4. Estimate Residue Cover in the Field |
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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.
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To
begin measuring, walk a predetermined distance into the field—such
as 100 or 150 paces. Keep the starting point away from end rows. |
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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. |
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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. |
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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. |
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20
percent corn residue |
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40
percent corn residue |
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60
percent corn residue |
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20
percent soybean residue |
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30
percent soybean residue |
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40
percent soybean residue |
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20
percent wheat residue |
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30
percent wheat residue |
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50
percent wheat residue |
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