Fertilizer

The yellow leaves on corn plants means one thing: Nitrogen fertilizer applied last fall or early this spring is gone. It washed deep into the soil, beyond reach of the young roots. That means most fields will need additional nitrogen to reach full yield potential, says Peter Scharf, University of Missouri Extension soil scientist....More

Extra nitrogen left in the soil after drought reduced corn yields last year has likely been lost with excess soil moisture in the winter and spring, says Jim Camberato, a Purdue Extension agronomist. Most leftover N was in the form of nitrate, which is easily lost with soil moisture and to the air....More

Nitrogen loss is difficult to predict because it depends in many factors such as time of N application, type of N source, soil type and temperature and the amount of precipitation received. While it is difficult to know how much N is lost without a direct analysis of soil N, you can determine what to do about N applications this growing season....More

Modern hybrids absorb more than half of their final N content after flowering. In fact, they absorb 27% more total N from the soil after flowering than hybrids grown between 1950 and 1990, says a newly released Purdue study. Today’s hybrids absorb more grain-N during grain fill, as opposed to N being remobilized from plant leaves and stems. The higher amount and duration of N uptake contributed to better grain yields, even as actual grain N concentrations decline; hybrids are much more efficient. But as corn plants increase N use, they increase their uptake of other nutrients....More