Crop Rotation Reduces Gas

Here’s another reason to rotate your corn and soybean crops every year – help prevent global warming. Scientists at the University of Illinois have been studying the effects of crop rotation and tillage on greenhouse gas emissions, such as nitrous oxide. The long-term research was conducted at a research station near Monmouth, Illinois.

Gevan Behnke is a senior research specialist at the University of Illinois. He says the main cause of nitrous oxide is denitrification.

"That’s when the soil is usually waterlogged or damp, and the nitrogen that’s in the soil either from fertilizer or fixed from soybeans doesn’t get completely denitrified into gas, and nitrous oxide is an intermediate in that step," says Behnke. "So, we found that a corn-soybean rotation decreased nitrous oxide emissions by 35%."

 Behnke says farmers usually apply fertilizer in the spring, so not surprisingly, nitrous oxide levels were high at the beginning of the season and lower at the end.

"When you take a gas sample, there’s a chamber, it looks kind of like a PVC pipe put into the ground," he says. "We measured the rate coming off from the soil over time and from that we were able to calculate a rate per-day, and then extrapolate that to the year for accumulative emission, which is kind of like a yield for greenhouse gas emission."

Behnke says the corn-soybean rotation also showed a 20% increase in corn yield.