Even though it appears that we are headed for a record corn crop, some farmers have noticed signs of nitrogen deficiency showing up in their crops. According to some of the Seed Consultant professionals, these growers applied the nitrogen fertilizers by splitting application and side-dressed as late as possible. However, the drenching rains that followed a week after caused nitrogen to leach down and, later in the season, fields showed up with N-deficiency symptoms. It is too late for this year’s crop but what can you do for the growing crop to compensate for N loss due to too much water and what may be done to reduce nitrogen leaching for future?
Consider the following approaches to nitrogen management:
• If it happens again, to rescue a growing crop in the field, you might consider reapplying up to half your N fertilizer if it rained three to six inches over a day or two, or if you have field ponding lasting three days or more.
• Nitrate form of nitrogen is highly mobile and volatile, especially in water- logged soils. Use urea or ammonium form of N when possible.
•Use of nitrogen stabilizers will reduce leaching. Yes, it does add to fertilizer cost but it is cheaper than losing nitrogen you have already applied and getting a poor crop. It is a good insurance.
• Along with fertilizers, use manure to supplement nitrogen needed by your crops. It will also improve organic matter content of your soils.
• Use crop rotation to add nitrogen and organic matter to your soils. Crop rotations also reduce insects and diseases and improve yields.
• Use cover crops to add nitrogen as well as organic matter. Studies have shown that soils with 1% to 2% organic matter can release 30 to 60 pounds of nitrogen per acre thru microbial activity.