By Randall Reeder, Faculty Emeritus, Ohio State University Extension
You’ve probably seen the commercial for gold that asks, “If I offered you $5,000 in either gold or paper money, which would you take?”
The commercial implies that gold is better, but if I’m going to use the money tomorrow as a down payment on a truck, I’ll take the cash. Otherwise, I’ll have the expense of selling the gold first.
Cover crops may present a similar question for you. If you knew the 2013 growing season would be just as dry as 2012, would you want to have cover crops in your fields today? Your ground may be covered with snow, so you won’t see any difference between a dormant cover crop and bare ground. But dormant cover crops have living roots (the same as winter wheat), and those roots provide sustenance to the biology in the soil, and continue to take up nutrients. Those roots increase infiltration of rainfall. Plus, a cover crop that stands a few inches to two feet tall traps snow more uniformly, which means the moisture is uniform in the soil.
Cover crops and corn yields
Did cover crops hurt corn yield in 2012? You may be surprised (or shocked) to learn that cover crops increased yields. Of course they have to be managed properly (just like a cash crop). David Brandt’s corn (continuous no-till with a variety of cover crops) averaged 140 bushels per acre compared to the Fairfield County average of 85. In a “normal” year Brandt’s yields are about 10% above the county average. Brandt has also found that cover crops also replace about 25% of purchased nutrients, another boost to net profit.
For University of Illinois research, Mike Plumer reported yields of 20 to 100 bushels per acre higher for cover crops in 2012. Naturally cover crops, like any living plants, need water to grow. But the net effect is that they use less water during their growing season than the moisture conserved by a residue cover on soil during the summer. Evaporation from bare soil is high compared to soil covered with residue. And the soil temperature under residue is much lower on a hot, sunny day.
Learning about cover crops
Ohio farmers have many opportunities to learn, first hand, about the best practices for no-till and other conservation tillage systems. The Ohio No-till Conference in December drew 220 people to learn about no-till and cover crops. The Ohio No-Till Field Day in September attracted over 300. The 2-day Conservation Tillage Conference at Ada has averaged 950 attendees over the last three years.