630.7 I6b no, 776 cop, 8 UNIVERSITY OF ILLINOIS LIBRARY AT URBAN A -CHAMPAIGN AGRICULTURE JIRCU Alternative Definitions for ty3mc^ of Broken Corn and Foreign Mai Lowell D. Hill. Mack N. Leath, Odette L. Shotwell, Donald G. White, Marvin R. Paulsen, and Philip Garcia Agricultural Experiment Station College of Agriculture University of Illinois at Urbana-Champaign Bulletin 776 EJCV Lowell D. Hill, L.J. Norton Professor of Marketing, Department of Agri- cultural Economics, University of Illinois at Urbana-Champaign Mack N. I .oath, Agricultural Economist, Economic Research Service, USDA, stationed in the Department of Agricultural Economics, University of Illinois at Urbana-Champaign Odette L. Shotwell, Research Leader, Northern Regional Research Center, SEA-AR, USDA, Peoria, Illinois Donald G. White, Associate Professor, Department of Plant Pathology, University of Illinois at Urbana-Champaign Marvin R. Paulsen, Associate Professor, Department of Agricultural Engi- neering, University of Illinois at Urbana-Champaign Philip Garcia, Assistant Professor, Department of Agricultural Economics, University of Illinois at Urbana-Champaign Urbana, Illinois October, 1982 The Illinois Agricultural Experiment Station provides equal opportunities in pro- grams and employment. Contents Introduction 1 Data Collection 2 Problems With the Present Definition of BCFM 4 Differentiation Between Broken Corn and Foreign Material 4 Blending of BCFM 5 Screen Size 6 Description of the Samples 6 Study Results 7 Chemical Properties 7 Physical Properties 8 Statistical Differences 10 Storage Tests 12 Feeding Value 14 Alternative Screen Sizes for Defining BCFM 18 Differentiation of Chemical Properties 18 Differentiation of Physical Properties 18 Distribution Among Grades 19 Summary and Conclusions 20 Appendix A: Statistical Differences in Chemical and Physical Properties 22 Appendix B: Distribution of Corn Samples, by BCFM Content 31 Appendix C: Cumulative Frequency Distribution of Corn Samples, by BCFM Content 33 Abstract ties, although in this research none of the sieve sizes clearly differen- tiated between corn and BCFM on all properties. The purpose of the research re- To improve the information pro- ported in this publication was to vided by the BCFM factor in the evaluate the current definition of corn standards, any revision of the the grade factor for broken corn factor must involve more than just and foreign material (BCFM) and a change in sieve size. It must also to examine alternative definitions include a redefinition of foreign based on various sizes of screens. material, alteration of the maxi- The data were obtained through mum allowances for each grade, analysis of 1 ,080 samples of corn and development of some means of from Illinois elevators. The data identifying broken kernels. In addi- show that the 12/64-inch round- tion, these revisions must take into hole sieve currently used does not account the requirements of proces- result in maximum differentiation sors, feeders, and merchandisers, between corn and BCFM since This study provides data on which much of the material passing an evaluation of the alternatives through the sieve is broken corn. can be based. Other sieve sizes would increase the contrast between corn and BCFM Keywords: corn grades, corn qual- on physical and chemical proper- ity, grades and standards Acknowledgments The research reported in this publi- cation is a contribution to the North Central Regional Research Project NC-151, Marketing and De- livery of Quality Cereals and Oil- seeds in Domestic and Foreign Markets, and NC-139, Economic Analysis of the U.S. Grain Export- ing System, funded through the University of Illinois Agricultural Experiment Station. Supplemental funding for the research was pro- vided by The Andersons Fund of The Ohio State University Develop- ment Fund; the Illinois Agricultural Association; Growmark, Inc.; the Il- linois Department of Agriculture; and the Federal Grain Inspection Service of the USDA. Corn samples were obtained through the coopera- tion of the managers of many Illi- nois grain elevators. Figures 1 . Location of Elevators That Provided Corn Samples From the 1976 and 1977 Crops 3 2. Relationship Between Particle Size and Fat Content, 1976 and 1977 Corn Samples 8 3. Relationship Between Particle Size and Ash Content, 1976 and 1977 Corn Samples 9 4. Relationship Between Particle Size and Crude Protein, 1976 and 1977 Corn Samples 9 5. Relationship Between Particle Size and Fiber Content, 1976 and 1977 Corn Samples 10 6. Relationship Between Particle Size and Nitrogen-Free Extract, 1976 and 1977 Com Samples 10 7. Relationship Between Particle Size and Percentage Corn, 1976 and 1977 Corn Samples 11 8. Relationship Between Particle Size and Percentage Dust and Inert Material, 1976 and 1977 Corn Samples 11 9. Relationship Between Particle Size and Percentage Weed Seed, 1976 and 1977 Corn Samples 12 10. Relationship Between Particle Size and Percentage Corn By-Products, 1976 and 1977 Corn Samples 12 11. Mold Development During Storage of Selected Particle Sizes of Corn and Corn Screenings 14 no. 7 7k Tables 1 . Grades and Grade Requirements for Corn 1 2. Number of Corn Samples Collected From Illinois Country Elevators and Subterminal Elevators in 1976 and 1977 4 3. Average Monthly Illinois Prices and Discounts for Corn Screenings, October, 1975, Through September, 1976 5 4. Physical Properties of Materials Passing Through a 1 2/64-Inch Round-Hole Screen, Illinois, 1976-1977 Average 5 5. Physical Properties of Corn Samples, Illinois, 1976 and 1977 Crops 7 6. Distribution of Particle Sizes in Corn Samples, Illinois, 1976-1977 Average 8 7. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Country Elevator Receipts, Illinois, 1976 Crop ...... 13 8. Frequency of Aflatoxin Contamination, by Particle Size and Level of Contamination, Illinois, 1 976 and 1 977 Corn Crops 15 9. Specifications for Corn and Corn Screenings 15 10. Value of Corn Screenings Based on Prices of Protein and Energy 16 1 1 . Prices of Ingredients Used in the Least-Cost Feed Formulation Model for Swine 16 12. Least-Cost Rations for Growing Swine, Using Corn and Corn Screenings, Balanced on Amino Acid Requirements 17 1 3. Comparison of Actual and Implicit Discounts for BCFM 17 14. Differences in Chemical Composition Between Corn and BCFM Under Alternative Screen Sizes Used to Define BCFM, 1976-1977 Average 18 15. Differences in Physical Properties Between Corn and BCFM Under Alternative Screen Sizes Used to Define BCFM, 1976-1977 Average 19 16. Distribution of Corn Samples Among Various Grades Based on the Maximum BCFM Limits for Alternative Screen Sizes, Illinois, 1976 and 1977 Crops 20 Al- A9. Statistical Tests of Differences in Chemical and Physical Properties 22 Bl- B4. Distribution of Corn Samples, by BCFM Content 31 Cl- C4. Cumulative Frequency Distribution of Corn Samples, by BCFM Content 33 Introduction The official U.S. Department of Ag- riculture (USDA) grade standards for corn include a factor identified as broken corn and foreign material (BCFM), which is defined as "ker- nels and pieces of kernels of corn and all matter other than corn which will pass readily through a 12/64-inch sieve, and all matter other than corn which remains in the sieved sample." The implicit, if not explicit, justification for includ- ing BCFM as a factor for determin- ing grade is that material smaller than 12/64 inch is of less value than whole kernels and larger bro- ken pieces and that its presence in a sample reduces the value. In establishing the grade of a sample, the amount of fine material (often referred to as corn screen- ings) is combined with the amount of larger foreign material such as cobs and pieces of plants, and all types of BCFM are treated as hav- ing equal value in establishing price discounts. Under the harvesting conditions of the early 1900s when the standards were first published, the primary content of screenings may well have been dirt and weed seeds, especially at the time the corn was delivered from the farm. But with the development of field shelling, artificial drying, and high- speed handling equipment, the con- tent of screenings has changed until most of the material called BCFM consists of pieces of broken corn. As the corn moves through the market channels, the proportion of BCFM composed of matter other than corn decreases. In addition, the broad definition does not differ- entiate between potentially harmful materials such as jimsonweed seeds, materials such as pieces of cob that are innocuous but of little value, and pieces of corn that are similar in value to whole kernels. The pop- ular reference to BCFM as foreign material therefore does not give an accurate indication of the value and composition of the material against which discounts are often levied. The way in which numerical standards are used in determining discounts leads to an additional problem in using BCFM content as a grade factor. For each numerical grade, a maximum allowable BCFM content is specified (Table 1). Corn is priced on the basis of No. 2 grade, and discounts are ap- plied if the BCFM content is greater than 3 percent. However, a premium is almost never offered if the BCFM content is less than 3 percent. Therefore, the system pro- vides a strong economic incentive to add screenings to any grain con- taining less than 3 percent BCFM and to remove screenings if it con- tains more. Since each handling generally increases the breakage and thus the BCFM content, the multi- ple transfers that normally take place as corn moves from the farm to its final destination may result in successive cleaning and blending by several different firms, adding to costs and aggravating the problem of broken corn. Previous research has shown that in many cases screenings are removed and por- tions returned to the grain several times before the corn reaches its fi- nal destination. 1 This system also encourages farmers to adjust their combining, drying, and handling practices so as to approach the 3 percent BCFM limit if by doing so they can in- crease the total weight delivered to the elevator or decrease their har- vesting costs. Although these prac- tices do not add to the value of the corn, they increase the farmers' re- turns per acre because corn com- bined with up to 3 percent BCFM can be sold to an elevator at the same price as corn with no FM. The appropriate screen size for determining BCFM content was the subject of research and debate in the 1920s 23 and again in 1937." Unfortunately, no record of the re- 1. L. Hill, M. Paulsen, and M. Early, Corn Quality: Changes During Export, Illinois Agricultural Experiment Station Special Publication No. 58 (Urbana, Illinois, 1979), pp. 15-16. 2. Correspondence from O.F. Phillips, Chairman, Board of Review, Office of Mar- kets and Rural Organization, U.S. Depart- ment of Agriculture. Washington, D.C., to H .}. Besley, Grain Division, Bureau of Mar- kets, Chicago, January 20, 1 920 (from USDA files). 3. Correspondence from O.F. Phillips to H.J. Besley, March 30, 1921 (from USDA files). 4. "Research Observations of the Grade Factor. 'Cracked Corn and Foreign Mate- rial,' " April 16, 1937, Bureau of Agricul- tural Economics. USDA, Washington, D.C. (unpublished document from USDA files). Table 1. Grades and Grade Requirements for Corn Maximum limits of: Rrnkpn Damaged kernels Grade Min. test corn & Heat- weight per foreign damaged bushel, Moisture, material, Total, kernels, pounds percent percent percent percent No 1 560 14.0 2.0 3.0 0.1 No. 2 54.0 15.5 3.0 5.0 0.2 No. 3 52.0 17.5 4.0 7.0 0.5 No 4 490 20.0 5.0 10.0 1.0 No. 5 46.0 23.0 7.0 15.0 3.0 U.S. Sample grade U.S. Sample grade shall be corn which does not meet the requirements for any of the grades from U.S. No. 1 to U.S No. 5, inclusive; or which contains stones; or which is musty, or sour, or heating, or which has any commercially objectionable foreign odor; or which is otherwise of distinctly low quality. Source: The Official United States Standards for Grain, Federal Grain Inspection Service, U.S. Department of Agriculture. search results was preserved. From the information contained in avail- able documents, it appears that the grain trade objected to the use of the 14/64-inch screen specified in the Grain Standards Act of 1916 because it resulted in large amounts of broken corn and small kernels being classified as BCFM. The USDA's 1937 report states that "the first corn standards pro- mulgated by the Department in 1913 were permissive in character and contained two special limita- tions for 'cracked corn and foreign material.' in the application of which the 16/64-inch round-hole perforation sieve was used to re- move large pieces of broken kernels and the 9/64-inch round-hole per- foration sieve was used to remove fine pieces and mealy material. Widespread public opposition arose to the use of two sieves, and when the Federal corn standards were promulgated under the United States Grain Standards Act in 1916, they specified only one sieve for the determination of cracked corn and foreign material, namely, the 14/64- inch sieve. This sieve was used from 1916 to 1921 and was dis- carded in 1921 as a result of repre- sentations made to the Department that its use resulted in lowering the grade of much kiln-dried corn which reasonably met consumers' demands and warehouse require- ments with respect to this grade factor. For this reason the 12/64- inch sieve was adopted in 1921 and has been in use for 16 years." 5 The writers quoted in these docu- ments state that the trade's primary reason for seeking a change in screen size was that the grade of good corn was being lowered unjus- tifiably on the basis of a factor that did not accurately measure con- sumers' demands. The description of USDA research on screen size in the 1937 document indicates that although several screen sizes were evaluated the 12/64-inch screen was the only one considered feasible. If smaller screens were used, the BCFM content of No. 2 corn would consist mostly of dust and fine material; broken kernels previ- ously classed as BCFM, using the larger screen, would be classified as whole corn, using a smaller screen. Cleaning would not be required un- less more than 3 percent of the sample passed through the 8/64- or 6/64-inch screen. The quality of No. 2 corn would therefore be low- ered by using a smaller screen. This conclusion is valid only if the grade limits remained un- changed. Although the assumptions were not clearly stated in the 1937 report, it is implied that the change in screen size would not be accom- panied by a change in the limits for BCFM content. Consequently, the effect of a smaller screen would have been to liberalize the stan- dards, increase the amount of dust and meal in No. 2 corn, and in- crease the amount of large broken kernels accepted as whole corn above the screen. The evaluation criteria implicit in the report are (1) that the percentage of samples fall- ing into each of the grades should remain unchanged and (2) that the amount of meal and dust that would be left in the corn as part of the 3 percent allowable BCFM con- tent should not be increased. The reports do not address the relative value of BCFM versus corn, nor do they provide a justification for the differentiation. Oscar Phillips, Chairman, Board of Review, Federal Grain Inspection Service, USDA, was aware of the economic implications of alterna- tive definitions of BCFM in his statement that "changing the sieves . . . would result in raising the grade in many instances, and justly so, as it is only the finer, smaller particles of cracked corn that are objection- able to the trade"* This review of past concerns about the "best" screen size for de- fining BCFM provides the point of departure for the research reported in this publication. The objective of the research was to evaluate the ef- fects of alternative screen sizes on the value of screenings, on the chemical and physical properties of material above and below the BCFM screen, and on the distribu- tion of samples (among the five nu- merical grades for corn) at the farm and the elevator. Although changes in screen sizes have been proposed in the past, major disruptions in the pricing and grading of corn in the market are likely to occur un- less these changes are accompanied by simultaneous changes in the grade limits. This study examines the issue of alternative screen sizes and simultaneous changes in the standards and considers the possible response by grain marketing firms. Data Collection 5. "Research Observations," April 16, 1937 (from USDA files). 6. Phillips to Besley, January 20, 1920 (from USDA files). The data for the study were ob- tained from two sources: a ques- tionnaire mailed to all Illinois ele- vators in 1976 and 1,080 samples of corn collected from country ele- vators, inland subterminals, and river elevators in Illinois. The 1976 survey of Illinois elevators was con- ducted primarily to determine the merchandising practices used for corn screenings, to identify grading and discount procedures, and to es- timate prices received by elevators for the excess corn screenings re- moved from the corn and sold sep- arately. A questionnaire was mailed to a complete list of Illinois eleva- tors (1,437). The 285 responses were assumed to be representative of the entire population for those variables of primary interest. The second source of data was samples of corn collected from ran- domly selected Illinois elevators in 1976 and 1977. The state was di- vided into four regions representing different production and marketing characteristics (Figure 1). In each region five country elevators and five subterminal elevators (river and inland) were selected to provide ten samples of inbound corn delivered from trucks and ten samples of outbound corn taken from the load-out stream. In district 3 the small number of subterminals and the lack of sufficient corn receipts following harvest precluded collec- tion of the full set of samples. Sub- terminal samples were therefore limited to the other three regions. In region 2 one of the five elevators was unable to provide a complete set of samples and was deleted from the 1976 sample collection. In areas near the river, the subterminal category included river elevators. In landlocked regions the subterminals were elevators sometimes referred to as inland terminals. In 1977, cost limitations made it necessary to reduce the sample size. Since geographical differences did not appear to be important in the 1976 data, the 1977 sample was not stratified by geographical loca- tion. Ten country and ten subter- minal elevators were selected to represent the grain deliveries for the state (see Figure 1 ). Insofar as pos- sible, the 1977 elevators were se- lected from the set for 1976. Some substitutions were necessary either because the elevator refused to pro- vide samples or because the season- ality of grain deliveries and ship- ments did not coincide with the availability of personnel to collect the samples. Each of the elevators agreed to provide ten samples of inbound corn as it was unloaded from trucks and ten samples of outbound corn as it was loaded into rail cars, barges, or trucks. Samples from country elevators therefore con- sisted of inbound corn from farm trucks and outbound corn destined for other elevators. Subterminal ele- II C country elevator T river or inland terminal elevator Q-1976 A 1977 III Figure 1 . Location of elevators that provided corn samples from the 1 976 and 1977 crops. vators (river and inland) provided inbound samples from country ele- vator deliveries and outbound sam- ples from their load-out spouts or belts. Most samples were collected by research assistants sent to the el- evator, although unpredictable re- ceiving and shipping schedules sometimes made it necessary to permit elevator personnel to take samples according to instructions from the researchers. Samples from the 1976 crop were taken between January and August, 1977. Samples from the 1977 crop were taken be- tween October, 1977, and August, 1978. The total number of samples collected is shown in Table 2. Table 2. Number of Corn Samples Collected From Illinois Country Elevators and Subterminal Elevators in 1976 and 1977 Country elevators Subterminal elevators Region Number of firms Number of samples Number of firms Number of samples Receipts Shipments Receipts Shipments 1976 1 .... 5 50 40 50 50 190 50 40 50 50 190 5 5 5 15 50 50 50 150 50 50 50 150 i 4 5 5 19 3 4 State total 1977 1 2 3 4 1 10 20 30 40 10 100 20 30 40 10 100 5 2 3 10 50 20 30 100 50 20 30 100 ? 3 4 State total Each sample was divided into seven size categories, using six dif- ferent screens in a Carter-Day dockage machine. Each particle size was then analyzed to determine what proportion of the material was corn, corn by-products (such as cobs and chaff), weed seeds, other grains, and inert materials or dust. Samples of each particle size were also sent to a commercial labora- tory to determine the percentage of crude protein, fat, fiber, ash, and nitrogen-free extract. The energy content in kilocalories per gram was calculated for nonruminant ra- tions. All particle sizes were indi- vidually tested with an ultraviolet light for bright greenish yellow fluo- rescence (BGYF). If any particle size showed a positive response to the BGYF test, the entire sample (all particle sizes) was sent to the USDA's Northern Regional Re- search Center at Peoria, Illinois, to determine if aflatoxin was present and, if so, the kind and quantity. Composites of all country eleva- tor inbound samples for each parti- cle size and a second set of com- posites for all outbound samples were equilibrated to approximately 18 percent moisture and placed in an open beaker in a growth cham- ber at 80 F. dry bulb temperature and 80 percent relative humidity. Samples from terminal elevators were prepared in a similar manner. At weekly intervals, over a period of 28 weeks, each sample was scored on a scale from 1 to 5 for mold growth. This scale was con- verted to a percentage of material molded to accommodate fractional values in the weekly averages. These results were analyzed to provide information on possible changes in the definition of the BCFM factor in current corn stan- dards. There are several alternatives to the present procedures for defin- ing BCFM and establishing limits. Evaluation of the alternatives re- quires an understanding of the limi- tations of the present standards and procedures for determining BCFM. Problems With the Present Definition of BCFM There are three basic problems with the BCFM grade factor used in the present corn standards: Foreign material (matter other than corn) is assigned the same rel- ative value as broken pieces of corn. Numerical standards with maxi- mum allowances for BCFM content encourage the blending of screen- ings (including dust) into any corn containing less than the maximum BCFM content permitted in the grade of corn being sold. The 12/64-inch screen used to identify BCFM does not result in maximum differences between corn and BCFM. Differentiation between broken corn and foreign material Most domestic and foreign buyers recognize that BCFM is primarily corn and hence has feeding value. Domestic feeders and feed manu- facturers frequently buy screenings to use as feed. Even corn dust is often pelleted and used for feed. Excess screenings at starch plants in Europe are sold to feed firms or added to feed by-products. The screenings clearly have value, and the price of screenings relative to the price of corn indicates the value placed by the market on the aver- age quality of screenings removed from the market channel. This price is influenced by the nutritive value of the screenings, the price of corn, the local demand and supply conditions, the proximity of the source to users, and the storability of the screenings. Prices will there- fore vary with time and location. The 1977 survey of Illinois coun- try elevators provided average monthly prices for corn screenings sold by Illinois elevators (Table 3). The unweighted annual average price of screenings was $66.75 per ton, ranging from a low of $61.83 in November, 1975, to a high of $70.96 in July, 1976. The price of screenings as a percentage of the price of corn varied from 69 to 77 percent, with an annual average of 72 percent. Data from a limited number of starch plants in Europe show that screenings are valued slightly lower relative to the price of corn than in the United States. The starch plants in Europe gen- erally purchase No. 3 corn rather than No. 2. The average price for "dust and brokens" (screenings) was about 60 percent of the deliv- ered price for No. 3 U.S. yellow corn. However, adjustments for the starch production refund and for exchange rates in the European Community add to the value of dust and brokens, so the realized price ratio is higher than 60 per- cent. Quantitative measures of the chemical content and physical properties of BCFM were obtained through an analysis of the 1 ,080 samples of corn collected at coun- try elevators and subterminals in Il- linois. Table 4 shows that in the 1976 and 1977 crops together, 83.4 percent of the material passing through a 12/64-inch screen was corn at the time the grain was de- livered to the country elevators from the farm. This amount in- creased to 87.9 percent when the grain was outbound from the coun- try elevator, 88.9 percent when in- bound to the subterminal, and 90.0 percent when outbound from the subterminal. In these samples the BCFM was composed mostly of broken corn and was therefore of higher value than foreign material consisting of inert materials, corn by-products, dirt, and weed seeds. Combining broken corn and foreign material into one category misrepresents its value and leaves the buyer unsure of what he or she will receive. Indi- vidual samples of BCFM (material passing through the 12/64-inch screen) contained as much as 30 percent noncorn materials and as little as 3 percent. Official grade Table 3. Average Monthly Illinois Prices and Discounts for Corn Screenings, October, 1975, Through September, 1976 Month Number of firms responding Avg. monthly price of: Screenings discount Price of screenings as a percentage of corn price Screenings Corn dollars per ton October 36 63.44 91.77 28.33 69 November 36 61.83 83.56 21.73 74 December 37 65.11 84.63 19.52 77 January 42 64.86 88.56 23.70 73 February 38 66.29 90.70 24.41 73 March 43 67.42 91.42 24.00 74 April 28 67.07 89.63 22.56 75 May 25 68.96 96.05 27.09 72 June 24 69.58 100.35 30.77 69 July 25 70.96 102.84 31.88 69 August 21 68.71 94.27 25.56 73 September 25 66.88 94.63 27.75 71 Annual avg. 66.75 92.37 25.61 72 Source: Bruce Brooks, "An Analysis of BCFM in Corn and the Market for Corn Screenings," in 1977 Corn Quality Conference, proceedings, Department of Agricultural Economics, University of Illinois (Urbana, February, 1978). Table 4. Physical Properties of Materials Passing Through a 12/64-Inch Round- Hole Screen, Illinois, 1976-1977 Average Country elevator Terminal elevator All samples Receipts Shipments Receipts Shipments Corn percent oj 83.4 87.9 total sample weight 88.9 90.0 (10.1) (8.0) ... b 0.2 (0.2) (1.4) 1.2 0.6 (5.0) (1.6) 9.8 9.2 (9.2) (7.6) 87.4 (11.2) 0.3 (1.5) 1.7 (5.0) 10.55 (9.8) Dust & inert mat Weed seeds (14.4)" (9.6) 0.7 0.4 (2.1) (1.4) 3.4 1.4 Corn by-products . . . (7.6) (3.2) 12.6 10.3 (11.9) (9.4) a The values in parentheses are standard deviations. b Less than 0. 1 percent. standards assure the buyer only of the maximum percentage of BCFM; there is no indication of whether the BCFM will consist mostly of dust and inert material or mostly corn pieces. If the material classified as BCFM is primarily corn pieces smaller than 1 2/64 inch, it is eco- nomically important to determine if whole corn, broken corn larger than 12/64 inch, and BCFM differ significantly in value. Since the market establishes a discount sys- tem that corresponds to the grade limits for BCFM, it is implicitly as- sumed that corn pieces larger than 1 2/64 inch are of greater value than smaller pieces. Further, since the price is established for No. 2 corn with discounts only if BCFM ex- ceeds 3 percent, it is implied that the first 3 percent of BCFM is equal in value to corn and requires no discount but that additional quantities of BCFM are consider- ably less valuable than the corn and thus do require a discount. Blending of BCFM The allowance of 3 percent BCFM in No. 2 corn gives grain handlers an economic incentive to make every shipment of corn contain as close to 3 percent as the supply of dust and screenings and the blend- ing capabilities of the plant will al- low. Putting screenings back into the grain stream adds to the cost of blending and cleaning and increases breakage. In addition, there is growing concern that this practice increases the danger of dust explo- sions. At the International Sympo- sium on Grain Elevator Explosions, several speakers identified the re- moval of grain dust from the grain as a necessary step in reducing the danger of elevator explosions. 7 In- vestments in control of air pollu- tion resulting from grain dust are becoming an important cause of in- creasing elevator operating costs. Yet, under the present grain stan- dards, grain handlers are penalized economically for removing the dust (unless BCFM exceeds the grade limit) since removal of the dust re- duces the weight of the grain. Some industry spokesmen and government agencies have recom- mended removing grain dust and prohibiting its reintroduction into the grain stream. 8 This measure will be resisted by operating manage- ment so long as the economic in- centives for blending outweigh the dangers and costs of explosions. The added cost of blending to the contract limit on BCFM is not off- set by added value at the destina- tion, especially if it is purchased by a corn dry miller. The extra BCFM seldom benefits the miller and must be removed and sold for consider- ably less than the purchase price. Screen size The 12/64-inch, round-hole screen currently used for defining BCFM replaced the 14/64-inch screen in 7. Robert M. Frye, "The FAR-MAR-CO Approach to the Prevention of Grain Dust Explosions," p. 46; A. Neal Fugett, "Eleva- tor Explosions," p. 47; Leland Bartelt, "In- surance Industry Views," p. 59; A.S. Town- send, "Grain Dust Explosions: The Time Has Come to Bite the Bullet." p. 61; In Proceedings of the International Symposium on Grain Elevator Explosions, Vol. 2, Na- tional Academy of Sciences. National Re- search Council, National Materials Advi- sory Board Publication No. 352-2 (Washington, D.C., 1978). 8. Ibid. October, 1921. The scientific basis for this change is not stated in any published work; it is stated only that the change was made. 9 Since particles smaller than 12/64 inch receive significant price discounts (see Table 3), one would expect the physical or chemical characteristics of the two particle sizes to be signif- icantly different. Most of the rea- sons given for the reduced value of screenings (such as handling prob- lems and restricted airflow) are re- lated either to the chemical or physical properties of the two parti- cle sizes. However, analysis of corn and corn screenings of various particle sizes fails to show significant differ- ences in the chemical and physical properties of particles larger or smaller than 12/64 inch. As shown 9. Historical Review of Changes in the Grain Standards of the United States, U.S. Department of Agriculture. Federal Grain Inspection Service Publication No. 5 (Wash- ington. D.C., 1980), p. 10. in Table 5, 97.2 to 100 percent of the material in the top three size categories was corn. Except for the percentage of whole kernels, the physical and chemical properties of material larger than 12/64 inch are indistinguishable from those of material passing through the 12/64- inch screen. Nor does the 12/64- inch screen uniformly or consis- tently separate whole kernels. In some samples of receipts at termi- nal elevators, the material passing over the 12/64-inch screen con- tained as little as 86 percent whole kernels. On the average, the per- centage of whole kernels is reduced with each successive handling. Although the significance of each of these problems has been docu- mented, few data are available to aid in finding solutions. The analy- sis of the 1 ,080 samples collected from country and subterminal ele- vators in Illinois following the 1976 and 1977 harvest provides data for evaluating alternative definitions of BCFM in the corn standards. Description of the Samples When the sample material from the 1976 and 1977 crops was separated by size regardless of its physical characteristics, the greatest propor- tion of every sample was retained on the 15/64-inch screen. Decreas- ing percentages were retained on each smaller screen down to the 4.5/64-inch screen (Table 6). For all samples the average amount of sample on the 15/16-inch screen was over 95 percent. Between coun- try elevator receipts and terminal elevator shipments, additional han- dling reduced the percentage of ma- terial retained on the 15/64-inch screen from 97.08 percent to 95.28 percent in the combined 1976-1977 results. Handling also increased the amount of the finest materials from 0.14 to 0.32 percent of the weight in the samples. According to these data, less than 2 percent of each sample collected from country elevator receipts passed through the 12/64-inch screen. The actual content of BCFM in corn delivered from the farm was below the maximum for No. 1 corn (2.0 percent). Shipments from the terminal elevator con- tained 2.59 percent BCFM. This figure reflects the increased break- age that results from handling and, more important, illustrates that be- fore selling corn most elevators blend or clean it to the 3 percent BCFM limit for No. 2 corn. Not all terminal elevators have facilities for blending, and some corn is shipped at less than 3 percent BCFM, re- ducing the average to 2.59. The distribution of the samples among the seven different particle sizes was nearly identical for coun- try elevator shipments and subter- minal elevator receipts. Most of the subterminal elevator receipts came directly from country elevators, but were not matched with the country elevator samples. The similarity of the samples is additional evidence that both were representative. The standard deviations associ- ated with each particle size did not show any relationship with the point in the market channel. There is no evidence that the quality of the grain was less uniform at the subterminal than it was at the country elevator. The smaller screens had a lower standard devia- tion primarily because the average BCFM passing through them was smaller than that passing through the larger screens. Study Results This section analyzes the physical and chemical properties of the seven sizes of particles in samples collected from the 1976 and 1977 crops. Although this analysis reveals relationships between these proper- ties and screen size, it produces no clear, simple solution to the prob- lems stated above. Statistical tests comparing the characteristics of the samples ob- tained in 1976 with those obtained in 1977 showed very few significant differences. The two sets of data were therefore combined and treated as a single set of data in some of the analyses and tables in this publication to reduce the quan- tity of tabular material. Chemical properties The relationships between the chemical properties and particle size for the 1976 and 1977 crops are shown in Figures 2 through 6. In general, the fat content de- creased as the particle size de- creased for both years (Figure 2). In 1976, the fat content decreased from 4.66 percent in the material larger than 1 5/64 inch to 2.64 per- cent in material passing through the 4.5/64-inch screen. In 1977, the pattern was quite similar, with fat content decreasing from 4.29 per- cent to 2.21 percent as particle size decreased from larger than 1 5/64 to smaller than 4.5/64 inch. The dif- ferences among the three smallest size categories were not significant for either 1976 or 1977. However, material in the three smallest cate- gories was significantly lower in fat content than material in the other four categories for both years. Val- Table 5. Physical Properties of Corn Samples, Illinois, 1976 and 1977 Crops Particle size groups 3 Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" 1976 Country elevator receipts Corn 100 97.82 93.20 0.08 0.83 6.10 95.28 0.10 0.48 4.14 96.32 0.00 0.44 3.24 96.77 0.01 0.24 2.99 percent 89.06 0.19 1.81 8.94 89.33 0.00 2.80 7.88 90.38 0.00 3.93 5.69 93.25 0.05 1.16 5.54 83.84 1.27 4.20 10.74 87.57 0.79 1.60 10.04 86.89 0.00 3.13 9.98 89.45 0.09 1.11 9.36 78.87 1.98 3.17 15.92 82.83 1.17 0.63 15.37 84.14 0.00 0.00 15.86 86.12 0.20 0.28 13.40 61.92 0.93 3.10 34.05 74.33 0.27 0.29 25.11 75.17 0.00 0.74 24.09 79.63 0.14 0.34 19.90 Dust & inert mat. . . 0.00 Weed seeds 0.15 Corn by-products ... 2.03 Country elevator shipments Corn 100 97.91 Dust & inert mat. . . 0.00 Weed seeds 66 Corn by-products ... 1 .42 Subterminal elevator receipts Corn 100 98.41 Dust & inert mat. . . 0. 1 5 Weed seeds 0.05 Corn by-products ... 1.39 Subterminal elevator shipments Corn 100 98 54 Dust & inert mat. . . 0.00 Weed seeds 0.36 Corn by-products ... 1.11 1977 Country elevator receipts Corn 99.88 99.03 96.53 0.00 2.61 0.86 97.68 0.00 1.43 0.89 98.09 0.00 0.41 1.49 98.71 0.00 0.61 0.68 90.00 0.09 7.21 2.70 90.93 0.00 5.71 3.36 96.78 0.00 0.53 2.69 96.74 0.00 0.54 3.01 88.89 0.20 5.48 5.42 92.43 0.00 1.86 5.72 92.33 0.00 0.98 6.69 92.03 0.43 0.88 6.66 86.12 1.17 1.94 10.83 89.45 0.37 0.25 9.92 88.15 0.24 0.23 11.37 87.26 1.51 0.29 10.94 74.15 0.00 6.93 18.92 88.35 0.90 0.38 11.27 86.79 0.00 1.06 12.16 82.75 0.00 0.74 16.51 Dust & inert mat. . . 0.00 0.00 Weed seeds 05 45 Corn by-products . . . 0.07 0.52 Country elevator shipments Corn . 99.88 97.24 Dust & inert mat. . . 0.00 0.00 Weed seeds 05 2 28 Corn by-products . . . 0.07 0.49 Subterminal elevator receipts Corn . 99.92 99.11 Dust & inert mat. . . 0.00 0.00 Weed seeds 05 23 Corn by-products . . . 0.03 0.66 Subterminal elevator shipments Corn 99.92 98.60 Dust & inert mat. . . 0.00 0.00 Weed seeds 0.05 1.03 Corn by-products . . . 0.03 0.37 a The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. ues for the three smallest screen sizes were always lower than those for the larger screens. Ash content was quite similar for the two crop years and changed very little as particle size was re- duced from larger than 1 5/64 inch to smaller than 6/64 inch (Figure 3). The greatest difference in ash content was between the smallest particle size, which contained 4.94 percent ash, and the next larger particles, with 2.32 percent ash. The ash content of the whole corn was 1.39 percent. Crude protein also differed only slightly among particle sizes down to 6/64 inch in both the 1976 and 1977 data (Figure 4). As with ash content, the percentage of protein Table 6. Distribution of Particle Sizes in Corn Samples, Illinois, 1976-1977 Average Particle size groups" Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Country elevators Receipts 97.08 (1.9SY 96.08 (1.98) ; 96.07 (2.48) 95.28 (2.28) 96.17 (2.27) percent of total sample weight 1.68 0.52 0.33 0.17 0.08 (0.80) (0.39) (0.35) (0.20) (0.14) 2.07 0.77 0.49 0.26 0.12 (0.82) (0.43) (0.32) (0.22) (0.13) 1.93 0.74 0.54 0.31 0.15 (0.77) (0.51) (0.47) (0.32) (0.19) 2.12 0.92 0.72 0.45 0.19 (0.54) (0.43) (0.51) (0.34) (0.16) 1.94 0.73 0.51 0.29 0.13 (0.76) (0.46) (0.44) (0.29) (0.16) 0.14 (0.37) 0.21 (0.31) 0.26 (0.45) 0.32 (0.31) 0.23 (0.37) Shipments Terminal elevator; Receipts Shipments . . . All samples " The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. h Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. c The values in parentheses are standard deviations. 3 if 2L 4.66 4.51 4.29 4.04 401 3.89 I976px^| I977| | 2.91 2.90 2.73 2.05 Corn J5/64 12/64 10/64 Screen size 8/64" 6/64" 4.5/64" Figure 2. Relationship between particle size and fat content in corn samples from the 1976 and 1977 crops.* (See footnote on page 9.) increased in the very smallest size categories. The increase between the two smallest size categories was 1.19 percentage points in 1976 and 1.42 percentage points in 1977. The percentage of fiber in each sample increased consistently as particle size decreased (Figure 5) in both 1976 and 1977. There was a relatively large increase between the 8/64- and 6/64-inch material. But the greatest difference was between the material passing through the 6/ 64-inch screen and that passing through the 4.5/64-inch screen. In both years the difference was ap- proximately 1.7 percentage points. There was little pattern in the re- lationship between nitrogen-free ex- tract (NFE) and particle size, except in material passing through the 4.5/ 64-inch screen (Figure 6). The dif- ferences between adjacent screen sizes were neither large nor consis- tent in direction, except for a large decrease in both years between the 6/64- and 4.5/64-inch material. The NFE of the 1976 samples dropped from 80.00 to 74.26 percent; that of the 1977 samples decreased from 80.26 to 75.23 percent between those two screen sizes. The decline is related to the increased fiber and ash in the fine materials. Physical properties Differences in the chemical proper- ties of the samples are partially ex- plained by differences in their phys- ical properties. As indicated earlier, most of the material in all particle size groups was corn. The percent- age of corn varied from 100 in the material remaining on the 15/64- inch screen to 72.22 in material passing through the 4.5/64-inch screen (Figure 7). The differences between the 1976 and 1977 sam- ples were relatively small in the larger particle sizes. However, in the smaller particle sizes considerably higher proportions of corn were found in the 1977 data than in the 1976 data. The reason for this dif- ference is that a larger proportion 8 of noncorn materials, particularly weed seeds and corn by-products, were found in the 1976 crop. Material identified as dust and inert material was seldom found in the four largest particle size groups. The quantity was always very small relative to total sample weight. The largest percentage of dust and inert material (less than 1 percent) was found in the 6/64-inch category (Figure 8). In the 1977 data, the material passing through the 8/64- inch screen contained only 0.16 percent dust and inert material, compared to 0.6 percent in the pre- vious year's samples for that screen size. The kind and amount of weed seeds in the samples varied with screen size. Relatively large quan- tities were found in the material passing through the 10/64- and 8/ 64-inch screens (Figure 9). Smaller amounts were found in material passing through the 6/64- and 4.5 / 64-inch screens. Weed seeds were present in the 1977 samples in all particle sizes except 8/64 and 6/64 inch. In the 10/64-inch size group, the percentage of weed seeds in- creased from 2.41 in 1976 to 3.50 in 1977. The percentage of corn by-prod- ucts (which include cobs and pieces of stalks, bees wings, and leaves) in the samples from both years in- creased uniformly as particle size decreased (Figure 10). In 1976, the percentage of corn by-products in- creased from in material above the 15/64-inch screen to a maxi- mum of 26.23 percent in material passing through the 4.5/64-inch screen. In 1977, the samples con- tained considerably less corn by- products but still increased from 0.05 percent in material above the 15/64-inch screen to a maximum of 14.71 percent in material passing through the 4.5/64-inch screen. These comparisons between the 1976 and 1977 crop data show more differences in physical (corn, dust and inert material, weed seeds, 3 s. 2.32 239 1.63 1.64 1.66 1.67 1.78 1.39 1.39 1.39 |.38 1.59 77. 4.24 Corn 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Screen size Figure 3. Relationship between particle size and ash content in corn samples from the 1976 and 1977 crops.* 13 12 7.0 0.7 0.3 2.0 2.5 10/64 inch U.S. No. I.... 1.2 81.7 68.2 66.0 41.3 U.S. No. 2. ... 1.8 9.7 16.2 18.0 27.7 U.S. No. 3. ... 2.4 5.8 8.0 5.6 14.3 U.S. No. 4. ... 3.0 1.1 4.1 3.8 8.3 U.S. No. 5.... 4.0 0.7 2.8 4.0 4.9 Sample >4.0 1.0 0.7 c 3.6 2.5 8/64 inch U.S. No. 1.... 0.6 83.4 68.9 65.2 38.8 U.S. No. 2. ... 1.0 8.0 15.9 17.6 28.6 U.S. No. 3. ... 1.4 4.8 6.9 6.4 14.0 U.S. No. 4. ... 1.8 1.4 3.1 3.2 9.5 U.S. No. 5.... 2.6 1.7 4.2 4.0 5.8 Sample >2.6 0.7 1.0 3.6 3.3 6/64 inch U.S. No. I.... 0.3 84.5 69.2 64.4 46.3 U.S. No. 2. ... 0.6 7.6 18.0 19.6 25.2 U.S. No. 3. ... 0.9 4.8 5.2 7.6 15.3 U.S. No. 4. ... 1.2 0.0 3.5 2.4 6.2 U.S. No. 5.... 1.8 2.1 2.4 2.8 4.5 Sample >1.8 1.0 1.4 3.2 2.5 ' Each screen size was used to identify an alternative definition of BCFM and represents all material falling through that screen. b BCFM limits for the 12/64-inch screen are those currently used in corn grading. BCFM limits for other screen sizes were selected so that the samples from a given location would be distributed approximately the same, regardless of the screen size used. have a very small effect on the physical and chemical properties of corn because the quantity of such materials as broken corn and weed seeds is small compared to the weight of the rest of the sample. For example, changing from a 12/ 64-inch screen to a 10/64-inch screen would add 0.52 percent of the average sample delivered by Illi- nois farmers that is now BCFM to the 98.63 percent of the sample that is now considered corn (Table 6). Since the chemical and physical properties of the 10/64-inch mate- rial differ very little from those of corn, the chemical and physical analysis of the corn fraction of the samples would not be appreciably altered. Summary and Conclusions Many economic and engineering relationships and trade practices are involved in any change of grade standards for grain. Because of the complexity of market relationships and the difficulty in predicting the 20 response of the market to a change in standards, it is impossible to pro- vide quantitative proof that chang- ing the definition of BCFM would result in greater benefits than costs. For the same reasons, it is equally impossible to prove that the bene- fits of the present standards exceed their costs. The research reported in this publication provides information that should help the grain industry and Federal Grain Inspection Ser- vice, USDA, evaluate the potential improvement in market informa- tion that might result from chang- ing the screen size used to define foreign material in corn. Unfortu- nately, the results do not provide the basis for a clear, unequivocal mandate. The following conclusions should help the reader better under- stand the implications of this re- search by bringing its results to bear upon the operational problems of grain production and marketing industries. Whole corn, broken corn, and noncorn materials cannot readily be separated by sizing devices such as screens because particles of all three kinds of material vary widely in size and because the size groups overlap. Although hand-separation of large noncorn material from the sample will increase inspection costs, it is being done in other ma- jor corn-exporting countries. It may be possible to make coarse foreign material a separate factor in con- junction with a change in screen size. The maximum number of chemi- cal and physical differences between corn and foreign material was ob- tained using an 8/64- or 6/64-inch screen. The two screens do not dif- ferentiate with equal success for all chemical and physical properties, but either screen would separate most dirt and weed seeds from corn. No criteria have been established for determining the "best" distribu- tion of the corn crop among the five numerical grades. It would be less difficult to establish price rela- tionships and discounts if the pres- ent distribution were maintained. Using smaller screen sizes would re- quire a reduction in the foreign material allowances for each grade. Using one of the smaller screens would minimize the amount of ma- terial that must be removed to meet the standard for No. 2 corn at all points in the marketing channel. As a result, the smaller screen would sharply reduce the amount of cleaning needed and the volume of screenings marketed. If screen- ings were treated as dockage (zero value), one may conjecture that the sharply reduced allowances and amounts of screening material would lessen the incentive for farm- ers to intentionally permit some foreign matter to get mixed with the corn. Treating screenings as dockage should also remove the in- centive for blending screenings back into corn. Much of the foreign matter would be concentrated, in a relatively small quantity of screen- ings, for which errors in pricing would not be a major concern. If broken corn is considered lower in value than whole corn (and there is evidence supporting this belief), an additional grade factor, whole kernels, might be required in con- junction with the definition of for- eign material by a smaller screen. This factor could be similar to the categories, splits versus whole beans, in the soybean grades. Using a smaller screen size for defining FM and creating a broken kernel factor would have several advan- tages. The chemical properties of No. 2 corn purchased by the feed industry would be very similar to those of corn now purchased. The industry would have little or no reason to discount against broken kernels. Processors could encourage the market to direct corn with less breakage to the processing industry by appropriate discounts for broken kernels. If there were appropriate market discounts against foreign material, most of the corn dust would be removed at its origin, and grain handlers would have no in- centive for reblending dust or mate- rial smaller than 6/64-inch. With these small pieces removed, much of the broken corn that became dust as a result of increased han- dling would also be removed. The value of foreign material (or dust) going through the small screen would be much less than at present. The screenings market, as it now exists, would probably disappear. Using a smaller screen size would result in several changes in the characteristics of corn and foreign material. The value of screenings could be reduced since they would then be higher in fiber and lower in digestible energy but higher in pro- tein than screenings passing through a 12/64-inch screen. They would also contain more weed seeds and would be more difficult to dry and store because of re- stricted airflow. Although no change in the chemical properties of the corn would be detectable, there would be more broken pieces of corn in the corn fraction, and these pieces would be smaller than under the present standards. For corn pro- cessors the presence of more bro- ken pieces would generally be a dis- advantage. Although the majority of U.S. corn is used for livestock feed (domestically and overseas), processors needs and influence on market prices cannot be ignored. There is no alternative (including the status quo) that does not have some disadvantage to some groups. The choice of an alternative should be reached through compromise and minimization of negative ef- fects. Additional research is needed that includes the export elevators. Information is also needed about the effect of particle size on pro- cessing costs, handling procedures, and grading costs, and about the ef- fect of redefining the grade factors on prices. Differences between crop years and over a larger region should also be evaluated. This study provides much of the basic information on which a more com- prehensive research project can be built. 21 Appendix A: Statistical Differences in Chemical and Physical Properties Table Al. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, All Samples, Illinois, 1976 Crop Sample property Particle size groups' Grouping Corn b 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.66 4.51 B 4.04 3.89 C 2.90 2.73 2.64 Ash A 1.39 1.39 1.63 1.66 1.67 B 1.63 1.66 1.67 2.32 C 4.94 Protein A 10.18 10.01 10.28 10.37 B 10.18 10.28 10.37 10.45 C 10.93 D 12.12 Fiber A 2.31 2.41 B 2.74 3.01 C 3.50 D 4.24 E 5.92 NFE A 81.47 82.10 81.06 81.54 B 81.47 80.83 81.06 81.54 C 80.83 81.06 79.99 D 74.26 Physical Corn A 100 98.13 B 95.26 C 90.35 D 86.79 E 82.74 F 72.22 Dust and A 0.03 0.05 0.06 0.37 inert mat. B 0.60 0.93 C 0.60 0.37 Weed seed A 0.32 0.51 1.12 1.19 B 2.41 2.55 1.12 1.19 By-products A 1.52 B 4.23 C 7.18 D 10.07 E 15.20 F 26.23 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. " The size of panicles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. 22 Table A2. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, All Samples, Illinois, 1977 Crop Sample property Particle size groups 3 Grouping Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.29 B 3.71 C 4.01 D 2.91 E 2.05 2.12 2.21 Ash A 1.39 1.38 1.64 1.59 1.78 B 2.39 C 4.24 Protein A 10.21 10.12 10.42 10.39 10.43 B 11.00 C 12.42 Fiber A 2.07 2.27 B 2.27 2.54 C 2.54 2.77 D 3.52 E 4.23 F 5.90 NFE A 82.05 82.52 82.35 82.22 B 82.05 81.39 8222 C 80.26 *. D 75.23 Physical' Corn A 99.90 98.49 97.75 B 93.61 91.42 C 87.75 D 83.01 Dust and A 0.00 0.00 0.00 0.02 0.16 0.22 inert mat. B 0.82 Weed seed A 0.05 1.00 1.26 0.68 B 1.00 1.26 2.30 0.68 2.28 C 3.50 2.30 2.28 By-products A 0.05 0.51 0.98 B 2.94 C 6.12 D 10.77 E 14.71 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. ' The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 1 5/64-inch screen. 23 Table A3. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Country Elevator Receipts, Illinois, 1977 Crop Sample property Particle size groups 3 Grouping Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.21 B 3.33 3.41 C 2.65 2.36 2.44 D 2.17 2.36 2.44 Ash A 1.40 1.36 1.66 1.94 B 1.66 1.94 2.43 C 2.43 3.32 D 5.98 Protein A 10.13 9.92 10.53 10.96 11.09 B 10.13 10.53 10.96 11.09 11.43 C 13.70 Fiber A 2.14 2.47 2.93 B 2.93 3.41 C 4.35 4.68 D 6.44 NFE A 82.11 82.92 81.45 81.04 B 82.11 81.45 81.04 79.96 C 79.96 78.22 D 71.45 Physical Corn A 99.88 99.03 96.53 B 96.53 90.00 C 90.00 88.89 86.12 D 74.15 Dust and A 0.00 0.00 0.00 0.09 0.20 0.00 inert mat. B 1.17 Weed seed A 0.05 0.45 2.61 7.21 5.48 1.94 6.93 By-products A 0.07 0.52 0.86 2.70 B 2.70 5.42 C 10.83 D 18.92 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. * The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. 24 Table A4. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Country Elevator Shipments, Illinois, 1976 Crop Sample property Particle size groups 3 Grouping Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.40 4.16 4.56 B 4.16 3.70 C 2.85 2.72 2.99 Ash A 1.39 1.47 1.63 1.64 1.50 2.68 B 6.36 Protein A 10.16 10.07 10.23 10.32 10.34 10.94 B 12.28 Fiber A 2.29 2.54 2.76 B 2.76 3.06 C 3.06 3.40 D 4.35 E 6.00 NFE A 81.76 81.62 80.82 81.27 81.90 79.41 B 72.33 Physical Corn A 100 97.91 B 97.91 95.28 C 89.33 87.57 D 82.83 E 74.33 Dust and A 0.00 0.00 0.10 0.00 0.79 0.27 inert mat. B 0.79 1.17 Weed seed A 0.00 0.66 0.48 B 0.66 0.48 1.60 0.63 0.29 C 2.80 1.60 By-products A 0.00 1.42 4.14 B 4.14 7.88 C 7.88 10.04 D 15.37 E 25.11 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. * The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 1 5/64-inch screen. 25 Table A5. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Country Elevator Shipments, Illinois, 1977 Crop Sample property Particle size groups 3 Grouping Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.20 4.42 B 4.20 3.98 C 3.03 D 2.01 2.09 2.17 Ash A 1.38 1.43 1.70 1.56 1.77 B 1.70 1.56 1.77 2.30 C 3.64 Protein A 10.10 10.15 10.39 10.20 10.12 10.78 B 12.05 Fiber A 2.16 2.31 2.60 2.73 B 2.73 3.26 C 4.05 D 5.73 NFE A 82.16 82.13 80.90 80.78 B 82.16 82.13 82.48 82.84 C 76.42 Physical Corn A 99.88 97.24 97.68 B 90.93 92.43 89.45 C 90.93 89.45 88.35 Dust and A 0.00 0.00 0.00 0.00 0.00 0.37 0.90 inert mat. Weed seed A 0.05 2.28 1.43 1.86 0.25 0.38 B 5.71 By-products A 0.07 0.49 0.89 B 3.36 C 5.72 D 9.92 E 11.27 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. a The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. h Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. 26 Table A6. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Terminal Elevator Receipts, Illinois, 1976 Crop Sample property Particle size groups" Grouping Corn 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.91 4.86 B 4.06 4.13 C 2.82 2.61 2.50 Ash A 1.35 1.30 1.66 1.56 1.47 1.79 B 4.10 Protein A 10.04 9.74 10.16 9.98 10.16 B 10.04 10.16 9.98 10.16 10.49 C 11.37 Fiber A 2.27 2.22 2.65 B 2.65 2.81 C 2.81 3.25 D 3.25 3.70 E 5.66 NFE A 81.43 82.68 80.68 81.52 82.30 81.46 B 76.25 Physical Corn A 100 98.41 96.32 B 90.38 86.89 C 86.89 84.14 D 75.17 Dust and A 0.00 0.00 0.00 0.00 0.00 0.00 inert mat. B 0.15 Weed seed A 0.00 0.05 0.44 3.93 3.13 0.00 0.75 By-products A 0.00 1.39 3.24 B 1.39 3.24 5.69 C 5.69 9.98 D 15.86 E 24.09 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. ' The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 1 5/64-inch screen. 27 Table A7. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Terminal Elevator Receipts, Illinois, 1977 Crop Sample property Particle size groups' Grouping Corn" 15/64" 12/64" 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.33 3.98 B 3.79 3.98 C 2.86 D 2.06 2.10 2.22 Ash A 1.37 1.38 1.58 1.49 1.48 1.86 B 4.48 Protein A 10.24 10.17 10.39 10.27 10.37 B 10.88 C 11.88 Fiber A 1.91 2.24 2.37 B 2.24 2.37 2.62 C 3.34 D 3.94 E 5.56 NFE A 82.15 82.41 81.70 82.76 82.75 81.22 B 75.86 Physical Corn A 99.92 99.11 98.09 B 99.11 98.09 96.78 C 92.33 D 88.15 86.79 Dust and A 0.00 0.00 0.00 0.00 0.00 0.00 inert mat. B 0.24 Weed seed A 0.05 0.23 0.41 0.53 0.23 B 0.23 0.41 0.53 0.98 0.23 1.06 By-products A 0.03 0.66 1.49 B 0.66 1.49 2.69 C 6.69 D 11.37 12.16 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. a The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 1 5/64-inch screen. 28 Table AS. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Terminal Elevator Shipments, Illinois, 1976 Crop Sample property Particle size groups 2 Grouping Corn" 15/64* 12/64' 10/64' 8/64' 6/64' 4.5/64' Chemical Fat A 4.52 4.24 4.56 B 4.24 3.93 C 2.54 2.18 2.08 Ash A 1.34 1.38 1.63 1.43 B 1.34 1.38 1.43 1.25 1.32 C 2.45 Protein A 10.02 9.89 10.02 10.11 9.90 B 10.11 10.40 C 12.01 Fiber A 2.15 2.26 2.50 B 2.26 2.50 2.66 C 3.26 D 3.74 E 5.67 NFE A 81.96 82.22 81.29 81.87 B 81.96 82.22 81.87 82.45 C 82.22 83.05 82.45 D 77.93 Physical Corn A 100 98.54 96.77 B 93.25 C 89.45 86.12 D 79.63 Dust and A 0.00 0.00 0.01 0.05 0.09 0.20 0.14 inert mat. Weed seed A 0.00 0.36 0.24 1.16 1.11 0.28 0.34 By-products A 0.00 1.11 2.99 B 2.99 5.54 C 9.36 D 13.40 E 19.90 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. ' The size of particles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. b Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. 29 Table A9. Duncan's Multiple Range Test for Significant Differences in the Chemical and Physical Properties of Corn Samples, by Particle Size, Terminal Elevator Shipments, Illinois, 1977 Crop Sample property Particle size groups' Grouping Corn" 15/64* 12/64' 10/64" 8/64" 6/64" 4.5/64" Chemical Fat A 4.41 4.25 B 3.72 C 3.08 D 1.96 1.94 2.03 Ash A 1.40 1.35 1.62 1.38 1.43 B 1.40 1.62 1.38 1.43 2.09 C 2.85 Protein A 10.37 10.23 10.39 10.12 10.13 B 10.90 C 12.05 Fiber A 2.07 2.07 2.25 2.32 B 3.14 C 4.24 D 5.89 NFE A 81.77 82.63 81.50 80.83 B 81.77 81.50 C 82.63 83.10 83.35 D 77.18 Physical Corn A 99.92 98.60 98.71 96.74 B 92.03 C 87.26 D 82.75 Dust and A 0.00 0.00 0.00 0.00 0.43 1.51 0.00 inert mat. Weed seed A 0.05 0.61 0.54 0.88 0.29 0.74 B 1.03 0.61 0.54 0.88 0.29 0.74 By-products A 0.03 0.37 0.68 3.01 B 6.66 C 10.94 D 16.51 Note: Means within the same grouping are not significantly different at the 95 percent confidence level. Each physical and chemical characteristic was evaluated independently of other characteristics. a The size of panicles in each category lies between that screen size and the next smaller one. For example, the material in the 10/64-inch category passed through the 10/64-inch screen but was too large to pass through the 8/64-inch screen. h Includes whole corn and large pieces of broken corn remaining on top of the 15/64-inch screen. 30 Appendix B: Distribution of Corn Samples, by BCFM Content Table Bl. Distribution of Corn Samples, by BCFM Content Based on Segregation Using a 12/64-inch Screen, Illinois, 1976 and 1977 Crops BCFM content, Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments 1976 00-10 58 percent 31 of samples 31 11 1 1-2.0 21 36 38 23 2 1-30 13 18 17 31 31-40 6 7 6 21 4 -50 1 5 3 8 5 -6.0 2 1 2 6 1-70 2 Over 70 1 1 2 4 Avg BCFM content .... 1 30 1.81 1.90 2.79 1977 00-1 62 27 24 2 1. -2.0 24 34 41 47 2. -3.0 8 23 16 38 3-40 3 14 8 11 4-50 2 2 6 2 5 -6.0 3 6. -7.0 1 Over 7.0 2 Avg. BCFM content 1.11 1.88 2.13 2.20 Table B2. Distribution of Corn Samples, by BCFM Content Based on Segregation Using a 10/64-Inch Screen, Illinois, 1976 and 1977 Crops BCFM content, Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments 1976 0.0-05 58 percent 33 of samples 33 12 0.6-1.0 16 29 30 15 1 1-1 5 9 17 16 21 1 6-20 11 8 9 19 2.1-2.5 3 3 3 16 2.6-3.0 1 5 1 6 3.1-3.5 1 2 3 4 Over 3 5 1 3 5 7 Avg. BCFM content 1977 00-05 0.76 60 1.04 27 1.16 18 1.80 3 0.6-1 25 24 34 31 1.1-1.5 5 23 23 33 1.6-2.0 3 11 6 16 2.1-2.5 4 10 8 9 2.6-3.0 1 3 4 15 3.1-3.5 1 2 1 Over 3 5 2 5 1 Avg. BCFM content 0.64 1.13 1.39 1.42 31 Table B3. Distribution of Corn Samples, by BCFM Content Based on Segregation Using an 8/64-Inch Screen, Illinois, 1976 and 1977 Crops BCFM content, Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments 1976 00-03 65 percent 49 of samples 48 16 0.4-0.6 17 23 23 22 07-09 7 11 12 18 10-12 . ... 6 5 6 15 1 3-1.5 2 4 2 15 16-18 1 2 1 1 1 9-2 1 1 2 2 3 Over 2. 1 1 5 6 10 Avg BCFM content 0.42 0.57 0.65 1.03 1977 00-0.3 70 37 30 12 0.4-0.6 18 28 26 34 7-09 4 14 21 24 10-12 . .. 3 12 5 13 1 3-1.5 1 5 9 6 1.6-1.8 2 2 2 8 1 9-2 1 1 1 Over 21 2 1 7 2 Avg BCFM content 0.33 0.60 0.82 0.81 Table B4. Distribution of Corn Samples, by BCFM Content Based on Segregation Using a 6/64-Inch Screen, Illinois, 1976 and 1977 Crop BCFM content, Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments 1976 0.0-0.2 76 percent 66 of samples 61 30 03-04 10 15 20 26 05-06 5 7 7 11 0.7-0.8 6 3 3 16 09-1 2 2 4 1 1-1 2 2 1 4 1.3-1.4 1 1 1 2 Over 1.4 2 4 5 7 Avg. BCFM content 1977 0.0-0.2 0.24 83 0.31 49 0.36 41 0.55 29 03-04 . 6 23 23 38 0.5-0.6 5 15 14 12 0.7-0.8 2 8 12 5 09-10 1 1 3 10 1.1-1.2 3 2 4 1.3-1.4 2 1 1 Over 1.4 1 1 4 1 Avg. BCFM content 0.18 0.33 0.47 0.46 32 Appendix C: Cumulative Frequency Distribution of Corn Samples, by BCFM Content Table Cl. Cumulative Frequency Distribution of Corn Samples, by Maximum BCFM Content and Origin of the Sample, Illinois, 1976 and 1977 Crops, 12/64-Inch Screen Max. BCFM content, Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments percent of samples 0.2 13.1 1.7 0.8 0.0 0.4 27.9 5.9 3.2 0.0 0.6 39.3 14.2 13.2 1.2 0.8 48.6 23.2 22.4 2.1 1.0 59.7 29.8 27.6 7.0 1.2 66.9 35.6 36.4 9.9 1.4 69.6 44.6 44.4 16.1 1.6 74.8 50.9 53.2 24.8 1.8 78.3 58.1 58.8 34.7 2.0 81.4 64.7 67.6 40.1 2.2 83.4 70.6 72.4 49.2 2.4 86.9 76.1 76.4 55.4 2.6 88.6 78.9 80.4 59.9 2.8 90.7 81.7 82.4 66.5 3.0 93.1 84.4 84.4 73.6 3.2 94.8 86.5 87.2 77:3 3.4 95.9 88.2 88.4 81.0 3.6 96.5 90.3 89.6 85.1 3.8 97.2 92.7 90.4 89.3 4.0 97.9 94.1 91.2 90.9 4.2 98.3 94.8 92.4 92.6 4.4 98.6 96.2 92.3 93.8 4.6 98.6 96.9 93.6 94.6 4.8 99.0 97.2 95.2 95.5 5.0 99.0 98.3 95.2 96.3 5.2 99.0 98.3 95.6 96.7 5.4 99.0 99.0 95.6 97.1 5.6 99.0 99.0 96.8 97.1 5.8 99.0 99.3 96.8 97.1 6.0 99.0 99.3 97.2 97.5 6.2 99.0 99.3 97.6 97.5 6.4 99.0 99.7 98.0 97.5 6.6 99.0 99.7 98.0 97.5 6.8 99.0 99.7 98.0 97.5 7.0 99.3 99.7 98.0 97.5 33 Table C2. Cumulative Frequency Distribution of Corn Samples, by Maximum BCFM Content and Origin of the Sample, Illinois, 1976 and 1977 Crops, 10/64-Inch Screen Max. BCFM content, Counry elevators Terminal elevators percent of weight Receipts Shipments Rceipts Shipments percent of samples 0.1 23.1 4.8 2.0 0.0 0.2 36.6 13.1 7.6 0.8 0.3 42.1 19.7 15.2 2.1 0.4 54.8 26.0 21.6 4.1 0.5 59.0 31.1 27.2 8.3 0.6 63.4 38.1 35.6 10.7 0.7 69.0 43.3 40.8 13.6 0.8 72.4 48.8 45.2 19.0 0.9 75.5 53.6 52.8 23.6 1.0 78.3 57.8 58.0 30.2 .1 80.7 64.4 62.4 36.8 .2 81.7 68.2 66.0 41.3 .3 82.4 72.3 70.8 45.9 .4 85.2 75.4 72.4 51.2 .5 86.2 77.9 77.6 55.8 .6 88.6 80.3 80.4 59.9 .7 89.0 82.4 81.2 64.5 .8 91.4 84.4 84.0 69.0 .9 92.8 86.2 84.4 71.1 2.0 94.1 87.2 85.2 73.6 2.1 95.2 88.6 86.4 75.2 2.2 95.9 88.9 88.0 79.3 2.3 96.6 91.0 89.2 81.8 2.4 97.2 92.4 89.6 84.3 2.5 97.6 92.4 90.4 86.8 2.6 97.9 93.4 90.4 88.4 2.7 97.9 94.5 91.6 89.7 2.8 97.9 95.1 91.6 91.3 2.9 98.3 95.8 92.0 92.6 3.0 98.3 96.5 92.4 92.6 3.1 98.3 96.5 93.2 93.4 3.2 98.6 96.5 94.0 93.4 3.3 98.6 96.9 94.4 94.2 3.4 98.6 96.9 94.4 94.2 3.5 98.6 98.3 95.2 95.5 3.6 99.0 98.3 95.2 95.5 3.7 99.0 98.6 95.2 95.9 3.8 99.0 99.0 95.2 96.3 3.9 99.0 99.0 96.0 96.7 4.0 99.0 99.3 96.4 97.5 34 Table C3. Cumulative Frequency Distribution of Corn Samples, by Maximum BCFM Content and Origin of the Sample, Illinois, 1976 and 1977 Crops, 8/64-Inch Screen Max. BCFM content, Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments percent of samples 0.1 42.4 21.8 15.6 4.5 0.2 60.3 35.3 29.2 9.9 0.3 66.6 45.0 40.8 14.5 0.4 74.5 55.7 49.6 21.1 0.5 78.6 62.3 58.4 29.8 0.6 83.4 68.9 65.2 38.8 0.7 84.8 73.4 69.2 47.1 0.8 88.6 78.2 75.6 56.6 0.9 90.0 81.7 80.4 61.9 1.0 91.4 84.8 82.8 67.4 .1 92.4 86.9 85.2 71.9 .2 94.8 88.6 86.0 75.6 .3 95.9 90.3 87.6 79.3 .4 96.2 91.7 89.2 81.4 .5 96.6 92.7 91.2 85.5 1.6 97.2 93.8 92.0 88.0 1.7 97.2 94.1 92.4 89.3 1.8 97.6 94.8 92.4 90.9 1.9 97.9 95.5 92.8 92.1 2.0 98.3 96.2 92.8 93.0 2.1 98.3 96.2 93.6 93.4 2.2 98.3 96.5 94.4 95.0 2.3 98.6 97.2 94.4 95.5 2.4 98.6 97.6 95.6 95.9 2.5 98.6 97.9 96.0 96.3 2.6 99.3 99.0 96.4 96.7 2.7 99.3 99.3 96.4 96.7 2.8 99.3 99.3 96.4 97.5 2.9 99.3 99.3 96.4 97.5 3.0 99.3 99.3 97.2 96.7 3.1 99.3 99.6 97.2 98.3 3.2 99.3 99.6 98.0 98.3 3.3 99.3 99.6 98.4 98.8 3.4 99.3 99.6 98.4 99.2 3.5 99.3 99.6 98.4 99.2 35 Table C4. Cumulative Frequency Distribution of Corn Samples, by Maximum BCFM Content and Origin of the Sample, Illinois, 1976 and 1977 Crops, 6/64-Inch Screen Max. BCFM content. Country elevators Terminal elevators percent of weight Receipts Shipments Receipts Shipments 0.1 66.6 percent 43.9 of samples 38.0 16.1 02 78 6 592 51 6 28 1 0.3 84.5 69.2 64.4 46.3 04 86 9 76 8 724 58 7 5 890 824 800 65 7 06 . . 92.1 87.2 84.0 71.5 0.7 95.2 90.7 88.4 77.7 0.8 96.6 92.4 90.4 83.1 09 969 92.7 91.6 868 96.9 93.8 92.8 89.3 1 96.9 94.5 93.2 91.3 .2 96.9 96.2 94.0 93.0 3 969 962 944 946 4 97.9 96.9 95.2 95.5 .5 97.9 96.9 95.2 95.9 6 98.3 97.2 95.6 96.7 .7 99.0 97.9 96.0 97.1 g 990 986 96.8 97.5 9 99.0 99.0 97.6 98.3 2.0 99.3 99.3 98.0 98.8 36 UNIVERSITY OF ILLINOIS-URBANA Q 630 71168 C008 BULLETIN URBANA 7761982 30112019531232