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' This is to certify that the thesis entitled EFFECTIVENESS OF PHOSPHATE ROCKS IN COLOMBIAN SOILS AS MEASURED BY CROP RESPONSE AND SOIL PHOSPHORUS LEVELS presented by Lawrence Leroy Hammond has been accepted towards fulfillment of the requirements for Ph.D. degree in Crop and Soil Science I Major professor Date October 54 1977 0-7639 EFFECTIVENESS OF PHOSPHATE ROCKS IN COLOMBIAN SOILS AS MEASURED BY CROP RESPONSE AND SOIL PHOSPHORUS LEVELS By Lawrence Leroy Hammond A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Crop and Soil Sciences 1977 ABSTRACT EFFECTIVENESS OF PHOSPHATE ROCKS IN COLOMBIAN SOILS AS MEASURED BY CROP RESPONSE AND SOIL PHOSPHORUS LEVELS By Lawrence Leroy Hammond Phosphate rocks from North Carolina, Central Florida, and Tennessee in the United States, from Huila and Pesca in Colombia, from Sechura in Peru. and from Gafsa in Tunisia were compared with triple superphosphate and/or basic slag as sources of P. A greenhouse experi- ment with guinea grass and a field experiment with cassava were conducted using an acid oxisol deficient in P, and a field experiment with beans was conducted on an acid andosol deficient in P. Yield responses to P fertilization were obtained in all three experiments. Marked differences in agronomic effectiveness were noted between the sources of phosphate rock. The solu- bility of P in neutral ammonium citrate was a good measure of the availability of P in different phOSphate rocks. Based on both crop response and citrate solubility, the effectiveness of the phosphate rocks was: Lawrence Leroy Hammond 1. North Carolina = Gafsa = Sechura > 2. Central Florida = Huila > 3. Tennessee = Pesca Crop response was related to soil P extracted with Bray P-l solution, but response curves obtained with the phosphate rocks did not coincide with those obtained with superphosphate. Water-soluble P in the soil was well related to P uptake at high rates of application in the greenhouse, but did not adequately predict crop response in the field. Soil pH and exchange- able Ca increased with rate of application and relative availability of the phosphate rock, while A1 saturation of the effective CEC decreased correspondingly. This dissertation is dedicated to Jenny, Linda and Patricia ii ACKNOWLEDGMENTS The author wishes to express gratitude to Dr. Bernard D. Knezek for the assistance and cooperation offered as Chairman of my guidance committee, and to Dr. Charles Cress, Dr. Boyd G. Ellis, Dr. Gerald Schwab, and Dr. Darryl Warncke for their participation on my guidance committee at Michigan State University. Special appreciation is extended to Dr. Eugene C. Doll for his support and guidance throughout the course of this study, and for the part he played in making possible the investigations carried out in Colombia. The author is indebted to the International Center for Tropical Agriculture (CIAT) in Cali, Colombia for the assistance and facilities which they provided. Special thanks are due to Dr. James Spain, Dr. Reinhardt Howeler, Dr. Luis Alfredo Leon and Mr. David Harris for their cooperation at CIAT. Acknowledgment is also given to Ing. Agr. Carlos Medina, Ing. Agr. Miguel Angel Ayarza, Ing. Agr. Luis Fernando Cadavid and the entire staff of the CIAT Soils Laboratory for their assistance in the field and in the laboratory. This research was made possible through financial assistance provided by the International Fertilizer iii Development Center (IFDC), Muscle Shoals, Alabama. Appreciation is due to Dr. Richard Booth of IFDC for his assistance with the computer analysis. iv TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES INTRODUCTION LITERATURE REVIEW . Agronomic Potential of Ground Phosphate Rock Phosphorus Availability from Phosphate Rock . Soil and Plant Factors Related to Utilization Residual Effect of P from Phosphate Rock . METHODS AND MATERIALS Phosphorus Fertilizer Materials . . Characterization of the Phosphate Rock . Chemical Reactivity of the Phosphate Rock Standard Sources . . . . Greenhouse Experiment . . Field Experiment with Cassava Field Experiment with Beans Laboratory Procedures Soil Analysis Plant Analysis Statistical Analysis RESULTS AND DISCUSSION Greenhouse Experiment with Guinea Grass Plant Response to Phosphorus . Extractable Soil Phosphorus (Bray P— l) Water Soluble Soil Phosphorus . . Effect of Phosphate Rocks on Soil pH Field Experiment with Cassava . . Cassava Yields as Affected by Rate and Source of P . . . . Extractable Soil Phosphorus . Water Soluble P . . . . . . Soil Acidity . . . . . Page vii ix H Page Field Experiment with Beans . . . 76 Bean Yield Response to Rate and Source of P . 80 Soil Phosphorus Status . . . . . . . . 86 SUMMARY AND CONCLUSIONS . . . . . . . . . . 91 APPENDICES . . . . . . . . . . . . . . 100 APPENDIX A: Greenhouse Data . . . . . . . . 101 APPENDIX B: Cassava Data . . . . . . . . . 141 APPENDIX C: Field Bean Data . . . . . . . . 155 LITERATURE CITED . . . . . . . . . . . . 187 Vi Table 10. 11. 12. 13. 14. LIST OF TABLES Particle Size Distribution of the Phosphate Rocks .' . . . . . . . . . . . Chemical Composition of the Phosphate Rocks Calculated Formula for Apatites Sources and Citrate Solubility of P in the Phosphate Rocks . . . I . . Initial Soil PrOperties Carimagua Climatic Data Total Yield (Dry Weight) of Three Cuttings of Guinea Grass in the Greenhouse as Affected by Rate and Source of Phosphorus Relative Agronomic Effectiveness (RAE) of Nine Phosphate Fertilizers in the Green- house Experiment with Guinea Grass Extractable P (Bray P-l) in Greenhouse Soils 90 Days After P Application as Affected by Rate and Source of P . . . Exchangeable Ca in Cropped Greenhouse Soil at Time of Final Harvest (190 Days After Application) . . . . . . . Water Soluble P'in Uncropped Greenhouse Soil 70 Days After Application pH in 1:1 Soil-Water Mixture in Uncropped Greenhouse Soil 70 Days After Application Yield of Edible Cassava Root Relative Agronomic Effectiveness of Eight P Fertilizer Materials on Cassava in the Field . vii Page 21 22 24 25 28 3O 39 41 44 47 51 57 62 64 Table Page 15. Correlation Coefficients Between Cassava Production and Citrate Soluble P205 of Phosphate Rock as Affected by Rate of Application . . . . . . . . . . . 64 16. Extractable P (Bray P-l) in Field Experiment with Cassava 51 Days After Application . . 67 17. Water Soluble P in Field Experiment with Cassava 51 Days After Application . . . 73 18. pH of 1:1 Soil-Water Mixture in Field Experiment with Cassava 51 Days After Application . . . . . . . . . . . 74 19. Exchangeable Al in Field Experiment with Cassava 51 Days After Application . . . 77 20. Yield of First Crop of Beans . . . . . . 81 21. Yield of Second Crop of Beans . . . . . 84 22. Correlation Coefficients Between Citrate Soluble P O :anhosphate Rock and Yield of 2 5 Beans . . . . . . . . . . . 87 23. Extractable P (Bray P-l) in the Field Experi- ment with Beans 30 Days After Application . 88 viii Figure 10. LIST OF FIGURES Relationship between yield of three cuttings of guinea grass and citrate soluble P in phosphate rocks Relationship between yield of three cuttings of guinea grass and Bray P-l extractable P measured 90 days after application Relationship between Bray P—l extractable P in greenhouse soil and citrate soluble P in phosphate rocks Relationship between water soluble P and Bray P-l extractable P in greenhouse soil 90 days after application Relationship between uptake of P by three cuttings of guinea grass and water soluble P in greenhouse soil Relationship between yield of three cuttings of guinea grass and water soluble P in greenhouse soil Relationship between concentration of water soluble P in greenhouse soil receiving 400 ppm P and time following application Relationship between water soluble P in greenhouse soil 70 days following applica- tion and citrate soluble P in phosphate rocks Aluminum saturation of effective CEC of greenhouse soil 190 days after application as affected by Rate of application Relationship between A1 saturation of green- house soil and citrate soluble P in phosphate rocks ix Page 42 45 49 52 53 54 55 58 59 60 Figure 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Yield of edible Cassava as affected by rate of application . . . . . . . Bray P-l extractable P in Carimagua soil as affected by time following application Relationship between Bray P-l extractable P in Carimagua soil and citrate soluble P in phosphate rocks Relationship between yield of Cassava and Bray P- 1 extractable P in the Carimagua soil . . . . . . . Relationship between yield of Cassava and water soluble P in the Carimagua soil Relationship between exchangeable A1 in the Carimagua soil and soil pH Aluminum saturation in the Carimagua soil as affected by rate of P application Relationship between bean yield (1st crop) and citrate soluble .P205 in phosphate rock . . . . Relative agronomic effectiveness of phosphate rocks for the first two crops in the field experiment with beans Relationship between Bray P-l extractable P in the Popayan soil and citrate soluble P205 in phosphate rocks Page 65 69 70 71 75 78 79 82 85 89 INTRODUCTION Large areas of agriculturally undeveloped soils are found in the tropics which are strongly acid and deficient in phosphorus (P). The use of phosphate rock as a source of P is attractive for these soils since it is a relatively inexpensive source of P. In countries like Colombia which have local deposits of phosphate rock, both the development costs and energy investments of the deposits would be much lower if the finely ground phos- phate rock could be applied directly to the soil. Many experiments to evaluate the effectiveness of directly-applied phosphate rock have been conducted during the past 60 years, but the results of these experiments have been extremely variable. Generally, broadcast applications of finely ground phosphate rock can result in increased yields of many crops grown on P deficient acid soils. However, the magnitude of this response has almost always been less than that obtained with soluble phosphates, and the degree of response has been erratic. In the early experiments, only one source of phosphate rock was generally used, with yields being com- pared to those obtained with superphosphate. In more recent years, however, it has been recognized that 1 different phosphate rocks vary with respect to their effectiveness as sources of P for plants. The use of the more reactive phosphate rocks can produce yields economi- cally attractive when compared to those obtained with the more costly superphosphate. It is probable that the real fertilizer value of phosphate rock cannot be adequately evaluated by the results of a single short-term cropping experiment, since the relative residual effects must also be considered. The majority of the investigations conducted with phosphate rock have concentrated primarily on crop yields as the measure of phosphate rock effectiveness with little effort to determine the effect on soil chemical parameters. If phosphate rock is to be used as a fertilizer, decisions regarding its application should be made on the basis of the reactivity of the material to be used and of soil test correlations developed specifically for phosphate rock rather than using those obtained from experiments with soluble P sources. The objectives of this investigation, therefore, were to: ll. Evaluate the agronomic effectiveness of phosphate rocks from sources with different mineral composition. Evaluate relevant soil reactions associated with the direct application of the phosphate rocks, and Relate the results of the first two objec- tives to the citrate solubility of the phosphate rock to aid in selection and utilization of phosphate rocks for direct applications. LITERATURE REVIEW Ground phosphate rock has been used as a source of fertilizer phosphorus for more than 150 years (Terman, 1971). Phosphate rock used for direct application accounts for only a small proportion of the phosphate fertilizer utilized worldwide, but its continued importance is shown by the fact that the amount of phosphate rock con- sumption rose from 1.8 x 106 tons in 1954 to 4.0 x 106 tons in 1974 (Annual Fertilizer Review, 1974). Most of the increase in consumption has been in the U.S.S.R., Africa, Asia, and South America. Consumption in the United States began to decline in the mid-1960's and continues to be low. Deposits of phosphate rock have recently been found in a number of developing countries. In Colombia, phosphate rock reserves and resources are now estimated at 690 x 106 tons (G. H. McClellan, personal communication). Colombia's soil resources include extensive areas which are acid and P deficient. Direct application of finely ground phosphate rock in these undeveloped areas may represent the most rapid and economical means of utiliza- tion of the new phosphate resources. Agronomic Potential of Ground Phosphate Rock The effectiveness of directly applied phosphate rock has been reported over the years to be relatively low when compared to superphosphate. However, until recently, the differences in the agronomic potential of phosphate rocks due to the source of the deposit had not been recognized (Terman, 1976). As a result, the sources largely utilized for direct application were not those best adapted for that use. Russell (1973) states that "rock phosphates differ considerably in their fertilizer value, ranging from samples that are completely ineffec- tive on all soils and on all crops to others that can be as good as superphosphate for some crops with a pH below 6." Bartholomew (1935) recognized the difference in the availability of P from different phOSphate rocks. In an experiment with six types of phosphate rock, he reported that P availability to sudangrass decreased as the fluorine (F) content of the rock increased. In sup- plemental tests, he found that F itself was not detri- mental to plant growth and therefore attributed the cor- relation to an effect of the F on the solubility of the phosphate rock. Later experiments by Brown and Jacob (1945) and by Bennett, et a1. (1957) showed no definite correlation between F content and yields of crops. Comparisons between P availability and the citrate solubility, however, did show strong correlation where seven sources of phosphate rock were compared in the greenhouse using sudangrass and ladino clover as the test crops. Other experiments in which the citrate soluble P content of phosphate rock was a good measure of P availability were reported by Caro and Hill (1956), Armiger and Fried (1957), Terman, et al. (1970), Engelstad, et a1. (1972), and Engelstad, et a1. (1974). Armiger and Fried (1957) compared the same ten sources of phosphate rock which previously had been characterized by Caro and Hill (1956) in greenhouse experi- ments with buckwheat and alfalfa. In addition to the good correlation between agronomic response and both ammonium citrate and citric acid solubility, they noted that the most precise relationship was between the apatite-bound carbonate in the phosphate rock and the agronomic response. Lehr and McClellan (1972) reported that the "bound-carbonate" was due to the carbonate substitution for phosphate (P205) within the crystal lattice of the apatite. Their work identified the apatite in many phosphate rocks as a range of substituted fluor—apatites with the average formula: ca10-0.42xNa0.BXMgO.12x(PO4)6-X(C03)XF2+0.4X For the phosphate rocks which contained these substituted apatites, the chemical reactivity of the rock increased as the degree of carbonate substitution increased. The ratio between the citrate soluble P205 and the theoretical content of P205 in the apatite was termed the Absolute Citrate Solubility (ACS) by Lehr and McClellan (1972). Since the ACS was determined by the properties of the substituted fluor-apatites, the ACS index does not apply to the phosphate rocks which contain hydroxy- apatites. Engelstad, et a1. (1974) found a better rela- tionship between yields of flooded rice and the ACS index than was obtained with the standard ammonium citrate solubility test which is the standard method in the United States (AOAC, 1950). Other measures of phosphate rock reactivity outside of the United States include P extrac- tions with 2% citric acid and 2% formic acid. Phosphorus Availability from Phosphate Rock The reactivity of a phosphate rock is a measure of its potential as a source of fertilizer phosphorus rela- tive to other phosphate rocks. Phosphate rock, however, is relatively insoluble and rarely produces initial yields equal to those obtained with soluble Superphosphate. Plant response to P is a function of the concentration of P which can be maintained in the soil solution (Khasawneh, 1971; Khasawneh and Copeland, 1973; Soltanpour, et al., 1974). When a soluble P source such as superphosphate is applied to an acid soil, the P rapidly enters into solution and is immediately available for plant uptake or retention by the soil (Lindsay, et al., 1962). The major portion of the P obtained by the plant follow— ing application of a soluble fertilizer, therefore, is from the reaction products. Phosphate rock, however, is relatively insoluble and its dissolution in the soil is slow. Russell (1973) statesthat most phosphate rocks can maintain a P concen- 6 7 to 10- tration of 10‘ M (.031 to .003 ppm) in mildly acid soils, and possibly more as the acidity increases. He classified a soil with a concentration of 10—6 M P as being deficient. The concentration of P in the soil solution required for maximum growth varies with the plant. Various levels which have been reported include 0.3 ppm P for wheat (Ozanne and Shaw, 1968), 0.2 ppm P for millet (Fox and Kamprath, 1970), and 0.1 ppm P was sufficient for 90% of the maximum yield of rice (Hossner, et al., 1973). It has been shown that the mechanism which most commonly limits the uptake of P by plants is the diffusion of P to the thin absorption zone surrounding the plant root (Barber, et al., 1963; Olsen, et al., 1962; Olsen and Watanabe, 1963 and 1966). Because the concentration of P made available during the dissolution of phosphate rock is low, the diffusion of P from the rock particle is small. As a result, distribution of the phosphate rock in the soil as affected by fineness of grinding, method of appli- cation, and rate of application, all influence agronomic effectiveness. In an early investigation regarding the fineness of grinding of phosphate rock, Salter and Barnes (1935) found no significant difference in efficiency by grinding so that 97% would pass 100 mesh as compared to 60% passing 100 mesh. The phosphate rock utilized in their experiment, however, was the Tennessee brown rock which is relatively unreactive. Joos and Black (1950), also using the Tennessee brown phosphate rock, did find an increase in effectiveness with material that was ground to less than 400 mesh. Armiger and Fried (1957) evaluated the effect of fineness of grinding on several rocks that did vary in reactivity. They reported that the finest material tested (—325 mesh) was only slightly more effective than material less than 100 mesh in size. It was also noted that the citrate solubility of the various sources influenced the agronomic effectiveness more than the difference in the fineness of grinding. Increased yields with decreased particle size were also reported by Howeler and Woodruff (1968) with igneous apatite from Missouri, and by Fass— bender (1967) with Sechura phosphate rock from Peru. 10 In an incubation study with North Carolina phos— phate rock, Barnes and Kamprath (1975) found that 60 days was required for maximum P availability on a Hyde soil at pH 4.1 when the rock was ground to 100-115 mesh, while 90 days was required when 32% of the material was <65 mesh. At pH 4.7, both size fractions required 90 days, but the courser material was only 67 to 83% as effective. In reviews of experiments with finely ground phos- phate rock in the United States (Rogers, et al., 1953), and in the United Kingdom (Cooke, 1956), it was concluded that the small degree of increase in P availability obtained by grinding to extreme fineness was not justified. Cooke (1956) suggested that it was not necessary to grind finer than for 80% of the material to be less than 100 mesh. Soil and Plant Factors Related to Utilization Soil pH has been identified throughout the years as the single most important agronomic factor influencing the utilization of P from directly applied phosphate rock (Joos and Black, 1950; Barnes and Kamprath, 1975). In order for a raw phosphate rock which has been finely ground and applied to the soil to release P, the rock must undergo a partial dissolution which, due to its apatitic composi- tion, is enhanced by an acid environment. Jones (1948) found that at pH 5.0, 235% more P was taken up by rye from phosphate rock than when the soil was limed to pH 6.5. 11 In an experiment with cats, Ellis, et a1. (1955) found the yield and P uptake from phosphate rock to be equal to superphosphate between pH 5.0 and 5.5, but when limed to pH 7.0, the availability from phosphate rock was greatly diminished. In a series of field experiments in the United Kingdom between 1951 and 1953, Russell (1973) reported that the relative effectiveness of Gafsa phosphate rock (PR) was greatly reduced for both swedes and potatoes with the pH above 6.5 as shown below: Kg of P from Superphosphate Required to Give Equivalent Yield Obtained with 100 Kg Gafsa PR pH 6.5 Swedes 91 86 12 Potatoes 34 37 4 In greenhouse experiments with corn, Barnes and Kamprath (1975) reported that with a pH at or below 5.2 on Hyde and Cecil soils, North Carolina PR was 73 to 100% as effective as superphosphate. However, when these soils were limed to pH 5.7 and 6.0, respectively, there was no response to the phosphate rock. It was suggested that the effective pH range for directly applied phosphate rock was pH 5.8 to 6.2 for soils low in organic matter and pH 4.8 to 5.0 for organic soils. 12 Paauw (1955) showed that the optimum pH for the release of P from phosphate rock varied with the source of the rock. He found that effective P utilization by rye and potatoes was encountered at a pH in KCl of 4.2 or lower with Gafsa PR, while pH 3.8 or lower was required with Florida PR. It was noted, however, that although there was greater P availability in these pH ranges from phos- phate rock, it was too acid for optimum plant growth. An example where liming showed beneficial effects to plant utilization of P from phosphate rock was reported by Bennett, et al. (1957). In this case, lime was applied in amounts which did not raise the pH sufficiently to inhibit dissolution of the phosphate rock, but did provide improved calcium (Ca) nutrition. Phosphorus uptake by sudangrass and clover was greater from phosphate rock on an unlimed Eutaw clay (pH 5.0, Exch Ca 11.7 meq/100 g) than on an unlimed Cecil clay loam (pH 5.0, Exch Ca 1.2 meq/100 g). However, when lime was applied, the P uptake from the phosphate rock on these two soils was similar. Chu, et a1. (1962), in a study with five soils from Virginia, found best responsetx>phosphate rockcnisoils with low pH and relatively low free iron (Fe). With the high Fe soils, there was a greater total decomposition of phosphate rock, so the reduced response may have been due to a more effective removal of H2P04- in solution by Fe compounds. Paauw (1955) and Ensminger, et a1. (1967) also suggested 13 that soluble P is more completely fixed by aluminum (A1) at the low pH levels. The importance of the P fixation capacity as related to the Solubility of P fertilizers was addressed by McLean and Logan (1970). In their com- parison of several phosphate fertilizers with varying water solubility, it was found that the P content of corn decreased as the water solubility of the available P increased when applied to a soil with a high fixation capacity (Venago series). In contrast, when grown on an Alexandria soil which has a low P fixation capacity, the P uptake by corn increased progressively with the percent water soluble P of the available P. Their findings sug— gest that phosphate rock (raw or partially acidulated) may be well adapted to acid soils with a high P fixation capacity. McLean and Logan (1970) utilized six crops in Their studies of P fixation, and showed that the P fixation tendencies of the soil appeared to be more important than the crop species with regard to response to phosphate rock. It has been shown by other investigators, however, that the efficiency of utilization of P from phosphate rock varies considerably with different crops. The results referred to on page 11 from the United Kingdom (Russell, 1973) show the striking contrast in the effectiveness of Gafsa PR when utilized for the production of swedes and potatoes. The Gafsa rock was nearly as effective as 14 superphosphate with swedes when applied to acid soils while it was only about one—third as effective as superphosphate with potatoes in the same pH range. Rogers, et a1. (1953) cited findings of Odland and Cox (1942) showing that barley, oats, parsnips, spinach, and endive grown for one year were more responsive to super— phosphate than to phosphate rock (rock source not cited), but that cabbage, carrots, and rape showed phosphate rock to be more effective. McLean (1956) found that buckwheat responded better to phosphate rock than oats and alfalfa. Murdock and Seay (1955) reported that clover responded greater to P than wheat from both superphosphate and phos- phate rock, but that the percent yield increase exhibited by clover as compared to wheat was strikingly more pro- nounced with phosphate rock than with superphosphate. They concluded that clover was a better feeder on phosphate rock than is wheat. It is probable that the characteristics of the root system largely affect the differences in the plant species to utilize P from phosphate rock as compared to the soluble P fertilizers. With low concentrations of P released from the phosphate rock, diffusion of P from the site of the rock particle in the soil is minimal and the availability of this P to the plant may depend upon the probability of the roots coming in contact with the absorption zone sur— rounding the particle. This zone is much smaller with 15 phosphate rock than with superphosphate. It was general— ized by Rogers, et al. (1953) that most of the cereals are poor feeders on phosphate rock while buckwheat, and some of the legumes such as sweet clover, alfalfa, and red clover are strong feeders. It was concluded from green— house and field tests (Brown and Jacob, 1945) that raw phosphates can be used to better advantage for long season and perennial crops than for short season crops. Residual Effect of P from Phosphate Rock An assumption usually cited when comparing the value of phosphate rock to soluble P fertilizer is that, although the initial effect is usually lower for the phosphate rock sources, the higher residual value of these materials improve the overall fertilizer effective— ness. All phosphate fertilizers have residual value as demonstrated in areas which have received heavy applica- tions of superphosphate and eventually show low cr0p response to further P application. Russell (1973) esti— mated that 20 to 30% of the applied P is taken up during a 4 to 5 year period following application of superphos- phate. When the slow dissolution of phosphate rock occurs in the soil, it is subjected to the same processes of adsorption by the soil and absorption by the plant as the P supplied by superphosphate. The concentration of P 16 released by superphosphate, however, is initially very high,resulting in rapid and relatively complete reaction with the soil in the formation of Fe and A1 phosphate com- pounds. The availability of this P is then controlled by the desorption characteristics of the soil. The P from phosphate rock, on the other hand, is much slower to enter the labile pool of P in the soil, and the availability of P to the plants may be controlled by the concentration of P in the soil solution which can be maintained by the phosphate rock over a long period of time. Results obtained by Doll, et a1. (1960) show that the yields of corn, wheat, and hay in Kentucky were nearly as high 25 years after the phosphate rock applications were discontinued as when frequent applications of phos- phate rock had been continued. Moschler, et a1. (1957) reported finding apatite in the sand fraction of a soil 40 years after receiving applications of phosphate rock, while Mattingly (1963) found that up to 80% of the phos— phate rock in the sand fraction of a soil had not reacted three years after application. Chu, et al. (1962) found that at pH 5.2 in a Nason soil, only 18% of the applied phosphate rock had reacted after four years, and on a Wattston soil at pH 5.7, only 12% had reacted after ten years. Results of comparisons between the residual effect of P from phosphate rock and superphosphate have 17 frequently been published. In 1956, McLean compared finely ground Florida land pebble and superphosphate in a greenhouse test with oats. It was reported from this work that the superiority of superphosphate was not evident and that there was no significant difference in yield between the sources for the 3rd, 4th, or 5th crop of cats. The phosphate rock, however, had been applied at a rate of about 480 lb/ac P 0 while superphosphate was at a level 2 5 of only 180 lb/ac P O 2 5' McLachlan (1959) compared equivalent levels of P from both phosphate rock and superphosphate as a pasture top-dressing on two acid soils. It was found in this case that superphosphate was better than phosphate rock in the early years, but that over a seven—year period the total yield of pasture was similar for both, even though each source showed a good residual fertilizer value. It was suggested that superphosphate may be of more benefit if annual dressings are used, but that there was little difference between the two sources if dressings are in- frequent. Armiger and Fried (1957) also reported that there was increased relative value for phosphate rocks at later cutting of alfalfa as compared to superphosphate. This was attributed to a long growing season and consequent early depletion of the more readily available super- phosphate. This explanation conformed to results obtained 18 by Cooke (1956) who compared Gafsa phosphate rock to superphosphate in a greenhouse experiment with radishes on three acid soils. It was shown that 52% of the added P from superphosphate was recovered in the first crop of radishes, but only 6% in the second. On the other hand, Gafsa phosphate rock recovered only 19% in the first crop, but increased to 27% from the second. Other less soluble phosphate rocks included in the experiment also showed increases in P uptake during the second crop, but not to the extent as Gafsa phosphate rock. In an experiment with sorghum which compared milled Nauru phosphate rock with superphosphate (Arndt and McIntyre, 1963), it was found that during the first five years, the residues from superphosphate became pro- gressively less effective than the initial application, while the residues from the phosphate rock remained almost the same. For superphosphate, the residual value left after one year was 50% of the initial value, and after seven years, only about 8%. Phosphate rock was still 60 to 70% as effective as the initial value seven years after application. The positive residual value received from phosphate rock has also been reported by Cooke and Widdowson (1959) who found Gafsa phosphate rock as effective as superphosphate in the second year after application with grass experiments, and by Mokwunye (1977) who concluded that the performance of phosphate rock with 19 millet and maize approached that of single superphOSphate over a period of several crops. When comparing the residual effect over a five- year period in the greenhouse with ladino clover of a single application of Florida phosphate rock to super- phosphate which had been applied in annual portions to supply an equivalent amount of P205, Ensminger, et a1. (1967) found the phosphate rock to be generally less effective. However, on two soils, a Henry silt loam and a Leon fine sand, the results showed no difference between phosphate rock and superphosphate. When phosphate rock (source not cited) and superphosphate were both applied annually to a Bolivar fine sandy loam for a rotation of corn, oats, wheat, and clover, Fine and Bartholomew (1946) found that it took 15 years for yields from phosphate rocks to consistently approach superphosphate yields even when phosphate rock was used at twice the rate of P205/ac. Cooke and Widdowson (1959) suggested that the practical value of phosphate rock application probably depended upon economic considerations. In their investi- gations with swedes and kale, only two-thirds as much P from superphosphate as from Gafsa phosphate rock was required to give similar yields, but if the price of Gafsa was only one-half that of superphosphate, it would be economical to accept lower yields. METHODS AND MATERIALS A greenhouse experiment with guinea grass and field experiments with cassava and field beans were con- ducted in Colombia comparing seven phosphate rocks as sources of P for direct application. A Colombian basic slag and triple superphosphate were used as standard phosphorus sources. In addition to yield data, soil and plant samples from each experiment were obtained to more precisely evaluate the effectiveness of the phosphorus SOUI‘CGS . Phosphorus Fertilizer Materials The seven sources of phosphate rock were selected to represent a range of reactivity as measured by their citrate soluble P content. Samples of each source were characterized by chemical composition, X-Ray diffraction pattern, infrared absorption, and citrate solubility. The source and the particle size distribution of the phosphate rocks used are given in Table 1. Characterization of the Phosphate Rock Each phosphate rock was chemically characterized by determination of total Ca, P, Na, Mg, C02, and F (Table 2). Phosphate minerals other than apatite were 20 21 .mwmzaacw aw now: we: was :mmyom mane page mpaoaeaa mxcmflm* ¢.NN 0.0m b.HN 0.0 m.v I w.v I 0.H «stm 0.0a 0.0a H.0H v.0H m.va I 0.0a I v.0 momma 0.00 m.v 0.0 m.H I 0.0 I H.0 I mmmmmnamh 0.Hm 0.0H N.0N m.b I N.v I 0.0 I NUHHOHM Hahpcwo 0.00 m.¢¢ 0.0a H.m v.0 I v.0 I m.0 dmwdw m.H 0.0. N.0H Nnhv 0.0a I 0.0 I 0.H wusnoom H.h® m.mH 0.0 N.m I m.N I v.0 I «GHHOHmU Spuoz mmml mmm+ 00N+ oma+ 00H+ 00H+ 00+ 00+ mv+ 00ml 00HI 00HI owl mml wwl mounom *$ .umH>B .mfimmamq¢ oomgom .mxoom muasamoam may 40 noapznauumaa mmam mHoHpuamun.H mamas 22 0.0 0.0 00.0 00.0 0.00 0.00 00000 0.0 0.0 00.0 00.0 0.00 0.00 00000 0.0 0.0 00.0 00.0 0.00 0.00 000000000 0.0 0.0 00.0 00.0 0.00 0.00 0000000 0000000 0.0 0.0 00.0 00.0 0.00 0.00 00000 0.0 0.0 00.0 00.0 0.00 0.00 0000000 0.0 0.0 00.0 00.0 0.00 0.00 00000000 00002 0 000 002 0002 0000 000 000 00000000000 mohaom .00000 000000000 00 00000000000 00000000II.0 00000 23 not present in the accessory mineral groups of the phos- phate rocks as shown by X—ray diffraction and infrared absorption. The empirical formula (Table 3) of each apatite in the phosphate rocks, except Sechura, was determined from the unit cell a-dimension by the X-ray method as described by Lehr and McClellan (1972). The formula for the apatite of the Sechura phosphate rock was derived from the actual chemical analysis since the models of Lehr and McClellan (1972) do not apply to apatites with significant 0H substitution for F. The OR subStitution was identified by infrared absorption. Chemical Reactivity of the Phosphate Rock Citrate soluble P was extracted from a l-gram sample of each phosphate rock with 100 ml of neutral ammonium citratesolution at 65°C for 1 hour (Association of Official Agricultural Chemists, 1950). A second P extraction was also made with neutral ammonium citrate on the filtered residue from the initial extractions. Citrate soluble P205 was calculated both as percent of the rock and as percent of the total P205 in the rock (Table 4). The absolute citrate solubility (Lehr and McClellan, 1972), is defined as: AOAC citrate soluble P205, % Theoretical P205 (%) of apatite (1) ACS (%) = 24 00.0 0000 00 G) <11 H N m [LIN FT-IN ITS-IN FHN O (*3 (9 <1“ fiaN 00.H 00.0 m 00.M0000 00.w0000 00.M0o00 00.m0000 00.M0000 00.M0000 00.0 00000 VH.0 00000 00.0 00000 00.0 00o00 00.0 00000 00.0 00000 00.0 00000 00.0 00000 00.0 0: 00.0 0: 00.0 02 00.0 00 00.0 02 00.0 02 00.0 02 00.0 02 00.0 02 00.0 02 00.0 02 00.0 02 00.0 02 00.0 02 00.0 00 00.0 00.0 00 00.0 00 00.0 00 00.0 00 00.0 00 000.0 000.0 000.0 000.0 000.0 500.0 000.0 mfifism 00000 000000009 0000000 0000000 0m000 0032000 00000000 00002 0058000 000000080 00 .m0x0I0 00 000000 000500 .m000000< 0oM 00:80om 0000050000II.0 00009 25 0.0a 0.0a 0.0 0.0 0.0 00£EOHOO wfiwzm 0.0 0.0 0.0 0.0 0.0 00000000 00000 0.0 0.0 0.0 0.0 0.0 000000 000000 000000000 0.00 0.0 0.0 0.0 0.0 000000 000000 0000000 0000000 0.00 0.00 0.0 0.00 0.0 0000000 00000 0.00 0.00 0.0 0.00 0.0 0000 0000000 0.00 0.00 0.0 0.00 0.0 000000 000000 00000000 00002 0000 . 0000 . zpwwwmwmmm 00000 0 0000 0 00000 0 xoom 0 0000500 000500 00500000. 000000prm_05000m 00000000xm 00000 0500200000 0095000 0000000 .mmoom mudnmmonm 05p :0 m 00 hpflaflndaom madhpflo 0:0 mmohsomll.0 0400B 26 The ACS for all of the phosphate rocks, except Sechura, was estimated (Table 4) as described by Lehr and McClellan (1972) with the equation: ACS (%) = 421.4 (9.369 - A) (2) Where A is the a—axis length of the apatite unit cell as measured by X-ray diffraction. The ACS of the Sechura was calculated using equation (1) since equation (2) does not apply to apatites in which OH substitutes for F (Lehr and McClellan, 1972). Standard Sources The basic slag (Escorias Thomas) used as one of the standard sources of P was produced at the Pas del Rio steel works in Colombia and contained 15% total P205. The triple superphosphate contained 46% total P205. Greenhouse Experiment For the greenhouse experiment, samples of a silty clay loam surface soil were obtained from the agronomy field of the Carimagua CIAT-ICA Research Station in the eastern plains of Meta, Colombia. This soil, an oxisol, is classified as a typic haplustox; clayey, kaolinitic, isohyperthermic family. Upon arrival at the CIAT green- houses in Palmira, Colombia, the soil was fumugated with methyl bromide for four days, air—dried, screened, mixed, 27 and stored in plastic bags. Properties of the soil before fertilizatibn are shown in Table 5. Plastic pots, each containing 3 kg of air dry soil, were used as greenhouse containers. Each of the sources of phosphorus was added at rates to supply 50, 100, 200, and 400 ppm P. A treatment with no phorphorus was also included. The pots were arranged in a randomized block design with six replications. Uniform levels of urea, K2804, and MgSO4.7H20 were applied to all pots to supply 5 ppm N, 38 ppm K, and 38 ppm Mg, respectively. Lime was not applied. All fertilizer materials were thoroughly mixed with the soil prior to planting. Of the six replications in the experiment, three were not cropped, but were maintained at approximately field capacity to be sampled periodically for selected laboratory measurements. The three remaining replications were initially allowed to incubate for 30 days before planting the legume Stylosanthes guyanensis (CIAT 136). Because of inadequate stands and poor growth, the soil in the pots was remixed, incorporating the Stylosanthes residue, additional urea added to supply 200 ppm N, and planted to guinea grass (Panicum maximum). The total time between the initial application of the fertilizers and the planting of guinea grass was 90 days. Moisture levels were maintained at approximately 60% of field capacity in all pots during the cropping period. 28 m we mm mm Aomo m>flpommmm sv acupauspam He oo.vH mm.m H5.H em.m Aw ooH\umev omo m>Hpomcum mm.o mm.m om.H os.m AEm ooH\umsV H< noxm 06.0 Hm.o vo.o «0.0 Asa oofi\emev a scam Hm.H os.o No.0 mo.o Aew ooH\umev a: noxm om.mH 0H.m mH.o NH.o flew ooH\amev ac aoxm o.m m.m N.H m.H Am Educ and saum m.m m.v o.m s.e Anus“; HHom HNHV mg «.ma m.H m.v A&v mounds cacampo waflpqafim maflsfiq p< mnemmm pgooadnna: xoamSanm xOpmzaamm :oflpaoflmfimmdau .m.D vague ofimze Gamma m unmsflnoaxm caoflm H ucoeflnmmxm uaofim omaosnoouo .meHHmQOHm Hwom HdeHnHll.m m4m<9 29 Soil samples were collected from the uncropped replications 10, 30, 50, 70, 90, and 190 days after the initial fertilizer application. Three cuttings of guinea grass were harvested 50, 70, and 100 days after planting. Soil samples were also collected from the cropped pots at the time of the third cutting. Field Experiment with Cassava The field experiment with cassava (Manihot esculenta crantz), Llanera variety, was conducted in the Tabaquera field of the Carimagua CIAT—ICA Research Station in the eastern plains of Meta, Colombia. The soil in the experimental area was an oxisol with the same classification as the soil described in the green- house experiment. Properties of the soil at the begin— ning of the experiment are shown in Table 5. Rainfall in the area during the growing period of the experiment (October 20, 1975 to October 13, 1976) totaled 2,668.6 mm with a three-month dry period during January through March, 1976. The average temperature was 26.20C. Monthly climatic data are shown in Table 6. On September 25, 1975, dolomitic limestone was broadcast at the rate of one-half ton/ha and incorporated into the soil by disking. At the time of planting (October 20, 1975), each source of phosphorus (except Sechura phosphate rock) was applied at rates to supply 30 TABLE 6.--Carimagua Climatic Data. O “gm C Mean Max. Min. (%) October 75 210.6 26.2 30.4 22.0 81 November 136.5 26.3 30.3 22.2 79 December 158.7 26.0 30.1 21.8 77 January 76 0 26.1 30.8 21.3 — February 30.3 27.1 32.5 21.7 61 March 66.8 27.4 31.9 22.9 66 April 293.1 26.7 30.8 22.5 79 May 240.1 25.8 29.3 22.4 83 June 453.9 25.1 28.2 22.0 88 July 425.0 24.6 27.8 21.3 86 August 197.0 25.8 29.9 21.7 85 September 317.0 26.4 30.5 22.2 85 October 139.6 27.6 31.6 23.6 80 31 50, 100, and 400 kg P205/ha. A treatment with no P was also included. Each of the finely ground phosphate rocks and the basic slag were broadcast and incorporated to a depth of approximately 12 cm with a rototiller. The triple superphosphate was applied in a band 5 cm deep and 10 cm to the side of the seed. Uniform levels of nitrogen, potassium and zinc were applied to each treat— ment as follows: 1. Nitrogen: 50 kg N/ha as urea banded at the time of planting and 50 kg N/ha banded after 60 days. 2. Potassium: 100 kg KZO/ha as K2S04 banded at the time of planting and 100 kg KZO/ha as KCl banded after 60 days. 3. Zinc: 10 kg Zn/ha as ZnSO4 banded at the time of planting. The cassava was planted in plots 5.6 m by 6.4 m in rows 80 cm apart with 80 cm between plants within the row. The plots were arranged in a split plot design, with levels of application as the main plots and sources of P as the sub plots. There were three replications. Each treatment with triple superphosphate was duplicated so that the effectiveness of initial P application could be compared to annual applications of triple super- phosphate. 32 Soil samples were obtained 50, 110, and 360 days following application of the fertilizer from a composite of 10 random probes to a depth of 20 cm collected from each plot. On October 13, 1976 (360 days after planting), the center 12 plants in each plot were harvested. Fresh weights were measured for edible roots and above ground forage. Field Experiments with Beans The field experiment with beans (Phaseolus vulgaris L.), Variety Huasano P 588, was conducted at the "Las Guacas" Research Station, Cauca, Colombia. The soil in the experimental area is an Andosol which, under the U.S. comprehensive system, is classified as a typic umbrandept. It is situated on a gently sloping altiplane in a region of volcanic mountains. The average annual rainfall is 1923 mm with a ten-month wet and a two-month dry season. The average temperature is 17.50C. Agricultural limestone was broadcast at the rate of 4.7 tons/ha 42 days before planting, and incorporated into the soil by disking. Properties of the soil before liming and at planting are shown in Table 6. At the time of planting (March 11, 1976), all sources of phosphate rock and the triple superphosphate were broadcast at rates to supply 50, 100, 200, and 400 kg P205/ha. A treatment with no phopshorus was included, and all 33 treatments with triple superphosphate were duplicated for later evaluation of residual effect, as described in the field experiment with cassava. All sources were incor- porated into the soil to a depth of approximately 12 cm with a rototiller. Uniform rates of urea, KCl, MgSO4.7H2O, and Borax were applied to all plots in a band approximately 5 cm to the side of the bean row and 5cm deepat the time of plant— ing to provide 80 kg N/ha, 40 kg KZO/ha, 5 kg Mg/ha, and 1 kg B/ha, respectively. A solution of 1% MgSO4.7H20 was applied as a foliar spray at mid-season. Furadan was also applied in the band at planting at a rate of 30 kg/ha. The beans were planted in plots 3.15 m wide and 5.5 m long,with 45 cm between rows. The plots were arranged in a split-plot design with levels of application as the main plots and sources of phosphorus as the sub plots. There were four replications, but because of varia- tion due to a drainage system in one area, only three replications were harvested and sampled. Scil samples were collected from a composite of ten probes to a depth of 20 cm from each plot 30, 65, and 120 days after treatment application. Ten randomly selected plants (entire above ground portion) were col- lected 30 days after planting and five randomly selected plants were collected 65 days after planting. At the time of harvest (120 days after planting), the bean plants were 34 counted and pulled by hand. A border of 68 cm on each side and 75 cm on each end was left unharvested in each plot. The edible beans were weighed and analyzed for moisture content. Yields were adjusted to a uniform level of 14% moisture. The same variety of beans was replanted on October 4, 1976. Triple superphosphate was reapplied to appropriate plots at the same rate as the initial applica- tions in each replication. The treatments involving phosphate rock and the remaining triple superphosphate plots received no further additions of phosphorus, but were used for residual evaluations. Uniform rates of N, K, Mg, and B were repeated in the same manner as for the first crop. The second crop was harvested January 20, 1977. Laboratory Procedures Soil Analysis All soil samples were air dried and ground to pass a 20-mesh sieve. Available P was extracted for one minute with Bray P-l reagent (0.03 N NH F + 0.025 N HCl) at a 1:8 4 soil-solution ratio. The phosphomolybdate blue complex was developed using the Ammonium Molybdate—Ascorbic Acid method (Watanabe and Olsen, 1965). Transmittance was measured on a spectronic 20 colorimeter at 660 milli— microns. 35 Water soluble P was determined in 1:1 soil-water mixture (50 g soil + 50 ml distilled water) following a 24 hour equilibration which included three l-hour shaking periods. The mixtures were first vacuum filtered through Whatman #40 filter paper, and then through metrical 0.20 um filters. Phosphorus in solution was concentrated using the iso—butanol procedure described by Kempers (1975) but modified to develop color by the ammonium molybdate-ascorbic acid method (Watanabe and Olsen, 1965) . Soil pH was determined in both distilled water and 0.01 N CaCl2 in a 1:1 soil-solution ratio. The sus— pensions were allowed to equilibrate for 30 minutes with three periods of stirring. Readings were taken on a Coleman Model 38A pH meter. Exchangeable Al was extracted with l N KCl and measured by titration with 0.1 N NaOH (McLean, 1965). Titration with NaF on random samples of the three soils showed negligible amounts of exchangeable hydrogen, so analysis was limited to a single titration with NaOH and the resulting measurement of total acidity was assumed to represent exchangeable A1. Exchangeable cations were extracted for 30 minutes with l N ammonium acetate, pH 7, with a 1:5 soil-solution ratio. Calcium and Mg were determined by atomic absorp- tion spectroscopy with a Techtron AA 120 atomic absorption spectrophotometer. Lanthanum (La) was added to the 36 filtered extract to a final concentration of 2000 ppm La. Potassium in the filtered extract was determined by emission spectroscopy with the Techtron AA 120 unit. Effective CEC was calculated by summation of the exchange- able Al, Ca, K, and Mg. Plant Analysis Phosphorus, Ca, Mg, and K content of the plant tissue was determined following digestion of a 0.1 g sample of plant material which had been ground to pass a 40-mesh sieve and dried at 65°C. The samples were digested with a 2:1 mixture of nitric acid and perchloric acid in an aluminum digestion block. The digested material was diluted to 50 ml with distilled water. Concentration of P, Ca, Mg, and K were measured as described for the soil analysis. Aluminum, Mg, and Zn were determined following digestion of 0.5 g plant samples in the nitric acid and perchloric acid mixture, and dilution to 50 ml with dis- tilled water. Aluminum was measured by the alumincn method (Jackson, 1958 and Hsu, 1963). Transmittance was measured colorimetrically at 520 millimicrons. Manganese and Zn concentrations were measured on the Techtron AA 120 atomic absorption spectrophotometer. 37 Statistical Analysis A statistical analysis of variance was conducted for all data collected from the greenhouse, field and laboratory measurements. A randomized block design was utilized in the greenhouse while a split—plot design was used in the field. In both field experiments, level of application represented the main plots with source of phosphorus as the sub plots. A Duncan's Multiple Range Test was used to identify statistical differences between treatments. Simple linear regressions were calculated to describe the relationships between the citrate soluble P 0 content of the phosphate rocks and source effects on 2 5 yield and soil test measurements. RESULTS AND DISCUSSION The various phosphate materials were evaluated in a greenhouse experiment with guinea grass and field experiments with cassava and beans. The results of the field experiments are for the first year from plots designed for residual studies. Greenhouse Experiment with Guinea Grass The Soil used in the greenhouse experiment, an Oxisol, was extremely low in P (1.3 ppm P extracted with Bray P-l solution), and strongly acid (ph 4.7). Plant Response to Phosphorus When no P was applied, growth was so poor that no yields were obtained in any of the three cuttings. At rates of 50, 100, 200, and 400 ppm P, the average yields of all sources for each rate of P were 1.74, 6.44, 11.47, and 13.37 g/pot, respectively (Table 7). Comparisons of average yields of all rates for each P source were as follows: Basic slag = Sechura PR > North Carolina PR Gafsa PR > TSP = Central Florida > Huila PR = Tennessee PR > Pesca PR. The highest yield.(l9.67gj was obtained with Sechura PR at the 400 ppm rate. Highest yields when 50 38 Ame. u av pmme mmaam mflaflpfiss m.:wocsa spas anchommwc sandwOHmwcwww Ho: was pmupwa mEmm may saws mcams* 39 sm.mH >4.HH 44.6 wu.H mwmgm>< 00.0 1111 Honpcoo m ee.m mm.m mm.m se.m om.o mm aommm we mm.v wH.s ss.© we.m Hw.o mm mmmmmaqme c mm.m 84.8 He.s mm.v om.o mm «Husm o ow.m Hm.HH mm.m ms.v Hewfi mm aeflnoam Hapuamo a mm.oH mo.sH me.mH mm.» Hm.m mm «memo n Hm.oH mo.mH oH.mH mm.o mm.H. ma aqflfionao spuoz a oH.mH 56.8H mm.ma mH.m mm.m mm «nanoom a em.ma mm.sH ow.mH om.mH HH.¢ waam onwam o Ho.m om.mH 6H.NH em.m mm.H opaaamondnmmam mamfiue IIIIIIIIIIIIIIIIIIIIIIIIII poa\8w IIIIMIIIIIIIIIIIIIIIIIII *mwanm>< oow . com ooH on oousom Am Eamv aofipdoflaqmm Ho opwm .msnonmmona mo wousom can ovum mp noncommm mm mmsonqmmuo on» an mmauo «mango mo mwnflppso amuse Ho Apnmflma sync cams» Havoenu.s mamas 40 and 100 ppm P were applied were obtained with basic slag, but yields with basic slag were lower than those with Sechura and North Carolina PR when 440 ppm P was applied. Tissueanalysis suggest that Zn may have been limiting and Mn excessive for plants grown at the 200 and 400 ppm levels of P when basic slag was applied (Appendix Tables A34-A39). This may have been related to the higher soil pH values when basic slag was applied with respect to the Zn and to the high Mn content of the slag. The lower yields obtained with TSP as compared to those obtained with basic slag, Sechura, North Carolina, and Gafsa PR is probably related to the lower pH and Ca values asso- ciated with the TSP treatments. These effects will be discussed in detail in a later section. The Relative Agronomic Effectiveness (RAE) has been related to the citrate solubility of P in phosphate rocks (Caro and Hill, 1956; Bennett, et al., 1957; Terman, et al., 1970; and Engelstad, et al., 1974). If the RAE of the average yield of all rates of application of basic slag is 100%, the RAE of the phosphate rocks varied from 27% to 94% (Table 8). The citrate soluble P content of the phosphate rocks was linearly correlated (p = 0.01) with yields of guinea grass at all rates of application (Figure l). The degree of correlation as measured by R values increased as the rate of P applica- tion increased. This may indicate that, although the 41 TABLE 8.--Relative Agronomic Effectiveness RAE) of Nine Phosphate Fertilizers in the Greenhouse Experiment with Guinea Grass. Source RAE (%) Triple superphosphate 62 Basic slag 100 Sechura PR 94 North Carolina PR 82 Gafsa PR 30 Central Florida PR 53 Huila PR 41 Tennessee PR 35 Pesca PR 27 42 .wxoou madnnmona :H a mannaom mpmapfio can wwwnm seesaw mo wmcfipuso mouse mo naoflh ammspon anchwpaHmMIl.H madman 62. s. mcan. “1.53% 35:8 N. m n v m N _ o _ 7 4 fl q Lisl‘hall‘ ‘ _ o \\ 9.6.1.1 on in M E 2b.». 0 00. lo. 9 l d 0 I.- 1m. 50...: CON . . now 000.». 00¢ 43 citrate solubility of P in phosphate rock is a highly significant factor in determining its relative effective— ness, the lower number of phosphate rock particles in the lower rates of application do not provide sufficient probability for near contact between phosphate rock particles and plant roots to fully reflect the phosphate rock potential. Extractable Soil Phosphorus (Bray P-l) Extractable soil P (Bray P-l) was higher when TSP was applied than when basic slag or the phOSphate rocks were applied (Table 9). At the time of planting 90 days after P application, the extractable P levels were as follows: TSP > basic slag = North Carolina PR > Gafsa PR = Sechura PR > Central Florida PR > Huila PR = Tennessee PR > Pesca PR. Yields followed the same order except for TSP and Sechura PR. Possible reasons for the deviations of these two materials will be discussed later. The response curves (Figure 2) for the phosphate rocks and TSP were separate and distinct. The plant response Was much lower at a given Bray P-l level with TSP than with the other sources. Barnes and Kamprath (1975) found this same relationship with corn on a Hyde soil, and suggested that this could indicate the presence of some acidulation product from the phosphate rock that the plant can utilize but is not measured by the extractant. .Amo. u ac amme mmcam mfidfipfiss m.:mocso news pampwHMHp zapcaoflwficmflm #0: ohm noupma mEmw may saws memo: 44 * m.H Hospcoo w N.m b.5a ¢.m ®.® N.m mm momma o N.¢H m.¢m ®.bm m.m m.m mm owmmmccwe mm m.NH N.om m.mH w.w 5.6 ms «Mann 6 ®.mH m.um m.om m.mH N.® mm mafihon Hmsucmu o v.Hm m.H® w.®m >.mH m.m ma «made 9 m.>m ©.ow H.6v m.®H 6.5 mm acwaondo sphoz o b.mm m.©m v.>m N.®H w.w mm «panoom n b.5m m.m> m.$¢ m.om m.> wwam ofimwm a m.mv m.Hm «.mv o.mH m.m mnanmmonanmmsm mamfiue *owmno>< oov oom OOH on Am Eamv a mo mpdm oopsom AEQQV m manwuowupxm .m Ho mousom can ovum an vmuoowmm mm aofluaofladda d pmpw< msao om mHHom omsonaooau an Aaum sanmv m mHBApoanpxmnu.m mqm55 00. om cm on om Om ow on ON 0. o _ _ _ + _ _ _ _ . n :1 o I w M 3 m l m .. 9 / d m | | ‘X .I. 1 0. 63m 064m oillllolll O xoom 35¢on .1 l 8 46 Higher levels of exchangeable Ca where PR and basic slag were applied may explain the yield difference (Table 10). Calcium levels probably do not explain the results of Barnes and Kamprath since lime had been applied at the rate of five tons per acre in their experiment. Barnes and Kamprath (1975) alternatively suggested that the possible difference in response curves could be due to the fact that P diffusing from the TSP granules was immediately available for reaction with the soil and subsequent extraction with the Bray P-l solution. The dissolution of the phosphate rock, on the other hand, is a slow process and only a relatively small portion of the P from this material would be extracted by the Bray P-l solution. It is possible that both of these factors con- tributed to the difference in the shape of the response curves obtained in this greenhouse experiment where sup- plemental Ca had not been supplied. The response curve obtained with basic slag (Figure 2) as the source of P would tend to suggest the contribution of Ca as the pri- mary factor since it is a source which is highly soluble, and yet showed the maximum response to a given level of extractable P while, at the same time, having the highest levels of extractable Ca. This trend continued up to the highest rate of application where both a Zn deficiency and Mn toxicity limited plant response as described previously. The extractable soil P (Bray P-l) was highly correlated A88. n 88 8888 88888 8H8H8H88 8 888859 anB pcmanHHc mecmonchHm Ho: 888 HmupwH @888 ms» nHHB mc882* 47 mmm.o Honpcoo 8 888.8 88H.H 888.8 848.8 884.8 88 88888 8 848.8 884.H H48.H 888.8 H88.8 88 888888888 8 888.H 88H.8 888.H .H88.H 888.8 88 8HH88 8 88H.H 888.8 88H.H 888.8 888.8 88 88888H8 H888888 8 888.H 888.8 448.H 884.H 888.8 88 88888 88 H88.H 888.8 8H8.H 48H.H 888.8 88 88HH8888 88888 88 884.H 484.8 888.H 888.H 8H8.8 88 8888888 8 888.8 888.4 8HH.8 8H8.H 888.H 88H8 8H888 8 888.8 888.H 888.8 888.8 884.8 88888888888888 8H8H8H IIIIIIIIIIIIIIIIIIIII Ew ooH\dme IIIIIIIIIIIIIIIIIIII 888888>8 884 888 88H .88 888888 Am 899v aoproHHma¢ Ho 898m .A888888HH888 88888 8888 88H8 Hmm>u8m Hmch Ho mEHB H8 HHom 8850888080 UmaQono 8H 80 oHnmmqunoxmln.oH mqm<9 48 (P = 0.01) with citrate-soluble P in the phosphate rock at each rate of application (Figure 3). The degree of correlation increased (higher 3 values) as the rate of application increased, but the magnitude of their increases was not as great as that noted for yields. Extractable P was removed by a solution that was in contact with all soil particles in the sample used, while uptake by the plants was probably related to the extent and distribution of the root system. Assuming a random distribution of both PR parti- cles and plant roots in each pot, the probability of an adequate number of roots being close enough to a suffi- cient number of PR particles to absorb enough P to reflect differences in reactivity between different phosphate rocks is much greater at higher rates of application. Variation from the phosphate rock potential would there— fore be amplified to a greater extent at low rates of application than would be measured by P extraction. When a soil sample is extracted with a relatively large volume of extracting solution, a more complete contact between soil, phosphate rock particles and extracting solution would be expected, and differences in reactivity between phosphate rocks would be more precisely reflected. Water Soluble Soil Phosphorus Extractable P (Bray P-l) was highly correlated with water soluble P in the soil for all rates and 49 90'- , 400 80 ‘- r =O.96l 60*- 50- 200 r=O.982 4O*‘ 30"- BRAY PIEXTRACTABLE P, PPM X O I I I I I I O I 2 3 4 5 6 7 CITRATE SOLUBLE P205 , °/o ROC K Figure 3.—-Relationship between Bray P-l extractable P in greenhouse soil and citrate soluble P in phosphate rocks. 50 sources of P (Figure 4). The amount of water soluble P varied from 0.004 ppm P in the control treatment to 0.061 ppm P when 400 ppm P was applied as basic slag (Table 11). The concentration of water soluble P was highly corre- lated with P uptake (Figure 5) and to yield (Figure 6). There was a single linear relationship between water soluble P and P uptake for all sources while yields demon- strated one curvilinear relationship with TSP and a dif— ferent curvilinear relationship for the basic slag and the phosphate rocks. This would tend to support the con— tention previously discussed that a factor other than P was limiting yields when TSP was applied. Water soluble P 10 days following TSP application was much higher than when the other sources were applied, and decreased rapidly for all sources (Figure 7). Measure- ments obtained from completely remixed samples at each sampling date showed that by the time of the final harvest, the phosphate rocks from both North Carolina and Gafsa were maintaining higher, but nonsignificantly higher, levels of water soluble P than the TSP treatment, while the Sechura PR was equivalent to the TSP (Appendix Table All). The decrease in water soluble P between the time of planting and the time of the final harvest was greatest at the high rates of application. The level of water ‘ soluble P at the time of planting was highly correlated with the citrate soluble P in the phosphate rocks at both 51 .Amo. av umme mmcam mHQHHHSE 8.88ocsa 88H? 8:888HHH8 >HHG80HHH8me 80: 888 88888H 888m 888 nuHB 88882 * woo. Houpcoo 8 HH8. 8H8. 8H8. 8H8. 888. 88 88888 8 888. 4H8. 888. 888. 888. 88 888888888 8 488. 888. 8H8. 888. 888. 88 8HH88 888 888. 888. 488. 8H8. 8H8. 88 8888888 H88888o 88 888. 888. 888. 888. 488. 88 88888 888 888. 8HH. 888. H88. 888. 88 88HH8888 88882 888 888. 888. H88. 8H8. 8H8. 88 8888888 8 888. H8H. 888. 8H8. HH8. 88H8 88888 88 848. 888. 848. 8H8. 8H8. 88888888888888 8H8H8e IIIIIIIIIIIIIIIIIIIIIIIIII m Ema IIIIIIIIIIIIIIIIIIIIIIIII 88888888 884 888 88H 88 888888 Am BQQV aoHH80HHmm< Ho 888m .80H880HHQQ< 888H8 8889 08 HHom 8850888880 cmgmonoao 8H m mHnsHom 88883II.HH mqm¢B 52 .IZO— .IOO *— .080 *— .060 I— WATER SOLUBLE P, PPM .040 *- .020 ‘— l J l l I O 20 4O 60 80 IOO BRAY EXTRACTABLE P, PPM Figure 4.--Relationship between water soluble P and Bray P-l extractable P in greenhouse soil 90 days after application. 53 .HH08 mmzoaaowaw 8H m mHnaHom 88883 888 mmmuw amaHaw Ho mwcHuano 88888 as A Ho @8889: 8083882 QHnmaoHumHmmlu.m mustm Sun. .a meDJOm cubs? 88.. 88.. 888. 888. 848. 888. 8 _ _ 4 _ 4 4.. .81 8 10:! Id 6w ‘ smudn d 54 .HHow 0800888888 :H m manHow 80883 088 8888M wmcsz H0 wwaHupso @0888 H0 chH8 8883800 QH8880HH8H0m|n.m mnanm 2mm .8. unaqjom KMFSS ON... 00.. 80. 80. 80. ONO. — A _ H _ _ O 93m 295 m . xoom whdramOIQ . 10d / 9 013M '76F .72 ~— .68 — .64— .60— o-- TSP .56— o— N.CAROL|NA PR A- PESCA PR .52— x— HUILA PR WATER SOLUBLE P, PPM FINAL HARVEST IO 30 50 70 ISO ' DAYS FOLLOWING APPLICATION Figure 7.-—Re1ationship between concentration of water soluble P in greenhouse soil receiving 400 ppm P and time following application. 56 the 200 and 400 ppm P rate of application (Figure 8). At the low rates of application, water soluble P was very low and was not significantly correlated with citrate soluble P in the phosphate rocks. Effect of Phosphate Rocks on Soil pH Soil pH increased as the rate of P application increased for basic slag and for the North Carolina, Sechura, Gafsa, Central Florida, and Huila phosphate rocks (Table 12). When soil pH was increased by phOSphate rock applications, exchangeable Al decreased and exchange- able Ca increased. The percentage of the effective CEC that was saturated with Al decreased when phosphate rocks were applied which had high citrate solubility of P, but decreased very little with TSP or phosphate rocks with low levels of citrate soluble P (Figure 9). Marked decreases in Al saturation were noted when basic slag was applied. Correlation coefficients indicate that the effect of citrate solubility on Al saturation is greater at high rates of application than at low rates (Figure 10). This would suggest that the liming effect of phos— phate rock would not be of substantial benefit, regardless of rock reactivity, unless it were applied at heavy rates. 57 .Amo. 8.888850 8883 888888886 8888888888888 808 888 888888 8888 8a» 8883 88882* n av 888B 88:8m 8HQHHH=2 88.8 8088808 8 85.8 85.8 85.8 88.8 85.8 88 88888 8 88.8 85.8 85.8 88.8 85.8 88 888888888 88 88.8 58.8 88.8 88.8 58.8 88 88888 88 88.8 88.8 88.8 85.8 85.8 88 8888088 8888888 8 88.8 88.8 88.8 58.8 55.8 88 88888 8 88.8 88.8 58.8 88.8 88.8 88 88880888 88882 88 88.8 58.8 88.8 88.8 85.8 88 8888888 8 88.8 88.8 88.8 88.8 85.8 8888 88888 8 88.8 58.8 88.8 88.8 55.8 88888808888888 888888 IIIIIIIIIIIIIIIIIIIIIIIIIII mm IIIIIIIIIIIIIIIIIIIIIIIIII 888888>8 888 888 888 88 888808 A8 888v 8088888H88< mo 888m .80888888888 88888 8889 on 8808 8890888880 88880888: 88 8858882 88883I8808 H88 88 mQII.NH mqm8808888 80 8088888888 8888888<|I.m 888888 2% 8 20:49.53 “.0 82¢ 00¢ 008 00. 08 838 0.848 8 _ _ mm .88 10.: 0/ / $408 0828 III/I III?” $1.08 30.. III 7" I ’I’ am» ll“./. 01/ [I] [In]! I [I .Il.ll:¥lll.ll lllwllllol.l! an 0. ON C) 88 8 2 8 3 % ‘Nouvamvs IV C) O) 5 60 .88008 888888088 88 8 8888808 8888880 888 8808 8880888888 80 8088888888 8< 8883888 88888088888m||.o8 888888 0608 8.808“. 8.5308 828:0 8. 8 n v m m _ 0 _ 8 8 8 8 8 8 0 I0. 08 v 880;». 1 1 00¢ . I 08 m . m . 10¢ v u Nmmfnb o 0 all on M 008 I 108 % O / 3 82..-». . 4. 00. a . o / . 108 M 83.0-2 < a .. . . :08 m on 4 ‘ . a! I M 3 cm 0 3 3 00. 61 Field Experiment with Cassava The field experiment with Cassava was located on an oxisol similar to that used in the greenhouse experi— ments; the greenhouse soil sample was obtained about 10 km from the site of the field experiment. Extractable P (Bray P-l) was 1.2 ppm P, about the same as that of the soil used in the greenhouse, while the soil pH of 5.0 was slightly higher. Cassava Yields as Affected by Rate and Source of P Marked yield increases were obtained with applied P. The average yields from all sources at each rate of applied P were increased 96%, 145%, and 180% with applications of 50, 100 and 400 kg P205/ha, respectively (Table 13). Yields were significantly increased by all rates and sources of P as compared to that when no P was applied. Yields at each rate of P application were related to the source of P. Highest average yield for the three P rates for each source were obtained with TSP and basic slag at 20.3 t/ha of edible roots. Since the TSP was applied in bands, the results with TSP cannot be used to evaluate the other sources; therefore, basic slag was used as the standard P source. The yield obtained with basic slag was significantly higher than that obtained with any of the phosphate rocks. 62 0V 888B 8808M 88088002 8.080009 0883 808088880 0080808880808 800 808 088888 8888 808 0803 8088s .00888088>8 808888 88508880 00m* in"... * .00888088008 880008 00m * 0.0 0000000 0 0.00 0.00 0.00 0.00 00 00000 0 0.00 0.00 0.00 0.00 00 000000008 00 0.00 0.00 0.00 0.00 00 00000 00 0.00 0.00 0.00 0.00 00 0000000 0000000 0 0.00 0.00 0.00 0.00 00 00000 0 0.00 0.00 0.00 0.00 00 00000000 00002 0 0.00 0.00 0.00 0.00 0000 00000 0 0.00 0.00 0.00 0.00 0000000000000000 000008 0 0.00 -0.00 0.00 0.00 000000000000000 000008 IIIIIIIIIIIIIIIIIIII 80\8008 IIIIIIIIIIIIIIIIII 00088808>< 000 008 on 800008 000\0000 000 00000000000 00 0000 .800m 8>88880 manwvm HO UHmwwll.mH mqm¢9 63 Yields obtained with the North Carolina and Gafsa phosphate rocks were significantly higher than those obtained with the Tennessee and Pesca rocks, with inter— mediate yields from the Central Florida and Huila rocks. As seen in Figure 11, yields tended to increase with increasing rates of all sources to 40 kg/ha of phosphorus except TSP. In similar experiments on this soil type, maximum yields were obtained with about 300 kg/ha of banded phosphorus (R. H. Howeler, Personal Communication, 1976). It is probable, however, that maximum yields can— not be obtained with band applications of P on soils as severely deficient in P as that where this experiment was located. Even higher yields might have been obtained with broadcast rates of TSP. The mean RAE (Table 14) indicates the same rela- tive order of effectiveness in the field as in the green- house, but the relative differences between sources was less in the field. Coefficients measuring the degree of correlation between citrate soluble P205 in the rocks and yields indicate that when 50 kg P205/ha was applied, there was no significant effect on yields as citrate soluble P in phosphate rocks increased (Table 15). At this rate, there was little difference between the sources with only 3.3 t/ha separating the highest and lowest yield of edible root, and 4.4 t/ha difference in total plant yield (root and forage combined). 64 TABLE l4.-—Relative Agronomic Effectiveness of Eight P Fertilizer Materials on Cassava in the Field. Source RAE (%) Triple superphosphate 100 Basic slag 100 North Carolina PR 82 Gafsa PR 84 Central Florida PR 73 Huila PR 70 Tennessee PR 66 Pesca PR 67 TABLE 15.—-Correlation Coefficients Between Cassava Production and Citrate Soluble P205 of Phosphate Rock as Affected by Rate of Application. Rate of Application (kg P205/ha) 50 100 400 Citrate Sol. vs Root Production .377 .808 .489 Citrate Sol. vs Forage Production .273 .718 .847 Citrate Sol. vs Total Production .355 .792 .795 65 26- BASIC SLAG 248 TSP 22— , FLORIDA N.CAROLINA _ 0,. GAFSA 2° // PESCA / /, 0’ ,vTENNESSEE l8 // ,zf’HUILA 2 ,-0 0 ‘7 \ ' / / b— ,’ 3 l6 / E >- '5 0 I4 I: <1 > < 3 I2 4 0 no 8 6 1 1 1 1 J l 1 A O 50 IOO ISO 200 250 300 350 400 RATE OF APPLICATION, KG P205 lha Figure ll.-—Yield of edible Cassava as affected by rate of application. All sources were broadcast except TSP which was banded. 66 As the rate of application increased to 100 kg P205/ha’ citrate solubility was significantly correlated with both root and total plant yields. However, at the highest rate of application, total plant yields continued to be related to the citrate solubility, but root yield was not. In this case, as with the low rate of applica- tion, root production was relatively constant regardless of P source, with only 2.9 t/ha difference between the highest and the lowest. This would suggest that the cassava plant, by continuing to respond to increased application of phosphate rock, depleted available K to a level which restricted root growth (Appendix Table B-lB). CIAT (1974) has shown that cassava root production is significantly decreased by low K levels. Thus, it is possible that con- tinued response to P would be obtained only at higher levels of K. Extractable Soil Phosphorus The level of Bray P—l extractable P was related to both the rate of application and the phosphate source (Table 16). The mean available P increased over the con- trol plot by 185%, 335%, and 1023% with applications of 50, 100, and 400 kg P205/ha, respectively. For the sources which were broadcast, the level of Bray P-l extractable P when basic slag was applied was significantly higher than 67 .880. u 0V 8888 8008a 88088802 8.088009 0883 808888880 8880888880888 800 888 888888 8888 808 0883 80882 * 8.8 8088000 8 0.8 8.0 8.8 8.8 mm 88880 8 0.0 m.8 8.8 m.N m0 888880088 0 0.0 0.8 0.0 8.8 mm 8880m 8 0.0 8.8 0.8 0.8 mm 8088088 8888080 0 m.w 0.08 8.0 8.8 mm 88880 0 8.0 m.w8 m.m m.m m0 80880880 08802 8 8.88 8.0m 8.8 8.8 0888 8888m IIIIIIIIIIIIIIIIIII a San IIIIIIIIIIIIIIIIIII 080888>0 000 008 on 808008 800\8o80 000 00000008000 00 0000 .00888088000 88888 0800 88 0>00000 000a 0000000000 08000 00 88:0 00000 0 08000000000uu.00 00008 68 the phosphate rock sources. Among the phosphate rocks extractable P levels were higher when North Carolina PR and Gafsa PR were applied than when the other rocks were applied. No statistical differences were found between the Central Florida PR, Huila PR, Tennessee PR, or Pesca PR. As time progressed, the available P increased with all treatments on which cassava was planted (Figure 12). This was in contrast to the results obtained in the green- house experiment with Guinea grass in which there was a progressive decrease in Bray P—l values. It is possible the increase was due either to the mineralization of organic P following the first tillage of a virgin soil, or excretions from the cassava root systems which were not associated with the Guinea grass in the greenhouse. The correlation between extractable P and citrate solubility of P in phosphate rocks was highly significant (p = 0.01) at all rates of application (Figure 13), and the Bray P-l values served as a good indicator of the final cassava root yield (Figure 14). It was observed that 90% of the maximum root yield was obtained with Bray P-l available P at a level of 7 ppm P. The curvi- linear relationships obtained also indicate that although total plant production continued to respond to high levels of available P, the edible root yield failed to respond in the same degree, and that the majority of the 69 .0o888888am8 008308808 8E88 an 88888888 88 8808 800888880 08 m 888888888x8 8am >88mnu.88 880888 8:5 .82: 0.0 888 808 888 . o: o. _ on 1 _ _ 8 _ \ N .6528 c «8080 , 0 35: «0.00.: .\ \ 8 888882288 \\\ I 0. 48040 \ \ \ 4230048 .2 \ \ I 0. 1 0. 041.8 0.848 de 'd 378VlOVHiX3 l-d AVBB BRAY Pl EXTRACTABLE P, PPM 70 20P- 4oo l8—- 0 o '6'" H.986 l4— I2— IO— 8}— 0 ~00 6L ' 100 O r=.674 48 ' I - r ' 8. 4 2__ I ' . r 82 / . . o 1 l 1 l 1 l J O l 2 3 4 5 6 7 CITRATE SOLUBLE P205, °/. ROCK Figure 13.--Relationship between Bray P-l extractable P in Carimagua soil and citrate soluble P in phosphate rocks. 71 440- 40.. CASSAVA ROOT 8 FORAGE CASSAVA ROOT YIELD, Tl ha O I 4L L l l l J O 4 8 l2 l6 20 24 28 BRAY Pl EXTRACTABLE P, PPM Figure l4.--Relationship between yield of Cassava and Bray P—l extractable P in the Carimagua soil. 72 plant response to high levels of P was in the above ground forage production. Water Soluble P The amount of water soluble P in the soil was not as good an indicator of cassava yield as the Bray P-l extractable P (Figure 15), but did follow the same general pattern. When measured 51 days following application, basic slag and the North Carolina, Gafsa, and Tennessee phosphate rocks had statistically higher levels of water soluble P than the Central Florida, Huila. and Pesca rocks (Table 17). In all cases, the amount of water soluble P was extremely low, ranging from 0.004 to 0.028 ppm P. Soil Acidity When measured 50 days after application, soil pH in a 1:1 soil/water mixture was significantly increased by all sources except the Central Florida, Tennessee, and Pesca phosphate rocks. Basic slag, with a CaCO3 equiva- lent of 67%, was the only source which significantly increased the pH at the 50 and 100 kg P205/ha rates. At the 400 kg PZOS/ha rate, the greatest increases for phos- phate rocks were with the North Carolina, Gafsa, and Huila sources which raised the pH by 0.27, 0.34, and 0.25 units, respectively (Table 18). 73 .880. u av 8886 80080 88088802 8.08800Q 0883 808888888 8880888880088 800 888 888888 8888 808 0883 80882 * 000. 8088000 0 080. >80. woo. 000. mm 88888 8 880. 080. 080. 000. mm 888880089 0 080. 000. 880. 880. mm 88800 0 O80. 080. 800. 880. mm 8888088 8888080 8 080. 080. 880. 080. mm 88880 8 880. 080. 080. 880. mm 80880880 08802 8 880. 080. 880. 080. 0880 88880 IIIIIIIIIIIIIIIIII A San IlnlnlIIIIIIIIIIIIII 008 008 O8 *80888>¢ 888008 880\8088 888 00888088008 80 0888 .00888888008 88888 888a 88 8>8888o 088B 8088888888 08888 08 8 8800808 8888BII.>8 08009 74 .880. 00 8889 88088 88088802 8.088000 0883 808888888 8880888880888 800 888 888888 8E88 808 0883 80882* 88.8 8888000 on 88.8 88.8 98.8 N8.8 mm 8888& 8 08.8 88.8 88.8 88.8 88 888880089 08 88.8 88.8 98.8 88.8 mm 88808 on 88.8 88.8 88.8 88.8 88 8888088 8888080 08 88.8 88.8 88.8 88.8 88 88880 on 88.8 08.8 88.8 88.8 88 80880880 08802 8 88.8 88.8 08.8 88.8 8888 08888 IIIIIIIIIIIIIIIIIIIII mm IIIIIIIIIIIIIIIIIIIII 008 008 08 *88888>< 888008 A88\8888 880 80888888008 80 8888 .00888888QQ< 88888 8880 88 8>88880 088B 808E8880xm 88888 08 8808x82 88883|88om 808 80 80:1.88 88889 75 080. .8808 808888880 808 08 0 8800808 88883 808 8>88880 80 88888 0883880 08080088888m||.88 880888 291 .m wquJOm «H.525 880. 880. 8.0. So. 05. woo. 800. o _ _ _ _ _ _ _ _ o 18 . 18 1 _ O O u 0 N . . . u . 18. a o o o l O 0 0 ON . 188 188 W /J. 'O'BIA 1008 VAVSSVO 76 The exchangeable soil Al decreased as the soil pH increased (Figure 16). The decreases in exchangeable A1 were as follows: Basic slag > North Carolina PR = Gafsa PR = Huila PR > Central Florida PR = Pesca PR > Tennessee PR (Table 19). The actual change in the amount of exchangeable Al resulting from application of the phos- phate sources was small, but the percentage of the effective CEC saturated with Al was markedly decreased (Figure 17). Part of the reduction in Al saturation was due to increased exchangeable Ca which was also related to phosphate rock reactivity. At harvest, 360 days after P application, A1 saturation had been reduced from the level of the control plot by 44% and 39% with the North Carolina and Gafsa phosphate rocks, respectively, at the 400 kg P205/ha rate of application. The greatest decrease at this rate was 86% with basic slag, while the smallest change was 15% with Pesca phosphate rock. There was no significant reduction in A1 saturation at either the 50 or 100 kg P205/ha rates. Field Experiment with Beans The beans were grown on an Andosol which had an initial level of extractable P (Bray P-l) of 2.6 ppm P and an original pH of 4.9. Lime applied at the rate of 4.7 t/ha raised the pH to 5.5 at the time of planting. 77 .880. n 00 8889 88080 88088802 8.088000 0883 808888888 8880888880888 800 888 888888 8888 808 0883 80882* 0.8 8088000 80 0.8 0.0 0.8 0.0 00 88880 8 8.8 8.8 8.8 8.8 00 888880089 80 8.0 8.0 0.8 0.8 00 88800 88 0.8 0.8 0.8 0.8 00 8888080 8888080 80 0.0 8.0 0.8 8.0 00 88880 0 8.0 8.0 0.8 8.0 00 80880880 08802 8 8.0 8.0 8.0 8.0 8888 88888 IIIIIIIIIIIIIIIII 88 008\088 IIIIIIIIIIIIIIII *88888>< 008 008 08 888008 A80\8080 880 80888088088 8o 888m .0088888800< 88888 8880 88 8>88880 088B 8088888080 88880 08 88 8808880808x0II.88 00089 EXCH. Al , MEG llOOG 78 4.4 4.6 4.8 5.0 5.2 Figure 16.—-Re1ationship between exchangeable A1 in the Carimagua soil and soil pH. 79 .08888888008 0 80 888p >0 88888888 88 8808 808858080 808 08 0088800888 8008808¢|n.b8 800880 00¢ T 0448 0.848 40.804... . (omma cl llllllll of new. 9. .zoonaaq “6 828 00. 08 4 _ 0. ON 0n 0? on 00 0h 00. 030 3Al133533 °/.‘Nouvan1vs IV 80 Bean Yield Response to Rate and Source of P In the first crop of beans following P application, mean yields of all P sources were increased 64%, 76%, 115%, and 138% by applications of 50, 100, 200, and 400 kg P205/ ha, respectively, as compared to the no P treatment (Table 20). Using the mean yields of the TSP treatments as maximum production, 90% of the maximum yield was obtained when 190 kg P205/ha was applied as TSP, 290 kg P205 as Gafsa PR and 375 kg P205 as Sechura PR. Yields obtained with all the other P sources were less than 90% of the maximum yield with TSP. A statistical comparison of the yields obtained with phosphate rocks shows that the yields using the rocks from North Carolina, Sechura, and Gafsa were highest while those with Tennessee and Pesca were lowest. Yields with the Central Florida and Huila rocks were inter- mediate. This order is consistent with the results obtained in both of the experiments previously described and as shown in Figure 18, is highly correlated with the citrate solubility of the P in the phosphate rocks at each rate of application. Following the harvest of the first crop, TSP was reapplied at the original rates to plots which had also received TSP before the first planting. The set of plots which received two applications of TSP produced consis— tently higher yields during both the first cropping when 81 .880. n 00 8888 88088 88088802 8.088000 0883 808888888 8880888880888 800 888 888888 8888 808 0883 80882 0o888088>8 888888 88008888 808 x. *8;— * 08888888008 880008 880 .w 888 8088000 88 8888 8888 8888 8888 8888 80 88808 8 0888 8888 8888 8088 8088 00 88880 88 8888 8858 8888 0888 8888 mm 888880088 88 8888 8888 8088 8888 8888 80 8888o88 8888080 8 8888 8888 88mm 8888 0888 80 88880 8Q 8888 8888 8088 8888 8888 80 8800888 89 8888 8888 8088 8888 8888 80 80888880 08882 n mmom 8888 8088 8888 8888 **8888080808omsm 880888 8 0888 888m 888m 8808 8888 *88800800088008 880889 nnnnnnnnnnnnnnnnnnn 880888O8 888 © 80\8x IIIIIunIIIIIIIII ***88888>< 008 008 008 08 888008 Aas\8888 888 80888088808 80 8888 .8088m 80 0080 888Hh mo 088HNII.ON W8m<8 82 .88808 888088008 08 8088 8830808 8880888 808 88088 888v 88888 0889 0883889 88280088888mll.88 880888 x008 .8608“. 38308 828:0 s 8 8 c m 8 _ 0 _ _ _ _ _ 8 4 008 000. 008. 00¢. n w ¢88... 008. A on 008. u 888. u . .0 00. 0008 2 av / 0088 w 888.". 008 00¢~ .888. 00v 0088 l 0088 0008 83 compared fresh TSP to residual TSP. The difference in yield between these plots was as follows: Rate of Application (kg P205/ha) 50 100 200 400 Yield TSP 1 minus TSP 2, lst Crop = 208 225 437 498 kg/ha Yield TSP 1 minus TSP 2, 2nd Crop = 147 672 703 299 kg/ha Since these large differences were present in both crops, it is probable that reapplication yielded signifi- cantly higher only at the 100 and 200 kg P205/ha rates. The yields obtained with residual P in the second crop were in the order TSP = North Carolina PR = Sechura PR Gafsa PR > Huila PR = Central Florida PR > Tennessee PR Pesca PR (Table 21). The yields averaged over all sources were 33%, 64%, 111%, and 160% higher than the yields from the no P plots. The Relative Agronomic Effectiveness of the phos- phate rocks varied from 28% to 93% in the first crop and from 28% to 72% in the second crop when compared to yields obtained with the freshly applied TSP for each crop (Figure 19). For each source except Huila PR. the yields obtained from the second crop were higher than those obtained in the first crop. Little difference was 84 .Amo. n my umme mwcdm mamwpass m.:aonzo sues pcosowwwo zapaaoHMchfiw so: ohm poppoa osmm one news wade: .soflpmSHw>o poommo Hddbwmop pom * *** * .=0wpmoHHQQd assess nom * mwm HOHHGOU o mmos mmmm mmwfl wuwa coma mm «Haas u omvfi soon mmvfi mums vHHH mm «ommd o omoH mmam mmsfi owes mafia mm mmmmwaaoe 0 news mswm wmom mama ommfi mm «canofim Hanpamo n osam mowm Hfivm mama moms mm amyao a snow msom mesa mama onus ma «gunomm n msfim omam amen mmmfl «was mm «afiaouao spuoz n wssm sHom Hmmm mesa mama **mpmnmmosmpmgsm manage a snow mama «mom eavm ovsfi *ouanamonmumdsm manage nnnnnnnnnnnnnnnnnn osspmflos fiva ©.wn\mx Ilnnlnlullllllunn cow oom ooH on ***ommho>< monsom Aan\m0md may noapaofiflaaa no mpam .mnamm Ho mono encomm mo ufioflsuu.fim mqmwpoommo oHEoconwm m>flpmaomul.ma opswwm 20.52005 23:. .mmmzm>_5m..r..u 0.202054 “3.2.5”. domo Maw 1010 W. n 0 no. N 10» 10¢ 10m 40me ... a Low ummmmzzms u » 3E3“. .2523 u .,_ no» 35: u x V 423050 1502 u oz .8 «mazomm u m «mug u u now ..Zaoaumcufizamozammaam 3&5 & mm» L Suzvuzzamoxmmmaam 3&5" . amp 59 E9. 00. ommdnzzoo mmwN_u_.._.mwm w._. Sechura PR > Central Florida PR = Tennessee PR = Pesca PR = Huila PR. 87 mam. sms. was. ass. mono scoomm .ssmss camm osm. mam. was. wmw. mono amass .sfimns swam .m> Am fiance so .Hom mpaapflo Hsm. mam. New. mwm» mono scoomm .cflmas namm Hmm. mam. sew. wmm. mono swung .cfimfis smmm .m> Axoom so so .Hom opmupflo oov com ooa om Aan\momm was :oflpdowama< we mpam oumnawosm as m N .msaom mo cams» and xoom o a mansHom mpanpno cmwsnmm mpcmnonmwmoo soapssonaoonu.mm mamas 88 .Amo. av pmme macam mfianssss w.cmocsn nufls psosowmwv hapswofimwsmfim p0: was umppmfi oEmm on» :uwB madm2*** .soflpasaa>o poommo Husbands som** .soflasOdedw Hassss nom* m.m sonncoo m m.m w.w m.m m.m v.m ma snflsm w s.m v.v m.m o.m H.m ma momma m H.e m.m m.¢ m.v o.m mm mmmmmaams on s.v m.s m.v m.m s.m ma seasons Haapamo as o.m m.ms H.0H o.m o.¢ mm «made so w.m m.m m.o v.m m.m mm «nanomm on s.m s.m w.m ©.v w.m ma masseuse spuoz pa m.w «.mn w.oH H.m s.m **mpanamonqamasm mfianns a w.m m.mH v.oH s.s m.¢ *mpanamosaumasw mflasae ***mmaam>< ooe com ooH on monzom Asa\m0mm mac canpmonaaa< no nude .soHsmowHQQ¢ umpmm mass on madam suns pamsflamaxm camnm man as sand saamv a manauoaanxmuu.mm mqm Huila >Pesca Sechura 2. The P in the phosphate rock soluble in neutral ammonium citrate is a good measure of the relative reactivity of the rock when expressed as "percent of the rock." 3. Phosphate rock can be described as having high, medium or low reactivity with citrate soluble P205 in the range of 5.4 to 6.7 for high, 3.2 to 3.4 for medium, and 1.9 to 2.7 for low. 4. Phosphate rock chosen for direct application on the basis of citrate solubility will show erratic and unpredictable crop response unless applied at high rates. 5. Crop response could be influenced by reduced Al saturation and increased exchangeable Ca as well as the level of available P when phosphate rocks are applied to acid soil without added lime. APPENDICES 100 APPENDIX A GREENHOUSE DATA 101 102 .Amo. u my paws mmaam oaaauasz m.sdoc=o news asmnwwuwu smucsowmwawww son was Hoppofi mean one sass madmsa 00.6 Houusoo a mm.o mm.m mw.o no.0 Ho.o ma.a0mmm mm oo.H NH.4 mm.H 66.6 «0.6 mm mmmmmasme we mm.m oo.¢ m¢.m Hm.H Ho.o mm afiasm u om.m mo.m em.v ww.H no.6 mm aenaoam Hanuaoo n mm.w sm.m mm.m .mm.m vs.o ma amass n Hm.v ma.m Hm.m as.» H¢.o ma asaaonao spaoz as mm.m mH.m so.s no.4 om.o ma «nanomm a sm.m mm.m mm.s ms.m mm.m maam oamam o ms.m mm.m mm.m ms.m NH.o measamoanamasm manage. IIIIIIIIIIIIIIIIIIIIIII poa\8w Illnulllulllulnlllnl *mmano>a cow com ooH om weapon an Emmy sowpmowaaa< no ovum .Hmm>o~dm GWSOQQQQHC Hmhflh On“ EOHH wmdhc “mama—aw HO UHOHV HOQHdS MHQII.H¢ m4m¢9 103 .Amo. u no paws mamas oaaapass m.smoasa spas poopmwmws sauswUHMfiawwm so: who soppma mean one :HHB msmoza oo.o Houpnoo m om.o mo.H mo.o mo.o oo.o mm momma m om.o wo.H mm.~ oo.o mo.o mm mommmaaoe H mo.o ss.H om.H Hm.o Ho.o mm aflasm 0 mo.H oo.m «H.m oo.o om.o mm aoHpon Haapsmo so Ha.m oo.o oH.m Hm.o oo.o mm amuse on ow.m ss.o mo.m mm.H ma.o mm «caHoHao spuoz a oo.m oo.m oo.o os.H om.o mm anssoom pa mm.m HH.o oH.o sm.m oo.o maam oamam 0o ow.H om.m mo.m oo.H oH.o opanomosanmosm manage IIIIIIIIIIIIIIIIIIIIII pon\ew IIIIIIIIIIIIIIIIIIII: aowoso>¢ oov com OOH om . mousom Am 899V QOwudowana¢ mo ovum .HmmeHNN @WSOSGOQHU UGOOQW 02H ECHH mmdhu dmflfifimu HO UHQHV HGHHNE EHQII.N€ mqm<9 104 .Amo. u no paws mmnam maaapass m.saossa saws pnmnmwmsv hapsmonsswww nos was Hovuoa mean one saws masms* 00.0 Honuaoo o so.m Hm.m mm.m sm.m oH.o mm aommm o as.“ mm.H ow.m om.m ms.o mm oommoaams o oH.m ms.m on.m oo.m oH.o mm «Has: on oo.m oo.m mm.m oo.H oH.H mm soauofim Hanpomo a on.m Ho.o oo.o om.m mH.m ma ammao as mm.m oo.o sH.o mH.m os.o on aaaaonao spnoz a oo.m mo.m oo.m om.m om.H ma annooom a mH.o om.o om.m om.m mo.a mafia oamam on sm.m as.m mm.m mH.m so.H opaaamooaaoosm manage lllllllllllllllllllllll pon\ew Illlllnnnlslllllllllll *mmano>< ooo oou ooH om moasom Am SQQV soHusowHQQ< mo mpsm .umm>nsm omsonaoonw space was 809% wmduc «onwsc Mo UHmHV H0996: hhnll.m< mam¢8 105 my puma qusm oHQHpHsz m.aoossn news pcouowwfiu handsonaswfim so: who Hopped mean on» saws mssoza m.H Hahucoo 0 m.oa m.om o.o~ H.HH o.w ma momma moo H.mm m.oo o.om o.mH o.oH mm commoname mo «.mm s.om H.om w.oH H.HH mm «Hana so H.om m.om o.Hm m.Hm «.ma mm «canoflm Happamo n m.mm o.oo m.mm o.om H.mm mm amuao pa o.oo o.oHH o.ow o.om m.mm mm aaaaoaao apnoz o o.mo m.mo o.mm o.oH m.oH mm aaosomm as m.oo o.wHH H.oo o.mm o.Hm mafia oamam a m.so o.oma m.Hw o.sm m.mm opanamonaamosm manage IIIIIIIIIIIIIIIIIIIIIIII A Eng IIIIII1I1IIIIIIIIIIIII *mwaam>< ooo oom ooa on monsom an Emmy noHpsOfiHQm¢ mo ovum .sowpdowanm< scams whoa om psoEHHmme omsonsomaw as AHIA smnmv manonmmonm Hwom mpcsaad>¢ ooo oom ooH on moasom Am Emav soHpmowHQQ« Ho ovum .sofipaowanad scams msdn om unmawnomxm omsosswono as AHIA zsnmv mayonnmonm Hfiom mansawd>< ooo oow ooH on an Easy sOdeowHQm< Ho mudm monsom .Ampom ummmouo 9H cowamOHann< poems whom omHV uw0>nwm awash no mass as Homewhoaxm masonaoouo as “Hum asumv masonamonm Hwom mandawd>¢nl.®¢ mqmm oom oom ooH om monoom Am Emmy soflpmomamm¢ mo opmm .soHumoHHQQ< sopmm mama 0H Hwom omsonsmmuu am mahonnwonm oHDsHom homeII.b¢ wands 109 u do some omsmm oHQHaHBE m.smossa saws psonommmo mapsmosmH:Mam so: was smegma 05mm on» npr m:o02* moo. Hoapaoo o mmo. omo. mmo. mmo. mmo. mm aommo n Hmo. Hmm. moo. omo. mmo. mm oommmoome o omo. oso. omo. omo. smo. mm amass ooo Hmo. mos. omo. mmo. omo. mm aoauoam flagpomo on mso. mom. mmo. smo. mmo. mo ammao on oso. mom. mmo. mmo. sHo. mo somaoaao opaoz oo moo. mso. moo. sHo. mmo. ma aassomm a mos. ooo. mma. mao. oao. maam oawom a mad. ham. omo. moo. mmo. moaoomoaonooom manage IIIIIIIIIIIIIIIIIIIIIIII a Bag IIIIIIIIIIIIIIIIIIIIII *omaao>o ooo oom ooH om oopsom Am Easy :ofipmomamam mo opmm .sOmpmoHHQQ¢ nopwm mama om Hwom omsoasooao :H manonqmonm oHQDHom nomeI|.m¢ mamme 110 .Amo. u av amok mwaom mHQaQHzE m.cooqsn cums psonowwfio mapcmommficwmm so: who noppoa 08mm on» cums msoo2* moo. Hospsoo o mmo. sHo. smo. omo. omo. mm aomoa m omo. mHo. omo. moo. omo. ma oommoooos mo Hmo. smo. mmo. omo. mmo. mm oaaom oo soo. ooo. moo. Hmo. mmo. mm ooapoam Honpooo oo moo. mos. oso. sHo. moo. mm amooo on omo. obs. mas. Hmo. sao. ma ocaHoaao sonoz o mso. mom. omo. Hmo. omo. mm oaoooom a Hos. omm. oHH. moo. sao. moam oamam o mom. Hmm. mmo. omo. sHo. opaoomooonoaom magmas IIIIIIIIIIIIIIIIIIIIIII A Eng IIIIIIIIIIIIIIIIIIIIII *omono>o ooo oom ooH om oousom Am EQQV :oHpoofiHQn< mo opmm .sOmpmomaaam sopmo mmoo on Hmom omsosnooau as monogamous mansaom soposun..W< mqmo ooo oom ooH oo ooaoom Am Emmy :Omuoomanm< mo opom .AsoHpooaamQ¢ Hopwo whoa omav pmo>aom Hosmm no mass so Hmom owsonqoono as msuonamonm oHQsHom Houosln.oH¢ mqm¢s 112 .Aoo. n no name omoam oflaapsos m.soossn gums usonommmn mausoOHHHGwmm so: who noppoa memo was puma mnoo2* mo.o Hoapooo o mo.o mo.o oo.o os.o mo.o ma «coma o oo.o mo.o oo.o mo.o mo.o mm oommoooos on ms.o mo.o om.o ss.o mo.o mm amass mo os.o ms.o ms.o mo.o mo.o ma aomuoam Haywooo on ms.o mm.o ss.o so.o os.o ma ammao o mm.o so.o mm.o om.o mo.o mm aomfiouao opaoz oo os.o mm.o ms.o os.o so.o mm anoooom a mm.o om.m mm.o mo.m mm.o moam oamam m so.o mo.o oo.o oo.o mo.o ooosomoooaoasw manage IIIIIIIIIIIIIIIIIIIIIIII ma IIIIIIIIIII|IIIIIIIIIIII *omano>o ooo oom ooH om monoom Am anmv cowaoowamm< yo mama .omsonaoono as ooaoaoaaooo noumo mama om masons: nooasuaaom Hum on moun.HH< mamos 113 .Amo. u so some oooam madaoasz m.noonsn spas pcohomufic >Husoowmwswwm so: who poppoa oEow on» sums msooza mm.o Honuqoo o oo.o sm.o oo.o mm.o oo.o mm aomom so oo.o oo.o oo.o oo.o oo.o ma ooomooooe oo so.o mH.o oo.o oo.o oo.o ma «Has: o oH.m mH.o mH.o so.o oo.o mm ooanoam Haapooo on oo.o oo.o oo.o oo.o mm.o ma ammoo o mH.m mm.o mH.m mo.m oo.o mm aoafionoo ooaoz on oo.o oo.o so.o mo.m .mo.o ma anoooom a Hm.o oo.o so.o so.o mH.m maam oamam o mm.o oo.o oo.o- oo.o mm.o ooooomooqaoosm magmas IIIIIIIIIIIIIIIIIIIIIIII mm IIIIIIIIIIIIIIIIIIIIIIII *omaao>o ooo oom ooH om monsom Am Enav soHpmoHHanm Ho opom .omoooomono on soapooaaooo nopmo mama om waspxas nouasuaaom Hum an moau.mHo mqmoe 114 .Amo. u no ammo omoam ofioapmos m.moossn saws phonowmmo hapsmowumamHm 90: ohm noppoa meow one sums muooz* o.m monocoo no o.m m.m m.m m.m o.m mm demon o o.m m.m o.m m.m m.m mm oommoooos oo o.m m.m o.m o.m m.m ma «Homo on m.m o.m m.m o.m o.m mm aoaaomm Haupooo mo m.m m.m m.m o.m o.m mm ammao o m.m o.m o.m o.m o.m mm ooaaoaoo apnoz oo m.m o.m o.m m.m m.m mm anoooom m o.m m.o m.o m.m m.m moflm osmom a s.m m.m m.m o.m m.m opooamooonooom oflomas IIIIIIIIIIIIIIIIIIIII Em OOH\doE IIIIIIIIIIIIIIIIIII *omauo>o ooo oom ooH om ooaoom Am Enqv newuoomaaa¢ Ho ouom ..oomoaoaaooo aopmo msoo ooH pmo>uom Hogan so Hflom omsonsooHU umnmouo cw assassad,oHnoowsonoxmll.nH< mqm¢s 115 .Aoo. u so some omoam oHoaoHoz m.:ooasn sums pnosommws mapsoommaswmm so: who noupoa mean was spas msooza o.m Houoooo n m.m o.m o.m s.m m.m ma momma o o.m o.m m.m o.m s.m mm oommoooos on o.m m.m o.m o.m m.m ma mamas o o.m m.m o.m m.m m.m on ooaaomm Haaoooo o H.m m.m m.m o.m s.m ma ammoo oo m.m H.m m.m s.m m.m mm aoafioaao souoz o o.m o.m m.m m.m m.m ma annooom o m.m m.o mLH H.m o.m moflm camom a o.o m.m m.m H.o H.o ooooamooonoosm magmas IIIIIIIIIIIIIIIIIIIIII Ew ooH\doE Illllllllunlulllll *omaao>o ooo oom ooH om monoom Am anv qupooHamn< mo opom .sofipoofiann¢ nopmm moon omH Hwom omsonsooao commonosb so Edsmssa< o~noomnoaoxmuu.ofi¢ mqm< ooo oom ooH om oousom Am EQQV :ofipmofiana< mo opmm .noHmeHHQQ< nopmm whoa om Hmom owsonsoonu as Esmoamo manoowqonoxmll.mH¢ mqmda 117 .Aoo. u no poms omoam oaoapaos w.aoossn saws ucosommwc mapsoofiwficmfim so: mum Hoppoa 05mm on» spas maooz* mmm.o Honwsoo o www.o wom.~ mmw.0 omb.o mom.o mm momma o wam.o oom.a omm.o oob.o m~m.o mm oommocsoe o mom.H Hom.m som.H mom.o mmm.o mm oaflsm o oom.a me.m moo.a Nam.o mH®.o mm ooHnon Hopscoo n Hmb.H H>H.m owm.H boH.H mmm.o mm ommoo n mww.a o~o.m soo.m mmN.H How.o mm ocfiaouoo apuoz o me.a mmw.m mo®.H omH.H Hm®.o mm onusoom o Hmm.m omo.m omm.m moo.m mom.H mon oamam o Hwo.o me.H mom.o mmm.o obo.o oposnmosanoasm wagons IIIIIIIIIIIIIIIIIIIII Em ooH\UoE IIIIIIIIIIIlIIIIIII ammono>< ooo oom ooH om monsom Am EQQV acmpmofiamg< Ho opom .aoHmeHHQm« popmm moon omH Hmom owsonsooso commence: so Sdfiofioo manoowaonoxmll.ofi< mam¢s 118 .Amo. n my pmmB mmamm wHQfipazz m.coocso no“; econommwo >Husmoowfiswmm so: mam nouaoa oEom may spas mamo2* NVH . HOHPCOU o sad. mam. omH. oHH. oHH. ma oomoa o omH. mam. omH. mHH. HmH. mm oommoooos oo omH. omH. omH. HmH. mmH. ma «Hana oo omH. omH. omH. HmH. mmH. ma oomaomm Hanpooo on omH. omH. mmH. omH. mam. mm ammoo o omH. omH. mmH. smH. omH. mm anaaonoo nonoz o mmH. ooH. mmH. omH. omH. mm oaosoom a mom. mam. msH. ooo. omH. moam oaoom o omH. mmH. mom. omH. oHH. opaoamooanoaom manage IIIIIIIIIIIIIIIIIIIII Sm ooH\doE IIIIIIIIIIIIIIIIIII *omaao>o ooo oom ooH om monoom Am Eaav soHpoomamqs mo opom .sowumo«aanm sopwo moon om Hmom omsonsoonu no Edmwoswos o~noomamnoxmun.o~¢ mqm< ooo Am ammo :oHpmoHHQQ< mo opom Houusou wHH. mm oomom NNH. mm mowmoccoe boa. mm oawsm NNH. mm ooHHon Honpsoo mma. mm ommoo HNH. mm osmaouoo spaoz mma. mm onsnoom moH. woam ofimmm oNH. ouonawongnomsm onHHB on oonsom .QOmpoomamq¢ nopmm whoa omH pmo>nom Hosmh pm Hmom omsoncooac oommono so Esfimoswos oHQoomnonoxmll.mH¢ mqmo ooo oom ooH oo monoom AA Emmv aofiuoofioam< Ho opom .sofipoOHHQQ¢ nopmo maoa ooH Hflom omsossoono oomaonocs so Edomoswoz oanoomsoaoxmul.oa< mqm¢e _ 121 .Amo. u do some omaom oHQHuasz m.moossn sass pconowwflo mascoonHcMmm so: who nouuofi osom on» sums msoo:* HNH. Hoapsoo o ooo. mmo. mmo. Hmo. HHH. mm oomom o omo. omo. omo. mmo. mom. on oomooooos on ooo. omo. omo; mmo. ooo. mm ofiaom ooo ooo. omo. mmo. omo. Hmo. mm oooooflm monsooo moo ooo. mmo. omo. omo. mmo. _ ma ommoo oo ooo. mmo. omo. mmo. ooo. mm oooaonoo soaoz o mmo. omo. mmo. omo. mmo. mo onoooom mo smo. ooo. omo. mmo. mmo. ooam oomom ooo ooo. mmo. mmo. omo. ooo. oposomooonoasm manage IIIIIIIIIIIIIIIIIIIIII Em ooH\ooE IIIIIIIIIIIIIIIInII *oooao>o ooo oom ooH om ooosom Am Emmy sofiuooflamn¢ mo opom .soHpooHHQQ< sopwo whoa ooo pmo>nom Hosmm no Hmom omsonnoopo oomaouo so snowmouom manoowsonoxmn|.om< mqmo ooo oom ooH om monsom Am EQQV sofipoowama« mo opom .sowpoomaaam hopmo whoa ooH Hmom omsonsoono oommouosb so snowmopoa manoomsonoxmln.am< mqm<9 123 .Aoo. u no poms omoom ofloapfios m.moossn gums psosowwwo mapcoOHmmawwm poo who soppoa oEom was spas msooz* l HOHHGOU 0 mos. ooH. mos. ooH. . mm oomom on Hos. osH. mom. mmH. ooo. ma oommoooos o mmo. omH. was. sum. omo. mm oaaom on HoH. mom. boa. mom. mmH. ma ooanoam mongooo on moH. mom. sHH. oHH. Hon. mm ommoo o ooo. mam. mmH. omo. moo. mm ooaaouoo ooooz o smH. mom. moH. mom. moH. ma oooooom no Hos. mmo. omH. mmo. ooH. mon oamom o omm. mom. mos. mom. sod. ooooomooonooom manage uuuuuuuuuuuuuuuuuuuuuuuu a s unuunuuuunnnnuunuuunun- *omoao>m ooo oom ooH om ooaoom Am Emnv soflpooflanm< mo opom .pmo>nom omsonsooho “whom map scam mmonu oosmsw mo unopsoo masonmmonmlu.mm¢ mam¢e 124 .Amo. u no poms oooom oaoaofios w.sooasn sums pcoaommoo sapsoomwocmfim you who noppofl oEom on» cums mcooza I Honpaoo o mmo. ooo. mmo. ooo. omo. mo oomoa o man. ooo. mos. ooo. moo. ma oommoooos o ooo. mmH. was. Hoo. - ma oHoom oo mus. ooH. oam. omo. ooo. ma ooaooam Honpooo on boa. mmo. mmH. ooH. ooo. mm omooo o oam. mom. moH. omo. ooo. mo ooofloaoo noaoz on boa. mam. soH. ooH. moo. mm oooooom o How. omm. soa. ooo. omo. mon oamom no sms. mmm. omH. mmo. mso. ooooomoooaoosm wagons uuuuuuuuuuuuuuuuuuuuuuuu a s -1---:-uu--u-u-:uuu:uuu *omooo>o ooo ooo ooo om oouoom Am Egmv sowpoomanm¢ Ho opom .pmo>nom omsonsooao ocooom on» Sony mmoho mousse mo pcopaoo monogamonmul.mN¢ mamme 125 .Amo. u no name oooom oaompaos m.soocsa sums pcosommwo mapsoowmwsmHm you who noppoa oEow was sums maoo2* I HOHPfiOU o omo. ooo. omo. mmo. . ma oomom oo oHH. soH. mos. moo. ooo. mm oommoooos ooo omH. mom. mom. woo. woo. mm oamsm ooo ooo. mmm. omH. mmo. Hso. ma ooaaomo Houpooo ooo mos. ooo. sod. mmo. ooo. mm ommoo no omm. omo. soH. mmo. ooo. ma ooafloooo opaoz on mos. mum. osa. oHH. ooo. mm oooooom o sum. mmo. som. mmo. moo. oomm oamom o omm. ooo. soH. oHH. ooo. oponomoooaooom magmas uuuuuuuuuuuuuuuuuuuuuuuu a s -----unuuuunuaunu--uuuu *ooooo>o ooo ooo ooH oo ooaoom Am ammo sofluoomammm mo opom .pmo>uom omsoasooso usage was Scum mmonu oososw Ho unopsou msaoammonmll.om¢ mamo ooo oom ooH om ooooom Am Sago scapoOfiHmam mo opom .Hm0>Hdm GWQOQQGOHU HWHHM QQP EOHH MMdHU dmflflfiw wo HGOPfiOU BdfiOHdUII.MN< mflm<9 127 .Amo. u go some omoom omoaoaos m.moossn spas pconommmo hapsoommwswam poo who poppoa osow on“ spas maoo2* u Houoooo o omo.o moo.o omm.o ooo.o mom.o mo oomom o mmo.o mas.o mmo.o «oo.o omm.o mm oomooooos o «oo.o oom.a Hos.o moo.o n ma oaaom o mmm.o mmH.H som.o moo.o omm.o mm oooaoflm Houoooo o omo.a ooH.H oHH.H sos.o omm.o mm ommoo o mmo.H oom.a mso.H smm.o omm.o ma ooomonoo ooooz on mom.o moo.H omo.~ on.o mom.o mm oooooom o smo.H oma.m mmo.H mom.H Hso.o ooom oamom o moo.o oms.o moo.o mmm.o mmH.o ooooowoooaooom ofiooae nnnnnnnnnnnnnnnnnnnnnnnn oo & unuaauuunnunnnnsnnnanuu *omoao>o ooo oom ooo om ooooom Am Eamv noHpooflamnm mo opom .flwmxrhde mmfi—OQGQOHU UQOOGW man. EOHH WWNHU GQGHQU HO #GOPQOU SHOHNUII.®N¢ qudpfi .Aoo. u no woos omoom omoaoaos m.moossn cuss pcoaomwmo mapsoowmmcwsm so: who nouuoa osow on» sums msooza l HOHHGOU o omo.o oos.o moo.o msm.o n ma oomoo o sos.o moo.H oms.o mom.o mom.o mo oommooooe o moo.H mmo.a mmm.a mmo.o on.o ma oHasm o mmm.o omm.H smo.o mom.o oom.o mo ooouoam Honoooo m on moH.H omm.H oom.H mmo.o omo.o mo ommoo o mom.H moo.H smm.H oom.o omo.o ma ooofioooo oppoz n omm.H mmo.H oom.H moo.o mom.o mm oaoooom o oos.H Hsm.m Hmo.H mom.a mom.o oomm oomom o mms.o omo.o mam.o moo.o mmH.o opooomonoaooom ofiooas uuuuuuuuuuuuuuuuuuuuuuuu oo s unnunununununuuuuununnu *oooao>o ooo ooo ooH om oonoom Am Enmv soHuooHHQQ¢ mo opom .pmo>nom omsonsoono phone may Scum mmomo oosmzo mo poopsoo Edmoaoonl.bm¢ mqmHucooflmflcwfiw so: who hoppoa oEom was spas muoo2* I Hospsoo o oo.o Ho.m sm.o oH.m . ma oooom o oo.m mH.m oo.o oo.o mo.m mm oomooooos on sm.m mm.m as.m oo.o oo.o mm oaasm oo oo.m oo.H Ho.m mm.m Ho.m mm oomaofim monocoo Ho mm.H mH.H mm.H oo.o om.m mm omooo mo om.H Hm.o om.H oo.m om.m mm ooasonoo sonoz mo mm.H mm.o sH.H oo.H oo.o mm ononoom m oH.H oo.o oo.o oo.o mo.m ooom ommom mo oo.m om.H mm.H sm.m oo.o ooooomooonoaom wagons uuuuuuuuuuuuuuuuuuuuuuuuu m s nuu-uanuuuuniuuuuuuuuuu *omoao>o ooo ooo ooH om ooaoom An Easy soHuoomama¢ mo opom .umo>nom omsonsoono swash was Scum mmono oosmso mo Hampuoo Efiflmmovomll.mmd mam¢9 130 .Amo. u do poms oooom ofioaoaos m.soocsn spas pcosowmmo >Hpsoowmflswfiw so: ouo soupoa oEom may 2pm? msoo2* l HOHPCOU o om.m oo.m oo.m oo.m oo.m mm oomom o om.m sm.o so.m oo.m oo.m mm oommooooe o oo.m oo.o oo.m oo.m . mm omasm o oo.m oo.o oo.m oo.m oo.m ma ooaaon monocoo o oo.o oo.o as.o om.H oo.m mm ommoo o os.o oo.o oo.o oo.m HH.m ma ooaaoaoo ooooz o oo.o mo.o mm.o so.H oo.m mm onoooom o oo.o oo.o oo.o oo.o oo.m oon oomom o oo.o as.o oo.o os.H om.m ooooomoooaooom manage ......................... m s ------uuuuuuuuuuuuuu--- *omooo>o ooo oom ooH om ooasom Am 899v aofiuoowammo mo opom .pmo>aom omsonsoono osooom was Bony mwonc oosmso mo unmaaov BSHmwdpomll.mN< m4mo ooo oom ooH om ooooom Am EQQV acmpoomamn< mo ouom .Pm®>o~dm GMSOQflQQHU UHHSB 05». EOHH wdeU dQflHfiU HO PQGPGOU SHMMGFOQII.OMI¢ ”mm—Ham... 132 u av some owcom oaqfipasz m.=ooazn as“? pcopommmo mascoomwmsmmw so: who noppoa oEom map sums msoo2* I Honesoo on mom. mom. mom. mam. I ma oomom on Hmm. mom. mmm. mom. omm. mo oowmoooos on omm. ooo. omm. msm. omo. mm oaoom on omm. Hom. mom. mom. omm. ma oooaon monsooo o osm. ooo. Hum. Hmm. Ham. on ommoo on Hom. som. mom. mom. omm. mm ooaaoooo ooaoz on omm. omm. mom. Hmm. sum. mm onoooom o Ham. ooo. moo. omm. mom. mono oomom o mam. Hom. mom. Hom. omm. ooooowoooaooom wagons IIIIIIIIIIIIIIIIIIIIIIII ms & IIIIIIIIIIIIIIIIIIIIIII oomouo>o ooo oom ooH om ooasom Am Enmv soapoomamo¢ mo opom .fimmsrhdm mmfioflflwwhu thfim Gnu. EOHH m.m.mHU GOGHSU HO PQGHQOU SHWOQMQSII.HM¢ Mdmflh 133 .Aoo. u do poms omoom oaoaoass m.:oossn cums psosommflo aapcoowwoswwm p0: who hoppoa oEom one cpHB memosa I Hospcoo no on. soo. sow. sow. oom. ma oomoa no som. . omm. Hom. omm. mom. on oommooooe o omm. omm. mom. som. . mm onsm no mam. oom. omm. omm. mom. mm ooanoam monocoo no Hmm. omm. mam. omo. mom. on ommoo o mmo. omm. mom. omm. mom. on ooaaoaoo ooaoz o oom. «Hm. mom. oom. mom. on oaoooom no omm. Ham. mom. Hom. omm. oon oamom no oom. mam. oom. oom. Hon. ooooomooonooom wagons IIIIIIIIIIIIIIIIIIIIIIII w: & IIIIIIIIIIIIIIIIIIIIIII ooo oom ooH om *owoso>¢ ooszom Am Emmv nofipooHHQQ¢ Ho opom .pmo>nom omzonsoohw osooom map 80AM mmouo ooswsc Mo poopsou Esmmosmosll.mm¢ mqm¢e 134 .Amo. I no poms omoom mannnnos m.moocsa new? puosowwfio aapsmowwficmwm you who hopuma meow on» spas msoos * I Honpnoo no som. omm. oom. Hmm. I ma oomon no mom. mmm. omm. oom. oom. mm oommoooos no «Hm. omm. omm. mom. mum. on onasm no How. omH. omm. mom. omm. ma oonnon Honnooo on oom. omm. mom. oom. non. mm omooo on omm. mmn. mom. smm. mom. on ooanonoo nonoz on mom. Hon. mam. mom. oom. ma ononoom o mam. omm. omH. omm. omm. oonm oamom o omm. omm. Hmm. oom. oom. ononnmonnnonom manage IIIIIIIIIIIIIIIIIIIIIIII w: $ IIIIIIIIIIIIIIIIIIIIIII *ooono>o ooo oom ooH on monsom Am Emmy sowpoomamm< mo ouom .Hm@>Hdm ww305flwmhw UHHSB GS“ SOHH mmdhc dOdHH—U HO #dGHGOU SHMOQMGSIIIMM< m4mo oouoasoaoo opo meow: m.moosso sums anonommwo >apsoommwswwm no: ono noupoa oEow on» spas mcoosa .coHpoofianao mo .Aoo. n no woos oooom monsoon: I Honnooo I won son I I ma oomom n on mmm omm now I ma ooomooooe o sun son osn omH I ma onnsm o mmH moo non omm I ma ooanonm Hounnoo oo moo Hon oon «on sHm mm ommoo o omH oma omn oon non on ooanonoo nonoz o NNH mmH man mmn ooH on ononoom o omm ooo smo mod mos mon oawom o smn son omn oon I ononnmonnnonom manage IIIIIIIIIIIIIIIIIIIIIIIII s2 Ema IIIIIIIIIIIIIIIIIIII *ooono>o ooo oom ooH om monoom as easy acmpoOHHQQ< Ho opom .pmo>nom omsonaoono umsmm on» Scam mmoao ooswsu no unousoo omosowsozII.om¢ mqmo oosoflsoaoo who meow: psouommwo hapcoommocmfim so: who houuoa meow was spas wcoo2* .nofiuooflaano mo av some owsom oamopass I HOHHGOO I mom oom I I ma oommn n oom oom oom mom I ma oommooooe o mom mmn mmm mom I ma oHaom o omn mon oom omn I ma oonnonm Honnooo o oon ooH omH mom snm ma omooo o omn mom Ham mun I on onononoo nonoz o oom son Hon oom mam mm ononoom o mom Hmo oom oom omH oon oomom o «mm mom omm mmn I ononnmonnnonsm manage IIIIIIIIIIIIIIIIIIIIIIIII :2 San IIIIIIIIIIIIIIIIIIII *ooono>o ooo oom oom on ooaoom An Easy soflpoOHama< mo opom .Pm0>Hdm mmfiOflflmth UGOOQM 059 EOHH wwwho dmflfifiw HO PGGHGOU mmmfldMfidzll.mm¢ qu¢9 137 mopoh amonmfin moan» on» no>o oopoasoaoo ono waooz m.soossn cums unonommmo zapcoOHmflswwm poo who noppoa meow map spas maoo2* .soHvoofiHQQo mo .Aoo. n no name oonom oanonfios I Honnooo I oon moH mon I ma oomon o mmm on onm mmn I ma oowmoonos o mon omm mom man I ma onasm o oon mom omn mom mmH on oonnonm Honnooo o mon Hon mon mod osn on omooo o son mos «on non Hon ma ooanonoo nonoz o oom I Hon oom man ma ononoom o Hmo mmo mam ooo oom mono oamom n How mom mom msn mom ononnmonnaonom manage IIIIIIIIIIIIIIIIIIIIIIII s2 Ema IIIIIIIIIIIIIIIIIIII *ooono>o ooo oom ooH on oonoom Am Sago sofipooflana¢ wo opom .pmo>aom omsonnoonw phone was Sosa mmono ooqfiso Ho unopsoo omosomsoSII.om< mam¢e 138 .:0mpoooaado mo mopon Hmonwwn mouse on» so>o oopoasoaoo ouo mnoos .Amo. u go some owsom manapazz m.moossa sums psonowmfio haunoommmnmmm so: who hopuoa oEom on» gas? maom2* I Houpsov I om om I I ma oomoo o Hm om om mm I mm oommosnoe no om om so om I ma onasm on om mm om om I ma ooanonm Honnooo no om om om am mm mm omooo on om om mm om om on ooanonoo nonoz oo om om mm mm om on ononoom o om on om om om mono oomom oo om mm mm om I ononnmonnnooom manage IIIIIIIIIIIIIIIIIIIIIII :N Ema IIIIIIIIIIIIIIIIIII oooono>o ooo oom ooH on monnoo An easy coflpooaaaa< mo opom .meerdHM OMSOfi—QOQHU fimhflh m2». EOHH WWdHO dmflfifimv HO #flmfiflOU UflflNll.bm¢ "NJ—”m4? 139 m0 mwwou emwemsn wwena was ew>o owpoaeoaoo weo meow: .eowpooflaqmo .Ano. u no some meanness m.eooeea nus? pewewwwmo mapeoosmfiewsm woe who nwuuwfi wEom was sums meowz * I Hoepeoo I am mm I I ma oomwm n mm om om mm I on oommonoos on no no no no I on oeeom n mm no om so I on ooseoHe Honnooo o mm mm mm mo mm on omooo n mo sm mm mm I on onesonoo nonoz 0 mm mm om om no me ononoom o me as om mm on moem oomom on so mm mm mm I ononewoneeoeom onesns IIIIIIIIIIIIIIIIIIIIII eN see IIIIIIIIIIIIIIIIIII *omono>o ooo ooo ooe on oonoom Am Seay ecspoosaae< Ho wuom .PWOsVHdE 0W5OH~G®®HU UQOOQW mn—P BORN mmeU dQGfiH—O HO HQGflGOU OGHNII.mm¢ Wflmdfifl 140 no mwpoe pmwewsn wweep we» ew>o owpoaeoHoo weo meow: .eoHpoooaeao .Aoo. n no woos meanness m.eooeem euHB Hewewmmso saueoosmsewsm woe who ewppwa wEom was spas meow2* I Honoooo I oo mm I I ma oomws o mo mm oo so I on oommonoos no so oo oo mo I on oeoom n oo oo oo mo so me ooenoee Hoenooo no mo mo oo om no me ommoo no mo Hm oo mo no mo oeeeonoo nonoz no so I no mo mo mo ooonoom o on m so no oo ooem osmom no so mo mo mo no ononemonenoeom moneys IIIIIIIIIIIIIIIIIIIIIII eN Ema IIIIIIIIIIIIIIIIIII ooooeoso ooo ooo ooe on monsom Am Eamv eoHpoooHee< Ho wuom .pmw>nom wmeoeewweo asses was Eons mmoeo oweoeo mo pewpeoo oefiNII.mm¢ mqmde APPENDIX B CASSAVA DATA 141 142 .Amo. u go pmws wmeom wHeouHez m.eooeea epsB uewewmmso sapeoosmsemsm woe weo ewppwa wEom was epHB meow: .eoopoeao>w powwow Hoeosmwe Mona *** * .eOspoosHeeo Hoeeeo oom * m.v HOAflQOO o o.m o.m m.m o.o me oomoo oo o.m H.oH o.s o.s mo oowmoooos oo m.m o.m o.m m.s on ones: o o.m o.on o.m o.o me ooonoee Hoanooo n m.on H.on o.m o.s me omooo n s.oe o.me n.oe o.o mo oooeonoo nonoz o m.oe m.me H.oe o.m mono oomom n H.HH o.oe o.oe o.s *Iononemonenoeom onoons o H.on o.oe o.ne o.m *ononnoonenoeom oeeoes IIIIIIIIIIIIIIIII on\e0p IIIIIIIIIIIIIIII oooomonoso ooo ooo on son\oooo ooo onenoooeeeo no onom woeeom .wwoeom o>ommoo oeeerIw>on¢ Ho oawowII.Hm mam¢a 143 .Amo. n av pmwe wweom waespaes m.eooesn nus? pewewmmso saueoowmsewom woe who ewupwa wEom was spas meowzo o.m Honpeoo o o.o m.m o.m m.m mm oomwm on o.m o.HH H.o o.m mm wwmmweewe o o.m o.s N.o o.m mm oaoem o m.o H.m o.o s.m mm ooseon Honpewo o N.oH m.oH o.s H.o mm omwoo o o.m o.sH o.s H.o mm oesaoeoo epeoz no s.m m.oH m.m s.m mono oemom IIIIIIIIIIIIIIIII m Ema IIIIIIIIIIIIIIII *wwoew>< ooo ooH on woeeom Aon\m0oe ooo nosnooeeooo no onom .eOHHoooHee< ewpmo moon oHH o>ommoo nnos noosoooexe oeooe no AHIe soomo mononemone oenoeoosoII. om memos 144 .Amo. u av pmws wweom wHQHpHe: m.eooeem news sewswmmso saseoOHMsemsm woe wso swsuws wEom was essB meow: * s.o eonnooo o m.o s.o s.o o.o me oomoe oo s.o o.m: o.s m.m mo oommonnos on m.s m.me o.m m.o me oeoom oo o.m o.oo m.o o.o me ooonoem Honnooo on o.mn o.om o.s s.o me omeoo no o.oo o.sm o.s m.o me ooeeonoo nonoz o o.oo o.oo o.oo o.m ooem onmom IIIIIIIIIIIIIIIII A Eng IIIIIIIIIIIIIIII *ooonoso ooo ooo on woseom Aon\m0oe ooo ooonoooeeeo no onom .o>ommoo sass uewEstmxm oawsm es eoHpoosaem< ewpmo msoe oom noo>eom no mass no AHIe sonmv mononemone oenoeoosoII.mm memos 145 .Amo. u av pmwe wmeom weespae: m.eooeea ewes pewswmmso :Hueoosmsewsm woe who swpswa wsom was eves meow:* om.o Hospeoo n oo.o mo.m mo.m oo.o mm oomwm n mo.m sH.m oo.o oo.o mm wwmmweewa n oo.m om.o oo.m 00.0 mm oasem n mo.m sH.m so.o oo.o mm oosson Hospewo n oo.m om.o sH.m oo.m mm ommoo n NH.m mm.m so.m so.o mm oesaosoo essoz o om.o so.m mm.m oo.m woam osmom IIIIIIIIIIIIIIIIIIII me IIIIIIIIIIIIIIIII *wwoew>e ooo ooo om woseom Aon\oooe moo noenooeeeeo so onom .e0spoosaeme swaso moon oom smw>som so o>oomoo noes noosenooxm oeoem no oeonxes eonosIeeom ene mo meII.om memos 146 .Amo. n av smws wmeom weesuae: m.eoweeo ewes pewswmmso sapeoosmseMsm woe weo swpswe wEom wee ewes meow:* mo.v Hospeoo o oo.o oo.o mo.o oo.o mm oomwm o oo.o mo.o oH.o oo.o mm wwmmweewe a oo.o mm.o 0H.o oH.o mm oHHem on oo.o oH.o so.o oo.o mm oosson Hoepewo n ma.o mm.o oo.o oo.o mm omsoo n mH.o mm.o oo.o oo.o mm oesaosoo epsoz o mm.o oo.o om.o oo.o moam osmom IIIIIIIIIIIIIIIIIII we IIIIIIIIIIIIIIIII *wmosw>¢ ooo OOH on woseom Aon\ooom ooo noenooeeneo so onom .eOHuoooanme ewuwo moon on o>ommoo ewes pewEestxm sawem ea wheuxo: HeomImauoo : Ho. 0 so meII. mm memos 147 .Amo. I my vmwe wweom wsmspae: m.eooeeo ewes pewswssso hapeooessemsm uoe wso swppwfi wEom we» ewes meow:..n ON.¢ Hospeoo 0 NN.¢ om.o mm.v ha.v mm oomwm on wN.v om.o hm.v om.o mm wwmmweewe n om.o b¢.e om.o om.o mm oawnm on wN.v mm.¢ hm.v mN.¢ mm oUsHon_HoHpewU on Hm.v oo.o om.o om.o mm omwoo n mm.v om.o om.o om.o mm oeHHOHoU nusoz o m®.w mo.m mm.v mm.¢ wofim osmom IIIIIIIIIIIIIIIIIII we IIIIIIIIIIIIIIIII *omonoso ooo ooe om woseom Aon\o0om moo ooenooeeeeo so onom .eOspoosHmmm swpso mmoa oom pmw>som so o>ommoo eves sewEHHwexm onsm es weaves: HsomImHooo : oo.o so meII.®m mam¢s 148 .Amo. u no pmws wweom weespae: m.eooeen ewes pewswssso saueoosssewsm poe weo swuuwe wEom we» ewes meow:* o.H Hospeoo we o.H o.o o.s o.o mm owmwm o H.H s.o H.H s.o mm wwmmweews on o.o w.o o.H o.s mm oasem so o.s o.s o.s o.H ma ooHson Hospewo on o.o w.o o.H o.o mm ommoo Q m.o w.o o.s 9.0 mm oesaosoo essoz o s.o o.o w.o o.o mon osmom IIIIIIIIIIIIII 8w ooH\owE IIIIIIIIIIIIII somono>o ooo ooe on woseom Aon\mooe moo ooenooeeeeo mo onom .eOHuoosanm< swpmo whom an o>ommoo epss uewEeswexm sewsm Boss Hsom es Seesaea< wHeowmeoeoxMII.sm memes 149 .Amo. u my smws wweom wemssee: m.eooeem ewes pewewmsso seseoosseewem poe wso swsswe wsom wee eves meow:* o.e eonoooo o o.e o.o o.e e.e me oomoe on o.e o.o o.e e.e me oommoooos on o.o o.o o.o o.e me oeeom on o.o o.o o.e o.o me ooeHOem eonnooo on o.o s.o e.e. o.e me ommoo n o.o o.o e.e o.e me ooeeoeoo nneoz o o.o o.o s.o o.o moem oemom IIIIIIIIIIIII 8w ooH\owE IIIIIIIIIIIIIII *omonoso ooo ooe om woseom mon\n0oe ooo noenooeeeeo mo onom .eOHHoosemee swpmo msom oom pmw>som so o>ommoo ewes sewssswmxm sewsm Boss esom es seeweeee weeowweoeomeI.mm memes 150 .Amo. u my »mws wweom wees»me: m.eooeem e»s3 »ewewmmso se»eoossseMsm »oe weo ew»»wH wEom we» e»e3 meow:* mme. econooo o mso. mmm. ooo. ooo. me oomoe o mem. smm. mom. mmo. me oommoooos n soo. ooo. soo. mso. me oeooe o mmo. mom. mmo. oeo. me ooeeoem eoenooo n eom. ees. men. mmm. me ommoo n moo. omo. smm. som. me ooeeouoo nneoz o omm. oos.e eom. mom. moem oemom IIIIIIIIIIIII Em ooH\owE IIIIIIIIIIIIIIII *omono>o ooo ooe on woseom Aon\mooe ooo noenooeeeeo so onom .eOs»ooHeeme sw»so msom Hm o>ommoo e»os »ewssewmxm onHm Boss meow es Besoeoo weeowmeoeomeI.mm memes 151 .Amo. u no »mws wweom wees»ee: m.eooe:m e»s3 »ewewsmso se»eooemsewem »oe who sw»»we wEom we» e»es meow:* oom. Hos»eoo 0 saw. ooo. oom. omm. mm oomwm on mom. mom. emm. mom. mm wwmmweews n omo. omo. mmo. omm. mm oesem on How. Nsm. omm. Non. mm oosson Hos»ewo n mmo. mws. oom. omm. mm ommoo on sew. mmo. oom. omm. mm oeseosou e»soz o omm. oes.e oos. oem. moem oemom IIIIIIIIIIIII Em ooe\ow8 IIIIIIIIIIIIIIII *wmosw>< ooo oom om woseom Aon\mooe moo ooenooeeeeo so onom .eOe»oosenm< sw»mo whom oom »mw>som »o o>ommou e»s3 »ew8oswmxm newsm sons Hsom es Bosweoo weeowweoeomeI.oem memes 152 .Amo. n my »mws wmeom weem»ee: m.eooeem e»H3 »ewmwmmmo >H»eoomwseMsm »oe wmo mw»»wm wEom we» e»m3 meow: .w mom. Hos»eoo o mom. on. smm. omm. mm oomwm o wwm. omm. omm. omm. mm wwmmweews o mom. esm. smm. msm. mm oesem o oom. omm. omm. Hmm. mm oosson Hos»ewo o wmm. mom. mmo. oom. mm omsoo o omo. moo. mmo. mso. me ooeeonoo nonoz o mam. omm. omm. sow. woem ommom IIIIIIIIIIIII aw oce\ows IIIIIIIIIIIIIIII *wmomw>< ooo oOH om womeom Aon\mooe moo ooenooeeemo so onom .e0m»oomeeeo mw»mo msom em o>ommoo noes noosenoeom oeoem some eeom om eoewoomoe menoomoonomeI.eem memos 153 .Amo. n av »mws wweom wems»me: m.eooeem e»m3 »ewswmsso se»eoossmemsm »oe wmo mw»»we wEom we» e»s3 meow:* th. HOHHCOO o smo. moe. smo. mmo. me oomoe o mmo. eoe. ooe. omo. me oommonoos o eoe. smo. oee. mmo. me oeeom o emo. omo. smo. omo. mm ooenoem eonoooo o omo. emo. moo. eoe. me ommoo o mmo. soe. omo. smo. me ooeeoeoo nonoz o mmo. omo. moe. omo. moem oemom IIIIIIIIIIII Em ooe\owE IIIIIIIIIIIIIIIII *omono>o ooo ooe on m woseom Aon\ com moo noenooeeeeo mo onom .eOs»oosHmmm sw»so msom oom »mw>som »o o>ommoo noes nooseeoexm oeoem some eeom oe anemoomos menooooonomeI.oem memos 154 .Amo. u my »mws wweom wemm»ee: m.eooeem e»s3 »ewswssso :H»eoossmewsm »oe wso mw»»we wEom we» e»m3 meow:* mam. Hos»eoo o ooe. ome. ome. eee. me oomom o mse. meo. emo. omo. me wwmmweews n mee. eoe. soe. moe. me oeeom n nee. mme. ooe. oee. me ooenOem monsooo o moe. sme. ooo. moe. me ommoo n soe. mmo. ooe. eee. me ooeeonoo nneoz n oee. ooe. oee. eee. moem oemom IIIIIIIIIIIII Em ooe\ows IIIIIIIIIIIIIIII oomono>o ooo ooe on woseom Aon\moom moo onenooeeoeo so onom .eom»oosemm< sw»so mmom oom »mw>mom »o o>ommoo e»ss »ewasswexm oewmm Eons esom es Sesmmo»om weeowweoeomeI.mem memos APPENDIX C FIELD BEAN DATA 155 156 .Amo. n so »mws wweom wemm»ee: m.eooeem e»s3 »ewmwssso se»eoomsmewsm »oe wso mw»»we wEom we» e»s3 meow:*** .e0s»oeeo>w »owssw Hoeosmws mom * * .e0m»ooseeeo eoeeeo mom * mo.o eonnooo o so.o eo.e em.o os.o os.o me oeesm o os.o om.o es.o mo.o mo.o me oomoe o os.o mo.o es.o so.o so.o me oommoooos o om.o oe.e mo.o os.o os.o me ooenoem eonnooo n eo.e en.e so.e me.e mo.o me ommoo on so.e em.e om.o oo.m ms.o me oeonoom n om.e sm.e so.e oo.m eo.e me ooeeoeoo nonoz o so.e ss.o oo.m eo.e mo.o **ononemoneeoesm memens o om.e eo.m om.e em.e so.o *ooonemoneeoeom oeeens IIIIIIIIIIIIIIIIIIIII »eoem\8m IIIIIIIIIIIIIIIIIIII Iooomono>o ooo ooo ooe on oonoom Aon\oooe moo noenooeeeeo mo onom .moenooee nonmo msoe om mnooee ooom mo ooenoooone nemeos seeII.eo memos 157 .Amo. u no poms omoom memeneoe o.oooose e»sB »ewmwssmo se»eoomsmewmm »oe wmo mw»»wH wEom we» e»m3 meow: .eOs»oeeo>w »owsmw Homosmwm homo all. * .e0m»oomemeo Hoeeeo mom * eon\mooe ooo oneoooeeeeo mo onom om.o Hos»eoo o om.o mm.o om.o om.o mm.o mm oemem oo om.o mo.o om.o om.o om.o mm oomwm no om.o om.o om.o om.o om.o mm wwmmweews ow mm.o oo.o om.o om.o mN.o mm oUHHOHm Hos»ewo e om.o om.o oo.o so.o om.o mm omsow on mo.o mo.o om.o om.o om.o mm oseeowm e mmoo mo.o em.o mo.o mm.o mm oesaosoo e»moz o ms.o sN.H mo.o mo.o om.o **w»oemmoemswmem wHQHss o om.o mm.e mo.o Nm.o om.o *w»oemmoemmwmem wmemss IIIIIIIIIIIIIIIIIIIIIII »eoem\8m IIIIIIIIIIIIIIIIIIII ***wmomw>m ooo oom oom om womeom .moenooem ooomo msoe om mooom oeoem an omo»eo mononemoneII.oo memos 158 .Amo. u so »mws wmeom wemm»ee: m.eooeem e»sB »ewmwswme >H»eoo«smemmm »oe wmo mw»»we wEom we» e»mB meow: .eoe»oeeo>w »owssw Hoeemmwm mom* 33.31 * .e0s»ooseemo Hoeeeo mom * Aon\oooe ooo ooemooeeeeo mo onom oo.m Hom»eoo so om.o mo.o mo.o oo.m mo.o mm oemem e oo.m mo.o mo.o om.o om.o mm oomwm so so.o oo.m mo.o mm.m mo.o mm wwmmweews we ss.o oo.m om.o oo.m om.o mm oomson Hom»ewo e mo.o oo.s em.s mo.o so.m mm omsoo we mo.o mo.o om.o oo.o me.m mm omeeowm we mo.o mo.o ss.o mo.m oo.m mm oeseomoo e»moz o mm.s He.m om.o os.o mo.o **w»oemmoemswmem wemmms o oo.m em.me mw.s mm.s om.o *w»oeemoemsweem wemsss IIIIIIIIIIIIIIIIIIIIIII »eome\ew IIIIIIIIIIIIIIIIIIII ***wmosw>e ooo oom oom on womeom .we«»eoam sw»so msom no m»eoHA eowm so e0m»oeeomm »ewst smmII.mU memes .Amo. n my »mws wweom wees»ee: m.eooeem e»m3 »ewmwssmo >H»eoomsmeMmm »oe who mw»»we wEom we» e»m3 meow:*** .eow»oeeo>w »owmsw Hosesmws mom * * .e0s»o0memmo Hoeeeo mom * 159 Aon\oooe moo ocenooeeeeo mo onom oe.e Hos»eoo mo oo.o om.o so.o so.o om.e me oeenm o oo.e oo.o oo.m eo.e oo.e me oomoe mo om.o oo.m om.o em.e oe.e me wwmmweews on oo.m oo.m oo.m os.o oo.o me ooenOem eonnooo n mo.o os.o om.o ss.o so.o me ommoo oon oo.m om.o om.o os.o oo.m me ononoom on oo.m os.o sm.m ss.o oo.m me ooeeonoo nonoz o oo.m os.o om.o ms.m mo.m **ononemonenoesm oeeens o mo.o oo.m om.o om.o om.o *ononeoonenoesm oeeens IIIIIIIIIIIIIIIIIIIIIII »eoHQ\Em IIIIIIIIIIIIIIIIIIII ooo ooo ooe on ***wwosw>e wosdom .moenooee eonmo msoe mo mooom oeoem sn omonee mononemoneII.oo memos 160 .Amo. u my »mws wweom wems»ee: m.eooeem e»s3 »ewswssso >H»eoomssewsm »oe wso sw»»we wEom we» e»o3 meow: ‘33." .e0o»oeeo>w »owmsw Hoeommwm mom ** .e0m»oomeeeo Hoeeeo some o.e Hos»eoo o m.m m.o m.o s.o o.o me oeesm o o.o m.o m.o m.e o.o me oomoe o o.o m.o m.o s.e e.o me oommoooos o o.m o.o m.o o.o m.o me ooenoem eonnooo n s.o o.s m.o m.m o.m me ommoo o o.m o.m o.m o.o o.o mm oeonoom n m.o s.s o.m o.m m.o me ooeeonoo nonoz o m.o o.ee m.o m.o m.o *oononemonenoesm memens n m.o o.m m.o o.m m.o *ononemonenoesm oeeens IIIIIIIIIIIIIIIIIIIIIIII a Ema IIIIIIIIIIIIIIIIIIIIII *ooomonoso ooo ooo ooe om monoom Aon\m0oe moo compooeeeeo mo onom .meowm e»H3 »ewEmstxm pewsm we» es e0m»oosemme sw»so msom mm HIm sosm he ewsemow: mo memoemmoem weeoeso>eII.mU memes 161 my »mws wmeom.wees»ee: m.eooeem e»m3 »ewewssmo se»eoommeemmm »oe wso sw»»wH wEom we» e»sB meow: .eo«»oeeo>w »owssw Homosmwm mom * :27... * .e0m»oomemeo Hoeeeo mom ... m.m Hom»eoo o o.o m.o o.m m.o e.s me oeesm n m.m o.o e.m m.o m.m mm oomoe n m.m o.o m.o o.m o.o me oommoooos n m.m o.m o.o o.o s.o me ooenOem eoeoooo n m.m o.o o.m m.o o.m me ommoo no o.o o.o m.o o.o o.m me onsnoom no o.o m.m m.o o.o o.o me ooeeoeoo nonoz n o.m o.o o.m o.m o.o *oononemonenoeom oeeens no o.o o.o o.m m.o o.m Iononeoonenoeom mesons IIIIIIIIIIIIIIIIIIIIIIII m Ema IIIIIIIIIIIIIIIIIIIII Iooomonoso ooo ooo ooe om monsom Aon\oooe moo onenooeeeoo so onom .e0m»o0eemme sw»so msom owe »mw>som eowm »o eIm zoom me ewmemow: mo memoemmoem wHeoHso>eII.©o memes 162 .Amo. n av »mws wweom wees»ee: m.eooeem e»m3 »ewmwmsso se»eooeseemHm »oe wmo mw»»we wEom we» e»m3 meow: *** .eOm»oeHo>w »owssw Hoeommws mom s21 .e0m»oomemmo Hoeeeo mom * ooo. eoenooo o soo. moo. oeo. meo. ooo. mm oeeom o moo. eeo. moo. eeo. moo. me ooooe o oeo. oeo. seo. moo. ooo. mo oommoooos o moo. ooo. moo. meo. ooo. mm ooenoem eoenooo o moo. ooo. oeo. soo. moo. me ommoo o oeo. ooo. oeo. oeo. moo. me oeonoom o moo. moo. meo. soo. moo. me ooeeonoo nonoz o moo. oeo. ooo. ooo. eeo. *Iooonemonenoeom oeeens o meo. moo. oeo. meo. soo. *ononemonenoesm oeeens IIIIIIIIIIIIIIIIIIIIIIII m Sam IIIIIIIIIIIIIIIIIIIIII Iooomoeo>o ooo ooo ooe on monoom eon\mooe moo ecs»o0memee so w»om .meowm e»m3 »ewssmwaxm oeoem one am onenooeeneo noomo msoe om mononemone oeneeom eo»osII.so memos 163 .Amo. u no »mws wmeom weem»ee: m.eooeem e»ss »ewswmsso >H»eoomssewsm »oe wso sw»»wH wEom we» e»m3 meow:* ** .eoH»oeeo>w »owsmw Hoeoomws mom ** .e0m»oomeemo Hoeeeo mom * mmo. HOhHGOD o ooo. meo. eoo. eeo. soo. mm oeenm o ooo. meo. ooo. ooo. ooo. me oomoe o ooo. omo. eoo. smo. oeo. me ooomoonos o eoo. meo. seo. oeo. omo. me ooenoem eoenooo o ooo. moo. soo. ooo. moo. me ommoo o moo. moo. omo. moo. meo. me oeonoom o omo. omo. ooo. ooo. eoo. me ooeeoeoo nonoz o moo. smo. ooo. omo. ooo. ooononemonenoeom oeeees o ooo. omo. oeo. ooo. moo. *ononemoneeoeom menses IIIIIIIIIIIIIIIIIIIIIII 9 8mm IIIIIIIIIIIIIIIIIIIII ooo ooo ooe om **wmosw>e womeom Aon\n0oe moo onenooeeeeo mo onom .meowm e»m3 »ewEmswexm eewmm we» em ecs»o0meeme sw»so msom mm memoeemoem wmeeeom mw»osII.mQ mqm<8 164 .Amo. n so »mws wweomfiwees»ee: m.eooeem e»s3 »ewswmsme se»eoosssewsm »oe wmo sw»»we wEom we» e»sB meow:** .e0m»oeeo>w »owssw Hoeosmws mom ** .eOs»o0seeeo Hoeeeo mom * mmo. Hos»eoo o meo. meo. eoo. ooo. eoo. me oeese o ooo. oeo. moo. moo. ooo. me oomoe no moo. omo. omo. ooo. ooo. me oommoooos o eoo. ooo. omo. moo. oeo. me ooeeoem eoe»ooo o emo. omo. moo. moo. mmo. me ommoo on ooo. ooo. meo. omo. ooo. me ononowm on ooo. omo. eoo. ooo. moo. mm ooeeonoo nneoz on ooo. ooo. moo. moo. eoo. ooononemonenoesm oeeees on ooo. seo. oeo. ooo. moo. *ononemonenoeom oeeens IIIIIIIIIIIIIIIIIIIIIII A Sea IIIIIIIIIIIIIIIIIIIIII *ooomonoso ooo ooo ooe on monoom eon\moom moo onenooeeeeo mo onom .e0m»ooHHmee sw»so msom owe »mw>som eowm so wEms »o mesoemmoem weeeeom sw»o3II.oo memes 165 .Amo. n so »mws wweom wees»ee: m.eooeem e»s3 »ewmwssoe ma»eoomssemHm »oe wmo mw»»wH wEom we» e»sB meow:** .eOs»oeHo>w »owssw Hoeosmwm mom** .e0s»oomemeo Hoeeee som* so.o econooo o om.o mo.o so.o os.o om.o me oeeom o om.o os.o mo.o om.o em.o me oomoe o om.o os.o om.o os.o om.o me oommonoos o mo.o om.o om.o os.o mo.o me ooenOem eonnooo o om.o mo.o oo.m os.o so.o me ommoo o em.o oo.m om.o om.o om.o me ononoom o so.o om.o om.o om.o em.o me ooeeoeoo nneoz o om.o om.o os.o om.o om.o ooononemonenoesm oeeens o om.o om.o om.o os.o om.o *ononemonenoeom oeeens IIIIIIIIIIIIIIIIIIIIIIIII IQ IIIIIIIIIIIIIIIIIIIIIII *Ioooono>o ooo ooo ooe om oonoom Am Emev e0s»oosemme so w»om .meowm e»m3 »ewEsmwexm oeoem on» no noenooeeeeo eonmo msoe om AnonosIeeom eneo meII.oeo memos 166 .Amo. n no poms omoom oeeeneos m.oooooe SwHB Newswwssv thedowwsmwwm #0: who HmppwH wEdm mew SHHB mmow2** .eOs»oeeo>w »owssw Homesmws som** .e0s»ooseeeo Hoeeeo mom* oo.m Hom»eoo no me.o me.n om.o om.o so.o me oeenm no om.o so.o om.o oo.m oo.o mm oomoe n so.o oe.o so.o mo.o so.o me oommoooos no om.o om.o se.m so.o om.o me ooeeoem eoenooo no om.o mo.o me.o so.o se.n mm ommoo no om.o oo.m se.m mo.o om.o me omonoom o om.o se.o oo.o mo.o om.o me oneeonoo nonoz no se.o se.o oe.n om.o om.o ooononemoneooeom oeeens no om.o om.o om.o mo.o om.o *ononemonenoeom oeeens lllllllllllllllllllllllll 3Q llllllllllllllllllllllll ooo ooo ooe on ***wwosw>e woseom Am Emmv ecs»ooseeee so w»om .meowm e»s3 »ewEsmwmxm oeoem one oe ooenooeeeeo nonmo msoe no AnoposIeeom eneo meII.eeo memos 167 .Amo. n my »mws wweom wens»ee: m.eooeem e»e3 »ewswssso >H»eoomssewem »oe wso sw»»we wEom we» e»m3 meow:* ** .e0s»oeeo>w »owssw Hoeosmws mom .eOm»o0sHer Hoeeeo somuo ms.o econooo no ms.o ms.o ms.o mo.o ss.o me oeeom o os.o ms.o ms.o ss.o os.o mo ooooe o os.o os.o ms.o os.o om.o me oommoooos n os.o ss.o oo.o mo.o es.o me ooeooem eonnooo no ms.o os.o os.o em.o so.o me ommoo no os.o os.o os.o es.o os.o me oeonoom o ss.o om.o os.o ms.o ms.o me ooeeonoo nonoz o os.o om.o mo.o ms.o ms.o ooononemonenoeno menses no os.o om.o os.o os.o os.o *ononeooneeoeoo oeeens IIIIIIIIIIIIIIIIIIIIIIIII mm IIIIIIIIIIIIIIIIIIIIIII ***omono>o ooo ooo ooe om oonoom Am Emmv ecs»oosemee so w»om .eOs»o0sHeQe nonmo msoe ooe noosnom noom mo oses no AeonosIeeomeueo meII.oeo memos 168 .Amo. u go »mws wmeom weem»ee: m.eooeem e»H3 »ewswmseo se»eoomsmemmm »oe wso ew»»we wEom we» e»H3 meow: .eOs»oeHo>w »owmsw Hoeosmws somHH* .eOs»ooHHemo Hoeeeo som* mo.o Hoe»eoo o oo.o ms.o so.o os.o so.o mm oemem o so.o so.o ms.o so.o om.o mm oomwm o mo.o mo.o so.o os.o os.o mm wwmmweews o mo.o os.o os.o so.o so.o mm oeseomm Hoe»ewo o ms.o mm.o ms.o mo.o ms.o mm omsoo o os.o om.o ms.o so.o ss.o mm omeeowm o ms.o ss.o ss.o mo.o so.o mm oeseosoo e»soz o os.o ms.o os.o ms.o os.o ooononemonenoeom memens o mo.o ms.o so.o mo.o so.o *ononemonenoeom memens IIIIIIIIIIIIIIIIIIIIIIIIII me IIIIIIIIIIIIIIIIIIIIIII ooo oom OOH om ***wwosm>e wosmom Am Emmv e0m»oosemme mo w»om .meowm e»m3 WewEmswmxm oowem we» ew ecs»oomemee »ew8»owss sw»so msom mm eooo 2 mo.o noes ooonxee onenoeomIeeom Hue o me meII.meo memos 169 .Amo. n av »mws wmeom wHes»He: m.eooeem e»Hs »ewmwmsHo sH»eooHsHemHm »oe wso sw»»wH wEom we» e»o3 meow:** .eoH»oeHo>w »owsmw HoeeHmws mom .eoH»ooHHemo Hoeeeo momH* om.o Hom»eoo o om.o sm.o mm.o sm.o oo.o mm onem o om.o mo.o om.o Ho.o om.o mm oomwm o om.o om.o mo.o om.o mo.o mm wwmmweews o sm.o Ho.o sm.o om.o mm.o mm oonon Hom»ewo o oo.o wm.e oo.o mo.o mm.e mm ommoo o sm.o Ho.o sm.o mm.o mm.o mm oseeowm o oo.o mo.o om.o sm.o sm.e mm oeoHomoO e»soz o eo.o oo.o mo.o oo.o eo.o **o»onemoneeoesm memens o om.o oo.o om.o om.o om.o oononemoneeoeom memens IIIIIIIIIIIIIIIIIIIIIIIIII me IIIIIIIIIIIIIIIIIIIIIII ooo oom OOH om ***wmomw>e womeom Am Emmy eoH»oosHeme so w»om MeoH»ooHHeQe »ewa»owss mw»so msom ONH »mw>som eowm mo oses no oeooo s mo.o noes oeonxee onenoeomIeeom Hue o oe meII.oeo memos 170 .Amo. u no »mws wmeom meH»H:: m.eooeem e»H3 »ewswmsmo sH»eooesHemHm »oe wmo sw»»wH wEom we» e»HB meow: *** .eoH»oeHo>w »owssw HoeeHmwm mom ** .eoH»ooHHeeo Hoeeeo homo m.m econooo o o.m e.e o.m o.e m.m mm oeeom o o.e m.m m.o o.e o.m mm oooom o m.m m.m e.e o.m e.e me oommoooos o m.m m.m o.m e.e o.m me ooenoem eonnooo o m.o m.o s.o m.m o.m me ommoo o m.o m.o m.o o.m o.m me ononoom o m.o m.o m.o o.m e.e mm ooeeoeoo nonoz o e.e o.e m.e e.e m.m *Iononemonenoeom oeeees o o.e o.m m.o m.e m.o *ononemonenoeom memens IIIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIII ***omono>o ooo ooo ooe om ooeoom Am Eeev eoH»ooHHeee mo w»om .meowm e»e3 »ewEHmwam oeoem on» em onenooeeeeo nonmo msoo om assesseo menoomeonomeI.oeo memos 171 .Amo. n no »mws wmeom meH»He: m.eooeem e»H3 »ewewssmo sH»eooHsHemHm »oe wso sw»»wH wEom we» e»HB meow: 32....n .eoH»oeHo>w »owssw Homemmws mom ** .eoH»o0sHmmo Hoeeeo mom* o.m eonnooo o o.m e.e o.m o.m o.m me oeeom o m.m m.e e.e o.e o.m me oomoe o m.m o.e o.e o.m o.m me oommonoos o o.m o.m o.m o.e m.m me ooeeoem eoenooo o e.e m.o e.e m.m o.m me ommoo o m.m o e o.e o.m o.e me oeonoom o e.e m.m m.o o.e e.e me ooeeonoo nonoz o o.m e.e m.m o.m o.m ooononemonmnoeom memens o o.e o.e m.e s.e m.m *ononemoneeooom oeeens IIIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIII ooo ooo ooe om ***wwomw>e wosdom Am Emmy eoH»ooHHeee so w»om .meowm e»m3 »ewEstmxm onHm we» eH eoH»o0HHQee »ewE»owms mw»mo whom no SeemEeHe wHeowmeoeomeI.mHo memes 172 .Amo. n av »mws wmeom mee»He: m.eooeem e»H3 »ewswsmme sH»eooHsHemem »oe wmo sw»»wH wEom we» e»e3 meow: *** .eoH»oeHo>w »owsmw HoeeHmws mom ..Cw .eoH»o0mHmmo Hoeeeo mom * m.H Hom»eoo o m.m o.m o.e m.e e.e me oeesm o m.m o.m m.m o.m o.m me oomoe o o.m o.m o.e m.m e.e me wwmmweews o m.m o.e o.e o.e o.m me ooenoem eonnooo o m.m m.m m.e e.e m.e me ommoo o m.m e.e o.m o.m m.e me oeonoom o m.e e.e o.e m.e .m.e me ooeeonoo nonoz o m.e m.e o.e o.m o.m **o»onemonenoeom oeeens o m.m m.m o.m o.e m.m *ononeoonenoeom oeeens IIIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIII *ooomono>o ooo ooo ooe om monoom Am ammo eoH»oomHmee mo w»om .eoH»o0HHeee »ewE»owss sw»mo msom ONH »mw>som eowm mo wEHs »o EeeHseHe wHeowmeoeomeI.sHO memes 173 .Amo. n .eoH»oeHo>w »owmsw Hoeonwm mom* my »mws wmeom meH»He: m.eooeem e»H3 »ewmwmseo sH»eo0sseemHm »oe wso sw»»wH wEom we» e»HB meow: 5:1... * .eoH»o0HHmeo Hoeeeo mom * mmm.o Hos»eoo e mmo.o mos.m omO.m mom.m smo.m . mm oHHem e emH.o oos.m mmm.m omm.e mmm.m mm oomwm e mHm.o som.m som.m oss.m sos.o mm wwmmweews eo mmo.e msm.m omm.m mom.e smm.e mm oOHmon Hom»ewo o mos.o smm.o mmo.m ONO.o omo.e mm omsoo o meH.m mmH.m sem.m sOs.e mmo.m mm omeeowm o mom.o mos.e oom.m omm.e smm.o mm oeHHomoo e»soz e omo.m oom.m moH.e smm.m oos.e **w»oemmoemswmem meHms eo ome.o smm.o smH.m smo.m som.o *w»oemmoemswmem wHQHms IIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIII ***wmosw>e ooo OON OOH om womeom Am sumo eoH»ooHHQme so w»om .meowm e»e3 »ewEHmwmxm oeoem on» no onenooeeeeo nonmo msoe om soeoeoo menoomoonomeI.meo memos 174 .Amo. u so »mws wmeom wHeH»He: m.eooeem e»HB »ewswsmme sH»eooHseemHm »oe wso mw»»wH wEom we» e»mB meow: .eoH»oeHo>w »owmsw Hoeonws som*H* eoH»ooHHmmo Hoeeeo som* mos.m Hos»eoo o oHN.m mmo.m omm.m moo.m oom.m mm oHHem o moo.m osm.m sOH.o mmm.m Osm.m mm oomwm o mHN.m ooo.m moo.m mNH.m som.m mm wwmmweews o Hoo.m smm.m moo.m mmo.m ooo.m mm ooHson Hos»ewo o mmH.m smm.m smm.m OmO.m omo.m mm ommoo o mmo.m mom.m smo.o oom.m smo.m mm oseeowm o mmm.m mss.m msm.o oms.m smm.m mm oeHHosoU e»moz o oom.m ooo.m oom.m smm.m omo.m **w»oemmoeesweem wHeHss o omm.o ose.m mso.m mom.o sms.o *ononemonenoeow oenees IIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIIII ***wmosw>e ooo oom OOH om woseom Am Eemv eoH»ooHHQme so w»om .meowm e»H3 »ewEHmwmxm eHme we» eH eoH»o0HHmme »ewE»owss mw»so msom mm EeHoHoo wHeowmeoeomeI.oHU memes 175 .Amo. n .eoH»oeHo>w »owssw Hoeeemws som* ev »mws wmeom mes»He: m.eooeem e»m3 »ewmwmsHe sH»eooesHemHm »oe wmo sw»»wH wEom we» e»e3 meow: 33.3w * .eoH»o0HHmmo Hoeeeo mom * omm.e Hos»eoo o moo.o som.o oom.o oom.o oom.o mm oeeom o mmo.o moo.o oom.o oom.o soe.o mm oomoe o oom.o oom.o oom.o sso.m oem.o me oowooooos o mes.o sme.o oom.o som.o msm.m me ooenoem eonnooo o smm.o oom.o moo.o oom.o moo.o me ommoo o mem.o oom.o ooo.o oom.o oom.o me ononoom o oos.o oeo.o som.o oom.o moo.o me ooeeonoo nneoz o mem.o smm.o som.o moo.o smm.o. ooononemoneeoeom oeeens o sem.o sme.o moo.o oom.o see.o oononemonenoeom oeeens IIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIIII oooomono>o ooo ooo ooe om onoom Am Emmv eoH»o0eHmme so w»om .eoH»o0HHeee »ews»owss mw»mo msom ONH »mw>som eowm so wEHs »o eeHoHoo wHeowmeoeomeI.ONo memes 176 .Amo. n ev »mws wmeom wHeH»He: m.eooeem e»H3 »ewswsseo sH»eooHsmeme »oe wmo mw»»wH wEom we» e»HB meow:*** .eoH»oeHo>w »owmsw Hoeonwm mom ** .eoH»ooHHeeo Hoeeeo mom * moo.o econooo o oom.e som.e ooo.o ooo.e mem.e me oeenm on moo.o oom.o ooo.o smm.e sms.e me ooooe no oeo.o smm.e oom.o mom.e moo.o me wwmmweews o moo.o see.o ooo.o sme.o soo.o me ooenoem eoenooo o oom.o moo.o mes.o soe.o moo.o me ommoo no moo.o mme.o ooo.o oom.e oeo.o me ononoom o moo.o soo.o oom.o oom.o moo.o me ooeeoeoo nonoz n ooe.o mom.e soo.o meo.e moo.o *oononemonenoeom oeeees no meo.o moo.o mms.o oos.e mme.o *ononemonenoeom memens IIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIIII *ooomoeoso ooo ooo ooe on ooenom Am Emmy eoH»ooHHQme so w»om .meowm e»HB »ewSeswmxm oeoem on» me scenooeeeeo nonmo msoe om summonmo: menoomnonomeI.eoo memos 177 .Amo. u .eoH»oeHo>w »owmmw Hoeonwm som* ev »mws wmeom wHee»He: m.eo0eem e»H3 »ewswsseo sH»eoonHemHm »oe who mw»»wH weom we» e»H3 meow: *** * .eoH»ooeHeeo Hoeeeo mom * oso.e eonnooo ono omo.e som.e sse.e omm.e osn.e me oeenm o ome.e ssm.e moo.e msm.o omo.e me oomoe on moo.e omo.e soo.o smm.e som.e me oommoooos o oso.e mos.e moo.e mmm.e moo.e me ooenoem eoenooo ono omo.e ooo.e .som.o omo.e oes.e me ommoo ono nmm.e omo.e smo.e mom.e oes.e me onnnoom no mom.e mom.e meo.e oom.e sso.e me ooeeoeoo nonoz ono omm.e oem.e moo.e oom.e smo.e ooononemonenoesm oeeees ono omm.e smo.e smo.e omo.e smm.e *ooonewoneooeom oeeens IIIIIIIIIIIIIIIIIIIII Sm OOH\owEIIIIIIIIrIIIIIIIIIIII. *ooomonoso ooo ooo ooe om oonoom Am Emmy eoH»o0HHeQe so w»om .meowm e»HB »ewaeswmxm onem one am onenooeeeeo noosnoons nonmo msoe mo soemoomoe menoomoonomeI.ooo memos 178 .Amo. n my »mws wmeom wHQs»He: m_eooeem e»HB »ewewssse sH»eooesmem«m »oe weo sw»»wH wEom we» e»HB meow:** .eoH»oeHo>w »owmsw HoeeHmws som** .e0e»oosHeeo Hoeeeo som* moo.o Hom»eoo o ooo.o mso.H soo.o soo.o omm.o mm oHHem o mHo.o ssm.o mmo.o omo.H oos.o mm oomwm o mHo.o soo.o OHO.H moo.o moo.o mm wwmmweews o moo.o soo.o msm.o soo.o soo.o mm ooHson Hos»ewo o oHo.o soo.o sso.o moo.o oom.o mm omsoo o ooo.o mHo.O omo.o OHO.H moo.o mm omeeowm o Hmo.o smo.o smN.H omo.o oom.o mm oeHHomoO e»moz o meo.e omo.e soo.o mmo.e oom.o ooooonemoneeoeom oeeens o oom.o mHm.o moo.o oom.o soo.o *w»oeemoeesweem wHeHss IIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIIII ***wmomw>e ooo oom OOH om woseom Am Emmv eoH»o0HHer so w»om .eoH»ooHHmme »ewE»owss sw»wo msom ONH »mw>som eowm so wees »o Beemwemo: wHeowmeoeomeI.mNU memes 179 .Amo. u ev »mws wmeom wHee»He: m.eooeem e»s3 »ewmwssme sH»eooHsHemHm »oe wso sw»»wH wEom we» e»H3 meow: .eoH»oeHo>w »owmsw Hoeosmws somHH* .eoH»ooHHemo Hoeeeo mom* mom. Hos»eoo o mom. omo. oom. smm. smm. mm oHHem o mmo. smo. omo. smm. mom. mm oomwm o mmo. mmo. omm. ooo. Oms. mm wwmmweews o omm. moo. smo. OHo. oom. mm oeHmon Hom»ewo o omo. mmm. sos. mmo. smm. mm omsoo o ooo. mHo. smo. omm. ooo. mm oseeowm o mmo. smm. mms. omo. mos. mm oemHomoO e»eoz o omo. mHm. mos. mom. smo. *ow»oemmoeemweem meHss o ooo. smo. ooo. oeo. ooo. *ononemonenoeom oeeens IIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIII ***wmomw>e ooo oom OOH om woseom Am Sumo eoH»ooHHeee so w»om .meowm e»H3 »ewEestxm oeoem on» oe ooenooeeeeo nonmo msoe om snowmonoe oenoomoonomeI.ooo memos 180 .Amo. n av »mws wmeom mem»He: m.eooeem e»H3 »ewswsseo sH»eooesHemHm »oe weo sw»»wH wEom we» e»H3 meow: .eoH»oeHo>w »owsmw HoeeHmws momHH* .e0e»ooHHmeo Hoeeeo homo mHm. Hos»eoo o mmo. oom. ooo. omo. mso. me oeeom o ooo. moo. moo. soo. mso. me oooom o moo. smo. meo. omo. mmo. me oommoooos o mmo. soo. oeo. moo. ooo. me ooenoem eonnooo o omo. smm. oom. mmo. eon. me ommoo o men. een. esm. ooo. omm. me ononoom o oom. ooo. moo. mso. osm. mm ooeeonoo nonoz o oem. omo. mmo. seo. ooo. *Iononemoneeoeom oeeens o omo. meo. omo. smo. oem. *ononemonenoeom menses IIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIII *ooomonoso ooo ooo ooe om monsom Am Emmy eoe»ooHHmee so w»om .meowm e»m3 »ewEHmwmxm eHme we» eH eoH»ooHHQme »ewE»owss sw»mo msom mo seemmo»om wHeowmeoeomeI.mmo memes 181 .Aoo. u no poms omoom memeneos m.oooooe e»H3 »ewswmsse sH»eooesHemem »oe who sw»»wH wEom we» e»HB meow:*** .eoH»oeHo>w »owsmw Hoeonws mom .eoH»ooHHemo Hoeeeo somH* moo. eoe»ooo o mom. oso. omm. mmo. eon. me oeeom o moo. oom. mso. oom. mom. me oomom o omo. omo. mso. ooo. moo. me oommoooos o mso. omo. omo. moo. mom. mm ooenoem eonnooo o son. moo. mmo. oom. ooo. me oomoo o omo. oom. mso. eom. omo. me ononoom o omo. mom. seo. ooo. moo. me ooeeoaoo nonoz o mmo. omo. mmo. eem. omo. *oononemonenoeom oeeens o omo. mso. moo. omo. soo. oononemonenoesm menses IIIIIIIIIIIIIIIIIIIIII Em OOH\owE IIIIIIIIIIIIIIIIIII oooomoeo>o ooo ooo ooe on monsom Am Emmy eoe»o0HHmee so w»om .eoH»ooHHmme »ewe»owss mw»mo msom ONH »mw>som eowm so wEHs »o aeHmmo»om wHeowmeoeomeI.omo memes 182 .Amo. u so »mws wmeom wHQH»He: m.eooeem e»H3 »ewswssse sH»eo0HsHemHm »oe wso mw»»wH wEom we» e»H3 meow:*** .eOm»oeHo>w »owssw Hoeoemws mom ** .eoH»ooHHmeo Hoeeeo mom or moe. eonoooo o ome. soe. eoe. omo. ooe. me oeeom no sme. one. one. eme. ose. me oomoe on eoe. ooe. eoe. sme. ooe. me ooomoooos o ome. one. ome. ooe. mee. me ooenoem eonnooo o moe. ome. ome. ose. ome. me ommoo no mom. one. ooe. soe. mse. mm ononoom n eoe. ome. moe. mme. soe. me ooeeonoo nonoz o moe. moe. ose. eme. moe. *oononemonenoosm oeeees no one. ooe. soe. soe. one. *ononemonenoeom oeeens IIIIIIIIIIIIIIIIIIIIIIIII e s IIIIIIIIIIIIIIIIIIIIIII *ooomono>o ooo ooo ooe on oonoom Am ammo eoH»ooHHeme so w»om .Qomo »mmHm mo meH»eon mw»mo msom Om m»eon eowm we» so »ew»eoo memoemmoemII.sNo memes 183 .AmO. n mo »mws wmeom wHQH»He: m.eooeem e»H3 »ewmwsmHe sH»eoonHemHm »oe who sw»»wH wsom we» e»H3 meow: .eOe»oeHo>w »owssw Hoeoemwm somHH* .eoH»ooHHon Hoeeeo som* oom. Hos»eoo oo moo. moo. mmo. ooo. moo. mm oeeom o meo. omo. ooo. mme. ooo. me oomoe oo omo. ooo. soo. mmo. ome. me oommoonos oon mmo. smo. moo. mmo. ooo. me ooenoem eonnooo no mso. smo. smo. moo. soo. me omsoo oon omo. oso. omo. smo. owe. me ononoom ono ooo. sem. mso. mmo. meo. me ooeeoeoo nonoz o omo. omm. sso. mem. ooo. ooooonemonenoenm memens o omo. omm. smo. soo. omo. *ononemoneeoeom oeeens IIIIIIIIIIIIIIIIIIIIIIIII e s IIIIIIIIIIIIIIIIIIIIIII oooomonoso ooo ooo ooe on wonoom Am ammo ewe»ooHHeme so w»om .eomo »mmHm so meH»eon sw»mo msom no m»eon eowm we» so »ew»eoo mesoemmoemII.mNO memes 184 u no »mws wmeom wHQH»He: m.eooeem e»HB »ewswsmeo sH»eooesHemem »oe wmo sw»»wH wEom we» e»H3 meow: .eOe»oeHo>w »owmsw HoeeHmwm som*** .eos»o0eHemo Hoeeeo somH* om.H Hom»eoo o mo.e oo.m ss.e ss.e sn.e me oeenm o oo.m sm.e sm.e mm.e oo.m me oomoe o oo.m oo.m oo.m os.e so.e me oomwoonos o oo.m mo.e oo.m oo.m es.e me ooenoem eoenooo o os.e os.e oo.m oo.m oo.e me ommoo o os.e ss.e ms.e oo.m oo.m me ononoom o oo.m es.e oo.m oo.m os.e me oneeoeoo nonoz o os.e es.e ms.e oo.m so.e *oononemonenoeom oeeees o os.e mo.e oo.m em.e oo.m *ononemonenonom oeeens IIIIIIIIIIIIIIIIIIIIIIII m0 em IIIIIIIIIIIIIIIIIIIIIII ooo ooo ooe om ***wmomw>e .woseom Am Emmy eoH»ooHHeee so w»om .momo »mmHm so meH»eon Hw»wo mson mm m»eon eowm we» so »ew»eoo ESHOHoOII.mNU memes 185 .Amo. u av »mws wmeom meH»He: m.eooeem e»e3 »ewmwmseo sH»eooHsHemHm »oe who sw»»wH wEom we» e»s3 meow: .eoH»oeHo>w »owssw Hosesmws som*** .eoH»oomHemo Hoeeeo somH* om. eonnooo no om. mm. om. om. om. me oeeom n om. om. mm. em. em. me oomoe no om. mm. om. om. om. me oooooooos no om. mm. om. om. mm. mm ooenOem eonnooo o sm. mm. mm. oo. sm. me ommoo no mm. mm. mm. mm. mm. mm ononoom o om. om. mm. mm. mm. mm ooeeonoo nonoz no mm. sm. om. om. em. ooononemonenoeom oeeens no mm. om. om. om. om. *ononnmonenoesm menses IIIIIIIIIIIIIIIIIIIIIIIII m: & IIIIIIIIIIIIIIIIIIIIII ***omooo>o ooo ooo ooe om monoom Am Emmv eoH»ooHHmee mo w»om .momu »msHm mo meH»eon mw»mo msom mm m»eon eowm we» so »ew»eoo EeHmwemo:II.Omo memes 186 .Amo. n anB pcwhwmuwu zflucoofimficwfiw «o: wno kupwa wEom wnp suHB meow: av pmwe wwcmm wHQHpH=2 mucoocsa 33.3? .coflposao>w powmmw Hosvwwwu nom ...... .coHpmowanno amazed Mom ... ma.m Monacoo o Ho.m Ho.m mo.o nn.m oo.m mm ononm o oo.m «m.m oo.m mn.m wn.m an oomnn o un.m mo.o oo.m mn.m mn.m mm mmmmonnne o oo.m oo.m nn.m mn.m mn.m mn ovononm Honnnno o mo.o om.o «m.m oo.m mn.m mm ommou o Ho.m mn.m Hm.m oo.m nm.m mm onnnoom o mo.o mn.m om.o om.o mo.o mm onnnonoo nnnoz o mo.o na.m oo.m oo.m mo.o oomnonnmonnnnnnm nannne o oo.m oo.m no.m oo.m oo.m omnonnmonnnmnnm manage uuuuuuuuuuuuuuuuuuuuuuuu M & ------uuuaunuuunuuunuu- *ooowonm>< ooo oom can on nonnom Am Emav nowpdofiaanw mo wpom .mono umhwm Ho mawucmam prmw mama mm mucdfim :mwm wan MO ucwucoo Edfimmmuomll.HMIU mqm<8 L I TERATURE C ITED 187 LITERATURE CITED Adams, F. 1971. 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