Minimizing Harvest Losses

Every bushel of soybeans or corn left behind by the combine represents a loss of profits. While harvest losses cannot be completely eliminated, timely combine adjustments can reduce losses to 1 or 2 bushels per acre.

Measuring Soybean Harvest Loss

To determine soybean harvest losses, count the number of beans on the ground in a 10 square foot area.⁴ Divide the number of beans in the 10 square foot area by 10 to determine the number of beans lost per square foot. Four beans per square foot equals 1 bushel/acre loss. Dividing the number of beans per square foot by 4 will give the loss in bushels per acre. Make loss determinations at several locations and calculate an average.

Reducing Soybean Harvest Loss

Soybean combine losses can be as much as 15%. Careful maintenance and operation can help keep soybean harvest losses to 3 - 4% which would be 1.35 bu/ac in a 45 bu/ac crop (or 5.4 beans per square foot)². Most of soybean harvesting losses occur at the gathering unit of the combine between the header and standing beans². Loss at the gathering unit is often from shattering.

Shattering loss can be reduced by harvesting soybeans as quickly as possible when soybean moisture reaches 15%.³ Ground speed should be reduced to 3 miles per hour or less, and reels should operate about 25% faster than ground speed. The best guide for correct combine settings and adjustments is your operator’s manual.

Measuring Corn Harvest Loss

Determine total ear loss by counting the number of full-size ears, or the equivalent, in a 1/100 acre area (Table 1). Each full-size ear represents about 1 bushel/acre loss.

To measure kernel loss, count the loose kernels on the ground and those still attached to threshed cobs in a 10 square foot area for each row behind the combine. The area should have width equal to the planted row width. Two kernels per square foot equals a 1 bushel/acre loss.

Reducing Corn Harvest Loss

Proper combine setting will allow you to maximize income by reducing harvest loss and reduce volunteer corn issues next growing season. Mechanical losses may be due to ear drop, stalk lodging, and kernel shattering. Mechanical losses are expected, but keeping them to a minimum of 1% for ear loss, 0.3% threshing loss, and 0.5% loose kernel loss should be the goal.¹ Altogether, a 1.8% mechanical loss from a 150 bu/ac corn yield would be 2.7 bu/ac or an average of 5.4 kernels per square foot.

Ear loss can be minimized by setting snapping rolls to fit stalk width, and running snapping rolls at the same speed as ground speed. Cylinder or rotor speed can be adjusted to minimize threshing losses and kernel damage. Loose kernel losses can be affected by fan and shoe settings, and combines should be adjusted where stressed plants produced lighter kernels. Follow manufacturer’s settings to minimize losses.

Summary

Each harvest season producers have the opportunity to save yield potential through combine adjustments and careful operation of machinery. While some grain loss is expected during harvest, mechanical losses should be kept to a minimum. Measurement of grain left behind the combine is key critical to making adjustments to combines and combine operation.