THE EFFECT OF CULTURAL PRACTICES ON EMERGENCE AND UNIFORMITY OF STAND OF SUGAR BEETS By Irvin Mirle Wofford A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfilljnent of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Farm Crops ProQ uest Number: 10008453 All rights reserved INFORM ATION TO ALL USERS The quality o f this reproduction is dependent upon the quality of the copy subm itted. In the unlikely event that the author did not send a com plete m anuscript and there are m issing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10008453 Published by ProQ uest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This w ork is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQ uest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 ACKNOWLEDGMENTS The author wishes to express his sincere thanks and appreciation to Dr. S. T. Dexter, under whose inspiration, constant supervision, and unfailing interest this investi­ gation was undertaken and to whom the results are herewith dedicated. Grateful acknowledgment is also due to Dr. Dexter, to Dr. C . M . Harrison and to other members of the Farm Crops Department of Michigan State College for advice and counsel in the preparation of this manuscript. The author is also indebted to the Farmers and Manufacturers Beet Sugar Association for granting the funds which made this study possible. Appreciation is also expressed to my wife Marey for her continued assistance and encouragement through the entire program. VITA Irvin Mirle Wofford candidate for the degree of Doctor of Philosophy- Final examination, September 29, 1953, 10*00 A. M., Room 207, Agricultural Building Dissertation* The Effect of Cultural Practices on Emergence and Uniformity of Stand of Sugar Beets Outline of Studies Major subject* Minor subjects* Farm Crops (crop production) Botany, Soil Science Biographical Items Born December 11, 1916, White County, Georgia Undergraduate Studies, Oglethorpe University, 1933-35, Piedmont College, 1935-35, University of Georgia, 19^4-6—14.8. Graduate Studies, University of Florida, 1958-59, Michigan State College, 1951-53. Experiences Office Manager, United States Department of Agriculture, Farmer*s Home Administration, 1937-53, Member United States Navy, 1953-56, Graduate Assistant, University of Florida, 1958-59, Instructor in Agronomy, University of Florida, 1959-51, Graduate Research Assistant, Michigan State College, 1951-53. Member of Alpha Zeta, Phi Sigma, Alpha Phi Omega, Student Member, American Society of Agronomy. t h e effect o f cultural pra ctic es on emergence AND UNIFORMITY OF STAND OF SUGAR BEETS By Irvin Mirle Wofford AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Farm Crops Year Approved 1953 Irvin Mirle Wofford THESIS ABSTRACT To determine the effects of various seedbed preparation techniques, soil conditioning materials , green manure crops and seed treatments on the emergence and uniformity of stand of sugar beets, greenhouse and field experiments were conducted in Michigan during the 1951-1953 seasons. Green manure crops and a wheat straw mulch were turned under with a moldboard plow to give a "plowed" seedbed, disked into the soil to a depth of from three to five inches to give a ‘‘medium rough" seedbed, or disked into the surface soil to the extent that part of the material was uncovered and part was just covered with soil, forming a "rough" seedbed. None of these tillage methods gave significantly better stands, vigor or yields of sugar beets. Large amounts of green plant material was supplied by the rye, small amounts by peas, oats, and a mixture of oats and peas and intermediate amounts by barley and ryegrass. An inter­ mediate amount of green plant material added to the soil in the spring resulted in a significant improvement of stand count of sugar beet seedlings and yield of marketable beet roots in comparison with large amounts or small amounts of green plant material. Adding the wheat straw mulch to the soil produced a significantly lower yield of market­ able beets than adding an intermediate amount of green plant material. Various seedbed tillage methods were used on a good alfalfa sod where all, part or none of the hay had been removed the year before growing sugar beets. Emergence of sugar beet seedlings was as high on -1- Irvin Mirle Wofford plots where all the alfalfa hay was removed as on those where all or part of the hay was left the previous year. Seedbed preparation by plowing or field cultivating in the fall or in the spring gave no statistical stand count differences, the small differences obtained being in favor of spring tillage. In no case did the alfalfa present physical difficulties in the culture of sugar beets that followed. Weeds growing on the field cultivated plots were more vigorous than those growing on the plowed plots. Planting rye in fall field cultivated plots did not affect weed vigor, but resulted in significantly fewer broad-leaved weeds than when no rye was planted. A series of greenhouse and field experiments were set up to deter­ mine the effects of Krilium1 soil conditioning materials on sugar beets when applied in small amounts (one to 20 pounds per acre) on or in the planted sugar beet row or when applied in large amounts (100 to 1000 pounds per acre) broadcast and disked into the surface soil. No improve­ ment in emergence of seedlings or yield of sugar beet roots was found in these experiments from applications of CRD-186 and CKD-189. Lots of segmented sugar beet seed were soaked for six hours in running water or partially germinated for periods, ranging from 2h hours to it8 hours, prior to planting. Planting these soaked or partially germinated sugar beet seeds did not increase the rate or earliness of seedling emergence. 1 Krilium is the collective name given to all soil conditioner materials released by the Monsanto Chemical Company. -2- Irvin Mirle Wofford A field experiment was set up to study the effects of loose-wet, firm-wet, firm-dry and loose-dry seedbeds on germination and seedling emergence of dry and soaked sugar beet seeds. Data from this experi­ ment show that, (l) sugar beet seedlings emerged earlier from loosewet and firm-wet seedbeds than from firm-dry and loose-dry seedbeds; (2) rapid emergence of sugar beet seedlings compared with weed seedlings made weed control easiest on the loose-wet seedbed; (3) at all times throughout the growing season the beets appeared most vigorous on the loose-wet plots; (ij.) a more uniform stand and a higher rate of seedling emergence was obtained when loose-wet and firm-wet seedbeds were used than when the seedbeds were loose-dry or firm-dry; (5) a high rate of sugar beet seedling emergence resulted from compacting the row with tractor wheels in the process of planting on the loose-wet seedbeds. -3- TABLE OF CONTENTS PAGE INTRODUCTION................................................ 1 REVIEW OF LITERATURE........................................ 3 EXPERIMENTATION..................... 21 Experiment I .................... ........................ Discussion......... 21 22 Experiment II...... ..................................... Discussion....... ,................ ................... Stand Counts........................................ Number of Marketable Beets.......................... Weight of Marketable Beets.......................... 25 31 31 31 31 Experiment III ........................................ Discussion............................................ Number of Alfalfa Plants Remaining After Tillage...... Weed Size and Weed Population....................... Vigor of Sugar Beet Seedlings........................ Stand Counts of Sugar Beet Seedlings................. 32 36 1+0 1+0 1+0 1+1 Experiment IV............................................ Discussion............................................ Field Experiments With Krilium....................... Experiment 1 ..................................... Discussion...................... Stand Count................................ Number of Marketable Beets.................. Weight of Marketable Beets.................. Experiment 2 ..................................... Discussion.................................... Stand Counts ............................. Number of Marketable Beets.................. Weight of Marketable Beets.................. Experiment 3 ..................................... Discussion............................... Experiment 1+..................................... Discussion............... Stand Counts............................... Number of 1-foot Units Having No Beets...... Weight of Sugar Beet Seedlings............... Summary of Tests with Krilium Soil Conditioners....... 1+2 1+1+ 1+6 1+6 1+7 1+7 1+7 $0 50 52 52 52 52 53 51+ 51+ 59 59 59 59 60 iv PAGE TABLE OF CONTENTS - Continued Experiment V .............................................. Discussion .......... 60 62 Experiment VI...... Dis cus sion............................................. 62 6k Experiment VII............................................ Discussion............................................. Time of SeedlingEmergence............................ Vigor of Sugar BeetSeedlings.......................... Size of Weeds....................................... Soil Compaction..................................... Units Having No Seedlings............ „............... Stand Counts........................................ Weight of Seedlings............................... ... 6k 71 71 71 72 72 73 73 73 SUMMARY..................................................... 75 LITERATURE CITED............................................. 77 v LIST OF TABLES TABLE I II III IV PAGE Emergence Rates with Sugar Beet Planting Made on Two Degrees of Seedbed Preparation With and Without the Application of Water................................... 2k Total Green Weight and Total Oven Dry Weighty In Pounds Per Acre, For Wheat Straw and Green Manure Crops — 1951... 26 Stand Count of Sugar Beet Seedlings — 27 1952............. Number of Marketable Beets and Weight of Marketable Beets , In Pounds — 1952..................................... 30 Dates of Cutting and Average Yields of Alfalfa, In Pounds Of Green Material Per Acre, For Three Cuttings — 1952.... 3k Visual Estimates of Vigor of Beet Seedlings, Size of Weeds and Number of Alfalfa Plants Remaining................ 37 VII Average Weed Population on Sugar Beet Plots — 1953...... 38 VIII Stand Counts of Sugar Beet Seedlings Before Blocking and Thinning — 1953...................................... 39 Sugar Beet Seedling Emergence on Soil Treated With CRD-186 and CRD-189 Averages for Two Replications............... U5 Stand Count of Sugar Beet Seedlings on Krilium Treated Plots — 1952......................................... Ii8 Number of Marketable Beets and Weight, In Pounds, Of Marketable Beets on Krilium Treated Plots — 1952 . Average of Two Replications.................................... k9 Elmergence Rates of Seedlings, Number of Marketable Beets and Weight (Pounds) Of Marketable Beets — 1952. Averages for Three Replications................................. 51 Emergence of Sugar Beet Seedlings on Krilium Treated Plots — 1952............................................... 53 Effects of Krilium Treatments on Sugar Beets — 1953..... 58 V VI IX X XI XII XIII XIV vi LIST OF TABLES - Continued TABLE XV XVI XVII XVIII XIX XX XXI PAGE Stand Counts of Sugar Beet Seedlings One Week and Two Weeks After Planting, on Plots Receiving Soaked Seed and Germi­ nated Seed Treatments — 1952.............. 61 Stand Count of Sugar Beet Seedlings, One Week and Two Weeks After Planting. On Plots Planted to Different Size Seeds — 1952................................................. 63 The Order of Sugar Beet Seedling Emergence...... 66 Visual Estimates of Vigor of Beet Seedlings and Size of Weeds — 1953......................................... 67 Stand Count of Sugar Beet Seedlings on Compacted and NonCompacted Portions of Plots Receiving Loose-Wet Treatment — 1953............................................... 69 The Effects of Various Tillage Treatments on Sugar Beets From Plantings with Dry Seeds — 1953................... 70 The Effects of Various Tillage Treatments on Sugar Beets From Plantings with Soaked Seeds — 1953................ 70 LIST OF FIGURES FIGURE PAGE 1. Equipment Used for Applying Water with Sugar Beet Seed..,. 23 2. Two Middle Rows of Beets Growing onRye Plot............ 28 3. Two Middle Rows of Beets Growing onOats and Peas Plot,... 29 U. Plot Receiving 0.07 percent CRD-186.................... 55 5. Plot Receiving 0.05 percent CKD-189.................... 56 6. Untreated Check Plot................................. 57 7. Outside Rows of Two Four-row Drill Widths.............. 68 viii 1 INTRODUCTION Improvement of the percentage and uniformity of sugar beet seedling emergence in the field is at present one of the most important needs in sugar beet production. The unevenness with which sugar beet seeds germinate in the field contributes greatly to the problem. The sugar beet grower is well aware that there is a great deal more variation in rate and percentage emergence of sugar beets than of other seed types such as beans, corn, and small grains. The percentage of emergence fre­ quently varies 200 or 300 percent on different parts of the field or even from count to count down a row. There are several factors which it is logically believed influence the emergence of sugar beet seedlings. These factors may be conveniently divided into two classes. In one group are the characteristics inherent in the seed germ Itself. Why one seed will produce a strong plant and another seed similar in appearance will produce a weak seedling is a problem that has received some attention from different investigators (29,50,51). If there could be found some physical measurements which could be the basis for selection of these seeds inherently capable of producing a strong seedling, undoubtedly this would be a very considerable benefit in obtaining a higher percentage stand and more uniform stands of sugar beet seedlings. In the other group are the external factors which affect emergence rates. Some factors known to affect emergence 2 are seedbed fitting, planter, planting job, seedbed moisture, disease organisms and insects and soil temperature. In addition to its positive effect on beet yields, the improvement of percentage and uniformity of sugar beet seedling emergence in the field is necessary before complete spring mechanization can be accomplished. The line of approach herein reported is that of experimentally testing various seedbed preparation techniques, soil conditioning materi­ als, green manure crops, and seed treatments which might have the effect of modifying the environment in which the sugar beet seed is deposited. If some physical measurement could be discovered which, when applied at time of seedbed preparation and planting, could be correlated with emergence, it would be of value, at least as a research tool. 3 REVIEW OF LITERATURE Securing satisfactory sugar beet stands from whole or processed seed depends as well on a number of other factors. Along with seed, land preparation, seedbed preparation, seed treatment, environment surrounding the planted seed and growing seedling, and rate and depth of planting have equally important parts in producing desired stands. Culbertson (22) states that stand is composed of two major factors, first, the original allotment of soil surface determined by the row width and spacing within the row of the individual plants, and second, the number of blank spaces within the row. Dexter (29) states that “large numbers of seed must be planted, and later thinned, in order to get an acceptable stand, because the seeds cannot be planted accurately, nor depended upon to germinate promptly.11 According to Leach and Bainer (98) field plantings show the same tendency toward increased singleness with lower levels of emergence as is shown by controlled plantings. Evenari (37) reports that the presence of germination-inhibiting sub­ stances in plants seems to be a widespread phenomenon. all parts of plants — They occur in in fruit pulp, fruit coats, endosperm, seed coat, embryo, leaves, bulbs and roots, and are non-specific in their effects. Tolman and Stout (101,102) reported that water-soluble substances con­ tained in the corky pericarp of sugar-beet seedballs were toxic to the germinating seed and reduced both rate and total germination percentage . h Removal of the true seed or soaking in running water eliminated the injurious effects. Further studies by these workers (99) showed that the toxic effect on germinating seed to be largely due to the toxic action of free ammonia released from nitrogenous compounds in the course of seed germination. Repeated experiments by Barton (8,9) have shown that soaking injury to seeds is enhanced by passing oxygen through the water or salt solu­ tion in which the seeds are soaked; passing air or nitrogen in a similar manner reduced the harmful effect but did not permit normal germination. Hunter (50) in studying various facts concerned with the germination of seeds, particularly in relationship to the behavior of sugar beet seeds in the field and in the laboratory, reports that conditions of proper moisture, temperature, aeration and often light are necessary for germination and to overcome dormancy. Results by Hunter and Srickson (52) indicated that a soil should have a pF of at least 3.7 in order for segmented sugar beet seeds to germinate, whereas corn germinated in con­ siderably drier soil and at conditions slightly drier than this, the seed 11dries out” the surrounding soil without germinating. is no longer as critical once the seed has germinated. This value Working with segmented sugar beet seed Hunter and Dexter (5l) found, (a) that the seed failed to germinate in air at 100 percent relative humidity and that at this high humidity the seeds obtained a maximum of 29 percent moisture content; (b) in soil, germination did not occur unless the seeds took up somewhat over 30 percent moisture; (c) that germination took up somewhat 5 over 2b hours, but water absorption was complete in about four hours. On plantings made in soil adjusted to moisture levels ranging from near field capacity to near the permanent wilting percentage, Leach et al. (59) found that decorticated sugar beet seed germinated faster and showed a higher percentage of potential emergence than whole seed at low soil moistures. Only slight differences were noted in rates of emergence between whole, decorticated and segmented beet seed at high soil moistures. Pelleted seed showed a lower emergence and a longer emergence period, the delay being more pronounced in low soil moistures. Doneen {3b) reported that the growth of sugar beets is independent of soil moisture so long as readily available water is in the soil. According to Baver and Farnsworth (10) long tapering sugar beets, which produce a high tonnage are produced in a friable and well aerated soil. Results of research by Archibald (5) showed that there was a definite relationship between the aeration of the soil and the germina­ tion of sugar beets, Wiersma and Mortland (106) found that oxygen can be a limiting factor in growth of sugar beets, and its deficiency may be corrected by use of peroxides. When oxygen diffusion was very low, response to peroxide fertilization was obtained. Data presented by Syster (38) on the use of concentrations of 0.0015 to 15 percent hydrogen peroxide, show that the rate of water absorption by bean seeds is inversely proportional to the concentration of hydrogen peroxide. Various seed treatments have been employed in an attempt to stimu­ late sugar beet seed germination. Tests conducted by Skuderna and Doxtator (93) on presoaking of seed for two hours prior to conducting 6 germination tests versus dry seed, showed that with beetseed from a fresh crop this treatment is not necessary, unless presence of toxic substances in the seed has been shown. presoaking treatment was beneficial. However, on older seed, the Although sugar beets are regarded as a salt tolerant crop data indicate that they are relatively sensitive to salinity during gemination (U6,6) . Ayers and Hayward (6) found that the percent germination of sugar beet seeds in soil decreased as the amount of sodium chloride added to the soil was increased. Results of experiments by Hunter (£0) showed that germination of sugar beet seed treated with magnesium sulphate, sodium chloride, dextrose and sucrose was slightly less than that of the water treatment and these results suggested that the more rapid germination was due to the apparent beneficial action of the water rather than the chemicals in the water in which the seeds were soaked. Satchell (87) treated sugar beet seed with sodium chloride. Results showed that a more rapid germination was obtained with the sodium chloride treated seed than with the untreated seed, however, the sodium chloride treatments were not superior to treatment with water alone. Greenhouse and field experiments conducted by Garner and Sanders (i^l) indicated that treatment with strong sulphuric acid is effective in accelerating and increasing germination of sugar beet seed, giving a greater plant population at harvest. Milling of seed, however, was approximately as effective as the sulphuric acid treatment. Lackey (5>6) gives results of tests by the blotter method which showed that hydro­ chloric acid and sulphuric acid treatments hastened the rate and 7 increased the percentage germination of sugar beet seed over checks treated with distilled water. germination in soil also. The hydrochloric treatment hastened Seed treated with magnesium chloride and l1dreftl* solution showed depressed and abnormal germination in blotter tests and greenhouse conditions, but similar tests with water, phosphoric acid, calcium chloride and sucrose solution treated seeds gave normal germination and, in some cases, an increase in seedling emergence (76). The literature on the possibility of modifying growth of sugar beet plants through the application of certain synthetic growthregulating substances to the seed or to the foliage of plants is not in close agreement. Some claims have been made that the yield and quality of plants have been greatly increased by the use of these chemicals and commercial preparations. Other reports have shown that applications of different concentrations have produced no beneficial response to a wide variety of plants . In an attempt to stimulate germination and growth of sugarbeets, using water solutions and dusts and sprays of various hormone preparations, Dexter (31,32) found that growth was not improved nor germination hastened by their use. The differences that were noted among the plots were in favor of those planted with untreated seed. Stout and Tolman (98) found no significant benefits as to seedling emergence, vegetative growth, or yield of beet roots per acre from applications of synthetic growth-regulating substances applied in dusts to the sugar beet seed before planting and in sprays to the foliage of growing sugar beet plants. Data obtained by Mikkelsen et al. (69) Indicated that foliar treatments with maleic hydrazide, on sugar beets 8 grown under conditions conducive to extreme vegetative growth and late maturity, may improve the yield, sucrose content and sucrose yield per acre of the harvested beets . The results of tests conducted by Skuderna andDoxtat.or (93) 9 using various size seedballs, indicated a positive correlation with seed size and germination. Other workers (30,53*61) have also found that as size of seed increased, germination of sugar beet seed increased. Results of tests conducted by Bush and Brewbaker in 1910 and 1911 (lU), showed no significant differences between yields of sugar beets from plantings made with seed graded into different sizes. Bush (13) reports that segmented and whole seed of the same grades (graded with screens) appeared to give about the same results under comparable field conditions. He also found that field germinations produced a higher percentage of singles, for all types of seed, than was obtained in the laboratory. Results of experiments conducted by Buschlen (15) indicated that germination was most rapid when sugar beet seed was planted in towel tissue containers with loam soil as a germinating medium. He concluded that pre-packaging and space planting of sugar beet seed in small con­ tainers appears to be a feasible technique provided efficient machines for packaging and planting are developed. Dionne (33) presented results which indicated that yields can be increased four to five tons per acre by transplanting the sugar beets, but that it is difficult to maintain good shaped roots and mechanical transplanters are not adapted to the beet transplants. 9 All sugar beets carry some color pigment of either red or yellow color. Nuckols (72) attempted to determine whether color of seedling had any direct correlation upon weight of root or sugar content of beets at harvest time and found that color of plant does not seem to be correlated with either yield or sugar content in the varieties studied. Considerable agronomic attention has been given to spacing trials in an attempt to determine the optimum stand of plants that will allow the most economical use of the soil resources available. An extensive review of literature regarding space relationships as affecting yield and quality of sugar beets has been compiled by Coons (20) . In report­ ing on work during 1910, 1911 and 1912 Shaw (9l) states that the deficiencies of stand, representing a mean of 50 percent, may be divided into three groups s (l) those occurring in the germination stand, averaging 19.32 percent; (2) those due to improper spacing and thinning, averaging 29.53 percent; and (3) those occurring between thinning and harvest, averaging 7.26 percent'; „ In a study on sugar beets Maxson (65) found that, of the mean post-thinning loss of 8.63 percent, diseases accounted for i4-2.ll percent of the total loss. This worker also found that losses were less when beets were thinned in May than when thinned in June. Brewfoaker and Deming (12) concluded that uniformity of stand, or the elimination of the skips, is more Important than actual space allot­ ment in determining yield of sugar beets grown under irrigation. From research conducted over a period of 12 years on plant population experi­ ments with sugar beets Deming (25,26,27,28) concluded, (l) as stands 10 were reduced yields declined , but the declines were not proportional to the reductions in stand, a 70 percent stand producing about ninetenths as much as a full stand, a 50 percent stand three-fourths and a 30 to kO percent stand two-thirds of a normal crop; (2) that it would be more profitable for a grower to save as little as a half stand of timely planted beets than to replant in May; (3) the hill, irrespective of the number of plants it contained, was the unit of stand which de­ termined sugar beet yields; (I4) yields declined as row widths increased from 20 inches to UO inches; (5) additional plants present in multiple plant hills may have some adverse effects on yields under some conditions. Working with muck soils Davis (23) reports that spacings of 10.7, 12.14. or llul inches between plants in 28-inch rows had no significant effect on yields of sugar beets, and a significant correlation coefficient between stand and yield was not found until the average stand was less than 60 percent. In Ohio, Gray and Volk (1*2) found that the most pro­ ductive spacing of sugar beets was 22-inch rows and 12 inches in the row. The seedbed constitutes the environment of the young sugar beet plant as it advances from germ to the emerged seedling. Much work has been done on the effects of tillage practices as related to seedling emergence and crop yields . Results of these experiments vary as to which mfethod is considered best. This variation is expected because of the differences in the characteristics of the soils used for the studies . An extensive review of literature up to 1919 regarding tillage is presented by Sewell (90) . According to Shaw (9l) the loss of stand 11 caused by imperfect, germination was due largely to the poor preparation of the seedbed, since fall plowing was seldom practiced and rarely deep enough. Nutt and Reele (7U) * experimenting with row crops at South Carolina on Cecil sandy loam involving the use of summer crops as sources of mulch, reported that the mulch-disk method afforded a practical way of producing corn and maintaining high yields, while erosion and runoff were reduced to negligible quantities . Russell and Keene (86), from their comparative studies on different methods of tillage, concluded that plowing is the most satisfactory tillage operation for higher production of crop yields. Results of a study carried out by Dreibelbis and Nair (35) in Ohio on plowed and disked plots, on which there was a U-year rotation of corn, wheat and two years of meadow, to determine the effects on certain properties, showed that the percentage of soil moisture in the disked plots was consistently higher than in the plowed plots, the air space porosity in the four to seven inch depth was significantly higher in the plowed plots, the percentage of water stable aggregates were greater in the top It-inch layer on the disked plots but greater in the four to seven inch layer on the plowed plots, and even though corn plants were taller and thinner on disked plots, yields varied from year to year in favor of each treatment. Hill (1*9) pointed out, as early as 1922, that to secure good yields of sugar beets, deep plowing and subsoiling to a depth of 8 to 10 inches, to make a mellow deep seedbed, is essential to permit the development of a good long root. Farnsworth (39) reported that better sugar beet yields were obtained by farmers who prepared their 12 seedbed by disking and not by plowing and over-working. According to G**egg (k3) snd Gregg and Harrison (1U±) there was an indication that a soil should remain mellow for at least the first half of the growing season for best growth and production of sugar beets. Smith (95) and Smith and Cook (96) reported that compaction of the soil, following corn and legumes in pot cultures, resulted in a con­ siderable reduction in yield of sugar beets and compaction was found to be more serious than the addition of excess water. On compacted soils where normal moisture levels were maintained additional aeration materially increased yields. Cook (17) reports that sugar beet yields were depressed more than were yields of other crops when grown in the greenhouse in excessively packed clay loam soil. The depth of planting was found by Hentsbhel (U8) to have a greater effect upon emergence than did the method of fitting the seedbed and planting the seed. The average of two plantings made by McBirney (66) showed no significant differences in sugar beet seedling emergence between the harrowed and unharrowed portions of a seedbed which had been fitted for a week or so before planting and which had received O.lj. inch of precipitation. Painter (76) suggested that a heavily worked soil seedbed is not needed to obtain a sufficient stand of sugar beet seedlings under field conditions of excessive moisture, but is needed to obtain a sufficient stand where there is a shortage of moisture. He also found that the packing of soil over seed depressed seedling emergence and soil-seed contact was of greater importance. Correlation studies conducted by Barmington (7) between soil moisture, soil firmness and seedling emergence showed a 13 striking similarity between the shapes of the curves, indicating the relation between the three factors. Highest emergence of beet seedling was: obtained when soil moisture and soil firmness were highest and lowest when these factors were lowest. Pendleton (78) reports that Chehalis sandy loam, which had been compacted by conventional tillage operations to a point of only about five percent non-capillary porosity in the plow depth could be improved considerably by deep tillage or rotary tillage treatment. Results were characterized by better shaped beet tap roots, faster fall growth and a little improvement in seed yields. It has been reported (67) that if beets are planted on a loose seedbed the top soil is likely to dry out because the subsoil moisture cannot rise through the loose plow layer. Cook (17,18) reports that experimental results, over a five-year period, from comparisons of seven tillage methods, did not reveal any tillage method that resulted in yields greater than those obtained where the moldboard plow was used, and weed control was more difficult after soil was fitted by those methods which mixed the vegetation with the surface soil. Good yields of sugar beets were obtained from plots where the soil had been plowed and fitted in one operation, and at all times throughout the growing season the crop looked the best on those plots which had received the least pre-planting tillage. Cook and Rood (19) report that records of nine Michigan farmers showed their beet yields increased from below to above the factory averages during seasons in which minimum seedbed preparation was practiced, and all the farmers agreed that weed control was easier after the new method of tillage. Ik In Sanilac County, Michigan, several sugar beet growers have obtained increased crop yields during the past few years from the use of deep tillage and minimum seedbed preparation (1±5) , Deep tillage refers to the practice of working the soil with various types of field cultivators to a depth of several inches. Johnson (5W reports that farmers in Michigan are trying once-over tillage as a new system of preparing ground to plant corn. The literature on the subject of fall plowing versus spring plow­ ing is controversial. In the past, the matter of time was one big reason for fall plowing, but this situation has been largely eliminated with the use of the tractor. According to Millar (68) objections to fall plowing include exposure to erosion, use of cover and greenmanuring crops is prohibited, and reduction of land on which to spread manure during the winter and early spring. Observations by Schwartz (89) have shown that the soils of Indiana which are fall-plowed are unable to absorb the spring rains, while spring-plowed ground absorbs the moisture and is dry enough to work in two or three days. He further reports &h&t according to soil and crop authorities at Purdue University, whether or not to fall-plow depends a lot on the type of soil and it is most important that a soil which is fall-plowed must contain a lot of humus. Using a corn-oats rotation experiment, DeBoodt et al. (2I4.) show that yield increases from fall plowing, as compared with spring plowing, were in favor of fell plowing every year. Cox and Hill (21) and Wenner (105) report that fall plowing to a good depth is conceded to be the 15 best initial preparation for large sugar beet yields; however, when spring plowing is necessary it should be done as early as possible. These workers advocated the use of the cultipacker immediately after seeding and before the beets are up to pack the soil around the seed and to break any crust which developes. Workers at Michigan State College (67) reported that sugar beets should be planted on a firm, granular seedbed which is well supplied with moisture , this condition being most easily obtained on fall-plowed fields . Lill and Rather (60) found that beets yielded best when alfalfa was plowed August 12 and poorest yields resulted from spring (April 15) plowing. In a study made by Johnson and Wright (55), the yield of sugar beets ranged from 10.3 tons per acre for fall plowing, 10,2 tons for a combination of fall and spring plowing, and 9.5 tons for spring plowing. They further reported that spring plowing took about one-third less time and cost about a third less, but there was little difference in cost of fitting the ground after fall or spring plowing. Extensive research has been conducted on the use of soil building or green manure crops in crop rotations or crop sequences as to their influence upon the crops which follow. A complete discussion of various green manuring principles and practices with a comprehensive bibliography on the subject is presented by Pieters (80) . Ripley (83) gives an extensive review of material on crop rotations and influences of crops upon those which follow. According to Robertson (8U) and Robertson £t al. (85) highest sugar beet yields were obtained in the rotation where the crop followed 16 beans which in turn had followed two years of alfalfa-brome hay and lowest yields where there was no legume in the rotation. These workers found that beets did well after alfalfa when moisture and aeration conditions were favorable, but beets did poorly in such a crop sequence during wet seasons when soils became puddled. This suggested to them that possibly a lack of soil air resulted in the accumulation of certain toxic decomposition products where fresh alfalfa had recently been turned Tinder. In a report on new soil physics studies with sugar beets, Farnsworth (39) stated that beets following alfalfa or clover gave larger yields, but some farmers claimed that beets following alfalfa were usually injured by root rot. Morris and Afanasiev (70) concluded, (l) that if sugar beets follow alfalfa the soil should be plowed after the second crop of alfalfa, which should preferably be plowed under and some additional nitrogen (manure) and phosphorus should be added, and (2) the planting of sugar beets on late-fall-plowed alfalfa land, unless manure, nitrogen and phosphorus are added to the soil, is not recommended because the prevalence of root rots makes it difficult to obtain a satisfactory stand and yield. Nuckols and Harris (73) found that legumes, such as alfalfa and sweet clover, in the rotation almost doubled acre yields of sugar beet roots and gross sugar in comparison with results from non-legume rotations. Reeve (82) reports that land may be improved so as to double yields of sugar beets by the use of alfalfa and sweet clover together with heavy applications of commercial fertilizers if the first green manure crop of the season is cut and allowed to remain on the land, the second crop grows through, and the 17 entire mat plowed under before August 15. According to Garner and Robertson (ItO) , on land which is not well-fertilized with nitrogen carrying materials, alfalfa will contribute materially to crops which follow it in rotation, but where large quantities of nitrogen fertilizers are used the contribution of alfalfa is less important. Skuderna and Johnson (9W report that beets can follow many crops in rotation but do best after sweet clover left to lie fallow, potatoes, onions, beans and other vegetable crops. Crops with heavy residues like grain stubble and late-plowed or uncrowned alfalfa should be avoided, unless these residues have rotted well. They also report that, where alfalfa is used in the rotation, the practice varies as to whether the first, second, or third cutting is plowed under $ the important thing is to turn down some top growth. In recent years a number of synthetic chemicals have been tested for aggregating soils. Some early investigations (36,97*103) showed that silicates and volatile silicones were effective in aggregating soils, but have such drawbacks as high alkalinity, waterproofing effects or difficulty In application. The recent release to the public of synthetic polyelectrolyte soil conditioners has stimulated considerable interest in the possibility of soil improvement from their use. The two synthetic conditioners most widely available are a hydro­ lyzed polyacrylonitrile (yellow in powder form) and a modified vinyl acetate maleic acid compound (white in powder form). These materials, which were used in the experiments reported here, have been designated 18 Krilium CRD-189 and. Krilium CRD-186 by the Monsanto Chemical Company. Swanson (100), in an account of what the experiment station tests on soil conditioners have indicated, describes these materials as being long-chain polymers with extremely high molecular weights. Preliminary work by Hedrick and Mowry (24-7) suggests that at least some of the con­ ditioners have no apparent toxic effects on plant and animal life in the soil and no interference with the absorption of nutrients and trace elements has been detected. It is reported by Schulenberg (88) and Zorch (107) that Krilium does not provide additional crop or plant nutrients, but permits those nutrients already in the soil to become more effective. Soil structure has a predominant influence on seedling emergence and plant growth. Even though a desirable soil structure can be pre­ pared prior to seeding, it may break down unless there is some stability of the structural units or aggregates. Nason (71) and Zorch (107) state that the primary or direct effect of Krilium is to stabilize the natural soil aggregates against the dispersing or slaking action of water. Many workers (Ii7*62,63,61*,71 *81592) report that the addition of synthetic polyelectrolyte conditioners, especially to strueturally-poor or ^problem” soils, has increased the percentage of water-stable aggregates, and this, in turn, improves soil aeration, soil moisture relationships and soil workability and tilth. In a recent paper, Hedrick and Mowry (ii7) reported that additions of CRD-186 and CRD-189 increased the moisture equivalent of soils while leaving the wilting point unchanged, concluding that the use of such 19 conditioners will cause the soil to hold greater amounts of water available for plant growth. To the contrary, Bo dm an and Hagan (ll) and Peters et al. (79) found that applications of polyelectrolyte soil conditioners do not appear to offer a means of increasing the quantity of available moisture stored in soils. The changes in soil physical properties are not always reflected in better plant growth. Some plants, however, respond to treatments of soil conditioner materials. In some preliminary experiments, Allison (U) obtained full stands of corn on all CRD-186-treated alkali soils, but because of heavy crust formation, the stands on the untreated soils varied from 0 to kO percent with little or no yield. Additions of the polymer did not significantly increase corn yields on normal soil. It is reported by Martin et al. (63) and Swanson (100) that the Ohio Experiment Station obtained no statistically significant yield increases of potatoes and sugar beets as a result of applying 0.08 percent CRD-186 or CRD-189 to Brookston and Miami soils in the field. were more easily dug and came out of the ground clean. The beets, however, These workers reported that corn, oats, tomatoes and carrots were most responsive to conditioner treatments and significant yield increases were obtained. In some cases, these yield increases appeared to be closely related to better seed germination and to increased root penetration in the treated soil. Generally the powder forms were used in the research work reviewed here. However, liquid conditioners may have a place in surface treating of seed rows. Peck and Vittum (77) have developed a machine for accurate 20 placement of* bands of soil conditioner solutions directly over the planted row. Germination and emergence improvement were obtained with several crops including sugar beets from the use of "Krilium Soil Con­ ditioner Liquid" (3,100). In some experiments treatment resulted in a 1^0 percent yield increase in oats^ and no yield increase in sugar beets on an adjoining plot. Soil conditioners may prove useful in combating erosion. Swanson (lOO) 9 Weeks and Colter (IOJ4) and Zorch (107) report on their use in stabilizing surface soil against erosive action of rainfall9 and, reduc­ ing water runoff. Plant breeders are also attacking the problem of emergence and uniformity of stand of sugar beets . Programs on breeding for single and double germed seed balls have been going on for some time (75) . It has even been suggested that single germ seed will be the next significant development in sugar beet production (16) . 21 EXPERIMENTATION A series of greenhouse and field experiments was set up to determine the response of sugar beets to various seedbed preparation techniques, soil conditioning materials * green manure crops , and seed treatments. All field experiments were conducted on the Michigan State College Farm. Unless otherwise specified, segmented sugar beet seeds of commer­ cial variety 215x216 were used in all experiments during 1951 and 1952, and commercial variety 216x226, treated with Ortho Seed Guard Liquid, in 1953. The field planting rates, using a commercial four-row beet drill, were eight pounds per acre for dry seeds and six pounds per acre for soaked seeds. Results were analyzed statistically by standard methods (97) . Experiment I On June 26, 1951 a planting of sugar beet seed was made using two types of seedbed preparation and including the application of a small amount of water with the seed at the time of planting. Stand counts were used as the means of evaluating the results. The objective with these different seedbed treatments was to study the effect of seedbed refinement upon plant emergence. The entire area 22 on which this series of plots was planted was plowed, tandem disked, and dragged with the spring-tooth harrow. This was the degree of work­ ing that the plots with the minim-uin of seedbed preparation received. The next operation consisted of rolling strips 20 feet wide with a cultipacker. These cultipacked strips alternated with strips not culti- packed of the same width. The strips were at right angles to the di­ rection of the rows that were subsequently planted. Equipment was built on the planter to apply water in the seed furrow immediately after the seed was dropped and before it was covered by the press wheels. It was thought that a small amount of water applied in this manner might give the seed enough stimulus to markedly affect germination rates. Water was applied, at the rate of 22 gallons per acre, to one row only of the four drill rows. Four rounds were made with the drill, making a total of four rows per replication which were treated. The water was turned on and off alternately on each 80-foot section of row so that comparisons with and without water could be made. The planter equipment for applying water is shown in Figure 1. Data for these experiments are shown in Table I. Discussion If seedbed compaction and refinement were desirable under the field conditions that prevailed at the time this planting was made, it would seem logical to expect seedbed B, which was conventional preparation plus cultipacking, to show some Improvement over seedbed A, which is termed as conventional. Figure 1. Equipment used for applying water with sugar beet seed. Tops Water tank mounted on drill for appli­ cation of water with the seed in the extreme right hand row. Bottoms Water tank and shut-off valve for apply­ ing water with the seed. 23 2h TABLE I EMERGENCE RATES WITH SUGAR BEET PLANTING MADE ON TWO DEGREES OF SEEDBED PREPARATION WITH AND WITHOUT THE APPLICATION OF WATER Seedbed Preparation Water ^ Applied^ No Water Applied^ Average A - Conventional 1612 162U iiou.50 B - Cultipacked 1633 1728 li20.12 Average ii.05.62 1*19.00 •Sr -3e& i Total stand count Tor 4OO inches of row per treatment per four replications. Average for four replications. Treatment differences were not statistically significant. Results of this experiment show that total emergence rates were highest on the cultipacked seedbed, regardless of water treatment. Even though there were no consistent nor significant responses to the application of water, total emergence rates were higher on plots receiving no water . There was considerable difficulty with stoppage of the seed tube, used to supply water, by soil. If the planter was allowed to roll back­ wards just a few inches the seed tube was almost certain to become stopped with soil. 25 Experiment H A split plot experiment was conducted during the 1951-1952 season utilizing different tillage methods for incorporating green manure crops into the soil as the main treatments and different green manure crops and wheat straw mulch as the subtreatments. A field of Brookston clay loam soil, which had been summer fallowed in 1951, was selected for this experiment. The plots were plowed in September 1951 with a moldboard plow and no other seedbed preparation was used prior to seeding the green manure crops. The plots were fertilized and seeded at recommended rates the next day after plowing. Wheat straw was spread on designated plots at the rate of two tons per acre . Yields , as green weight and oven dry weight, of green manure crops were taken in November by harvesting the entire plant (top and roots) . These weights are shown in Table II. The total dry weight of wheat straw was taken as 90 percent of the total rate applied to the plots. Some cold damage was noted on the young field pea seedlings which partially accounts for the low yield of this crop. Additional harvests were made in Hay to determine the spring growth of rye and barley. Winter damage to the other crops prevented them from making any appreciable spring growth. Total green weight and dry weight of rye was 22,ii30 pounds and 588U pounds, and of barley 11,055 and 2399 pounds per acre. 26 TABLE II TOTAL GREEN WEIGHT AND TOTAL OVEN DRY WEIGHT, IN POUNDS PER ACRE, FOR WHEAT STRAW AND GREEN MANURE CROPS -- 1951 Green Manure Crop Total Green Weight Total Oven Dry Weight — 3600 Rye 2I4.8O k66 Ryegrass 1137 231 Barley 32U9 551+ Oats 1|I|.28 801 Oats and peas 1575 318 1U6 32 Wheat straw Field peas The different tillage methods used to incorporate the green manure crops and wheat straw included, (a) disking the material to the extent that it was partly uncovered and partly just covered with soil (rough); (b) mixing the material, by disking, into the top three to five inches of soil (medium rough); and (c) plowing the material under with a moldboard plow (plowed) . On May lii, one-third of each plot received one of these tillage treatments. Due to a rainy season immediately following the tillage treatments planting of sugar beet seeds was delayed until early June. Prior to seeding the sugar beets, the entire field was tandem disked and fertilized. Each plot consisted of six rows, 26 feet long. 27 Stand counts of sugar beet seedlings were taken three weeks after planting (two weeks after beets had started to come up) on 10 feet of each of the four middle rows. Total stand count per plot for six replications is shown in Table III. TABLE III STAND COUHT OF SUGAR BEET SEEDLINGS — 1952 Green Manure Treatments Rough Tillage Methods Plowed Medium Rough Average Per Replication Wheat straw 9k9 1131 1105 176.9 Rye 722 696 891 128.3 Ryegrass 1115 998 956 170.5 Barley 1120 1006 1311 190.9 Oats 1033 930 937 161.1 Oats and peas 1001 811 1037 158.3 922 872 9hk 152.1 162.6 X53.lt 170.9 Peas Average per replication 32.99 L. S. D. (5%) Treatment differences for tillage methods were not statistic­ ally significant. Stand count for 10 feet of four rows per treatment per six replications. The sugar beets were blocked and thinned by hand labor, then culti vated and hoed throughout the growing season to control weeds. Differ­ ences in growth conditions of sugar beets one month after blocking and thinning are shown in Figures 2 and 3. Figure 2. Two middle rows of beets growing on rye. plot. Tops Plot portion receiving the rough tillage treatment. Note the large amount of rye re­ maining on the plant bed. Middles Plot portion receiving the medium rough tillage treatment. Note the small amount of rye remaining on the plant bed. Bottoms Plot portion receiving the plowed tillage treatment. Note the absence of rye on the plant bed. Figure 3. Two middle rows of beets growing on oats and peas plot. Note the absence of plant residue on surface of plant bed. Tops Plot portion receiving the rough tillage treatment. Middle s Plot portion receiving tlie medium rough tillage tre atment. Bottoms Plot portion receiving the plowed tillage treatment. 30 The four middle rows of each plot were harbested on October 20 21, and the number of marketable beets and the weight of marketable beets per plot were recorded. These results are shown in Table IV. TABLE IV LUMBER OF MARKETABLE BEETS AND WEIGHT OF MARKETABLE BEETS, IN POUNDS — 1952 Green Manure Treatments Rough No. Wt. Tillage Methods Medium Rough No. Wt. Average Per Plowed Replication No. W t . No. Wt. Wheat straw 375 21+3 370 237 1*09 277 61*.1 1+2 .0 Rye 1*00 271+ 337 217 1*21* 309 61+.5 1+1+.1+ Ryegrass 1+75 321 1*33 291 5oi 359 78.3 53.9 Barley 1+69 320 i+i+i 268 1*77 327 77.0 50.8 Oats 1+20 301 1+31+ 290 1+17 301 70.6 1+9.5 Oats and peas 1+21 295 392 268 1+1+9 315 70.1 1+8.8 Peas 1+1+9 291 391+ 239 1+65 301+ 72.7 1+6.3 71+.0 1+8.7 69.1 1*3.1 Average Per replication 77.1+ 52.2 10.1+0 6.80 L. S. D. {&) Treatment differences for tillage methods were not statistic ally significant. 31 Discussion In no case was any one tillage treatment significantly better than the other tillage treatments. However, the slight differences obtained were always in favor of plowing under the green manure and wheat straw residues. Stand Counts The emergence rate of sugar beet seedlings, as shown in Table HI, was significantly higher on plots planted to barley than on plots planted to rye or field peas, and significantly higher on plots receiv­ ing a wheat straw mulch or planted to ryegrass than on the rye plots. Stand counts for other green manure treatments were approximately equal. Number of Marketable Beets Data presented in Table IV show that the number of marketable beets harvested from the ryegrass and barley plots was significantly greater than from the wheat straw and rye plots. There was no significant difference between number of marketable beets harvested from the other plots. Weight of Marketable Beets The weight of beets, harvested from plots planted to rye and plots planted to peas was significantly less than the weight of beets harvested from plots planted to ryegrass, and significantly less from the wheat straw plots than from the ryegrass, barley or oat plots. Weight differ­ ences of beets harvested from other green manure plots were not significant. 32 It appears , from the results of this experiment , that too much green plant material or too little green plant material , from spring growth, resulted in poor seedling emergence and yield of sugar beets. Significant improvement did result where intermediate amounts, as was furnished by barley and ryegrass, were incorporated into the soil prior to planting sugar beets. The low yield of harvested beets on the wheat straw plots may have resulted from the large amount of dry, carbonaceous material supplied by this treatment. The breakdown of this material did not begin in time to interfere with seed germination. In fact, the moisture relationship was increased due to the mulch, affording better conditions for germination. The reduction in stand count, number of marketable beets and weight of marketable beets from plots planted to rye was apparently caused by the soil drying out at a faster rate and the slow breakdown of such large amounts of green material. Perhaps if the rye had been plowed or disked before too much spring growth had taken place, these reductions would not have occurred. Sxperiraent III A field seeded to alfalfa in May 1950 and cut for hay was used for an experiment to determine the effects of, (l) various methods of handling the hay, (2) different methods of land preparation or tillage treatments for planting sugar beets, and (3) applications of Krilium soil conditioning materials on sugar beets. made and the hay removed. In 1951} two cuttings were The experiment, which was conducted during 33 the 1952-1953 season, included twenty treatments, replicated six times, and arranged in a randomized block design. The treatments used in these tests were as follows: One cutting of alfalfa (June 19) , all hay left on plots in -------- ------1952. 1. Fall plowed 2 . Spring plowed 3. Field cultivated and planted to rye in fall; rye field cultivated in spring U. Fall field cultivated 5. Spring field cultivated 6. Fall plowed and treated with CRD-186 7. Spring plowed and treated with CRD-186 8. Spring plowed and treated with CRD-189 9. Spring field cultivated and treated with CBD-186 10. Spring field cultivated and treated with CRD-189 Three cuttings of alfalfa, (June 19, August September 16), all hay removed in 1952 (to reduce stand and growth) . 11. Spring plowed 12. Spring field cultivated Two cuttings of alfalfa. (June 19, August 5) ♦ all hay removed in 1952^ 13. Fall plowed llu Spring plowed 15. Spring field cultivated 3h Two cuttings of alfalfa, (June 19, August 5) » first cutting removed, second cutting left on plots in 1952. 16, Fall plowed 1?. Spring plowed 18. Field cultivated and planted to rye in fall; rye field cultivated in spring 19. Fall field cultivated 20. Spring field cultivated Cutting dates in 1952 and yields of alfalfa are shown in Table V. TABLE V DATES OF CUTTING AND AVERAGE YIELDS OF ALFALFA, IN FOUNDS OF GREEN MATERIAL PER ACRE, FOR THREE CUTTINGS — 1952 June 19 August 5 September 16 17*11.80 pounds U ,577 pounds 5,815 pounds Leaving the first cutting of hay on the plots produced an average of approximately 16 percent more growth of alfalfa in second growth than removing the first cutting, and the plants were much taller and dark green color as compared with the smaller, light colored plants on plots having this first cutting of hay removed. The percent soil moisture was also higher (16.73$) when the hay was left on the plot than when the hay was removed (lU.21$) . 35 On August 13 , plots 3 3-nd 18 were prepared for planting rye by tandem disking and field cultivating, and planted to Balbo rye at the rate of two bushels per acre. Plots 1, 6, 13 and lo were plowed and plots b and 19 were field cultivated on September 12. On April 15,. the rye growing on plots 3 ajid 18 was field cultivated, and all plots receiving the spring plowing treatment were plowed. Rye yields on plot portions on which the alfalfa hay was not removed was 2.5 times greater (7800 pounds green weight per acre) than on plot por­ tions on which the hay was removed (3073 pounds per acre). During the second week of May, plots previously field cultivated and plots to be field cultivated in the spring were field cultivated. plots previously plowed were disked. disked to level plots for planting. At this time the The entire field was then cornerSugar beets were seeded in all plots on May 15. The Krilium soil conditioner treatments were applied to designated plots on May 16, by sprinkling the dry material over the planted beet rows in a band approximately one inch wide. The rate of application was 10 pounds per acre, unmixed with soil. Seedlings had begun to emerge on all plots on May 22. Plowing and field cultivating did not kill all the alfalfa plants . Observations were made on the number of alfalfa plants remaining in each plot. At the same time notes were taken on the amount of weed growth in each plot. Visual vigor readings, using an arbitrary standard, on sugar beet plants were made when stand counts were taken, again just after blocking and thinning, and later mid-way of the growing season. 36 The vigpr readings and observation ratings are given in Table VI. The weed population was determined for all treatments, by counting the number of grass plants and broad leaved weeds in one-foot square areas. The average weed population for a one-foot square area is given in Table VII. The predominating weed species observed in the field included barnyard-grass, Echinochloa. crusgalli (L) Beauv,, nut-grass, Cyperus esculentus L., foxtail-grass, Setari spp., tickle-grass, Panicum capillare L., purslane, Portulaca oleracea L., yellow wood sorrel, Oxalis stricta L., lambs-quarters, Ghenopodium album L., dandelion, Taraxacum officinale Weber, and wild buckwheat, Polygonum convolvulus L. There were also small patches of nut-grass, field bindweed, and quack-grass through the field. As a further measure of the effects of the different treatments stand counts of sugar beet seedlings were taken on the four middle rows of each plot before blocking and thinning. The results of these stand counts are given in Table VIII. Discussion The subsequent growth of alfalfa and the growth and yield of rye was best on plot portions receiving one cutting of alfalfa with the hay left on the plot. This may be attributed to the higher percentage soil moisture maintained on these plots after the hay was cut. None of the treatments appeared to affect time of seedling emer­ gence . 37 © q - °h ©- 'H P rH © © r-t © CM i—I © © s P x j ,a •H CO Td © Is td W CM ra !h O too *H Si 3 a & © © © q Td © q Td Td © P © © P © r> > © % © o o td © &E > <3 S < § © © © P © P © toO © © © too too P § £ P © •H © Td © © s Ph © •a p .q a toO > q -h •H P Ph rH ft P o a CO Td ^ Q © P Td Td © © ( 1 q q q © © > > © © © too © © J> q q q © © © >> > t © |> <£» -=ti © © SP © P © © © > > - > © > ■=3 & •5 © P © © 5 > > =3 ■=© © © © © toO too Ph © £» too © Ph © Ph © Ph © toO toO toO © © © too % © Td ©' ©* © © ?D © © © Td P*H © too too too © © © P U P hM © o a rH H © © © toOtoO toO © © © © too too © © P Ph > © p a <4 s s f> > p© © © rH © — © © g too© g © ■d P © q P p q q CO H 1 — 1© p ,S Hq *9 pH P © © U Td © © toO toO © © o o »> > cd t s ■< <£J © © Td toO toO © © toO toO > © P © •H © S q p q q M M © © p© •H © © © © <*J s <§ toO too © © © © O © > > © P nd Td © o o > > ,© l> M too too © MD d W © P © •H q © © P toO© 4©3 q p q © q H d H © t> < © £ p q o q © © © cd P © © -P © © PQ d © P © •H © q © © too > £ © H © o id & g P © Td Td H bG cd P © Hp H iH (H © p © T©d © ©Hr) s i H ■$ © Td 1 —) II x i Td © © Td Td p 0 0 td © p © •H CM i —I © toO bD •H *H •H O •H fl q H H M H M H H CD © S3 © © © to © 43 aJ •H *H ,_q u© ' t o bI s bOP © ^£ © P © Td Td © © © H P cd © *H -H © © toO - © Ph © Ph P I P4 © © © © ! > { > © © © © Td Td > rH © •H © P P -H © 1—I Ch > q P O 1 —1 Td * d rH © *H fin II « O o Td pc. > <=d ^4 *3s !3r ■< Td • ftn & h V O 'O O n 'O O n CO C O CO CO o o i—I rH i—I i—1 i—I •H rH *H I I I I Td o o o o o • © -P q © • © toOj + • ♦ o ° o . • • • x J * * 0 » * Td T d Td © rH i —I Ph U fcH P ^ C Q p H fe C O & irC O C O C Q C O •H • P h Td Ph • * p) • • • f t & • • f t f t • P h • P h C O CO P h * iH too Ph •H q Ph CO pCi q -o * • • Td * P h fan fq • 4 SH & O « ' Ph P h P h CO CQ + ° • ft _* Ph • • O • p ^T d . %m II • Td xi . * P h II Gt, CP pn, P1 4 CO Eh Oh Td © © *« > to Oo 3 g © Ph © q o q «NT d w © too > q 0 •H s P © P q q 0 i— | 3 -'Td CO © toO > q 0 •H £ P © p q q OH CM ^ o 92 1 —I § «• © • o I © Td I •\Td © © to O> 0 q *H E P © P q qp 0 © — 1 CM 1 * * • Qj P h CO O 38 TABLE VII AVERAGE WEED POPULATION ON SUGAR BEET PLOTS — 1953 Treatments Tillage Alfalfa 1 cutting, none removed 3 cuttings, all removed 2 cuttings, all removed 2 cuttings, 1st removed Krilium Grass Plants Broad-leaved Weeds Total Grass and Broad­ leaved Weeds F. P. Sp. P. Fd. C . + rye F. Fd. C. Sp. Fd. C. F. P. CRD-186 CRD-186 Sp. P. Sp. P. CRD-189 Sp. Fd. C. CRD-186 Sp. Fd. C. CRD-189 15.5 12.7 14.2 15.7 17.2 23.8 13.1 17.0 21.2 18.2 10.2 20.8 9.8 18.3 13.7 12.0 10.7 8.8 14.3 11.0 25.7 33.5 24.0 34.0 30.8 35.8 23.8 25.8 35.5 29.2 Sp. P. Sp. Fd. C. 14.5 18.7 6.5 13.8 21.0 32.5 F. P. Sp. P. Sp. Fd. C. 20.7 24.3 19.2 8.7 6.3 7.5 29.3 30.7 26.7 F. P. Sp. P. Fd. C . + rye F. Fd. C. Sp. Fd. C. 12.0 24.5 13.8 19.0 20.5 9.3 7.8 7.3 13.3 11.3 21.3 32.3 21.2 32.3 31.8 N. S. L. S. D. {$%) Summary of results t 1 cutting, none 3 cuttings, all 2 cuttings, all 2 cuttings, 1st 7.1 N. S. 16.8 16.6 21.4 18.0 13.0 10.2 7.5 9.8 29.8 26.7 28.9 27.8 18.0 17.7 16.9 19.1 10.0 10.2 14.7 11.9 Fall field cultivated + rye Fall field cultivated, no r^ 14.0 17.3 8.6 15.8 28.0 27.9 27.9 31.1 22.6 33.2 All CRD-186 All CRD-189_____________ 19.4 17.6 12.3 9.9 31.7 27.5 All All All All removed removed removed removed fall plowed spring plowed fall field cultivated spring field cultivated F. P. = Fall plowed F. Fd. C. * Fall field cultivated Sp. P. = Spring plowed Sp. Fd. C. = Spring field cultivated N. S. = Not significant 39 TABLE VIII STAND COUNTS OF SUGAR. BEET SEEDLINGS BEFORE BLOCKING AND THINNING — 1953 Alfalfa 1 cutting, none removed 3 cuttings, all removed 2 cuttings, all removed 2 cuttings, 1st removed Treatments Tillage F. P. Sp. P. Fd. C . + rye F. Fd. C. Sp. Fd. C. F. P. Sp. P. Sp. P. Sp. Fd. C. Sp. Fd. C. Average Beet Seedlings CRD-186 CRD-186 CRD-189 CRD-186 CRD-189 225.7 2J+2.7 311+.0 22I4.8 2ia.2 201.0 290.7 285.2 283.3 299.2 Sp. P. Sp. Fd. C. 2I+2 .0 325.0 F. P. Sp. P. Sp. Fd. C. 279.2 251+.3 321.7 F. P. Sp. P. Fd, C . + rye F. Fd. C. Sp. Fd. C. 21+9.7 285.7 232.8 251.0 266.0 Summary of resultss 1 cutting, none 3 cuttings, all 2 cuttings, all 2 cuttings, 1st All All All All Krilium removed removed removed removed fall plowed spring plowed fall field cultivated spring field cultivated Fall field cultivated + rye Fall field cultivated, no rye 260.8 283.5 285.1 255.8 238.9 266.7 255.7 289.1+ 273. k 237.9 258.3 All CRD-186 292.7 ___ All CRD-189 Treatment differences were not statistically significant. F. P. « Fall plowed Sp. P. = Spring plowed F. Fd. C. = Fall field cultivated Sp. Fd. C. = Spring field cultivated Stand dount per 20 feet of four rows per treatment per six replications. ho Number of Alfalfa Plants Remaining After T~mage As would be expected, plots receiving three cuttings of alfalfa were practically void of alfalfa plants following tillage treatments. Results presented in Table VI show that, in general, plots which were spring plowed had fewer alfalfa plants remaining than fall plowed plots, but plots which were fall field cultivated had fewer remaining than spring field cultivated plots. In no case, however, did alfalfa present physical difficulties in the culture of the sugar beets that followed. Weed Size and Weed Population Data presented in Table VT show that plowed plots had smaller weeds than field cultivated plots. The weeds growing on fall plowed plots were smaller than the weeds growing on spring plowed plots, and smaller on fall field cultivated than on spring field cultivated plots. Plant­ ing rye in fall field cultivated plots did not affect weed size. Results of weed counts given in Table VII show that the treatments included in this experiment had no significant effect on number of grass plants and total weeds per plot. However, planting rye in fall field cultivated plots resulted in significantly fewer broad-leaved weeds than when leaving the plots unplanted. Vigor of Sugar Beet Seedlings As shown in Table VI, vigor of sugar beet seedlings appeared to be associated with tillage treatments rather than with alfalfa treatments or soil conditioner treatments. Based on visual vigor readings, using an arbitrary standard, 11good” sugar beets were produced on fall plowed la plots and "weak” sugar beets on plots field cultivated in the fall. "Average" beets were produced on all other plots. Growing rye on fall field cultivated plots had no effect on vigor of sugar beets. Stand Counts of Sugar Beet Seedlings No statistical stand count differences were obtained between plots receiving the various treatments. However, results presented in Table VIII show that a slightly higher rate of sugar beet seedling emergence resulted when all hay was removed than when all or part of the hay was left on the plot, and a higher rate on CRD-189-treated plots than on CPiD-186-treated plots. In either case, seedling emergence appeared to be more closely associated with tillage treatments, the small differences obtained being in favor of spring tillage. Planting rye on fall field cultivated plots resulted in a slight increase in seedling emergence over fall field cultivated plots not planted with rye. A considerable amount of damping-off occurred during the early part of the growing season. Although there was no correlation between treatments and disease infestation, the effect of disease organisms was a factor in beet stand on those plots having a low rate of sugar beet seedling emergence. In field trials with sugar beets, Afanasiev et al. (2) found that seedling diseases were lowest when beets followed potatoes and highest when beets followed beets or alfalfa. Afanasiev (l) reported that low temperature and low moisture are favorable to sugar beets, from the standpoint of freedom from seedling diseases, and resistance to dampingoff diseases is enhanced by prompt emergence and subsequent growth. During the course of the experiment reported here, conditions of high temperature and average moisture prevailed during the germination period which may partially account for the disease infestation. The rapid growth following germination aided some of the seedlings to over­ come or Hgrow-out-of11 the disease attack. Although treatment differences for the most part were not statistic ally significant, and the results of this experiment are inconclusive, the amount of green plant material incorporated into the soil in the spring again appeared to be a factor influencing sugar beet seedling emergence. When only a small amount of material was available, as in the case of fall plowing or field cultivating, low stand counts were obtained. Likewise, if a large amount of green plant material was avail able, as in the case of removing none or only part of the alfalfa hay, stand counts were low. Spring tillage, following removal of two or three cuttings of hay, added an intermediate amount of green plant material to the soil, resulting in higher stand counts. When rye was grown on fall tilled plots, and incorporated into the soil before too much spring growth occurred, increased seedling emergence was obtained. Experiment IV In order to investigate the effects of Krilium1 soil conditioner materials on germination and uniformity of stand of sugar beets, 1 Krilium is the collective trade name given to soil conditioner materials released by Monsanto Chemical Company. h3 greenhouse and field experiments were carried out. These chemicals are presumed to alter the soil structure, aeration, and moisture condition surrounding the planted seed. Two different Krilium materials, CRD-186 and CRD-189, were used in these experiments. CRD-186 is a modified vinyl acetate maleic acid compound, white in powder form and easy to mix with soil. CRD-189 is a hydrolyzed polyacrylonitrile compound, yellow in powder form, and very difficult to mix with damp soil. Chemically they are long-chain polymers with extremely high molecular weights. Functionally the conditioners are water-soluble polyelectrolytes. Preliminary greenhouse tests, with Krilium soil conditions, were conducted in 1951 and 1952. Results of these preliminary tests, where Krilium was mixed with the soil, showed that water infiltered faster and penetrated to a greater depth on the CRD-186 and CRD-189-treated soil than on untreated soil. Under conditions of puddled soils, the degree of crusting and cracking was less on soils treated with Krilium. However, under conditions of normal soil moisture, soil cracking was negligible on treated soils. Failure to crack may be attributed to the faster rate of water infiltra­ tion, and infiltration to a greater depth, into the treated soil. CRD-189 appeared to be slightly more effective than CRD-186 in controlling cracking. Greenhouse tests were conducted to determine the effects of mixing various rates of CRD-186 and CRD-189 into soil on sugar beet seedling emergence. Results of stand counts were inconclusive, and none of the Krilium treatments produced germination and emergence earlier than the untreated check. It was also desired to study the effects of row applications of Krilium soil conditioner materials. Because this would involve applica­ tions of very small amounts of material, soil conditioners were mixed with hydrated lime and 0-20-0 fertilizer to increase the volume for a more uniform distribution. Duplicate greenhouse tests were set up, using different rates of CRD-186 and CRD-189 and three placement variables. Soil conditioners were mixed, at the rate of one and two pounds per acre, with 100 pounds of lime and 100 pounds of fertilizer for uniform distribution. For comparison, Krilium was applied alone at rates of one and one-half pounds and three pounds per acre. These treatments were applied (l) by spreading the material over the planted beet row, (2) by placing the material over seeds in opened furrows and before seeds were covered with soil, and (3) mixing the material with soil before planting the seeds. An untreated check was included for comparison. Stand counts of sugar beet seedlings were used as the means of evaluating the results. These stand counts are shown in Table IX. Discussion 1 Results of sugar beet seedling emergence, shown in Table IX, are inconclusive when comparing applications of CRD-186 and CRD-189 to the planted beet rows or applications over the seeds in opened furrows. US rH 03 •H bO O G CO •H 43 -p CxO 3 0 (D G O UNUN O 1A O O O 'o 5! Os O On c*N UN•UN UN O • • O i—1 On On rH rH [— On O n i—I U N O O O O UNO UN UN * i —i i —I r — U N O n CM U N rH • a * • • • b - o ON O (° O t —i i —t cm cm o • • « On On O - i —I & CO t3 % s 0 9 ? bo •rH 0 i —I G 0 !> G 0 O bD Sh 0 H H H IA i —Ii —Ii —1i —t O UN UN C O rH C O I —I1 —I i —(i —Ii —Ir —1 rH rH O O UN UN OUNQO O On O —G c— rH OnnO H - c t £>- tN -rH On O n CM rH U N UN rH NO UN CM ON ON O • • On o - O c o O o n q o g o o n rH pH • • C— rH CM c— » • • • • •r— «ao CMCM H CM rH rH CM i—Ii—f i—I i—I i—I i—[ i—I a !» o 03 ft g & G *H o <£} * O • —1 i —Ii —I O i o o UN o nO On m rH -G 0 X H o 1AUMA lAUNlAO i —| C \)CO o O CO CM nQ I —II —I I —I i —I i —!i —I UN O * • CM - G UN O • • --•J O n UN O • • ON NO UN UN » • O ON C'—nO On - G CM nO nO \Q • • • O O i — i i— I O- i— IO CN i I rH i— I i— I r—Ii — It—I i— I <— Ii— Ii —I & rvj PJ 9 e-t 03 bO G rH bfl •H rH G i—1 0 XJ G 0 -P o 0 o CO “ =3 •H O CO i Ai W'.' ... . 7 - -•■*. -,.• v .;•-*?* renter1*- . " • s - -j _ * . \.v -v.*.., v.V r* i • .* > > < 'v- -v* *».* •* 4( ) * *! w :-.Sa i- ' % ‘a r| ■V i * i i 69 planter or drill leaves deep wheel tracks because the soil is loose, thus some of the rows from a grain drill will come in these depressions, resulting in uneven seed coverage. Results of stand counts on five feet of each planter row, taken on a compacted portion and a non-compacted portion of loose-wet plots and planted with dry seed, are shown in Table XIX. TABLE XIX STAND COUNT OF SUGAR BEET SEEDLINGS ON COMPACTED AND NON-COMPACTED PORTIONS OF PLOTS RECEIVING LOOSE-WET TREATMENT — 1953 Planter Row Compacted Portion of Row Non-compacted Portion of Row 1 hZ 23 2 37 26 3 32 18 h 31 20 As a further measure of the effects of treatments included in this experiment, the number of one-foot units having no beets, the emergence rates of seedlings, on twenty feet of each of eight rows, and the weight, in grams, of eighty sugar beet seedlings per plot were recorded. Every fifth seedling in each of eight rows was taken until eighty were gathered for weighing. Because the planting rate of soaked seed was six pounds per acre and of dry seed was eight pounds per acre, the results were analyzed 70 separately as two randomized block experiments. The effects of the various tillage treatments on plots planted with dry seed are shown in Table XX and the effects on plots planted with soaked seed are shown in Table XXI. TABLE XX THE EFFECTS OF VARIOUS TILLAGE TREATMENTS ON SUGAR BEETS FROM PLANTINGS WITH DRY SEEDS — 1953 Tillage Treatments No. of 1-foot Units Having No Seedlings Stand Counts of Seedlings Loose-wet Firm-wet Firm-dry Loose-dry 37.2 3U.0 63.0 122.5 1131.2 1169.5 80l*.0 1*20.0 L. S. D. (550 66.63 671.1*6 Weight of 80 Seedlings 91.5 95 .U 96.0 71.3 N. S. N. S. = No significance Stand count for 20 feet of eight rows per treatment per four replications. TABLE XXI THE EFFECTS OF VARIOUS TILLAGE TREATMENTS ON SUGAR BEETS FROM PLANTINGS WITH SOAKED SEEDS — 1953 Tillage Tre atments Loose-wet Firm-wet Firm-dry Loose-dry No. of 1-foot Units Having No Seedlings 63.5 89.0 75.2 88.2 Stand Counts of Seedlings 1*82.0 1*83.0 1*11*.7 1*17.5 Weight of 80 Seedlings 65.7 78.2 115.1 78.7 Treatment differences were not statistically significant. Stand count for 20 feet of eight rows per treatment per four replications. 71 Discussion Time of Seedling Emergence Time of seedling emergence is determined in many instances by soil moisture conditions immediately after the seed is planted. The rains one day and two days after planting may have overshadowed the soaked seed treatment included in this experiment. The order of seedling emerg­ ence, as shown in Table XVII, cannot be explained. It is possible that the shock of soaking or toxicity of material released during the soaking period delayed the germination of seeds receiving this treatment. Or, the rain could have provided a better moisture condition for the unsoaked seeds than for the soaked seeds. It Is noted, however, that the rain water ran into and collected In the depressions made by the tractor wheels on the loose-wet plots, thus furnishing more moisture for the gemination of seeds planted in these depressions. On other portions of plots receiving the same tillage treat­ ment moisture infiltration was more rapid and probably seeped to a depth below the planted seed. Vigor of Sugar Beet Seedlings As shown in Table XVIII, visual estimates of vigor of sugar beet seedlings, using an arbitrary standard, indicated a higher score for plots receiving the loose-wet treatment and a lower score for plots receiving the loose-dry treatment. Close observations throughout the season correlated with the data obtained on the vigor of sugar beets. always appeared more uniform on the loose-wet seedbed. Stands There is no doubt, 72 however, that "the difference in planting rates of dry seed and soaked seed accounts for at least part of the response differences noted. Size of Weeds The differences in weed growth on the various plots should be stressed. Plots having a loose-wet soil condition were relatively free from weeds at the time stand counts were taken. This permitted the seed­ lings to get a good start in growth before weed seeds germinated and became a problem. Plots receiving the firm-dry treatment had the most weeds and the largest weeds. The weed seeds germinated before the sugar beet seeds , offering competition to the young beet seedlings. Of the other two tillage treatments , plots having a loose-dry seedbed had fewer weeds than those having a firm-wet seedbed. Soil Compaction Results of stand counts given in Table XIX show that a higher rate of seedling emergence was obtained on compacted portions than on noncompacted portions of planted rows. It is the opinion of the author that a lack of uniform rate and depth of planting or a lack of uniform seed distribution resulted from loose-wet tillage practices as applied to seed­ bed preparation. This opinion was also shared by Dr. R. L. Cook, of the Soil Science Department, Michigan State College, in a recent personal conversation. It may be possible, then, to overcome this lack of uniform­ ity by packing the soil immediately in iront of each disk opener, gaining, at the same time, a better seed-soil contact. Dr. Cook also stated that 73 he had noticed similar earliness and better germinations of corn seed­ lings in rows compacted by tractor wheels pulling the corn planter. This packing action was effective, but to a lesser degree, on plots receiving the loose-dry tillage treatment, and least effective on firmwet and firm-dry plots, The latter two groups of plots had already received considerable packing. The effects of the various tillage treatments on sugar beets from plantings with dry seeds are shown in Table XX. Units Having No Seedlings As shown in Table XX, significantly fewer units without beet seed­ lings resulted from the loose-wet and firm-wet treatments than from the loose-dry and firm-dry treatments . Stand Counts The rate of seedling emergence was significantly higher on the loosewet and firm-wet plots than on the loose-dry plots . Stand counts were intermediate on firm-dry plots. Weight of Seedlings No significant weight differences were obtained for any of the tillage treatments. The small differences that were obtained, however, were in favor of plots receiving the finn-wet and firm-dry treatments. Effects of the various tillage treatments on sugar beets from plant­ ings with soaked seeds are shown in Table XXI. Differences between treat­ ments, for 1 measurements made, were not statistically significant, Ik nor are any trends evident. The small differences noted between stand counts or plots planted with soaked seeds suggest that approximately 500 sugar beet seeds were planted and most of them germinated and came up on all plots. In comparing the variability of the results, data in Table XX and Table XXI show that sugar beets varied much more in response to plant­ ings made with dry seeds than to plantings made with soaked seeds. 75 SUMMARY A series of greenhouse and field experiments was conducted from 1951 to 1953 to determine the effect of various seedbed preparation techniques, soil conditioning materials, green manure crops and seed treatments on the emergence and uniformity of stand of sugar beets. The rate of emerg­ ence of sugar beet seedlings, weight of sugar beet seedlings, number of one-foot units having no seedlings, number of marketable beet roots and weight of marketable beet roots were used as a means of evaluating the results. The results may be summarized as follows: 1. Additional cultipacking of sugar beet seedbeds which had been prepared in a conventional manner, or applying a small amount of water (22 gallons per acre) in the seed furrow Immediately after dropping the seed and before covering the seed with soil, did not increase the rate of sugar beet seedling emergence. 2. An intermediate amount of green plant material added to the soil in i v the spring resulted in a significant improvement of stand count of sugar beet seedlings and yield of marketable beet roots in comparison with large amounts or small amounts of green plant material. 3. No method of tillage for seedbed preparation was found that gave better stands, vigor or yields of sugar beets over that of plowing in the spring. 76 U. Alfalfa sod, either plowed or field cultivated in the fall or spring, presented no physical difficulties in the culture of sugar beets that followed. 5. Planting rye in fall field cultivated alfalfa plots reduced the broad-leaved weed population. 6. Emergence of sugar beet seedlings was as high on plots where all the alfalfa hay was removed as on those where all or part of the hay was left the previous year. 7. "When soil conditioners CRD-186 and CRD-189 were applied in small amounts on or in the row or in large amounts broadcast and disked into the surface soil, no improvement in emergence or yield of sugar beets was found in these experiments. 8. Planting partially germinated sugar beet seeds did not increase rate or earliness of seedling emergence. 9. Sugar beet seedlings emerged earlier from loose-wet and firm-wet seed­ beds than from firm-dry and loose-dry seedbeds. 10. Rapid emergence of sugar beet seedlings compared with weed seedlings made weed control easiest on the loose-wet seedbed. 11. At all times throughout the growing season the beets appeared most vigorous on the loose-wet plots. 12. A high rate of sugar beet seedling emergence resulted from compacting the row with tractor wheels in the process of planting on the loosewet seedbeds. 13. A more uniform stand and a higher rate of seedling emergence was ob­ tained when loose—wet and firm—wet seedbeus were used than when the seedbeds were loose-dry or firm-dry. 77 l it e r a t u r e c it e d 1. Afanasiev, H. M. The effect of temperature and moisture on the amount of seedling diseases of sugar beets. Proc. Amer. Soc. Sugar Beet Tech. , 5th Gen. Meet. Pp. 412. 1948. 2 - _______ ^ Morris, H. E., and Carlson, W. E. The effect of pre­ ceding crops on the amount of seedling diseases of sugar beets. Proc. Amer. Soc. Sugar Beet Tech., 3rd Gen. Meet. Pp. 435-436. 1942. 3. Agricultural Chemicals. Soil Conditioners. Ag. Chem. 8s 97. 1953. 4. Allison, L. E. Effect of synthetic polyelectrolytes on the structure of saline and alkali soils. Soil Sci. 73s 443-454. 1952. 5. Archibald, J. A. Effect of soil aeration on germination and develop­ ment of sugar beets and oats. Unpublished M. S. Thesis, Michigan State College Library, East Lansing, Michigan. 1952. 6. Ayers, A. D., and Hayward, H. E. A method for measuring the effects of soil salinity on seed germination with observations on several crop plants. Proc. Soil Sci. Soc. Amer. 13s 224-226. 1948. 7. Barmington, R. D. Physical factors of the soil affecting beet seed­ ling emergence. Proc. Amer. Soc. Sugar Beet Tech., 6th Gen. Meet. Pp. 228-233. 1950. 8. Barton, L. V. Relation of different gases to the soaking injury of seeds. Contr. Boyce Thompson Inst. 16s 55-71. 1950. 9. ___________ . Relation of different gases to the soaking injury of seeds. Contr. Boyce Thompson Inst. 17* 7-34, 1952. 10. Baver, L. D., and Farnsworth, R. B. Soil structure effects in the growth of sugar beets. Proc. Soil Sci. Soc. Amer. 5* 45-48, 1940. 11. Bodman, G. B., and Hagan, R. M. Synthetic polyelectrolyte soil con­ ditioners. Unnumbered paper. Col. of Agr., Univ. Calif. Pp. 1-8. 1952. 12. Brewbaker, H. E., and Deming, G. W. Effect of variations in stand on yield and quality of sugar beets grown under irrigation. Jour. Agr. Res. 50* 195-210. 1935. 13. Bush, Hi L. Field compared with blotter germinations for processed, Jgraded single- and double-germ seed. Proc. Amer. Soc. Sugar Beet Tech., 5th Gen. Meet. Pp. 70-77. 1948. 78 1^. Bush, H. L., and Brewbaker, H. E. Size of seedball in relation to yield of sugar beets. Proc. Amer. Soc. Sugar Beet Tech..4th Gen. Meet. Pp. 270-272. 1946. 15. Buschlen, M. J. The use of different media and containers as a method of planting sugar beet seed. Unpublished M. S. Thesis Michigan State College Library, East Lansing, Michigan. 1951. 16. Chemurgic Digest. I-germ seed advances sugar beetindustry. Chemurgic Digest 11: 9. 1952. 17. Cook, R. L. Tillage practices and sugar beet yields. Proc. Amer, Soc. Sugar Beet Tech., 6th Gen. Meet. Pp. 286-293. 1950. 18. _________ . Are your tillage methods up to date? 98: 271. 1953. Hoard*s Dairyman. 19. _________ , and Rood, P. J.Minimum seedbed preparation. Proc. Amer. Soc. Sugar Beet Tech., Eastern U. S. and Canada. 7th Reg. Meet. Pp. 8-10. 1953. 20. Coons, G. H. Space relationships as affecting yield and quality of sugar beets. Proc. Amer. Soc. Sugar Beet Tech., 5th Gen. Meet. Pp. 252-268. 1948. 21. Cox, J. F., and Hill, E. B. Sugar beet growing in Michigan. Mich. Agr. Exp. Sta. Spec. Bui. 106. Pp. 1-23. (Reprint). 1924. 22. Culbertson, J. 0. Agronomic considerations of mechanized sugar beet production. Jour. Amer. Soc. Agron. 36: 558-565. 1944. 23. Davis, J. F. The effect of seed source and spacing of plants in the row on the yield of sugar beets grown on muck soils. Proc . Amer. Soc. Sugar Beet Tech., Eastern U. S. and Canada. 6th Reg. Meet. Pp. 117-123. 1951. 24. DeBoodt, M. F., Englehorn, A. J., and Kirkham, D. Fall vs. spring plowing and soil physical conditions in a rotation experiment. Agron. Jour. 45* 257-261. 1953. 25. Deming, G. W. Relative yields of reduced stands of sugar beets planted at a normal date and of replanted sugar beets. Proc . Amer. Soc. Sugar Beet Tech., 3rd Gen. Meet. Pp. 197-202. 1942. 2S. . Sugar Beet populations in relation to yields. ( Proc. Amer. Soc. Sugar Beet Tech., 4th ben. Meet. Pp. 474—494. 1946. 79 27. eining, G. W. The effect of variations in row width and plant popu­ lations on root yields and sucrose percentage of sugar beets at Fort Collins, Colorado. Froc. Amer. Soc. Sugar Beet Tech.. 5th Gen. Meet. Pp. 280-281. 191+8. 28. __ . Plant population experiments with sugar beets at Fort Collins, Colorado. Proc. Amer. Soc. Sugar Beet Tech., 6th Gen. Meet. Pp. 256-260. 1950. 29. Dexter, S. T. The germination of sugarbeet seedballs. Proc. Amer. Soc. Sugar Beet Tech., Eastern U.S. and Canada. 6th Reg. Meet. Pp. 1+5-1+6. 1951. 30. ______ . A study of sugar beet seedballs, segments, and plant­ ings by different methods. Unpublished data. Mich. Agr. Exp. Sta. 191+5. 31. ________ . Preliminary findings on the use of plant hormones as seed treatments for sugar beets. Mich. Agr. Exp. Sta. Quart. Bui. 2l+* 21+5-21+8. 191+2. 32. report. . Commercial hormone dusts for seed treatments A second Mich. Agr. Exp. Sta. Quart. Bui. 25* 279-282. 191+3. 33. Dionne, G. Transplanting sugar beets. Unpublished M. S. Thesis. Michigan State College Library, East Lansing,Michigan. 1935. 3i+. Doneen, L. D. Some soil moisture conditions in relation to growth and nutrition of the sugar beet plant. Proc. Amer. Soc. Sugar Beet Tech., 3rd Gen. Meet. Pp. 51+-62. 191+2. 35. Dreibelbis, F. R., and Nair, M. S. Comparison of effects of disking and plowing on some properties of soil. Agron. Jour, 1+3* 25-33. 1951. 36. Dutt, A. K. Effect of water-soluble potassium silicate and various other treatments on soil structure and crop growth. Proc. Soil Sci. Soc. Amer. 12 s 1+97-501. 191+7. 37. Evenari, M. Germination inhibitors. Bot. Rev. 15* 153-191+. 191+9. 38. Eyster, H. C. Factors which affect absorption of water by seeds. Amer. Jour. Bot. 28* 12s. 191+1. 39. Farnsworth, R. B. New soil physics studies with sugar beets. Proc. Amer. Soc. Sugar Beet Tech., Eastern U. S. and Canada. 1st. Reg. Meet* Pp. 51-55. 1939. 60 5-0. Gardner, R., and Robertson, D. W. The effect of alfalfa on the yields of non-leguminous crops in a rotation. Proc. Amer. Soc. Sugar Beet Tech., 7th Gen. Meet. Pp. 225-228. 1952. Ill. Garner, F. H.^ and Sanders, H. G. Investigations in crop husbandry. I. The effects of seed treatments on the germination and yield of sugar beets. Jour. Agr. Sci. 22: 551-559. 1932. 5-2. Gray, F., and Volk, G. ¥. The effect of row widths and spacing on root yields and sucrose percentage in sugar beets. Proc. Amer. Soc. Sugar Beet Tech., Eastern U. S. and Canada. 6th Reg. Meet. Pp. 37-38. 1951. U3. Gregg, C. M. A study of the effects of some different sods and fertilizers on sugar beet yields. Unpublished Ph. D. Thesis. Michigan State College Library, East Lansing, Michigan. 1950. , and Harrison, C. M. A study of the effects of some different sods and fertilizers on sugar beet yields. Proc. Amer. Soc. Sugar Beet Tech., 6th Gen. Meet. Pp. 306-310. 1950. 55. Ii5. Hall, A. T. Deep tillage raises more crops. 118-119. 1953. Sugar Beet Jour. 18: 5-6. Hayward, H. E., and Wadleigh, C. H. Plant growth on saline and alkali soils. Advances in Agronomy. 1: 1-38. New York: Academic Press. 195-9. 57. Hedrick, R. M., and Mowry, D. T. Effect of synthetic polyelectrolytes on aggregation, aeration, and water relationships of soil.- Soil Sci. 73s U27-UU2. 1952. 5.8. Hentschel, H. E. A study of principles affecting the performance of mechanical sugar beet seed planters. Unpublished M . S. Thesis. Michigan State College Library, East Lansing, Michigan. 195-6. k9. Hill, E. B. Sugar beet culture. Unpublished M . S. Thesis. State College Library, East Lansing, Michigan. 1922. Michigan 50. Hunter, J . R . Some factors affecting germination in sugar beet seeds (Beta vulgaris L.). Unpublished Ph. D. Thesis. Michigan State College Library, East Lansing, Michigan. 1951. 51 a £2. # and Dexter, S. T. Some seed-soil moisture studies with sugar beets . Proc. Amer. Soc. Sugar Beet Tech., oth Gen. Meet. Pp. 270-275.. 1950. , and Erickson, A. E. Relation of seed germination to soil moisture tension, Agron. Jour. 55: 107-109. 1952. 81 53. Ingalls, F. S. Relationship of seed ball size to gex*mination as found to be common to beet seed grown over the St. George areas. Proc . Amer. Soc. Sugar Beet Tech., 1st Gen. Meet. Pp. 97-101. 1938. 51+. Johnson, G. D. Once over - and ready to plant. 51: 38-39. 1953. Successful Farming. 55. Johnson, C. E., and Wright, K. T. Reducing sugar beet costs. Agr. Exp. Sta. Circ . Bui. 215. Pp. 1-31. 191+9. Mich. 56. Lackey, C. F. Chemical loosening of seed crops in relation to germination of sugar beet seed. Proc. Amer. Soc. Sugar Beet Tech., 5th Gen. Meet. 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