w... .Jm ~-.Av.—~——-=.'m.—. ' .1-” .- — ,— ——'—_‘_ ”31.3333333333" 3 “.3' 3333 33:3 33:5 .3 3 J33 9E3 3533 33333333 3.33 33 TON 33333333 -1. 3..-L3 335' 3 33.33 “5:43 3‘35 WW 33mm 39.57 C3 em..-“ j...— 3. ‘ LIBE’LA 7-." 3' Michigan State University LABORATORY THRESHING TESTS ON PEA BEANS USING LILLISTON CONVERTED PEANUT COMBINE by Mohammad Asrar A special report Submitted to The Department of Agricultural Engineering Michigan State.University in partial fulfillment of the requirements for the Degree of Master-of Science Summer 1967 Approved ”W Major Professor .35.! _ .‘- ‘Q._ . k.. “m 2“,.“ a‘ 1% ABSTRACT LABORATORY THRESHING TESTS ON PEA BEANS USING LILLISTON CONVERTED PEANUT COMBINE By Mohammad Asrar The previous studies indicated that Michigan farmers suffered large losses in the harvesting of navy (pea) beans because of adverse weather conditions and inadequate harvest- ing equipment. The primary objective of this investigation was to study the feasibility.in general.and threshing efficiency in particular of the Lilliston Peanut combine.for navy (pea) beans. The investigation was limited to laboratory studies. The work was carried out as follows: 1. Step by step changes.in the machine accompanied .by threshing tests. 2. Tests and analysis of data whengthe machine was ready.for threshing tests. From this study the:conclusions drawn were: 1. The laboratory studies.offeruamgood.preliminary solution for studies like this one. 2. The present machine can successfully be con- verted for navy Ipeal beans. probably with reasonable investment cost. The navy bean plants can be stored, even though not ideally, without apparent weather deteriora- tion for laboratory threshing tests. More threshing tests are needed to study in detail the variables involved in the threshing of pea beans. Changes—in the cleaning screen, seed lift .ldelivery tube, concave under cylinder number three and putting a new type of conveyor to replace the first-two cylinders are to be con- sidered—first in this-machine before releasing for field combining. From the-present threshing tests it can be said that efficient threshing by this machine will be at about.the following conditions: a. Cylinder three speed 150 RPM. b. Cleaning fan air door l/2 open. c. Tailboardnthree-fourths Open. ACKNOWLEDGEMENTS The author wishes to express sincere thanks to Professor Howard F. McColly for his guidance, constant supervision, and unfailing interest in this investigation. He also wishes to thank the Lilliston Implement Company, Albany, Georgia, for furnishing the machine and cooperation in the study. Appreciation-is expressed to Dr. Wayne M. Adams, Crop Science-Department, for providing bean plants. He also wishes to thank Dr. Carter M. Harrison and Dr. Stephen T. Dexter of CrOp-Science Department for valuable:consultation. Appreciation.is.extended to Mr. Larry S. Axthelm, Research Agricultural Engineer, University of Nebraska, Scotts Bluff Station, Mitchell, Nebraska, for sending some literature.regarding-the study. He is thankful to Messrs. James Cawood,.Glen Shiffer, and.Andrzei;Tabiszewski for;their—help in making changes in the machine.andqfor assisting with threshing tests. ii TABLE OF CONTENTS Page I. Introduction ............................ ...... . 1 II. Review of Literature............................ 8 A. Beans in Michigan........................... 8 B. Bean Harvesting Methods..................... 9 C. Defoliation of Beans........................ 15 D. Harvest Losses.............................. 16 III. Original-Research.................... ..... ...... 24 A. Bean Harvesting-Developments................ 24 B. Purpose of Present-Study.................... 25 C. .Description of.the-Machine...-.............. 25 D. Experimental.Procedure...................... 28 1. Preliminary Work........................ 28 2. Final Threshing Tests................... 38 E. Results and Discussion...................... 44 F. ASuggestions-for Future Research............. 48 G. Summary..................................... 51 H. BibliograPhYOCOOOOOOOOCO...OOOOOOOOOOOOOOOOO 53 iii TABLE II. III. IV. VI. VII. FIGURE I. II. III. IV. LIST OF TABLES PAGE ‘Dry Edible Beans, U.S. Acreage Harvested and Yield...0....0.0.0000000000000000000000000 3 Dry Edible Beans, Acreage, Yield, and Production by StateSOIOOOOOOOOIOOOOOOOOOOOOOOOOOOOOOOOOO 4 Beans, Dry Edible Production by Classes, Average l959~63, Annual 1964 and l965................ 5 Beans, Dry Edible. 'Acreage, Yield, and Production in Specified Continents 1955-59, Annual 1964 and 1965..outshone-000.000.000.00 6 Dry Edible Beans, Acreage, Yield, and-Production MiChigan 1947—19650000’0030'000000000000000000. 8 Results of Combining Navy Beans, 1955-56...... 12 Laboratory Threshing Tests of Navy (Pea) Beans with.Lilliston Peanut—Combine (1500 Series) 40 LIST OF FIGURES PAGE Right side view-of Special combine with the Chain coverS‘removed‘ooiolooo'oo0.000.000.0000 27 Sectional.view of special combine............ 29 Expanded”metal'lathooo‘oo-ooo-o007.000.00.000.ooo 35 Front view of cylinder three and expanded metal lath concaveO‘OOO00.000.00.000....0...O. 36 Top View of inside machine from top center coverAOOOOOOOOOOOOOOOOOOOOOOVOOOOOOOOOOOOOO... 45 iv INTRODUCTION Michigan contributed about one-third of the total edible dry bean production in the United States during the period 1954—63. The $37,957,000 annual return to Michigan farmers from this crOp ranks third in value of field crOps (8). Tables-I and II show the importance of beans as a crop in the United States and the leading producer states (26). As it is clear from Table II Michigan is the top producing state of beans, therefore, related studies to beans is—ofagreat-significance. Navy (pea) bean, or white pea bean, as it is called sometimes, is the most important class of dry edible beans—in Michigan. Michigan farmers in recent years, have produced more than 98 percent of navy (pea) beanswgrown-in the United States (8). The production of dry-edible-beansrby~classes—in the United States is given-in the Table III (26).-*Navy beans have a wide market across the country and, in recent years, up to 25 percent of the Michigan navy-beans have-been exported (8). The canning industry.usesumost-of the Michigan.grown navy and.red-kidney-beans: More than 90 percent of the navy beans consumedlin the United States are canned. Canners like the navy.(pea)»beansabecause they remain whole and retain their form in the can after processing. The production of dry edible beans is not only limited to the United States; many other countries con- tribute their-share to the total world production. Table IV shows~thehacreage, yield.and production, in specified continents, of this crop (26). TABLE I DRY EDIBLE BEANS U.S. ACREAGE HARVESTED AND YIELD ACREAGE AVERAGE1 YEAR HARVESTED YIELD 1,000 acres pounds 1930 2,160 663.9 1940 1,903 890.0 1950 1,511 1,001.0 1960 1,434 1,249.0 1964 1,452 1,225.0 19652 1,533 1,076.0 Source: U.S.D.A. Agricultural Statistics 1951 and 1966. 1Clean basis 2Preliminary -TABLE II DRY EDIBLE BEANS ACREAGE, YIELD AND PRODUCTION by STATES 1 TOTAL 2 ACREAGE YIELD PRODUCTION STATES 1964 19653 1964 . 19653 1964 19653 California 216 222 1,375 1,421 2,970 3,155 Colorado 217 228 740 860 1,547 1,883 Idaho 124 146 1,570 1,500 1,821 2,100 Kansas 8 13 1,100 1,100 77 110 Michigan 616 665 1,260 880 7,585 5,562 Minnesota 15 9 650 700 39 28 Montana 13 14 1,620 1,610 194 209 Nebraska 76 85 1,550 1,500 1,116 1,200 New York 107 111 1,100 850 1,166 910 New Mexico 7 7 700 560 42 39 North Dakota 27 25 610 900 110 198 Utah 10 8 300 500 30 40 Washington 22 22 1,850 1,750 407 385 Wyoming 51 51 1,370 1,450 685 682 Source: U.S.D.A., Agricultural Statistics 1966. 11,000 acres 21,000 cwt. 3Preliminary TABLE III BEANS, DRY EDIBLE (Cleaned basis) PRODUCTION By Classes, Average 1959—63, Annual 1964 and 19651 AVERAGE 2 CLASS 1953-63 1964 1965 1,000 cwt 1,000 cwt White Pea (Navy) 6,601 6,785 4,887 Pinto 4,613 3,609 4,551 Great Northern 1,846 1,711 1,477 Red Kidneys3 1,457 1,636 1,366 Large Lima 835 678 755 Black Eye, Calif. 759 787 668 Small red 585 372 385 ~Sma11 white 568 455 504 Baby Lima 479 275 211 Pink 339 354 406 Black Turtle Soup 168 265 239 Cranberry 126 100 96 Yellow Eye -'80 26 30 Flat small white 62 59 72 Garbanzo 49 42 87 White marrow 39 22 26 Other 666 613 741 Source: U.S.D.A. Agricultural Statistics 1966. 1Soybeans and mung means.not included 2Preliminary 3Include dark red kidney coma moaumaumum amnsuasoaumc .¢.o.m.a .uso ooo.am .mnam mwuom ooo.aa ”condom mmmmoa mmamaa nmmmm mum mow bum mooma mamma mvooa oauoz amuoa mmmm homm mmnm «mm mam va mam mam mom moaumd moam ommv chem whaa mam amoa omm mmv amm mamfi moama comma mowva mmw omm mnv awom oamm omam mmousm mmvmv mmmmv vnemm mam mew mom mvmh moms mmvm moanofid..ow mmhav mommv mvoam mvm mom mum omen vmwh mmmm moanofid .oz mwma coma mmummma mmma coma mmlmmma mmma coma mmummma maszHBZOU mu¢mm>¢ m0¢mm>¢ mwdmmud mo¢mm>¢ ZOHBUDaomm mmum mmm DamHN N mquom wmo..mz«mm >H mamas mmma 6:6 «mma acozzc .mmvmmma mazmzHazoo omamaommm 2H onaoooomm ozm .oqmaw .mocmmoa The losses during threshing of different crops are known to all those who are familiar with farming operations. In the United States almost all the crOps are harvested and threshed with combines. Most of the threshing losses are attributed to the design and improper use of a combine itself. A considerable amount of work has been done in this direction but there is much more to be done. The«introduction of spring-tooth cylinder and~concaves is an example of the recent developments-(14). 'The Department of Agricultural Engineering, Michigan StaterUniversity, in c00peration with the Department of-Farerrops, started work on bean harvesting and the losses-involved in harvesting and threshing in 1947. The present study covers the-possibilities of converting the Peanut Combine«(1500 series),-manufactured by Lilliston Implement-Company, Albany, Georgia, to navy (pea) beans, particularly the threshing efficiency.~ The study is conducted~in the~research-shop rather than in the-field.- The machine mentioned above-and the pea beans for storage are provided byvthe Lilliston Implement Company and the Department of—Farm Crops respectively. The study involves step-by-stepwchanges-in the machine and subsequent threshingzefficiency tests. REVIEW OF LITERATURE Beans in Michigan It-is reported that farmers in the French settle- ment of Detroit had supplied dry beans to Commodore Perry on Lake Erie in 1812. The Indian tribes-in Chippewa and Saginaw were growing beans in Michigan in 1819 (24). The name navy bean for white pea beans is believed to be because of its naval and military importance. Michigan produced more than 42 percent of all the edible dry beanswin the United States in 1964 (26). The bean-crop is an important crop for Michigan. Table V shows-the-acreage, yield,-and production-of-dry edible beansrin Michigan. TABLE V DRY EDIBLE BEANS, ACREAGEq YIELD AND PRODUCTION MICHIGAN 1947-1I9651 ACREAGE YIELD PER YEARr HARVESTED HARVESTED ACRE PRODUCTION pounds 1000 acres: (cleaned basis) . 1000 cwt. 1947 467 670 2,847 1950 420 950 3,312 1955 504 900 4,536 1960 525 1,190 6,248 1964 602 1,260 ‘ 7,585 1965 632 880 5,562 Source: U.S.D.A Agricultural Statistics 1949-1966 lPreliminary In Michigan the two general types of beans are the vine type and the bush-type. The bush type, the Michlite, stands fairly well and produces runners. The vine type called the Robust, grows profusely on the top of the soil and presents a difficult problem in harvesting. Seeds of five navy bean varieties have been re- leased to farmers during the period between 1957 and 1965 by the Michigan Agricultural Experiment Station and the United States-Department of Agriculture c00perating. The bush varieties hold their pods off the ground better than the vine type beans: therefore, are less susceptible to weather damage after maturity, and usually have a lower pick. .The vine type varieties can-continue to blossom and set pods under hotvand dry weather, whereas the bush.type»will suffer a substantial reduction of pod setting under such-weatherrconditions; The bush type varieties-give-good production on fine-textured soils while the vine types grow.better:onisandier soils. Saginaw, the Thumb, and West~Central Michigan have the main concentration of navy beans (8). BeanuHarvestingMethods In Michigan windrowing,.stacking:forlcuring, and then threshing with a.stationarycthresher was practiced for a long time (21).- Direct combining was considered 10 not practical until 1944, although combining from wind- row wasirecommended.under certain conditions.(24). The heater harvester-was.one of the first machines for har- rvestingmbeans in.North Caroli a and Virginia. Losses involved-in-this_machine.gave a variationcfrom 20 to 60 percent of the-gross.yield-. The mower was very p0pular Vin.harvesting different typesaof beans before 1922. .Theemowing“1oss, excluding threshing losSes, generally amounted to 24.7 percent of the total yield. Beans were also harvested with a binder and-threshed with a pea or bean separator, or grain thresher (26). A series of tests was conducted by Bainer and Winter in California, with a-combine using two rubber rollers. They succeeded in threshing very fragile beans without damage but the-cost~of~the machine was higher (3). The use of rubber rollers or rubber bars in combines has not been widely accepted in Michigan. The study of the different harvesting methods in Michigan has been;started in the late 1940's. The various known.harvestingrmethods as classified by McColly fare.pullingcbyuanblade-type cutter usually in the form ofra cultivator attachmentg~cutting with a rotary cr0p .cutter: windrowing with a side delivery~rake or with a -bean harvester; stacking byrhanduorrby machine; bunching by-moving-segments of windrows-into bunches or by using 11 a buncher attachment on a puller; hauling to a thresher or also into barn storage for winter threshing; station— ary threshing; threshing-machine converted to a combined harvester-thresher~by the addition of a chassis and pneu- matic tires» auxiliary motor» and Special pick-up feeder; use of special.bean combine; and-small grain combine fitted with bean ”attachment" equipment (14). Field beans harvesting-operations-usually includ- pulling, windrowing, and combining from-the windrow (8). In navy beans the operations involving bunching, stacking, baling, and stationary threshing~have declined because of the harvester-threshersror thevspecial~bean combines. A number of both pull-type»and~self-prOpelled type com- bined harvester-threshers,rfitted~with.a.special pick-up device and feeder, came into~use~by~converting threshing machines (14). Pulling and windrowinguofsfield beans can be done in two separate-operationssor as a.sing1e:operation. The number of rows placed.inhonexwindrowsdepends upon the density of crOp:and the size of the combinerused. The lower.stem and attached root parts should be dried in windrows before combining (8). ~Combine pick-up is the most-common method employed in harvesting navy beans in Michigan.- Some of these 12 machines are used for both bean and other grain crops which reduces-the overall harvesting cost per acre. Grain combines equipped with bean attachments are fre- quently used, although special bean combines are also used by farmers of larger bean acreages. Table VI shows the results-of combining:navy beans, utilizing a grain combine with bean attachment (8) (14). TABLE VI RESULTS OF COMBINING NAVY BEANS, 1955-56 Good Qperation Conditions Beans Too Dry Yield Losses Yield Losses Harvesting Method Bu/Ac Bu/Ac Percent Bu/Ac Bu/Ac Percent Direct combining 26.3 2.47 9.40 30.1 7.14 23.69 Cutter bar 2.37 9.03 7.00 23.22 Threshing 0.10 0.37 0.14 0.47 Combine pickup from rotary crOp cutter windrow 26.3 0.47 1.80 30.1 3.50 11.62 After pickup 0.39 1.50 3.40 11.29 Threshing 0.08 0.30 0.10 0.33 Source: McColly, H.F., Harvesting Edible Beans in Michigan, ASAE Trans., 1958. As it is evident from the above table-the cutter-bar loss exceeds 9 percent and 23:percent under good and too 13 dry operating condition respectively. The rotary cr0p cutter windrow, on the other hand, had a total loss of cutting and threshing of 1.8 percent and 11.62 percent under good and too dry conditions respectively. The rotary cr0p cutter windrows-Showed a pick up loss 11.29 percent, under too dry conditions, which means a saving of 11.93 percent. Bean attachments for grain-combines usually in- clude kits for cylinder speed reduction, seed and dirt screens, and-other parts whichwdepends~on the different makes~and-models. Some manufacturers have special cylinders, rubber covered bars and bean grates. The spike-tooth—cylinder~is quite popular. -Bean combines usually have two cylinders Specially designed for bean threshing and special separating.and threshing units (8) (14). The torsion springstooth cylinder and concave is a recent developmentsin threshing edible beans, being very effective in threshing; causing minimum mechanical damage of seed; and results in:lessxdelay:waiting for the-heavy bean root and lower stem to dry out enough to go through-conventional closeafitting cylinder parts. But this equipment.is.not as.effective in.threshing small grains asvother types of cylinders and concaves (14). 14 For the combine pickup the bean plants should be placed in fluffy windrows, free of clods, stones, and dirt. This prompted the development of bean windrowers. In case of heavy rains~the bean windrower is also a use- ful tool for relocating the windrow. ~A blade-type harvesting cultivator attachment fitted with vine turners, row dividers and windrowing rods isva commonly used machine but suffers from the drawback that it pushes dirt and stones to the-windrow with the beans and does not crush the root and lower-stem to'aid in«rapid drying. The side deliver rake, equipped withwbean teeth, is used to some extent with the idea to-move the pulled beans onto clean ground and~to lift them from clods-and stones (14). A rotary crop cutter has-beensunder constant develOpment in Michigan.- It has~given successful results in harvesting-beans—(lS).rtRecentrdevelopments have in- cluded a~six-row hydraulic motor driven mechanism mounted on~a—farm tractor. ~Field beans should be harvestedtand:handled at 17 to 18 percentvmoisture levelzinlotderitochold splitting and seed coat damage to a.minimumiw: o minimize the shattering losses and to reduce the.splittingxlosses, it may be necessary to harvest only.in the morning and evening 15 when the pods are tough. Spraying bean windrows with water to prolong or induce seed-coat toughening pro— tects the beans~from cracking~during combining without appreciably increasing their percentage-of moisture content.~ Excessive percentage of split beans~and checked seed coats occurs when harvesting is done at lower moisture levels (7) (8). Defoliation of Beans . The weather hazards at.navy-bean:harvest time necessitatedadefoliation:tests.—rThe~two-chemicals, dinitro-ortho-secondary—butyl and penta-chlorOphenol, are satisfactory.. Analysis~showedrthat defoliating chemicals absorbed by the bean.seed through the pods was negligible and not harmful to.people (18). The.three conditions in bean.fie1ds:where chemical defoliation is:needed are green.areas:due~to low wet spots which cause the plants to have a:slower start in ~growing, or morermoist:areas duringrsummer dry days, which keeps the beansrgreen;rthezpodsmareidry but the plant stemszand;leaves-are:green44and;theeplants have a new growth.of:1eaves while.the pods are ripe. The chemicalscwhichido not discoloribeansrcause more even ripening-and:maturecthexcropwearlier (18). 16 Both air and ground spray of defoliants may be applied. The main problem in the ground spraying is that of developing suitable vine lifters. An adaptation of the vine lifters from-the rotary cr0p cutter was applicable. Thesloss of weather hazard decreases by the use of rotary crOp cutter after defoliation, followed by the combine pickup-(14) (18). " Harvest LOSSES Harvest-losses vary‘from field to field and from farmer to-farmer. Accordingrto~a survey in the North Platte-Valley, Nebraska, the-range of~these losses was . from.44 to 559 pounds per acre,- It was estimated that 12 percent of the beans.were left in the field after harvest. -It shows that at present prices and acreage -such losses would bexin millionSwof dollars for the country (19) (22). -The factors resPonsible for these losses may be imprOper operation of machinery; mechanical limitation of machinery; poor cultural practices with regard to weeds and-field surface uniformity; climatic conditions; and plant characteristics with regard to pod~shattering, proximity of pods to soil surface,~and uneven ripening. Improper adjustment of machinery-is often the major source of these losses~(l9) (22). 17 The machinery now available for harvesting field beans can be improved. Better use of the available machinery needs to be made until new improvements are forthcoming. It has been demonstrated by some farmers that harvest losses can be held to a minimum if machinery is used at the correct time and proper adjustments are made (23). rGrain or seed losses generally include: shatter loss of overripe-grain prior to harvest, cutter-bar loss consisting of missed-and drOpped~heads-or pods and grain or seedshattered on the ground in cutting, cylinder loss of unthreshed-heads or pods passing out in the straw, rack loss-of-loose~grain~or seed-passing over~the rack with straw,wand shoe-loss-of-loose~grain or-seed blown or carried out with chaff. Shattering-loss in beansrmaywbe attributed to the overripeness of the cr0p before harvesting operations, or to the pulling and windrowingsoperations, or both. Every four orrfive beans leftrin the field per square foot-of land means a~lossrof:one~bushe1 per-acre. Windrow pick-lossesucan~be-kept6torminimumrbyacareful handling, and by harvesting-when-the«pods are-tough (8). Cutter-bar:loss~iS«determined by picking up the grain~or seed on sample areasgrafter:knowingnthe=shattering 18 losses. Cutter-bar loss amounts to 75 percent of the total grain lost (12).- In~a very dry crOp,.cutter-bar loss increases-but threshing loss—decreases; The bean pods~have a tendency to hang close to the.soi1 surface which causes increase-cutter-bar loss. :The uneveness of the ground and presence of-stones makes it very difficult.to get low enough-to pick.up all the pods (13). Carefu1-coordination.of rate of ground travel with reel rotation,.when.a power.0perated reel is used in direct harvesting of dry beans, is necessary. If the-ground speed is too low compared.to reel speed, the reel speed tremendously shatters beans-from the pods. In finger—type reels the tines can-be adjusted to in- cline slightly upward;as they:lift;the:bean-p1ant toward the cutter bar-and thus decrease cutterrbar;and shatter losses by 50 percent: For-thisrreason theLfinger-type reel is more efficient-than-the standardmbat-type reel (15). The.seedscare shattered-out.of.themheads or pods -by the impact of blows-from-thezcylindervandmthe concaves. With field-beans,2cylinder:lossesnaresusually very low but split beanszand cracked seedcoats.from~over threshing is a more serious problem 183:.:But this source of loss is the most important;one.becausecofcthe-effect of the action of the cylinder upon therotheralosSwsources (13). 19 Determination of the cylinder loss can accurately be done by catching the straw coming Off the rack over a measured area and threshing the grains or seeds from the unthreshed heads or pods. This loss can be minimized by more thresh- ing action without cracking seeds.~ It is often better to accept a small cylinder loss by lowering rack and shoe losses (6). Cylinder-concave clearance, uniform feeding, moisture content of the crOp, presence of weeds, cylinder Speed, number of concaves, and efficiency of the Operator are the various factors which effect-this loss. The cylinder-concave clearance from-1/2 to 3/4-inch, cylinder Speed Of about 1/3 to 1/2 of that required for threshing wheat, uniform feeding, no weeds, moisture content of 18 percent, enough concaves, and an efficient operator who is well acquainted with the mechanism and Operation of the machine keep this loss to the minimumra~Too narrow or too high cylinder concave clearance,.unparallel cylin— der and concaves, and-improper.functioningsof.separating mechanism which causes-rethreshing some-of the grain increases the percentagesof mechanical damage (13). Threshing-conditions«changeaappreciably~from season to season, from day to day, and even the same harvesting day.* The operator should make-appropriate adjustments in the machine according to the threshing conditions if 20 good results are to be Obtained.l Improvements in de- sign which can make possible threshing without being too sensitive to moderate changes in conditions need due considerations. Spring-tooth cylinders and-concaves is the new development of design in bean harvesting (13) (14). Rack»loss-is the loose grain shaken out with straw over a measured area. Straw rack loss is gener- ally quite low but may become heaviest byva too-high or a too-low Speed, overthreshed straw and green weeds, or plain overloading due to cutting too low or traveling too fast. The loss due~to~rack and shoe which is also called the separating loss, is the main loss and con- sidered to be a~standard of therother sources of loss in harvesting-smallcgrains.~ A very high-rack speed keeps the straw up~and does not allow-it to settle down enough to be fully caught by the next upward movement. A too-low speed does not pitch the.straw.sufficiently to allow for thorough separationl ,The.speed.of the rack needs adjustment according to the differentiloads passed over it.(6) (18) (17). Shoe loss is.determined by-collecting.the material coming.from the shoe over.a-measured area.s Sources of 21 this loss are primarily overloading, excessive air, and too little sieve Opening. High.shoe loss is associated with high rack loss, usually. Sometimes fine straw falls over the sieves-and to blow it away the air speed should be increased. This straw often carries some seed along with it. Beans separate easily from straw because of their heavy weight and large size as compared to other grain. Separating losses in beans are generally low. To reduce returning of the threshed beans to cylinder and consequently to reduce splitting.loss,.manufacturers recommend a specia1.sieve.with 3/8.inch-round holes for bean harvesting. Excellent cleaning will result by re- placing.the-coarse-adjustab1e~chaffer-with a lower adjust- able sieve (11). Mechanical Damage-of Pea Beans The mechanical-properties of a.material are those which describe_its behavior.under.applied-forces-. Strength, elasticity, stiffness, ductility,-plasticity,cand brittle- ness are the fundamental.mechanical;pr0perties (20). Pea beansrare fragile-and are oftencdamaged during normal handlingFOperations-c Beans with overcfive percent checked;seed coats.are difficult towmarket.(8)c. The grade regulations.on.3plit beans.and restrictions.imposed by 22 canners on checked seed coats show the undesirability of mechanical damage (9). Baldhead or other abnormali- ties in bean seedlings Often results from roughly treated seeds (25). The two types Of mechanical damage are the visible injury and the internal injury.. Beans without apparent seed coat damage.may have internal injury which can not be detected before germination. -The amount-of visible and internal injury of seed is a function of the variety used, the level of maturity, and the violence of the mechanical handling (8) (25). Brown.(5) was the.first.to-initiate work on the forces required to damage pea beans- .Variations in forces, from 12 to 42 pounds were found to crack the seeds,-when applied.by-f1at:surfaees:to sides of the beans, for-beans of from 6-9 to.9.2.percent moisture. Forces required for-beans of similar.moisture content, in edge position,.weremfromxtwo.totover.45 pounds. Harter (10) found “baldhead"-from10r30 percent and 10-20 percent-inwdryubeansand-snapcbean seedlings respectively. -He~also concludedtthat-Whaldhead" re- sults fromtthree distinct cause32-mechanical injury, damage by bacteria,:and damagecby.insectst ~Associated Seed Growers, Inc., (1) studied the varietycTendergreen 23 and reported that mechanical damage varied from 1-30 percent. Borthwick (4) studies on Lima bean seedlings showed that practically every part of the embryo is susceptible to some kind of threshing injury. Bainer and Borthwick (2) found that beans of low moisture content were damaged more by a threshing machine. The cylinder speeds needed to produce 15 percent of the total damage in Fordhook-beans containing 15.9, 17.3, and 18.8 percent of moisture were 1,150, 1,330, and 1,600 feet per minute respectively. Associated-Seed Growers, Inc., (1) drOpped seed of 8, 10, and 12 percent moisture K several~times—from different heights. ~The mechanical damage to beans showed to be cumulative; many low drOps may cause as much loss in germination as one-or two high drOps. They also-found that the lower the moisture level, the greatervthe-damage. ~Perry (20) reported in the variety Michelite that mechanica1~damage (D '0 -a m .p .C D”) -:-1 m Figure I. 28 header drives; paddle and saw drives; and the engine drive. Some of the important parts have been shown in Figure II. The initial price of the machine is $3500.00. If successfully adapted Or converted for navy (pea) bean, it could be one of the cheaper-combines for this crop. Experimentalgprocedure By studying the cOnstruction and Operation of the machine in detail, it was determined to divide the work into separate categories-~(l) the preliminary work which includes-the step by step-changes and rough obser- vations of the tests, and—(2) the final threshing tests which involved careful analysis of the results. Preliminary work: Before conducting any threshing tests it was obvious that the slots:of~theanEcmmm com noucpmomm .ma .Ooncu .02 oaoomo mcaumucoom .coouOm Qaa .ma .Osu .Oz anomc usaumumcom .cosoue muc>aaoo .na .oco .Oz macocm mcHucumcow .uwmcm mkmm .oa .c>mocoo occ coouom noocaawu .coonom 3cm .ma nopoom .uoEEoum .va .HSOm umcEsc MOOCaamU .bmeb aacB .ma .ocucu umnEsc MOUCaahu .cocbom @003 .ma .OBD MODESC EOUCaaxu .coonom anwcc .aa .cco MODESC MOUCaa>U OCHQEOU amaommm mo 3ma> aECOauowm \m:/ -51 A), . us -, \ 1 -\\ .16 .W/ \\ ..v\ \\ \ I _ 1 1 L n. 2 r / m E. -, r\ P; 1 MN I...... - -..ivL . LEFT-human r- [w A. xiv-AWN .cNCw-xml \ Hum 15 ‘ ea ~. {*7 .oa .m .m .e .o .m .q .m .N .a - ”ficoomq \)!?-11|J/ Sectional View of Special combine 30 from the peanut plants going through the cylinders section of the machine. The saw assembly was installed to chOp down the harder stems not blown out with the straw to smaller sizes to pass through the slots. Neither of the two problems-of heavy dust nor harder stems is a -serious problem in pea bean combining. Galvanized metal Sheet-(28vguage) pieces,~one856"x39 3/4", three 36"x6 11/16", and one 25 1/2"x39" Sizes were—used to cover the slots in sand screens, pan floor, and saw screen respectively. To get access to-the-sand-screens~and saws screen, the pipes of cylinder number-one-and two and saw assembly were removed.8 The cylinder pipes, saws-shafts and pulleys were replaced after covering the slots«with Sheets, SO that it would not change the other working-conditions of the machine. On October 7, 1966,.the-machine~was~tested for threshing~for the first—time: ~The-main~problem noticed was the threshing of-bean.plants-by.the~first-three cyl- inders; therefore few-other~tests-which~followed were most1y~concentrated~on~the-possibilities~of-using these cylinders-only«as-conveyorstw~TWOVpossible~approaches were tried. aFirst, each alternative-cylinder bar from cylinders-number two and three~was~removed with the plan 31 to minimize hitting action of the cylinder~bar springs to the pea bean plants, but-it-did not help appreciably. Second, different cylinder Speeds from maximum to gradu- ally slower ones were tried by controlling the throttle Speed. These tests were ended when the cylinder number one and two Speeds reached sufficiently belOWche ground speed of three miles per hour, the speed usually used in the field, and without noticeable change-in the thresh- ing amounts of-these cylinders, This clearly suggested that cylinder one and-two cannot be used-as~conveyors. The calculations~of.workablearevolutions~per minute of the-first-three cylinders.for»field~wo k and-respective RPM of the cylinders during-the~lastatest~of this kind are shown as follows: a. PTO Speed-= 264 feet/min=-=~3 miles per hour diameter of the-firstua cylinders = 26.5" (measured between~tips~ofrtwo—Opposite teeth) circumference Of-first 3 cyl. é 26.5"x83% = 83.3" RPM of these cy1."= 264" "8‘5‘73‘ = 38" (requiredeto matchuthe PTO speed of 3 MPH) b. RPM Cyl. NO.~2 (measured) = 24 Number of teeth of the sprocket~on~right cyl. #2 - 4 — shaft = 48 Number Of teeth of-the Sprocket-on left cyl. #2 »» Shaft = 17 32 Number Of teeth of the sprocket on left cyl. #1 shaft = 54 RPM cyl. #1 = 34X17 = 7.6 54 Number of teeth of the sprocket on right inside cyl. #3 shaft = 42 RPM cyl. #3 = i§§§i = 27.44 Number of teeth of the sprocket on the right outside - ~ cyl. #3 shaft = 42 Number of teeth of the sprocket on the right outside ~ - 'cyl. #4 shaft = 19 RPM cyl. #4 = 33§%;Lii = 60.65 As it is clear from thesewcalculations that the first three cylinders must run at-38 revolutions per minute to match the forward travel-speed of—three miles per hour, but the speeds-of the first two cylinders are 7.6 and 27.44 revolutions per-minute»respectively which are—well below the~initialvspeede~ Therefore the first and second cylinders could-not-be-used as-conveyors. Installation Of another kind-of conveyor to replace the first two cylinders iS“D€C€SSflfY$' The chain and pulley arrangement to drive the first and second cylinder was disconnected at-this point~for~further tests. -~The.next-step was to.usewcylinder.three and four for all the threshing job, vFor this.purpose, first of all, some kind of.hand feeder was needed; -Three pieces 33 of galvanized sheet-metal Of the sizes 38"x28.25", 38"x7", and 38“x5 5/8" were out. To make a hand feeder for the cylinders three and four, pieces were fitted such that it starts from beneath cylinder three and extends over the central bar-Of cylinder two and gives an Open Space from above of approximately one foot which is used for feeding the-bean plants-to cylinders three and four. The-lepe of this sheet hand feeder-is such that the plants pushed by hand through-the-Opening slip toward cylinder three. 'This—sheet made-hand feeder is repre- sented by (5) in Figure II. To test the threshing efficiency of the cylinders NOS. three and four,-two-bushels of bean plants were run -through the machine and more-unthreshed pods resulted at the-rear~and the delivery trough; very~few cracks and splits~atathe~rear-and~more cracks-and Splits in the seed . bag;-considerable-trash»in»the.seed bag;~some-whole pods drOpping to the-pan floorvthrough the large holes in cylinder screen underecylinder number three.~ To control the drOpping-of unthreshed-pods through cylinder screen some sort.of concave was necessary to be-put on this screen. -A galvanizedrmetal sheet (28 guage) 31"x40" with appropriate strip holes for the fingers~of stripper bars 34 number six and seven was fitted over the cylinder screen. The purpose of this concave was twofold; first to control the dropping of whole pods through the cylinder screen, and secondly to work as a concave and thus increase the threshing efficiency of the cylinders. The next thing, to increase the threshing effi- ciency was to-increase the~Speed-of'the two cylinders. The sprocket.with l9 teeth~on the outer right hand Side of the shaft of cylinder-four was replaced by a Sprocket 4 Of 15,teeth-u This.arrangement of sprockets-gave a Speed of 220 and 616 revolutionS’per-minute, at the maximum throttle Opening, for the cylinder three and four respec- tively. . The machine-was started to Observe the results of the new changes. But after threshing about half a bushel of bean plants, some heavy roots were stuck in the holes of the sheet, left for strippers bars fingers. Consequently-the sheet was raised from the surface of cylinder screennandiresulted in breaking the flexible wire used for tying the.sheet.on the cylinder screen, due-to the excessive~frictionhforce developed between the cylinder number three Spring-teeth and the tying wiresc .Toflovercome this problem this 40"x16" concave under cylinder.three Fig. I (6) was covered by expanded metal lath-as.shown in Fig. III and IV. 36 m>mocoo aura amume Umocmmxm can mean» Hmocaamo mo 3ma> ucoum .>H gunman new”: 1..- trial 37 The expanded metal lath was fitted such that strip- per bar NO. 6 was permanently kept at full engagement position...The stripper bar No. 7 could be used at full- and fifty percent engagement. Three Slots for full, and fifty percent, and completely out of engagement are pro- vided under every stripper bar handle. The clearance between the tips.of cylinder springs and the expanded metal concave varies from 1/4 to.1/2 inch at various points. In the next threshing.test the amountof unthreshed pods decreased-tremendously but still not negligible. These unthreshed pods were attributed to the larger Spaces between every two spring on-the cylinder three; therefore adding some more-spring teeth to the bars-of cylinder three seemed to be the next apprOpriate step. Holes 3/8" diameter were drilled, centered between every two cylinder-springs-and one in the center of the empty.space.at.one.end of the-barsl. Cylinder Springs from cylinder one and-two.were-removedcand fitted in all the new drilled holes excepthfour_holes- -These four holes were left only.on.four cylinder pipes, one-on.each of the four-pipes at the.long Openlends- .They werecleft empty because of no obvious need- rThe addition of the new 44 cylinder Spring to the 48 cylinder springs already mounted 38 on the 12 cylinder pipes gave a total.of 96 cylinder springs on cylinder number three. On June 22, 1967 the machine was tested again. About two bushels of bean plants-were threshed. The speed-of cylinder three.during this-test was kept near 220 RPM. -The bean plants were drier than normal field conditions. Cleaning of an air.Opening was little more than one—third.--The.resu1ts-were-no unthreshed pods at the rear, little seed damage in the delivery trough, more than 50 percent seed damage in-the seed,bag, and some trash.in-the seed bag. .By_carefuleobservation it was found out that mechanical damage in.the seed bag was mainly-due to the wire dust screen in the elevator de- livery tube which.hit the-beans very Sharply because Of the high.speeduof the beans in the-delivery tube. Sincemthe-investigationlat-this point-was mostly concentrateduat-the.threshing-efficiency-of.cylinders, it seemed advisable to detach the auger delivery hopper assembly and put-a box under the lip-screenifor collecting the threshed seed during therfuture tests. Final Threshing Tests -..Tomget best threshing_resu1ts from any combine it is important-to.know the propervadjustments Of the various 39 variables involved. These threshing tests were mainly centered at the cylinder losses and the relationship Of the cylinder losses to the other variables. Different cylinder Speeds, position of the stripper bars, cleaning fan air openings, and amount of water added were used to see the results. ~The quantity of bean plants stored was not enough for a detailed study; therefore, clear cut conclusions.can not.be drawn because of-insufficient data. The data Shown in the Table VII, however, give some impor- tant information related to-the problem. The 14 tests given in the Table VI were run on different dates and the data was carefully analyzed for moisture content of the threshed seeds,.threshed seed in the seed box, loss of threshed seed at theerear, unthreshed pods-both in the seed box.and the rear, visible mechanical damage to the seed in the seed box and:atfthe;rear, and trash accumulationiin:the seed box: -Counts were made of »cracked and split seeds. aAll the measurementszwere taken in grams. The amount of beanrplants:used-for each test was one bushel. Differentacylinder:Speeds ranging-from 150 to 283 RPM-forccylinder~three were used with theaidea to find ~Out the optimumccylinder Speedzforzgood:threshing. 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The plants were exposed to thawing and freezing which-was~inevitab1e under the-conditions described; however, the changing weather conditions did not result in.any apparent signs of deterioration except that the plants were drier than field conditions during harvest. To bringtthe plants to various conditions of dampness different amounts of water were—added five minutes be— .forezthe threshing tests.“ The-range of the amount of water-added per bushel—was.from.0 to 550 cc. for the firstztwelve tests. Increased.mechanical-damage«of-seed,.especially 4under.higher-cylinder.speeds,:was-observed-in the first 12 tests,.therefore,-the plants for the last two tests werentreated.differently:to.increase the moisture content of.thegseed-and-decrease the seed damage as a result. For_the-test.number.14.thehplantS-were9heavily‘steamed for 15 minutes, kept for 44 hours under plastic cover so 43 that the water absorbed by the pods could not evaporate but transfer to the seeds inside the-pods. Then the plants were-left to Open atmOSphere for one hour to evaporate the excess-moisture~from the pods before thresh- ing. -The principle behind thisrmethodeas that the seed of bean absorb water very slowly and then-release it also very slowly. On the other-hand the structure of the pods is such-that it both absorbs and releases water very quickly; The same principle was applied to the test number 13, but this time«the~plants~were dipped in water for one and oneehalf hours,.kept under plastic cover for 44 hours, and left for three hours in the open before threshing. ' Two-men were needed forrrunning the tests. One for feeding the cylinders by hand.and the other for hold- ing the canvas cloth attached to the rear of the machine for collecting the.straw.- The straw collected was ana- lyzed forrwhole-threshed seed,;damaged seeds:and:unthreshed pods,.damaged seed, and trashidueuto.inefficient cleaning.- -All the lossesain different.form-were later converted into ~percentibasis.iuAllithespercentagesewereacalculated on prethreshing.basis,iwhich meanszthe amount ofeseed present in the plants before threshing.: The tailboard was 3/4 44 raised when the-cylinder number three Speed was 150 revolutions per minute and the cleaning fan air opening was half. -For the tests where the speed of the cylinder three was 220 RPM or more the tailboard was full raised. A baffle of a rubber piece was inserted as shown in Figure V between the cylinder four and first paddle SO that the threshed seeds could'not hit directly the metalpieces behind and consequently decrease the mech- anical damage to the seeds. Results-and'Discussion For the tests where theccylinder~number three speed was 220-revolutions per~minute~the percent of threshed seeds-at the~rear-varied from 0.61 to 9.47. Thervariations were mainly attributed to changes in the cleaning air fan Opening'and-efficiency-of cleaning screens. The 0.61 and 9.47 percent~threshed seeds lost at rear were foraextra minimum Opening and full opening of cleaning fan-respectively.e For the extra minimum Opening a metalvsheet cover, Specially prepared for this purpose,-waS-put on each side—doorzof the-cleaning fan. The cleaning air blast alsoraffected~the amount of trash accompanying~therseed—to~the seed box.: It~wase22 percent Ho>oo Hmucoo mou Eoum mcacome 00amca mo Bma> 009 .> whomam in ... .. .- 6 e "(I .9 U- l' ‘5 3.0... In... .2... .I‘.;i..!l Size. :1: 'I: ...I:§U ll.‘ ‘1! ‘I 4 6.. NJ.‘ \6. .‘r. 9. n.‘ O 'l’. O . iii. : '11: 1.550;: ...:.ll.......:..:.‘1: ._ I I __ I .0... a.“ . BI. _ .I _ . ._ . - . . _ . .. 5.. V 0...; o. . g’ >!. -...I. ..- I pUa I q a I. b. .. .9. L026: 11.5... 1.....0...‘ A. lku.....:. 5... ‘lv 0 I o ‘ . ll .15.: :.l...l.-...I:. 7:10.142. .40....5‘: .- 3:...1:‘:8m@70;. . 0 a . . It . l O 46 seed in seed box under extra minimum cleaning air fan Opening and only 0.41 percent when the cleaning air fan Opening was in the halfway position. The range of cylinder loss was from 0 to 4.36 percent.depending upon.the cylinder Speeds and dampness of the bean plants- The 283 RPM of cylinder-three gave no cylinder losses in the form of unthreshed pods but the losses at rear and mechanical damage of seed in the seed box raised to 61.7 and 15.0 percent respectively. Visible mechanical damage in seed box varied from a minimum of 0.00 percent to a maximum of 16.3 percent. The main responsible factors for this were the cylinder Speeds and moisture percent of the seed. It was 16.3 percent under a moisture level.of about 11 percent when the cylinder three speed was 220 RPM.- The damage was decreased to.l.4 percent when the moisture level of the seed was raised to 18.9-percent by dipping the bean plants inmwater, although the Speedeof.cy1inder three .was 230 RPM.in this.test. -The effect Of cylinder Speed difference is clear—from the-test1numbers two and three where-other conditions.were the same. .In—these two tests ~the visible-mechanical damage was 3.2 and0216 percent for the cylinder number.three speed.of 220 andulSOVrevolutions perominuterrespectively. 47 The overall losses which include unthreshed, mechanically damaged seed, and threshed seeds thrown out with straw gave a range from 3.22 to 6.74 percent. The minimum overall loss of 3.22 percent was found in the test number four where the cylinder speed was 150 revolutions per minute, cleaning fan doors were half Open, tailboard was three-fourth raised, and amount of water added to the bean plants before threshing was 450 cc/bu. The different losses in these tests were 0.8-percent visible mechanical damage in seed box, 0.51 percent unthreshed in the seed box,.l.71 percent unthreshed at the rear, and 0.22 percentrthreshed seeds at the rear. Conditions for test number.three were the same as for the test number-four, except the amount of 300 cc. water added before threshing. -This difference in the amount of water decreased the unthreshed pods-butigave increased mechanical damageato.bean.seeds, resulting in overall damage of 3.95 percent. On the basiseof this data the results from test.numbers three and four seem quite encouraging. .The resultshof this study.show that such investi- gations should be.encouraged in the-laboratory wherever possible. SUGGESTIONS FOR FUTURE RESEARCH The bean plants stored were not sufficient to get enough data; therefOre, to find out the optimum condition of the machine, more threshing tests are needed in the future. Preferably it should be done during the coming harvesting season of beans when the plants-will be in exact-natural condition. The continued loss of threshed seed at rear during this investigation suggests the replacement of the present cleaning screen with some kind of adjustable cleaning screen. Placing and fixing finger teeth in the concave under cylinder three Should be tested. This will most probably increase the cylinder threshing efficiency by not allowing the bunches of bean plants to pass through under cylinder three without taking out the seeds from the pods. This arrangement will also .help in using the machine with slower cylinder speeds. This will consequently decrease the mechanical damage which results from the hitting Of seeds with frame walls and other parts of the machine because Of high cylinder Speeds. 48 49 To make the machine workable for field windrowed beans a chain-type or auger-type conveyor needs to be put in the area of the first two cylinders, or to feed bean plants to the threshing cylinders. Although the pickup and header assembly looks all right it still will be more desirable to test it after installing the new conveyor, and before any recommendation is made for field operation of the machine. This can be done in the laboratory if enough bean plants were stored from the harvesting season. The wire-dust screen in the-elevator delivery tube should be replaced or covered with some sort Of soft material like rubber or.canvas to eliminate the mechanical damage to seed in this area. The speed of air from-the air lift fan.needs-some inves- ' tigation to find out the Optimum.Opening-of the fan door which will give efficient liftinguof seed from auger delivery.hopper assembly andnaththe same time minimum mechanical damage. Proper.inspection and structuralwanalysis of bean plants in storage is suggested at different times of the storage period. This probably will help in comparing the stored bean-pod structural changes during storage to the bean pods at harvest time. Some study is desirable to be done on the energy required to Open the bean pods without damaging the seeds. Laboratory study on the bean pods during storage will offer a best solution to the problem. 50 S UMMARY The navy (pea) bean is one of the most important field crOpS in Michigan. Some development in bean har- vesting and threshing has been made but still it is far from the end. The Lilliston Peanut Combine (1500 series), now under the process—Of conversion to pea bean windrow combining can be a successful machine for«pea bean in the future. This machine gave encouraging results of threshing at the cylinder number three Speed of 150 RPM,-cleaning fan air door half Open and tailboard three-fourth Open. Modifications in the cleaning screen,-lifting delivery tube and concave-beneath-the cylinder number three and installation of a new conveyor are the most important factors to beoconsidered for future studies. More threshing tests need~to be carried~out before reaching to definite conclusions on this machine. Laboratory studies of this kind are a success and should be continued in the future.- This saves time and eliminates the long wait for harvesting season. Laboratory studies are needed-on-the~minimum energy required for Opening the bean pods without mechanical 51 damage to the seeds. The machine used for this study can be one of the cheaper and simple Operated machines. 52 10. 11. BIBLIOGRAPHY Associated Seed Growers, Inc.; A Study of Mechanical Injury to Seed Beans, Asgrow Monograph, I949? 1:1—45. Bainer, Roy, and Borthwick, H.A.; Thresher and Other Mechanical Injury to Seed Beans of the Lima Type. Cal. Agric. Exp. Sta., Bul. 580, 1934. Bainer, Roy, and Winters, J.S.; Results of Tests of a Rubber Roller to Seed Bean Thresher. Agric. Engin. Jrn., June 1938, 251-252. Borthwick, H.A.; Thresher Injury in Baby Lima Beans, Jrn. Agric. Res., 1932, 44: 503-510. Brown, E.E.; Bean Crackage Studies, Research Report, Ag. Engin. Dept. M.S.U., East Lansing, unpub. report. Carroll, Thomas, Combines, Agric. Engin.'s Handbk., McGraw-HilI BOOK Co., Inc., N.Y., 1961, 249. Dexter, SsTe; Conditioning Dry Bean Seed-for Better Processing~QualityIand Seed GerminatiOn. MICK. Ag. Exp.-Sta., E. LanSIng, Jrn. NO. 3860, 1966. Erdman, M.H., Robertson, L.S., James,-R.L., White, R.G., Adams, M.W.,~and Anderson, A.L.; Field Bean-Production in Michigan-, Farm Sci. Series Ext. Bul. 513, I965. Faust, Dale; The Inspection TriprThrough Pea Bean . Industry, N.E. Michigan.Engin. Res. Report, Stephens-Adamson Mfg. Co., Aurora., unpub. report, 1955, p.7. Harter, L.L.; Thresher Injury a Cause of Baldhead in Beans, Journ. Ag. Res. 1930, 40: 371-384. Hawthorne, Fred; Extra Bushels When Harvesting Beans, Country Gent.,fiV61. 114, Sept. 1944. 53 12. 13. 54 Hayles, W.A., thti g Best From Combine Harvester, Jrn. Ministry Of~Agric., Gt. Brit., V01. 55, June 1948. Khan, Amir U., Efficiency of Harvesting Navy Beans with a Combine, M.S. Thesis 1952. l4. McColly, H.F., Harvesting Edible Beans in Michigan, 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. ASAE Trans., 1958, 68-75. McColly, H.F., A Study of Bean Harvesting Methods, Res. Reports, Ag. Engin., M.S.U., 1950—1957. McColly,-H.F., Development‘of Bean Defoliation Vine Lifters, Res. 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Solorio, Celio Barriga, Mechanical Injury to Peg Bean Seed Treated at Three Moisture Levels. Thesis for M.S. Degree, M.S.U., E. Lansing, 1959. 26. Soybean Yearbook, Amer. Soybean Assn., Hendson, Iowa, 1951. 27. U.S.D.A., Agric. Statistics, 1949-66.