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•Watershed and Flood Control
•Groundwater
_____- Keys to Clean Water
•Cost-Share
•Conservation Trees
•Regulations to Protect Soil and
Water
 We
All Hold the Key To Clean Water
Agricultural Best Management Practices:
Nitrogen Credits for manure and legume crops
Nitrogen is an essential nutrient for corn, and fertilizer is
only one nitrogen source. Others are irrigation water, soil, organic
matter, previous bean or alfalfa crops, and manure. Farmers who
take advantage of these other nitrogen sources often can apply
less fertilizer.
Here’s how to calculate the amount of nitrogen corn can
obtain from manure and previous crops of bean or alfalfa, based
on University of Nebraska recommendations:
Manure: The amount of nitrogen released by manure spread
on a field can vary a great deal, depending on the type of manure
and soil conditions (mainly moisture and temperature). If possible,
have a sample analyzed at a laboratory to determine nitrogen content.
Otherwise, assume that beef cattle feedlot manure will supply
4 to 6 pounds of nitrogen per acre per ton of manure applied to
the next crop, and about half that amount the second year.
Previous bean or alfalfa crops: Dry edible beans, alfalfa
and other legumes fix nitrogen – that is, they take nitrogen
from the atmosphere or soil and convert it to a form they can
use. When these plants die, they release nitrogen back into the
soil. A good stand of alfalfa should leave 80 to 120 pounds of
nitrogen per acre to be used by the following crop. A 50-percent
stand should provide from 40 to 60 pounds per acre. Dry edible
beans will leave about 40 pounds of nitrogen per acre for the
following year’s corn crop.
More details:
Contact the Cooperative Extension or USDA Natural Resources Conservation
Service
More information on-line:
[ Estimating
Manure Nutrients from Livestock and Poultry (Extension NebGuide)
]
[ Determining
Crop Available Nutrients from Manure (Extension NebGuide)
]
[
University of Nebraska IANR Extension Publications ]
Other Agricultural Best Management Practices:
[ Fertilizer Rate and Expected Yield
]
[ Nitrogen Credits for Soil and Water
]
Developed for the Dutch Flats Groundwater Quality Project.
The project is partially funded by a Section 319 Clean Water Grant
from the U.S. Environmental Protection Agency through the Nebraska
Department of Environmental Quality.
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