By Andi Anderson
A recent study from the University of Illinois highlights how rotating corn after soybeans can improve crop performance, environmental impact, and profitability.
Researchers found that this rotation boosts corn yields by about 6.4% compared to planting corn every year. This benefit is most noticeable at normal nitrogen fertilizer levels.
The study used advanced agroecosystem modeling and over 10 years of data. Scientists explained that soybean residue breaks down quickly, which warms the soil in spring. This helps microbes release more nitrogen from organic matter, acting like a natural fertilizer for the next corn crop.
However, when farmers use higher fertilizer rates, this benefit becomes less effective. At high nitrogen levels, the difference between corn after soy and continuous corn becomes small.
From an environmental perspective, rotating crops lowers nitrous oxide and ammonia emissions. But the fast breakdown of soybean residue reduces the soil’s organic carbon. Nitrogen leaching also changes. It’s lower during soybean years but rises during corn years as residue breaks down.
Economically, the rotation brings higher returns—up to $458 more per acre—when using lower fertilizer rates and under typical market prices. Still, if corn prices are high and nitrogen use is heavy, continuous corn may become more profitable.
The study advises farmers to consider fertilizer use, market prices, and long-term soil health when choosing between continuous corn and rotation. “The more nitrogen you add, the less yield benefit you get from rotation,” said researcher Ziyi Li.
This research gives a clearer picture of how rotation affects yield, soil, and economy. While crop rotation has been recommended for decades, this study gives fresh insights into its advantages and trade-offs in today’s farming conditions.
Photo Credit: getty-images-elhenyo
Categories: Illinois, Sustainable Agriculture