|
|
|
Posted 21 May 2007. Crop Management. Plan Ahead to Get the Most from Nitrogen Fertilizer on Corn Michigan State University. www.canr.msu.edu East Lansing, Michigan (May 10, 2007)--With nitrogen (N) fertilizer costs at an all-time high, getting the most out of every ounce can improve farm income and reduce risks to ground and surface water. There are several steps that corn growers can take to maximize their fertilizer use for this growing season.
First, consider splitting N applications. Apply 10 to 40 pounds at planting and sidedress the remainder when corn is 6 to 12 inches tall. Split applications save time and costs at planting, can help reduce N loss from leaching and runoff, and volatilization to the atmosphere. They can also improve a grower’s ability to accurately match N rates with realistic yield goals using the pre-sidedress nitrate test (PSNT). For maximum nitrogen efficiency at planting, apply N in bands 2 inches to the side and 2 inches below the seed. The total amount of N and potash (K20) applied to corn should not exceed 100 pounds per acre. Don’t include potash in the banded fertilizer unless soil testing shows that potassium (K) levels are less than 30 parts per million (ppm). Though there is no need to limit the amount of phosphate (P205) applied in the band, about half of the soil samples analyzed at the Michigan State University (MSU) Soil and Plant Nutrient Laboratory have high phosphorus (P) test levels and do not require P applications. On soils with P levels at more than 30 ppm, N is the most important nutrient and should be applied in the banded fertilizer unless it has been broadcast applied prior to emergence. Broadcast N applications are less efficient for plant use and pose greater risks to water contamination. Applying fertilizer in contact with the seed is generally not recommended, as it can affect germination and reduce yield. In June, farmers can use the pre-sidedress nitrate test (PSNT) to determine the remaining N application needed for the corn crop. At this time the grower can more accurately assess the yield potential -- adjusting the yield goal upward or downward based on plant stand, weed control, weather and market conditions. If the PSNT shows the need for additional N, it can be knifed, dribbled or irrigated into the soil at rates that match the adjusted yield goals and nitrogen credits for each field. For additional information on nitrogen management on corn, see MSU Extension Bulletin E-2904, “Nutrient Recommendations for Field Crops in Michigan”. It is available from any MSU Extension county office or online at www.emdc.msue.msu.edu. Contact: |
