WEST LAFAYETTE, Ind. - Today's hybrid corn varieties more efficiently use nitrogen to create more grain, according to 72 years of public-sector research data reviewed by Purdue University researchers.
Tony Vyn, a professor of agronomy, and doctoral student Ignacio Ciampitti looked at nitrogen use studies for corn from two periods -- 1940-1990 and 1991-2011. They wanted to see whether increased yields were due to better nitrogen efficiency or whether new plants were simply given additional nitrogen to produce more grain.
"Corn production often faces the criticism from society that yields are only going up because of an increased dependency on nitrogen," said Vyn, whose findings were published in the early online version of the journal Field Crops Research. "Although modern hybrids take up more total nitrogen per acre during the growing season than they did before, the amount of grain produced per pound of nitrogen accumulated in corn plants is substantially greater than it was for corn hybrids of earlier decades. So, in that sense, the efficiency of nitrogen utilization has gradually improved."
Vyn and Ciampitti's analysis covered about 100 worldwide studies. Of those, 870 data points were taken from the earlier period through 1990, and 2,074 points were taken from studies after 1990, when transgenic hybrids started hitting the market. All studies involved analyses of total nitrogen uptake and grain yield by corn plants at maturity, usually in response to multiple nitrogen application rates.
Grain yields in these research studies averaged about 143 bushels of corn per acre over the last 21 years compared with an average of 115 bushels in the previous 50 years. Those studies showed that in the earlier period, one pound of nitrogen applied to a field produced about 49 kilograms of grain. In the more recent period, the same amount of nitrogen produced about 56 kilograms of grain.
About 90 percent of the corn dat
|Contact: Brian Wallheimer|