Cover Crops are an Option Worth Considering

The following article was put together by my collegue in Shelby County and wanted to share it with you here. Rogers and others in western central Ohio put together a similar report as we share.

Thinking Outside the Box on Cover Crops
By Roger Bender, OSU Extension, Shelby County, Agriculture & Natural Resources

Within the past week, we have had four inquiries about the seeding of cover crops after wheat harvest. Traditionally, many farmers have underseeded wheat or oats with red or sweet clover. With denser crop stands often choking out sometimes costly legume frost seedings, many crop producers gave up on the traditional approach. If that is your case, now is the time to prepare for planting cover crops after wheat or oats harvest this summer. Your local seed dealer may not stock brassica or pea seeds and need to make a special order. Control of summer annual weeds and volunteer wheat could be needed before planting these cover crops.

Cover crops offer many benefits to producers that increase farm profitability and environmental sustainability. Legume (peas and clovers) cover crops are typically used to produce homegrown nitrogen. Grass cover crops help increase soil organic matter, recycle excess nutrients, and reduce soil compaction. Brassica crops are grown to loosen the soil, recycle nutrients, and suppress weeds. Some other cover crops can suppress insects, disease, weeds, or attract beneficial insects. Therefore, cover crops should be considered an integral part of any farming system that wants to efficiently utilize nutrients, improve soil quality, and increase farm profitability, according to Alex Sundermeier, Ohio State University Extension Ag Agent in Woody County. Refer to this factsheet for more about cover crops: http://ohioline.osu.edu/sag-fact/pdf/0009.pdf.

Decisions on which cover crop to plant need to consider the following: Brassica Oilseed radish (see photo from fall 08 plots in Defiance County) has the ability to recycle soil nutrients, suppress weeds and pathogens, break up compaction, reduce soil erosion, and produce large amounts of biomass. Freezing temperatures of 20 to 25 degrees will kill oilseed radish, which allows for successful no-till spring planting of subsequent crops. As a fast growing, cool season cover crop, oilseed radish is best utilized when planted after small grain, early soybean or corn silage harvest. Excess nutrients in manure amended soil are rapidly absorbed by this cover crop, thus preventing leaching or runoff of nutrients into water systems. Without an abundant source of nitrogen, oilseed radish growth will be limited, therefore its use is recommended after a manure application. Refer to this factsheet for more information: http://ohioline.osu.edu/sag-fact/pdf/Oilseed_Radish.pdf.

Homegrown Nitrogen
The availability and amount of the nitrogen produced can vary widely depending on summer planted legume growth and nutrient content. Soybeans can be used as an economical cover crop but might contribute to a soybean cyst nematode problem. Cowpea is better adapted to hot, dry weather and will grow rapidly until a killing frost in the fall. Austrian Winter Pea is a legume that may or may not survive the winter when summer planted. If winter pea is planted in mid-September, fall growth will be limited but winter survival is improved, and spring growth will contribute nitrogen. Summer planted clovers usually do not establish well in hot, dry weather.