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4. Estimate Residue Cover in the Field

farmers making residue-cover estimates

Making residue-cover estimates on paper is a good way to plan your residue-management system, but it doesn’t replace actually going into the field and measuring residue.

The most accurate way to determine the percent of surface cover in a field is to use the line-point method. The only special equipment you need is a knotted rope with 100 evenly spaced knots.

farmer measuring a field To begin measuring, walk a predetermined distance into the field—such as 100 or 150 paces. Keep the starting point away from end rows.
diagram of how to use a rope for residue calculation Secure one end of the knotted rope halfway between two rows. Then stretch it diagonally, at a 45-degree angle, across the crop rows. Stake the other end halfway between another two rows.
rope for reside calculation Looking straight down on the rope, count the number of times you see residue directly underneath a knot. The percent of surface covered with residue equals the number of knots that touch crop residue. For instance, if you find crop residue under 40 of 100 knots, then 40 percent of the soil surface is covered with residue.
residue average diagram Estimate residue in at least three other areas of the field, and then take an average. Check your residue cover throughout the season. That way, you can make whatever adjustments are necessary. The following slides present various levels of corn, soybean, and wheat residue.
20 % corn residue 20 percent corn residue
40 % corn residue 40 percent corn residue
60 % corn residue 60 percent corn residue
20% soybean residue 20 percent soybean residue
30% soybean residue 30 percent soybean residue
40% soybean residue 40 percent soybean residue
20% wheat residue 20 percent wheat residue
30% wheat residue 30 percent wheat residue
50% wheat residue 50 percent wheat residue

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