Numerous tests of soybean combine losses show that up to 12 percent of the soybean crop is lost during harvest. Harvesting losses cannot be reduced to zero, but they can be reduced to about 5 percent. Combines can be operated to reduce losses without affecting the harvesting rate. This guide describes the major sources of loss

Ellis, Lyle V.

Hires, William George, 1930-

Shay, Charles W.

University of Missouri: MOspace

University of Missouri ExtensionG1280, Revised October 1993Measuring and Reducing Soybean HarvestingLossesCharles W. Shay, Lyle Ellis and William HiresDepartment of Agricultural EngineeringNumerous tests of soybean combine losses show that up to 12 percent of the soybean crop is lost duringharvest. Harvesting losses cannot be reduced to zero, but they can be reduced to about 5 percent. Combinescan be operated to reduce losses without affecting the harvesting rate. This guide describes the major sourcesof loss.Preharvest lossesThese losses are beyond the combine operator's control and cannot be called harvesting losses.Preharvest losses are caused by lodging and shattering. In most years, 0.25 percent of the total cropyield is lost before harvesting begins.Shatter loss at combine headerThese losses occur when the header is operated improperly or when the crop tends to shatter easily.Shatter losses increase with crop dryness.When the reel speed is too fast or the reel is positioned too far forward, soybeans are shelled in front ofthe combine. Reel peripheral speed should not exceed forward speed of the combine by more than 25percent. Peripheral speed is easier to adjust on combines with variable speed reel controls.Consider shatter losses of 2 percent acceptable. Average losses are 5 percent or more.Stubble lossOften many pods are left on the stubble because they have been missed by the cutterbar and were notgathered into the combine. Overcome this problem by keeping the field level and using a flexiblecutterbar or special row-crop head for soybeans.Stubble losses should be no more than 0.75 percent of the total crop yield. Average losses are 1.5percent or more.Lodged or loose stalk lossBeans left in the pods on downed stalks or those that are cut but do not pass through the combineshould be only about 1 percent of the total crop yield. Minimum losses occur when the machine is intop condition, the knife is sharp and the correct reel height is used. A pickup reel reduces these losses.Average losses are 2 percent to 5 percent of the crop yield.Cylinder lossBeans left in pods that have passed through the machine are the result of harvesting when the moisturecontent is too high or with incorrect cylinder-concave settings. There should be no loss, but improperoperation can cause losses as high as 0.5 percent of the crop yield.Separation lossLoose beans passing out of the machine can be held to a minimum with the correct blower and sievesettings. These losses can be as high as 0.5 percent but should be held to 0.25 percent of the crop yield.How to measure lossesG1280 Measuring and Reducing Soybean Harvesting Losses | University ... http://extension.missouri.edu/publications/DisplayPrinterFriendlyPub.asp...1 of 4 8/12/2010 11:06 AMTo get satisfactory combine operation, you need to identify and measure losses. Alone, you can check lossesin about 10 minutes. If you have help, even less time will be required. The extra soybeans in your grain tankwill more than pay for the delay.To determine losses, count the unharvested beans in an area of 10 square feet. An average of four beans persquare foot equals one bushel per acre loss. Make the area of 10 square feet equal in width to the combineheader (Table 1). A plastic clothes line and four pins made from number 9 wire make excellent material forforming the rectangle.Table 1Rectangular dimensions for 10-square-foot plot.Common machine swath Distance to enclose 10 square feet8 feet 15 inches10 feet 12 inches12 feet 10 inches13 feet 9.25 inches14 feet 8.6 inches15 feet 8 inches16 feet 7.5 inches20 feet 6 inches22 feet 5.45 inches24 feet 5 inchesBefore checking for losses, disconnect the straw spreader or chopper so you can get a more accurate count.Stop the combine where the crop is representative of the entire field. Stop the header and threshingmechanism. Back the combine a distance equal to its length. Shut off the engine.Place the rectangular frame across the machine swath and make counts for:Total crop loss (Step 1)Preharvest loss (Step 2)Header loss (Step 4)Step 1Total crop loss. Place the rectangular frame across the swath harvested at rear of combine. Count all loosebeans as well as the beans in loose and missed pods. Enter the number of beans per 10 square feet in Table 2,line 1.If the total crop loss is less than 3 percent of the crop yield, keep on harvesting. You are doing a better thanaverage job. If losses are greater than 3 percent, pinpoint the source of the losses to determine whereadjustments are needed.Step 2Preharvest loss. Determine the preharvest loss by placing the rectangular frame in standing beans. Count theloose beans on the ground and the beans in loose pods on the ground. Enter the number of beans per 10square feet in Table 2, line 2.G1280 Measuring and Reducing Soybean Harvesting Losses | University ... http://extension.missouri.edu/publications/DisplayPrinterFriendlyPub.asp...2 of 4 8/12/2010 11:06 AMStep 3Machine loss. Determine the machine loss by subtracting the preharvest loss from the total crop loss. Enterthis number in Table 2, line 3. If the machine loss is 3 percent of the total crop yield, you are doing a betterthan average job and adjustments are not necessary. If the loss is greater than 3 percent, check the headerlosses.Step 4Header loss. Determine header losses by placing the rectangular frame across the swath harvested in front ofthe parked combine. Place it over an area where there has been no discharge from the rear of the combine.Then make bean counts as follows and enter the numbers in Table 2.Shatter lossCount all loose beans on the ground and beans in loose pods on the ground. Enter the number of beansper 10 square feet in line 4a.Loose stalk lossCount all the beans in pods attached to soybean stalks that were cut but not gathered into the machine.Enter the number of beans per 10 square feet in line 4b.Lodged stalk lossCount all the beans in pods attached to soybean stalks that were lodged and are still attached to theground. Enter the number of beans per 10 square feet in line 4c.Stubble lossCount all the beans in pods still attached to stubble. Enter the number of beans per 10 square feet inline 4d.Obtain the total header loss by adding the losses for shatter, stubble, loose stalks and lodged stalk losses.Enter the total header loss in line 4.Step 5Cylinder and separation loss. Determine cylinder and separation loss by subtracting the total header loss fromthe machine loss. Enter this difference in Table 2, line 5.Table 2Loss data table.Source of loss Beansfound in 10square feetareaNumber ofbeans = 1bushel peracreYour beanloss inbushels peracre1. Total crop loss  40  2. Preharvest loss  40  3. Machine loss  40  4. Gathering unit loss. Totals of:  40  a. Shatter  40  b. Loose stalk  40  c. Lodged stalk  40  d. Stubble  40  5. Cylinder and separation loss    G1280 Measuring and Reducing Soybean Harvesting Losses | University ... http://extension.missouri.edu/publications/DisplayPrinterFriendlyPub.asp...3 of 4 8/12/2010 11:06 AMTips for keeping combine losses lowYour best guide for correct combine adjustment is your operator's manual.Remember that more than 80 percent of the machine loss usually occurs at the gathering unit. The followingsuggestions will help keep these losses to a minimum.Make sure that knife sections, guards, wear plates and hold-down clips are in good condition andproperly adjusted.Keep the seedbed level. Do not dig up soil around beans when cultivating.Operate the cutterbar as close to the ground as possible at all times. A floating header unit or anautomatic header control is nearly essential on self-propelled combines.Use a ground speed of 2.8 to 3.0 miles per hour. To determine ground speed, count the number of3-foot steps taken in 20 seconds while walking beside the combine. Divide this number by 10 to get theground speed in miles per hour.Use a reel speed about 25 percent faster than ground speed. For 42-inch-diameter reels, use a reelspeed of 11 revolutions per minute for each 1-mile-per-hour ground speed.Reel axle should be 6 to 12 inches ahead of the cutterbar. Reel bats should leave beans just as they arecut. Reel depth should be just enough to control the beans.A six-bat reel will give more uniform feeding than a four-bat reel.Complete the harvest as quickly as possible after beans reach 15 percent moisture content.A pick-up type reel with pick-up guards on the cutterbar is recommended when beans are lodged andtangled.G1280, reviewed October 1993Related MU Extension publicationsG1290, Measuring and Reducing Corn Harvesting Losseshttp://extension.missouri.edu/publications/DisplayPub.aspx?P=G1290G4470, Soybean Harvest Aidshttp://extension.missouri.edu/publications/DisplayPub.aspx?P=G4470Order publications online at http://extension.missouri.edu/explore/shop/ or call toll-free 800-292-0969.G1280 Measuring and Reducing Soybean Harvesting Losses | University ... http://extension.missouri.edu/publications/DisplayPrinterFriendlyPub.asp...4 of 4 8/12/2010 11:06 AM

Measuring and reducing soybean harvesting losses (1993)

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