Author: Jeff Mulhollem | Published on: September 8, 2016
Planting a multi-species mixture of cover crops — rather than a cover crop monoculture — between cash crops, provides increased agroecosystem services, or multifunctionality, according to researchers in Penn State’s College of Agricultural Sciences.
That was the conclusion drawn from a two-year study of 18 cover-crop treatments, ranging in diversity from one to eight plant species. Cover crops were grown at the Penn State Russell E. Larson Agricultural Research Center preceding a corn crop. The researchers measured five benefits provided by cover crops — ecosystem services — in each cover crop system to assess the relationship between species.
Those services included weed suppression and nitrogen retention during the cover-crop season, cover-crop aboveground biomass, inorganic nitrogen supply during the subsequent cash-crop season and subsequent corn yield.
The study was the first field-based test of the relationship between cover-crop species and multifunctionality — the quality of cover crops to simultaneously provide multiple benefits — noted research team member Jason Kaye, professor of soil biogeochemistry. Never before had this relationship been examined and analyzed in a crop rotation.
As continued research yields more precise information about optimal cover-crop seed mixtures and planting rates, Kaye predicted, farmers will deploy this strategy to enhance soil quality, control weed growth, manage critical nutrients such as nitrogen, improve crop yields and reduce nutrient runoff.
“This kind of ecological study identifying a positive relationship between biodiversity and ecosystem services suggests that higher plant diversity will increase services from agroecosystems, and that has immediate implications for management practices and policies for sustainable agriculture, including Chesapeake Bay water quality,” Kaye said. “In a corn production system, simply increasing cover-crop species richness will have a small impact on agroecosystem services, but designing mixtures that maximize functional diversity may lead to agroecosystems with greater multifunctionality.”