As cover crop usage continues to rise, Iowa Secretary of Agriculture Bill Northey says it’s important to share success stories and identify best practices. According to Northey, more than 1,600 farmers have invested an aggregate $4.2 million over the past two years to try new practices such as cover crops on their farms to better protect the state’s Iowa Water Quality Initiative.
“We have seen tremendous growth in the number of farmers using cover crops on their farm as they seek to reduce erosion, protect water quality and improve soil health,” he says.
Northey says a list of best practices surrounding cover crop management has been assembled with the help of the Iowa cover crop working group. This group includes representatives from the Iowa Department of Agriculture and Land Stewardship, Practical Farmers of Iowa, Iowa State University, Iowa Learning Farms and USDA Agriculture Research Service.
- Evaluate for winter kill. Determine successful winter kill by searching for brown above-ground plants with no green plant material near the soil surface. Some crops winter kill more commonly than others. Tillage radishes and oats, for example, are more easily winter killed than cereal rye, winter wheat, triticale and barley.
- Know your best termination options. There are three basic termination methods – herbicides, tillage or a combination of the two. Tillage may reduce the effectiveness of the cover crop residue to minimize erosion and suppress weeds and sometimes takes more than one pass. When using herbicides, make sure the plant has enough living (green) surface area for the herbicide to be effective. Experienced farmers recommend spraying during the middle of the day on days when air temperatures are higher than 50°F, Northey says.
- Consider nitrogen needs. Cover crops can sequester nitrogen and release it later in the season as the plant residue breaks down. That means there could be lower nitrogen available at the start of the growing season, especially following cover crops such as cereal rye. For these cover crops, consider starting with 30 to 50 lbs of nitrogen at or near corn planting. (Not additional nitrogen, but within your total fertilizer program.)
- Know crop insurance options. Make sure you are familiar with the USDA Risk Management Agency’s guidelines as described at http://www.rma.usda.gov/help/faq/covercrops2015.html.
- Start planning now for this fall’s cover crop needs. In particular, some herbicides you use this season could have carryover restrictions for some cover crop species.
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