Applying nitrogen to corn
June 12, 2020
“This is a key time to make sure you have enough nitrogen applied for the crop,” said Dave Nanda, Ph.D., SGD director of genetics.
Nitrogen was applied to the Corn Watch ’20 field about a month before planting. The operator applied anhydrous ammonia pre-plant. The field was planted May 13.
“Except for a few wet spots, the stand in most of the Corn Watch ’20 field is good, averaging around 30,000 plants per acre,” Nanda continued. “When you have a good stand, you want to make sure you have enough nitrogen applied so that it can reach its potential.”
Consider the following when applying nitrogen:
For more than a decade, Bob Nielsen and Jim Camberato, Purdue University agronomists and Extension specialists, conducted nitrogen field trials in large plots and on-farm to arrive at recommended nitrogen rates. Economic optimum rates vary from 170 to 210 pounds per acre, depending upon soil types and location. Agronomic maximum rates vary from 210 to 263 pounds per acre to reach top yields. While their data is specific to Indiana, the Iowa State University Nitrogen Rate calculator, available online, includes data from several different states.
Soil will supply some nitrogen, based on amount of organic matter and environmental factors, such as temperature and rainfall.
Sidedressing (providing extra nutrients to crops along the side of crop rows or in circles around individual plants) needs to occur before plants are too tall. However, if weather prevents this, high-clearance rigs are common at dealerships and allow application in taller corn. More people are choosing to apply a portion of total nitrogen with high-clearance rigs and Y-drops at V-10 stage or later. The theory is to get a portion of the nitrogen closer to the time most hybrids use a large chunk of nitrogen. However, testing by Nielsen and Camberato the success of this method is inconsistent.
If nitrogen loss is suspected after early application, test plants. Traditional tissue testing is one method that measures a plant’s nitrogen levels. Although an expensive tool, nitrogen levels can also be checked with a chlorophyll meter. A deep soil test developed by ISU can also check nitrogen content (a regular soil test is ineffective for nitrogen).. However, most consultants report a deep soil test is most effective where manure has been applied or in high-organic matter situations.
The Corn Watch ’20 field is sponsored by Seed Genetics Direct. Reports on the field’s progress are provided all season (#CornWatch20); read the latest Corn Watch ’20 articles here.