Quick fact sheet to support irrigation water nitrogen crediting.
- Nitrogen credits are part of the Right Rate in 4R nutrient management.
- Irrigation water in some parts of Colorado contains significant nitrate-nitrogen
- Nitrate in irrigation water is immediately available for crop uptake
- Nitrate concentrations greater than 10 ppm are most likely to have reduced N fertilizer requirements
- Irrigation water should be sampled for nitrate as part of any nitrogen recommendation in areas of high groundwater nitrate
- Nitrate-N ppm x 0.23 x inches of water applied = N credit (lbs/acre) or an acre-inch of water contains 0.23 lbs of N for each ppm of nitrate-N