The nitrogen availability calculator predicts the pounds per acre of plant available nitrogen released with time from soil organic matter and winter cover crops.
In order to calculate the available nitrogen released from the cover crops, the user needs to provide the following information in the
Cover Crop Nitrogen Availability Calculator Submission Form:
- the farm location (for weather information),
- an estimate of the pounds of dry matter of standing cover crop,
- a representative sample of the cover crop to the laboratory,
- the date the cover crop is killed,
- whether the cover crop will be left on the surface or incorporated,
- the planting date for the following cash crop, and
- whether the field sampled is managed conventionally or with conservation tillage/organic practices.
At the laboratory, the cover crop sample will be scanned with a Near Infrared Reflectance Spectrophotometer to provide the following information needed for the calculator: the % nitrogen, % lignin, % cellulose, and % non-structural carbohydrates.
The amount of nitrogen released by the cover crop (nitrogen credit) or the amount tied up by the cover crop (nitrogen debit) as it decomposes will be provided by the calculator.
The calculator will also provide the rate of nitrogen release from the cover crop residues every two weeks.
The nitrogen credits or debits can be used to adjust fertilizer nitrogen recommendations to meet the nitrogen needs of the next crop.
To select the climate data with which to run the model, select the weather station nearest to your field.