Critchley, B. R., A. G. Cook, V. Critchley, T. J. Perfect, A. Russell-Smith and R. Yeadon. 1979. Effects of bush clearing and soil cultivation on the invertebrate fauna of a forest soil in the humid tropics. Pedobio. 19:425- 438. Crossley, D. A. 1977. The roles of terrestrial saprophagous arthropods in forest soils: current status of concepts. Chapter 6, pp. 49-56. In: The Role of Arthropods in Forest Ecosystems (W. J. Mattson, ed.), Proc. Life Sci. Springer-Verlag, NY. Davidson, 5. J. 1979. Mesofaunal responses to cattle dung with particular reference to Collembola. Pedobio. 19:402-407. Davis, R. and M. Harris. 1936. The biology of Pseudosinella violenta (Folsom), with some effects of temperature and humidity on its life stages (Collembola: Entomobryidae). Iowa State Coll. Jrn. Sci. 10(4):421-430. Dhillon, B. S. and N. H. Gibson. 1962. A study of the Acarina and Collembola of agricultural soils. 1. Numbers and distribution in undisturbed grassland. Pedobio. 1:189-209. van der Drift, J. 1951. Analysis of the animal community of a beech forest floor. Tijdschr. Ent. 94:1-168. Dritschilo, W. and D. Wanner. 1980. Ground beetle abundance in organic and conventional corn fields. Env. Ent. 9(5):629-631. Edwards, C. A. and K. E. Fletcher. 1970. Assessment of terrestrial invertebrate pOpulations, pp. 57-66. In: Methods of Study in 5011 Ecology (J. Phillipson, ed.), Blackwell Oxford and Edinburgh. 120 Edwards, C. A. and J. R. Lofty. 1969. The influence of agricultural practice on soil micro-arthropod populations; pp. 237-247. In: The Soil Ecosystem (J. G. Sheals, ed.), Syst. Assoc. Pub. No. 8. Edwards, C. A. and J. R. Lofty. 1976. The influence of cultivations on soil animal populations, pp. 399-407. In: Progress in Soil Zoology (J. Vanek, ed.), Academia, Praque. Edwards, c. A., D. E. Reichle and D. A. Crossley, Jr. 1970. The role of soil invertebrates in turnover of organic matter and nutrients, pp. 148-171. In: Analysis of Temperate Forest Ecosystems (D. E. Reichle, ed.). Springer- Verlag, NY. Fox, C. J. 1964. The effects of five herbicides on the number of certain invertebrate animals in grassland soils. Can. Jrn. Plant Sci. 44:405-409. Ghilarov, M. S. 1978. Soil living invertebrates as indicators of conditions or trends of abiotic, biotic and soil forming processes. Pedobio. 18:300-309. Farrar, F. P. and D. A. Crossley, Jr. 1982. The structure of microarthropod communities in agroecosystems. Dept. Energy EV/00641-47. 33 pp. Gisin, G. 1952. Oekologische studien uber die Collembolen des blattkomposts. Rev. Suisse Zool. 59:543-578. Golebiowska, J. and L. Ryszkowski. 1977. Energy and carbon fluxes in soil compartments of agroecosystems. Ecol. Bull. (Stockholm) 25:274-283. Golueke, C. G. 1975. Composting. A study of the process and its principles. Rodale Press, Inc. Emmaus, PA. 110 pp. Hale, W. G. 1966. A population study of moorland Collembola. Pedobio. 6:65-99. Hale, W. G. 1967. Collembola, Chapter 12, pp. 397-411. In: Soil Biology (A. Burges and F. Raw, eds.), Academic Press, NY. 121 Hamence, J. H. 1948. The effect of organic manures on the auxin content of soils and the "auxin balance" in soils. J. Soc. Chem. lnd.,London 67:277-281. Hanlon, R. D. and J. M. Anderson. 1979. The effects of Collembola grazing on microbial activity in decomposing leaf litter. Oecologia (Ber1.) 38:93-99. Harmsen, G. W. and D. A. vanSchreven. 1955. Mineralization of organic nitrogen in soil, 7:299-398. In: Advances in Agronomy (A. G. Norman, ed.), Am. Soc. Agron. Harwood, R. R. 1982. Application of organic principles to small farms, pp. 127- 133. In: Research for Small Farms (H. Kerr, Jr. and L. Knutson, eds.), Proc. Spec. Symp. Beltsville Agric. Expt. Sta., USDA. November 15-18, 1981. Harwood, R. R. 1983. International overview of Regenerative Agriculture. Workshop on Resource-Efficient Farming Methods for Tanzania, May 16- 19, 1983. Univ. Dar es Salaam, Morogoro, Tanzania. (unpublished) Howard, A. 1943. An Agricultural Testament. Oxford Univ. Press, NY. 253 pp. Joose, E. N. G. and M. A. Verhoef. 1974. On the aggregational habits of surface dwelling Collembola. Pedobio. 14:245-249. Kevan, D. K. McE. 1962. Soil Animals. H. F. and G. Witherby Ltd. 237 pp. Loring, S. J. 1979. Comparative effects of three tillage methods on soil microarthropod populations. M.S. Thesis, Dept. Zool., Michigan State University. 51 pp. Loring, S. J., R. J. Snider and L. S. Robertson. 1981. The effects of three tillage practices on Collembola and Acarina populations. Pedobio. 22:172-184. Loucks, O. L. 1977. Emergence of research on agro-ecosystems. Ann. Rev. Ecol. Syst. 8:173-192. 122 Macfadyen, A. 1953. Notes on methods for the extraction of small soil arthropods. J. Animal Ecol. 22:65-77. Macfadyen, A. 1961. Metabolism of soil invertebrates in relation to soil fertility. Ann. Appl. Biol. 49:215-218. Macfadyen, A. 1963a. The contribution of the microfauna to total soil metabo- lism, pp. 3-17. In: Soil Organisms (J. Doekson and J. van der Drift, eds). N. Holland Pub. Co., Amsterdam. Macfadyen, A. 1963b. Heterotrophic productivity in the detritus food chain in soil. Proc. XVI Inter. Cong. Zool. 4:318-323. Marshall, V. G., D. K. McE. Kevan, J. V. Matthews, Jr., and A. D. Tomlin. 1982. Status and research needs of Canadian soil arthropods. Biol. Surv. Can., Ent. Soc. Can. Suppl. l4(1)1-5. Mengel, K. and E. Kirkby. 1982. Principles of Plant Nutrition. International Potash Inst., Switzerland. 655 pp. Milne, S. 1960. Studies on the life histories of various species of Arthropleone Collembola. Proc. R. Ent. Soc. Lond. (A) 35:133-140. Moore, J. C., R. J. Snider and L. S. Robertson. 1984. Effects of different management practices on Collembola and Acarina in corn production systems. I. The effects of no-tillage and atrazine. Pebobio. 26:143-152. Morris, H. 1927. The insect and other invertebrate fauna of arable land at Rothamstead. 11. Ann. Appl. Biol. 14:442-464. Moursi, A. A. 1962a. The lethal dose of C02, N2, NH3, and H25 for soil arthropods. Pedobio. 2:9-14. Moursi, A. A. 1962b. The attractiveness of CO2 and N2 to soil Arthropoda. Pedobio. 1:299-302. 123 Murphy, P. W., (ed.). 1962. Progress in Soil Zoology. London, Butterworths. 398 PP- Nishio, M. 1983. Direct-count estimation of microbial biomass in soil applied with compost. Biol. Agric. Hort. 1:109-125. Owen, O., D. W. Rogers and G. W. Winsor. 1950. The nitrogen status of soils. 1. The nitrification of some nitrogenous fertilizers. Jrn. Agric. Sci. 11(40): 1 85-1 90. Parkinson, D. and S. Visser. 1979. Effects of Collembolan grazing on fungal colonization of leaf litter. Soil Biol. Biochem. 11:529-535. Persson, T. 1983. Influence of soil animals on nitrogen mineralization in a northern Scots pine forest, pp. 117-126. In: New Trends in Soil Biology (Ph. Lebrun, H. Andre, A. De Medts, C. Gregoire-Wibo, G. Wauthy, eds.), Proc. VIII. Intl. Coll. Soil Zool. Louvain-la-Neuve (Belgium). Imprimeur Dieu- Brichart, Ottigines-Louvain-la-Neuve. Peterson, H. 1971. Parthenogenesis in two common species of Collembola: Tullbergia krausbaueri (Borner) and Isotoma notabilis Schaffer. Rev. Ecol. Biol. Sol. 8(1):133-138. Peterson, H. 1978. Some properties of two high-gradient extractors for soil microarthropods, and an attempt to evaluate their extraction efficiency. Nat. Jutl. 20:95-121. Poole, T. B. 1959. Studies of the food of Collembola in a Douglas fir plantation. Proc. Zool. Soc. London, London. 132:71-82. Poole, T. B. 1961. An ecological study of the Collembola in a coniferous forest soil. Pedobio. 1:113-137. 124 Popovici, 1., G. Stan, V. Stefan, R. Tomescu, A. Dumea, A. Tarta, and F. Dan. 1977. The influence of atrazine on soil fauna. Pebobio. 17:209-215. Reichle, D. E. 1977. The role of soil invertebrates in nutrient cycling. Ecol. Bull. (Stockholm) 23:145-156. Rubins, E. J. and F. E. Bear. 1942. Carbon-nitrogen ratios in organic fertilizer materials in relation to the availability of their nitrogen. Soil Sci. (54):411- 423. Schaller, F. 1970. Collembola (Springschwanze). Handb. Zool. 4(2)2/1:1-72. Sharma, G. D. and D. K. McE. Kevan. 1963. Observations on Isotoma notabilis (Collembola, Isotomidae) in Eastern Canada. Pedobio. 3:34-47. Sheals, J. G. 1956. Soil papulation studies. I. The effects of cultivation and treatment with insecticides. Bull. Ent. Res. 47:803-822. Snider, R. J. Department of Zoology, Michigan State University, E. Lansing, Michigan, personal communication. Solem, J. O. and E. Sendstad. 1978. Diversity and diel periodicity of Collembola communities at Spitsbergen, Svalbard. Norw. J. Ent. 25:9-14. Somme, L. 1976. Cold-hardiness of winter-active Collembola. Norw. J. Ent. 23:149-153. Steel, R. G. and J. H. Torrie. 1980. Principles and Procedures of Statistics. A Biometrical Approach. McGraw-Hill. 633 pp. Steiner, R. 1958. Agriculture. A Course of Eight Lectures. Biodynamic Press, London. 175 pp. 125 Stinner, B. R. and D. A. Crossley, Jr. 1980. Comparison of mineral element cycling under till and no-till practices: an experimental approach to agroecosystems analysis, pp. 280-288. In: Soil Biology as Related to Land Use Practice (D. Dindal, ed.). U.S. EPA, Washington, D.C. October 1980. 880 pp. Subajga, J. and R. J. Snider. 1981. The side effects of the herbicides atrazine and paraquat upon Folsomia candida and Tullbergia granulata (Insecta, Collem- bola). Pedobio. 22:141-152. Tamura, H. 1976. Biases in extracting Collembola through Tullgren funnels. Rev. Ecol. Biol. Sol. 13(1):21-34. Takeda, H. 1979. Ecological studies of collembolan populations in a pine forest soil. III. The life cycles and population dynamics of some surface dwelling species. Pedobio. 19:34-47. Tullgren, A. 1918. Ein sehr einfacher Ausleseapparat fur terricole Tierformen. Z. angew. Ent. 4:149-150. USDA. 1980. Report and Recommendations on Organic Farming. USDA Study Team on Organic Farming. Washington, D.C. 94 pp. USDA. 1983. Commercial Fertilizers. Consumption for Year Ended June 30, 1983. Crop Reporting Board. Washington, D.C. 34 pp. 9 Usher, M. B. 1969. Some properties of the aggregations of soil arthropods: Collembola. J. Anim. Ecol. 38:607-622. Wallwork, J. A. 1976. The Distribution and Diversity of Soil Fauna. Academic Press, NY. 355 pp. 126 Wallwork, J. A. 1983. Soil fauna and mineral cycling, pp. 29-33. In: New Trends in Soil Biology (Ph. Lebrun, H. Andre, A. De Medts, C. Gregoire-Wibo, G. Wauthy, eds.). Proc. VIII. Intl. C011. 5011 Zool. Louvain-la-Neuve (Belgium), 1982. Imprimeur Dieu-Brichart, Ottigines-Louvain-la-Neuve. Weed Science Society of America. 1983. Herbicide Handbook of the Weed Science Society of America. WSSA, Champaign, Illinois. 515 pp. Well, R. R. and W. Kroontje. 1979. Effects of manuring on the arthropod community in an arable soil. Soil Biol. Biochem. 11(6):669-679. LIST OF APPENDICES 127 Appendix 1. Log of Collembola species recovered from soil and compost at the Rodale Research Center, Berks County, Pennsylvania. Entomobryidae Pseudosinella violenta (Folsom) Entomobrya (Entomobrya) unostrigata Stach Lepidocrytus cinereus Folsom Lepidocrytus pallidus Reuter Lepidocrytus paradoxus Uzel Isotomidae Isotoma (Desoria) notabilis Schaffer Isotoma (Desoria) agrelli Delamare Isotoma (Isotoma) viridis Bourlet Isotomurus (Isotomurus) palustroides Folsom Isotomurus (Isotomurus) tricolor (Packard) Isotomiella minor (Schaffer) Folsomides americanus Denis Proisotoma (Proisotoma) minuta (Tullberg) Onychiuridae Onychiurus (Protaphorura) encarpatus Denis Tullbergia (Tullbergia) ygsiii Rusek Sminthuridae Hypogastruridae 128 Appendix 2. Summary of literature concerning the agricultural impact on soil populations of Collembola. Factor Impact Taxon Parameter Sourcel ’) Cultivation (-) Total PD“ 2,4,6,7,10,15 (-) Hemiedaphic PD 7 (-) Sminthuridae PD 11 (-) S, elegans PD (-) Edaphic PD (-) pg. parvula PD (-) .E. pallidus PD (-) .1. notablilis PD (NC)3 ‘2. grandulata PD 10 Compaction (-) Total PD 4 Fallow (-) Total PD 2,15 Acidification (+) I, krausbaueri PD 3 (-) Total PD 3 Manure (+) Total PD 2.5.6.12,17 (+) Species Diversity l,2,5,lZ,17 Manure plus fertilizer (+) Total PD 12 Compost substrate (+) Total PD 8 (+) Total Activity 8 (+) Total Hetabolism 8 Fertilizer (+) Total PD 6 (NC) Species Diversity 6 (RC) Total PD 2 continued (Appendix 2, continued) Increasing soil fertility (+) (+) (+.-) N2 gas (NC) C02 gas (-) 33$ gas (-) NH3 gas (-) Atrazine (NC) (NC) (NC) Paraquat (+) (-) (-) (+1-) DDT (+) (+) (+) BHC (-) continued Species Rare species Total Total Total Total Total Edaphic Lg. pallidus 'L. nocablilis S. elegans P candida 5:. candida Isotomidae Onychiuridae Hypogastruridae Symphypleona Total Hemiedaphic Euedaphic Entomobryidae P. candida ‘1. granulata Total Euedaphic Hemiedaphic Total 1JZ9 Diversity Diversity PD Survival Survival Survival Survival PD PD PD PD Survival Instar duration PD PD PD PD PD PD PD PD Survival Survival PD PD PD PD ‘0 13 13 13 11 11 11 11 16 16 19 19 19 19 ‘4 \l ‘J (Appendix 2, continued Aldrin (-) (-) Dieldrin (-) (-) Telodrin (-) (-) Heptachlore (-) (r) Chlordane (-) (-) Carbaryl (-) (-) Parathion (-) (-) Diazinon (-) (-) Henazon (NC) (NC) DXCC (NC) (-) Simizine (r) (-) Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedapnic Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedaphic Euedaphic Hemiedaphic 1L30 PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD PD 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ‘See Appendix 3 3 . 'Soil population denSity ‘30 change in population parameter 131 Appendix 3. Sources of information used for the preparation of Appendix 2. 10. 11. 12. 13. . Aleinikova, M. M., and N. M. Utrobina. 1975. Changes in the structure of animal populations in soil under the influence of farm crops, pp. 429-435. In: Progress in Soil Zoology (J. Vanek, ed.), Academia, Prague. . Artemjeva, T. 1., and F. G. Gatilova. 1975. Soil microfauna changes under the influence of various fertilizers, pp. 463-468. In: Progress in Soil Zoology (J. Vanek, ed.), Academia, Prague. Baath, E., B. Berg, U. Lohm, B. Lundgren, H. Lundkvist, T. Rosswall. B. Soderstrom and A. Wiren. 1980. Effects of experimental acidifica- tion and liming on soil organisms and decomposition in a Scots pine forest. Pedobio. 20:85-100. Critchley, B. R., A. C. Cook, U. Critchley, T. J. Perfect, A. Russell- Smith and R. Yeadon. 1979. Effects of bush clearing and soil cultiva- tion on the invertebrate fauna of a forest soil in the humid tropics. Pedobio. 19:425-438. . Davidson, S. J. 1979. Mesofaunal responses to cattle dung with part- icular reference to Collembola. Pedobio. 19:402-407. Edwards, C. A., and J. R. Lofty, 1969. The influence of agricultural practice on soil micro-arthropod populations, pp. 237-247. In: The Soil Ecosystem (J. G. Sheals, eds.), Syst. Assoc. Pub. No. 8. . Edwards, C. A., and J. R. Lofty. 1976. The influence of cultivation on soil animal populations, pp. 399-407. In: Progress in Soil Zool- ogy (J. Vanek, ed.), Academia, Prague. . Graff, O. 1953. Bodenzoologische untersuchungen mit besonden Beruck- sichtigung der terrikolen Oligochaeten. Z. Pflanzenernahr., Dung., Bodenkunde 61:72-77. . Hagvar, S. 1982. Collembola in Norwegian coniferous forest soils. I. Relation to plant communities and soil fertility. Pedobio. 24:255—296. Loring, S. J., R. J. Snider, and R. S. Robertson. 1981. The effects of three tillage practices on Collembola and Acarina populations. Pedobio. 22:172-184. Moore, J. C., R. J. Snider, and L. S. Robertson. 1984. Effects of difference management practices on Collembola and Acarina in corn production systems. Part I. The effects of no-tillage and atrazine. Pedobio. 26:143-152. Morrix, H. 1927. The insect and other invertebrate fauna of arable land at Rothamstead. Part II. Ann. Appl. Biol. 14:442-464. Moursi, A. A. 1962. The lethal doses of C0 , N , NH , and H S for . 2 2 3 2 8011 arthropoda. Pedobio. 2:9-14. continued 132 Appendix 3, continued 14. 15. 16. 17. l8. l9. Moursi, A. A. 1970. Toxicity of ammonia on soil arthropods. Bull. Ent. Soc. Egypt., Econ. Serv. 4:241-244. Sheals, J. G. 1956. Soil population studies. I. The effects of culti- vation and treatment with insecticides. Bull. Ent. Res. 47:803-822. Subajga, J., and R. J. Snider. 1981. The side effects of the herbi- cides atrazine and paraquat upon Folsomia candida and Tullbergia granulata (Insecta, Collembola). Pedobio. 22:141-152. Weil, R. R., and W. Kroonjte. 1979. Effects of manuring on the arthro- pod community in an arable soil. Soil Biol. Biochem. 11(6):669-679. Edwards, C. A. 1965. Effects of pesticide residues on soil inverte- brates and plants. 5th Symp. Brit. Ecol. Soc., Blackwell, Oxford. Popovici, I., G. Stan, V. Stefan, R. Tomescu, A. Dumea, A. Tarta, and F. Dan. 1977. The influence of atrazine on soil fauna. Pedobio. 17: 209-215. 133 g a a e .Ammmav macm>H>mccmm .>DGSOU mxumm .Hmucmo sommmmmm mammom map um musumummfima Ham EDEHXME mam Eseflcwz .v xwmcmmm< Nmmp mead 23.51 ewm emu emu m». ems ems ow. me am mu _ _ _ X i w: an EEEEE xzoo Ill 83::on .950 I11 3% 553.com o_onEo=oo x a c ... .5: i e: 1 02- 08 l OI- O I OI O o EtifllVElEdWEl 1 OZ 134 .Ammmav mflzm>ahmcamm .>ucmou mxumm .Hmucmu soummmmm mamcom mnu um musumummfimu Ham Eszxme mam Esfiflcwz .m xflocmmmd mmmp ”.55 2.3.5.. emu mNN cow 2.— QB mi 2: ms. ow mm o _ _ L _ _ L _ L _ L m. x M 2» X i 0 E:E_:_E Eon III . 53::on £00 111 1% 30v @5383 20352.00 x m. .. T. . l 1 g m ( a!) a 10 l a; t \f l a 1m gzé’é . . a t Z l _ . Tlo _ 8 1.0 O o BEHIWEdWEl 135 U3— r-ID v N Ill Temperature ‘ 1!] Moisture v ” "'° N /"\ us-l .0 en ., v v LIJ “J 0: 0‘ B P— s @814“? m 0 Cl. 2 2 DJ :1] J I'— O .1 00:3‘ E5 00 "’9. 0.1 N ‘2 1 I m 75 100 125 tsp 195 250 zzrs 250 JULIAN DATE 1983 Appendix 6. Soil moisture and temperature in sweet corn at the Rodale Research Center, Berks County, Pennsylvania. 136 10— -m V N It Temperature III Moisture Q... * i-c N 8 sir i“ E :3 3 5 1— - _ 98 5m C) 0. IE :5 Lu :5 F- O _J “’8‘ 5 U) -c O—I N (D r l 1 I I l m 75 100 125 150 175 200 225 250 JULIAN DATE 1983 Appendix 7. Soil moisture and temperature in clover at the Rodale Research Center, Berks County, Pennsylvania. 137 . Ammmfl manna/amchmm $3500 .933 £355 noummmmm mammom 05 um coflmuwmflomum 3me .m mainland Nmmp m3< .2. c2. .62 2?. to: no... :2. 0 8 we 9 P 9m... m nv U x...) am e8 $3 882:. x I z 138 . 3mm: mficm>a>mccmm £35.00 mxumm #3580 £0.80QO mag 05 um COUSHQHOQHQ >330: 0mm. o:< .3. :2. an: .a< to: no... :2. 0 9 8 6 (mo) uogioildgoold Asa 3.3 8.8.... x Z! . m xfloconmm 139 mama .NN maneuoom mama .mm Hansen Amufiumamo mwcmzoxm coaumUV w ooa\ucoam>aovmaaafiz n mumuomn\mzm w.HH m.m oo.~ Ho.o Mme a.“ pumOQEOU N.HH oo.m os.N mn.o can o.k emozsez N.mH oa.m m~.~ mc.o cow m.c omucoaumouu HH< Emumzm Hmcofiucm>cou m.HH m.w om.m No.o «mm m.o pumanoo m.HH q.w oe.~ om.o ooe m.o onmEooon m.oH 0.5 mm.H mm.o 0mm o.o omummaummuu HH< Emumxm owcmwuo w a mm mm sumo new a z ax mm m u an we .Ammmav mucoEummuu Hmaofiucm>cou mam oficmwuo cw mwmxamcm acmwuuoc HHow umm>umnlumoa pom unmamlmum .oa xfipcmam< 141) Appendix 11. Seasonal prominence values and relative prominence values of soil Collembola in clover, and clover-oats, to a soil depth of 15.24 cm (1983). Sampling date (Julian date) (33) 3 (97) 3 (116) 3 (:33) , March 24 April 7 April 16 May 12“ Taxon 1=v1 vaz PV 129v PV Rev 91' 39v 1:. violenta 0.23 6.33 o o 0.10 1.18 0.29 1.18 E, unostrigata 0 0 0 0 0 0 0 0 ‘l. notabilis 7.20 26.04 1.18 12.88 0.30 3.53 5.00 20.27 E, minuta 0.36 1.30 0.07 0.76 0 0 0.58 2.35 E, americanus 0.23 0.83 0.51 5.57 0.04 0.47 0.75 3.04 I, viridis 0.12 0.43 0.04 0.44 0 0 0 0 E, minor 1.65 5.97 0.04 0.44 2.94 34.63 0.52 2.11 .E. palustroides 0.04 0.14 0 0 0.15 1.77 11.42 46.29 ‘2. tricolor 0.02 0.07 0 0 0 0 0 0 I, vosiii 17.80 64.38 7.22 78.82 4.92 57.95 6.11 24.77 Sminthuridae O 0 0.10 1.09 0.04 0.47 0 0 continued 141 Appendix 11. continued Sampling date (Julian date) (152) 3 (167) 4 (182) a (196) 4 June 1 June 16 July 1 July 15 Taxon PV RPV PV RPV PV RPV PV RPV ‘2. violenta 0.04 0.26 0 0 0 0 0 0 ‘E. unostrigata 0.04 0.26 0 0 0.21 4.99 0.70 37.63 .1. notabilis 5.87 38.07 0.19 6.99 0.37 8.79 0.07 3.76 ‘3. minuta 0.29 1.88 0 0 0 0 0 0 E, americanus 0.30 1.95 0 0 0 0 0 0 ‘1. Viridis 0.39 2 53 0.04 1.47 0.07 1.66 0 0 ‘1. minor 5.68 36.84 0 O 0.04 0.95 0 O ‘1. palustroides 0.10 0.65 2.03 74.63 1.00 23.75 0.04 2.15 ‘1. tricolor 0 O 0.10 3.68 0.52 12.35 0 O I, vosiii 2.55 16.54 0.32 11.76 1.96 46.56 1.05 56.45 Sminthuridae 0.16 1.04 0.04 1.47 0.04 0.95 0 0 continued Appendix 11, continued 142 Sampling date (Julian date) (209) 4 (223) 4 (237) 4 June 1 June 16 July 1 Taxon PV RPV PV RPV PV RPV .2. violenta 0.04 1.26 0 0 0 0 E. unostrigata 1.65 51.89 1 95 83.33 5.44 97.32 .1. notabilis 0.50 15.72 0.19 8 12 0.04 0.72 ‘3. minuta 0.04 1.26 0 0 0 0 ‘5. americanus 0 O 0 O 0 0 ‘1. viridis 0 0 0 0 0 0 ‘1. minor 0.04 1.26 O O 0.04 0.72 ‘1. oalustroides 0 0 0 0 0 0 ‘I. tricolor 0.16 5.03 0.16 6.84 0 0 I, vosiii 0.75 23.58 0.04 1.71 0.07 1.25 Sminthuridae 0 0 0 0 O 0 1 . Prominence value . AD x A/AP (see text). ’1 - . . . . FE Relative prominence value a prominence value/fti (see text). 3. . . weedy clover Site (Figure 2). 41‘70vpr_oat~ ~‘f' (_I' a '7) d‘ - D 31-9 .flgur- -1. 143 wo:=_u:ou 2.: 2.: : o : : : : : : : : a..................: 3.2 .5... 8.... 5.: :08 ::.n 3.: 2.: 8.5 2.2 Rm: .5... $0.9 .H : : : : o : : : : : : : 3.395.... .m : : : : u; 2.: : o : : : : 111............4 A : : : : on... 8.. : : : : : : 3:35;... .M 3... E: 3.... :0: at: 8%. 3.8 5.. 2.... 3.: $4. 2.: 11125.... A : : : : : : : : :2: 6...: 8.: .3... 33.... A- : : : : 5.... 3.. 2... 2.: :3. 3.: 2.: 5.: 31.11.32,? .1. -.~ :2: : : : : 3.: 8.: : c 2..“ 3.: 3.3.1: .4 2.8 :2: 2...... 8.. 8.; 8; : : s... 3.: 3.2 2.... m... 3:31. 4 : : : : o : : o : : c : 3... ........1.....m ...._. : : : : : : : : a... 8.: 6...: 2.: 3.3....» .u r... e. .5... >.. a... r. r... r. r... e. 1.... .2. =3. .._... 3...: - 2:. 2.... - 8.... .56 1 : sag... - 3:. 2.... - .5... :c... 1 : Aaov :.:o= _.:m «:5. A... 3...... .3: .m ......_....z 7543—. .5239 "3.... «ff-1:52“ ... .3 .2393. :3.“ =5. 36%. .: .253: .=. «N...— .x..._.:.. .5: 9.33.0 :.. .....:.__:..:5... t. 2.5—.5 c.:....__.=o.=_ ...>.ao_...u .5: 22......» 22.2.2.3...— _...::.n......n _q a ._ I_.... .1...“ m _ :33}; 1x34 .AN u»:w.mv wu.m xavam .«unw\m:~e> oucmc.sc»: u v:_:> mucoc.ao.; z>.um~vz c N .AN whamwmv ouum um>oHu acuwzn .Auqu mam. ;< x :< n ~3~m> u.:u:.Eo.;. : : : : : .. .. : .. : .54 a. ... .5... 5.. E .5... : : : : E... 21: 2.2. 3.. 84.: 2... S... 2... 4.4.1....» .1. : : : : : : : : 24.. 2.: :1... 2.. z................ .m .. : : : 8.: £3: : : : : :5. ..~.: 5.3.4.. .1.- : : : : a:.m mm.: : : : : :..~ m~.: m.:.=..n=.mq am : : : : : : ::..N :..: :c.:. mm.: :..m. .q.. mamas .q : : : : : : : : : : : : m~=.... «a .. : c... N... 9...: o... : : $4. 2.: $4.. 2.. ma........._.1. ...1. : : : : : : : : : : .~.:. a... mammfla .m : : : : 8.. mm... :2... xx: 3...: m... .3... ..:.: 321.331. .M : : : : .:.~ 2.: : : : : : : 1:1... .222... ..1.. : : .. : S... 2.: Sun. .3... 8.. 2.: : : 3.5.2.. .m >..._ >.. >.... >.. 3... Z .r... >.. 2.. >.. >.... >.. .55.... 3...... 1 2.... ....:. 1 9...... .5... 1: «N... 1 2.... 2:. 1 .5... :5... 1 : Acnuv ._.:..= __..m e.»:~. . .zss..;om ..::~. :~ ..:: V Ao.c= :c_~=fiv $.32 u:__:§cm coacwucoo . N. x d .595... MICHIGAN STRTE UNIV. LIBRRRIES N HIM11111111111111 IWIWINIIINWW ”HI 31293106435864