This story first appeared in the May-June 2015 issue of Soybean Business, the magazine of the Minnesota Soybean Growers Association. This article comes from the Minnesota Soybean Research & Promotion Council, which has invested soybean checkoff money into the development and research of cover crops in Minnesota. Click here to read more articles from Soybean Business.
With environmental concerns, including soil conservation and health on the rise, the use of cover crops has been catching the attention of researchers and farmers in Minnesota. Nutrient loss, soil erosion, weed and pest control have been ongoing concerns for crop farmers.
Even though cover crops are not a cure-all for these issues, their implementation can be seen as a tool to move in the right direction toward long-term benefits.
“As farmers and producers, we need to be proactive and better conservationists,” says Dean Thomas, Soil Health Tech, Area 7 for the Fillmore Soil and Water Conservation District. “The use of cover crops pulls up nutrients for the next rotating crop.”
Research done by the Midwest Cover Crops Council has shown that cover cropping is extremely beneficial to the soil nutrients. Cover crops improve the soil quality by increasing porosity (reducing compaction), soil organic matter, water holding capacity, beneficial microbes, micronutrients, macronutrients, as well as retaining nutrients that otherwise would have been lost, adding nitrogen through fixation, combating weeds and breaking disease cycles. Cover crops are also beneficial to the environment, increasing soil infiltration, which leads to less flooding, leaching and runoff.
“Building soil health can eventually increase bushels per acre and decrease problems with disease,” Thomas says. “These crops also help avoid the leaching of nitrates after harvest, which could potentially contaminate nearby water supplies.”
Determining what to plant, when to plant and where to plant is no easy task. Liz Stahl, Extension Educator for the University of Minnesota, says that research is being done on various cover crop planting dates and how the practice can fit into the two-crop rotation of corn and soybeans that is common in Minnesota.
“We are hosting a Cover Crop Learning Tour on Sept. 15 for farmers to come and learn about different species based on benefits, planting dates, to see demonstrations and answer questions at the on farm research facility in Lakefield,” Stahl says. Stahl also notes that farmers who are cover cropping will be available to talk about their experiences and benefits they have seen.
“It’s a learning game,” Thomas says. “The success of cover crops comes down to good management skills. If treated the same as other crops on your farm, the benefits are apparent.”
Iowa State study
Iowa State Extension released the results of a three-year cover crop study, which looked at the use of no-tillage and cover crops. The use of rye cover crop overseeded into no-tillage soybeans reduced interrill tillage erosion by 54 percent and rill erosion by 90 percent compared to no-tillage without cover crops. The field studies also indicated that rye cover crops reduced nitrate loss by 96 percent while oat cover crops reduced losses by 75 percent. Lastly, the study showed that the usage reduced the number of weeds and provided