If you're pulling nitrate samples in corn where N was put on in banded applications, using a board with holes pre-drilled in it can speed up the sampling process. The board allows you to pull cores across the row evenly spaced, with one hitting the side-dress band, as shown.

Photo by Crop-Tech Consulting

If you’re pulling nitrate samples in corn where N was put on in banded applications, using a board with holes pre-drilled in it can speed up the sampling process. The board allows you to pull cores across the row evenly spaced, with one hitting the side-dress band, as shown.

If you question whether sufficient nitrogen is available to your customers’ corn crops, perhaps as a result of too much rainfall this spring, now’s the time to figure that out, says Missy Bauer, Farm Journal Associate Field Agronomist. The good news, she adds, is that if crops do need N, you still have time to make rescue treatments.

“The first step you need to take is to review the type and amount of N that’s been applied to the crop so far and the application timing,” Bauer says. “Then, think back to what kind of weather was underway after the application was made, particularly any rainfall, and also consider what the temperature was at the time.”

Soil temperature and the number of days the soil is water-saturated are two key factors in determining the amount of denitrification that’s occurred. The warmer the soil and the longer it’s saturated, the more denitrification losses typically occur. The opposite tends to be true as well.

According to data from the University of Nebraska-Lincoln, if soils are saturated for five days at 55° to 60° F, N losses will be about 10 percent, but at 75° to 80° F for only three days, losses could be 60 percent. If soils remain wet for two or more days, expect some amount of denitrification to have occurred. See Table 1.

Table 1. Potential loss of N via denitrification for soil temperature…