AMES, Iowa - The most recent annual results from a four-year Iowa State University study on using cover crops between rows of corn reveals that higher yields - by as much as 10 percent - are possible using the soil-saving approach to farming.
The results are the best yet in the ongoing research, according to Ken Moore, Distinguished Professor of agronomy and primary investigator on the project, who plans to carry on the trials for at least one more growing season.
Planting living mulch - or ground cover - between rows of corn is intended to perform several functions - maintain soil moisture, slow soil erosion, and sequester carbon.
There were factors in last year's weather that made the higher yields possible, according to Moore.
"This is really promising," said Moore of the results. "Last summer was hot, and the cover crop systems performed better because living mulch held the water in the soil better. It was the first year those ground covers went completely dormant. They weren't transpiring any water at all and they were serving as a barrier to moisture moving out of the soil, and that's good."
The study began with the 2008 growing season through support from a Sun Grant designed to look at the effect on the soil of removing corn stalks, cobs and leaves - called stover - to use as biomass for producing cellulosic-based ethanol.
After the 2010 planting season, funding for the project was exhausted, but Moore was able to carry on the tests on a limited basis, focusing only on those systems that showed the most promise.
Moore is working with Kendall Lamkey, chair of the Department of Agronomy and Pioneer Distinguished Chair in Maize Breeding, and Jeremy Singer, collaborator and assistant professor at the National Laboratory for Agriculture and the Environment on the study.
Removing the stover to make biofuel, it is feared, will reduce carbon in the soil and also speed erosion.
Moore says that the cover crop system helps solve both problems.
Moore and his group of researchers tested several different agronomic systems and cover crops to find which ones produce the best results.
In 2011, the three cropping systems tested included one that employed normal farming practices, a second system that used bluegrass as a cover crop and strip till practices, and a third that used red fescue as the cover crop and strip tilling.
When the results were tallied, Moore found the control plots averaged 220 bushels per acre, the bluegrass plots netted 230 bu./ac. and the fescue plots yielded 240 bu./ac.