Covers Preserve Soil

SEMO Demonstration Shows Value Of Cover Crops

MidAmerica Farmer Grower

   Planning cover crops into your planting decisions can help production efforts, environmental stewardship, moisture and nutrient management and many other issues, according to Dr. Indi Braden from Southeast Missouri State University. Braden spoke at a field day at the David M. Barton Agriculture Research Center recently.
“We are looking at cover crop plots today,” she said. “We have been doing some research, and have been trying to make this an environmental stewardship example for agriculture students and for producers in the area.”
   Much of Braden’s work is teaching focused on educational purpose. Research is done for the scholarship aspect of the university. However, in addition to that, the university makes an effort to communicate and connect to the community, producers and businesses in the area.
   “In our efforts into environmental stewardship which we teach in our classes, we instruct students to take care of their soil, for soil erosion potential and water quality improvements. We explain why it’s good to cover your soil, use plants and their roots to anchor the soil and take up nutrients. It only makes sense then that we demonstrate those ideas with plots here at the Ag Research Center,” Braden explained.

Dr. Indi Braden, professor at the David M. Barton Agriculture Research Center,
Southeast Missouri State University, discussed cover crops and their benefit 
to production efforts.

Photo by John LaRose, Jr.

   The university does research in cover crops with the U.S. Department of Agriculture Natural Resources Conservation Service. Research plots included five plots at the farm; crop species planted were cereal rye, annual ryegrass, hairy vetch, oilseed radish, and crimson clover.
   “Then we also put out plots with perennial ryegrass or barley, so we have several different species,” she said.
   “Benefits of a cover crop are that you not only are holding onto the soil with the root system of the cover crop, that root system from the cover crop is pulling in water also,” Braden continued. “As it’s pulling in that water it’s keeping that water in the area. In addition to mining the water, it’s also mining nutrients out of the soil. The plant is taking up nutrients so they will be available later, and the decomposing plants will release them slowly for future grain crops. This slow-release system allows nutrients to be held in cover crops instead of potentially losing the nutrients into water systems.”
   This builds up organic matter which helps with the water holding capacity of the soil. The root systems help in opening up air spaces not only for earthworms but also for plant growth for next year’s crop. It promotes the build-up of organic matter in the soil. All of that is beneficial. It also preserves soil sediment, so if there is a rain event, runoff is slowed before it actually goes into streams and waterways. That is a big effort that goes a long way in preserving environmental stewardship.
   “In addition to the nutrient conservation, some species are very beneficial in weed control,” Braden continued. “Species like cereal rye have shown some signs of allelopathy. Allelopathy means that it provides natural weed control, so cereal rye releases a substance that aids in its own survival. This process could help with weed control in cover crop fields.”
   Wildlife habitat has improved because of species like the hairy vetch; lovely flowers are blooming, providing nectar for the pollinators that are coming into the area. These are beneficial species.
   “I can hear and see a bird behind us that’s chirping, so wildlife species are drawn into the area. We have biodiversity that has been increased and improved,” she said.
   There also is a reduced need for certain species on fungicide and insecticide controls; some cover crops are very important in reducing those costs and inputs.
   “One of the things we have learned in our five plots here is that oilseed radish can be mixed into a cereal rye or hairy vetch plot,” Braden said. “This plot directly behind me is a hairy vetch plot, it had some oilseed radish and had perennial ryegrass put into it.
   “We’re actually standing near one of our controls, or checks, where we didn’t plant a cover crop. We’re learning, just as producers do, that you have to plan ahead for the benefits you want from a cover crop.
   “If I’m sowing a cover crop and I’m following corn, I have to consider how much atrazine was used on the corn. It’s not a good idea to put cover crops after applications of atrazine during the season, for example. So certain plant species are not going to follow corn very well.”
   Another thing to consider is timing. Planning  a cover crop behind soybeans, since soybeans are harvested later, means you have to consider whether your cover crop will have time to grow.
   “I’m probably not going to be able to put out something like oilseed radish if I’m following a late October or early November harvest of soybeans because the oilseed radish needs some time to establish before it gets cold,” Braden added.
   Farmers have to consider what they expect from a  cover crop and what difference it will make in yield.
   “There are some differences in yield from cover crop plots. When do I expect that? One of the things I do know about cover crops is the results are not going to be the very next year. I want to give it a little time. These plants will take some time to decompose in the soil and the slow decomposition is going to take time. It may be two, three years down the road before you see that result. So I have to plan ahead for what my final goals are for my plot,” she said.
   Weather always has to be considered. Sometimes weather doesn’t cooperate. In 2012 Braden had a plot planted after soybeans. Before the cover crops grew, cold temperatures set in, and it was a really cold winter.
   “We had a really wet spring that next year, so our cover crops really didn’t do well,” she explained. “We had to prepare for planting before cover crops matured. My plots for demonstration purposes didn’t even look like anything had been planted until about mid-April. In mid-April, the cover crop demonstration plots were thriving. By then, most producers are preparing their soil for corn and so forth. You couldn’t even see there was a cover crop in the fields.”
   Another option is to use a cover crop at the same time your crop is growing. A shade tolerant cover crop similar to a legume, something like a clover would be a lower growing shade tolerant species that you could put under corn. The corn is growing over the top of your legume, which is fixing nitrogen from the soil. That is happening while your crop is actually growing and in place. That cover crop doesn’t need to be removed.
   “We are thrilled that we are able to make an effort into environmental stewardship at this farm,” she concluded. “We want to demonstrate to our students what we teach in the classroom. We also do research to help producers in the area know financial economic inputs to allow them to calculate their return on investment. Seed doesn’t cost a whole lot but you do have to plan your decisions, keeping your intended outcome from cover crops in mind.” ∆
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower
MidAmerica Farm Publications, Inc
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