What is in this article?:
- In-season nitrogen tests can save money for corn growers
- Leaching losses
• Growing seasons vary from year to year. PSNTs provide producers the opportunity to measure the levels of nitrogen available in the soil that can be used to meet the nitrogen requirements for a corn crop.
Due to the dramatic rise in nitrogen prices over the past several years, producers are wondering how they can get the most bang for their buck.
Crop budgets from Virginia Tech show that nitrogen accounts for nearly 57 percent ($102) of total fertilizer input costs ($177) to produce 150 bushels of corn per acre.
Virginia Tech agronomists have stated that 146 pounds of nitrogen are needed to grow 150 bushels of corn per acre.
The nitrogen requirement for corn can be met in several ways:
• The decay of organic matter by soil organisms provides available nitrogen.
• Legumes (e.g. alfalfa, clover, soybeans) fix nitrogen from the air that can be used to meet the nitrogen requirements.
• Many Virginia producers apply cow and swine manure, poultry litter and biosolids (municipal wastewater treatment sewage sludge) and grow cover crops to help meet the corn’s nitrogen requirements.
The nitrogen in organic form becomes available to help meet the nitrogen requirement for the crop. When there is little available nitrogen from legumes, manure and biosolids, the requirements for the crop can be supplied with commercial fertilizer (e.g. urea, ammonium sulfate, liquid N).
Many producers split-apply fertilizer at planting and later in the growing season when nitrogen requirements are the greatest and yields estimates are more certain.
Corn requires only small amounts of nitrogen during the first month of growth because the plants are small and the root systems are not well developed.