Corn hybrids released in the past quarter-century have an improved ability to take up nitrogen fertilizer after silking, say Purdue agronomists, who reviewed 86 field experiments in the United States, China and other nations. The results could lead to a change in the timing of fertilizer applications, says a Purdue release. Modern hybrids take up about 36 percent of their total nitrogen use after silking, compared to 30 percent for earlier hybrids. The late-season nitrogen uptake suggests farmers might benefit from splitting their nitrogen applications rather than the usual approach of applying it once in the spring.
Nitrogen is a costly fertilizer but essential in building plant protein and raising grain yields. It also is easy to wash out of the soil and contribute to greenhouse gases and nitrate levels in streams. Late-season applications could mean more efficient use of fertilizer and less run-off.
“These fundamental genetic changes could give us the opportunity for more flexibility in timing nitrogen applications,” said agronomy professor Tony Vyn Vyn. “We’re researching this further because there could be gains in nitrogen fertilizer efficiency that could improve corn productivity and benefit the environment.”