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Robbie-Bevis_DSC_8665_BT_Edits.jpg Logan Hawkes
Robbie Bevis talks to farmers attending an Arkansas Soil Health Alliance and USDA Natural Resources Conservation Service field day in Cotton Plant, Ark.

Cover Crops: Top 10 reasons to plant in the fall

“This is not just a research project or a simple farming practice to me. It’s about a passion to grow quality cash crops and lowering my input costs,” Robertson said.

Regenerative farming is a term that literally has its roots dating far into farming’s history. The principles it promotes have been around almost as long as farmers have been tending the soil.

Cover crops, perhaps the backbone of “regenerative farming,” were used extensively by the Greeks and Romans and by Native Americans who developed a system they referred to as the ‘Three Sisters,’ where corn, beans and squash were grown together to maintain soil health.

The ancient Maya of Central America were said to have rotated crop varieties between raised earthen platforms, including plants that fortified soils, while the ancient Chinese discovered they could repeatedly plant rice on rice on rice by maintaining nutrients in their soils.

When high production agriculture arrived in the 20th century, “more yield” became more important than the old ways of farming. Planting earlier, faster and extending the growing season through biological and chemical technology enabled a shrinking number of farmers to grow more food and fiber.

Before long some farmers began to realize high production farming may not be earth-friendly agriculture and the price it demands from the soil is not sustainable. In the last five to 10 years, research has brought many in the industry full circle in their way of thinking.

Science and experimentation are showing soil health is the key to growing abundant and healthy cash crops, and in the long run, growing them more profitably as input costs are reduced.

Dr. Bill Robertson is cotton agronomist for the University of Arkansas System Division of Agriculture Research and Extension Service. He is also a farmer and runs ruminants and cattle across his farm.

Not only has Robertson been researching cover crops for several years, he has been employing them in his farming operation, making him a good resource and to talk with concerning the top 10 reasons Delta farmers should consider planting them.

“This is not just a research project or a simple farming practice to me. It’s about a passion to grow quality cash crops and lowering my input costs,” Robertson said.

Here are Robertson’s Top 10 reasons for planting cover crops:

  1. Weed suppression. “There are a number of things that cover crops will do, including inhibiting germination of other plants. With less germination we are getting less emergence of unwanted weeds.”
  2. Water infiltration/soil compaction. “We now have data that shows we have increased water infiltration four or five times by using cover crops compared to infiltration rates without cover. We also see cover crops as a way to prevent soil compaction because of the complex root systems they can develop.”
  3. Lowers erosion/increases water quality and fertility. “We’re seeing that cover crops help decrease erosion because of better root systems throughout winter rains. Also, using cover crops helps us improve edge of field water quality because the soil is staying in the field, and so is our soil fertility.”
  4. Improves soil organic matter. “Having living roots in the ground goes a long way in improving soil organic matter.”
  5. Reduce energy use and greenhouse gas emissions. “The supply chain (like big box stores) measures their success at being greener and being more sustainable by reducing greenhouse gas emissions. In agriculture, cover crops do that. We see a good impact by reducing tillage and using cover crops. It’s our green solution.”
  6. Improve nutrient efficiency. “What we’re doing here in the Mid-South is a little different than in some other areas. Most of our plants do their growing in the top six inches of the soil. That’s where most of our roots are. With cover crops, our plants can extract nutrients from deeper within the soil if they need them. Eliminating limitations associated with shallow root systems and making it possible for roots to reach deeper for nutrients is a major advantage. In this way, for example, we eliminate the need for adding potash.”
  7. Enhances biodiversity. “For agriculture to be successful we need to enhance diversity. There are several ways to do that. We can have diversity in crop rotation, and this helps. But selecting a mix of cover crops as well as rotating our cash crops gives us greater diversity, and it goes a long way in feeding our soil microbes and getting the soil more active.”   
  8. Facilitate earlier planting and reduce rutting. “This year we started with very wet soils. The farmers who used cover crops last fall were the first to get tractors into their fields because cover crops enhance internal drainage. Why do we grow cotton on a big bed? Because external drainage is all we have. By adding the internal drainage we get from cover crops, water soaks into the soil better and we can get the water off the field faster. That means we can plant earlier. Plus, the massive root system cover crops develop holds our harvest equipment up better during harvest.”
  9. Improves profitability. “Farmers using cover crops, especially those that have been doing it for a while, become more comfortable on what they can eliminate from the way they have been doing things. One farmer told me what he was doing was not working and he was about to go broke and needed to do something drastic to reduce his costs. He tried going no-till and starting using cover crops. He says it helped him to stay in business. Once a farmer gets into it, they find it’s easier to farm with cover crops, and it saves them money.”
  10. Conserve natural resources. “Everybody wants to leave their farm in better shape than when they got it. We want to leave our kids a farm that is healthy and in good shape. With no-till and cover crops we are saving water, using less chemicals and protecting our environment through stewardship.”

The bottom line:

University of Arkansas Research and Extension recommends the use of cover crops to protect and improve soils. A fall cover crop helps protect against water and wind erosion over the winter season. Broadleaf cover helps protect soil from the impact of rainfall and nutrient runoff. Cover crop root systems also help to stabilize soil, and a cover crop that is rolled or burned down into the soil can aid in the development of soil structure and provide needed nutrients and micronutrients.

Trenton Roberts, University of Arkansas Research and Extension soil fertility specialist, provides an online condensed overview, Understanding Cover Crops, that offers information about the advantages of utilizing cover crops in the Delta states. Some of the more common recommended cover crops for the region include grasses, legumes, and forbs (broadleaf cover).

Multiple species of winter cereals are commonly grown as cover crops in the Delta region to produce biomass, nutrient sequestration and relatively low cost of establishment. They may include wheat, oats, cereal rye, barley, and triticale.

Winter broadleaves might include tillage radish, oilseed radish, Kale, and turnip. Winter legumes may include Austrian winter pea, clovers, and hairy vetch.

The selection of a cover crop depends in part on the benefits the farmer hopes to gain and his choice of cash crop he plants in the spring. Often a mix of cover crops is better than a single cover variety. Extension agents and crop consultants can help in cover selection based upon your soil and the cash crop you will be planting in the spring season.

One man’s journey

Robby Bevis, President of the Arkansas Soil Health Alliance, agrees with the University of Arkansas’ Bill Robertson’s assessment of cover crop use. He should know. As a successful farmer, he adopted cover crop practices several years back and now he swears by them.

“I started using cover crops on about 900 acres of my 3,000-acre farm initially, and that increased over the next two years until almost everything I farm today is done with cover crops,” he said.

COVER-CROP-GRAPHIC-1.jpgBevis calls his method of farming a “have to” system:

“We basically operate a no-till farm and grow corn, soybeans and rice. We till only when we have to. I only want to irrigate when I have to. I only want to use fertilizers when I have to. But basically we no-till and use cover crops extensively, and, since we have developed a sustainable system, that has reduced our input costs; helped us suppress weed development; reduced pest problems; while increasing beneficials. It has maximized our profits.”

In recent years Bevis has been sharing his no-till, cover crop system with other farmers across the region.

“I try to tell farmers that if they would just cut out their tillage, I can put money in their pockets. Most row crop farmers in Arkansas and the Delta spend about $80-$100 an acre on tillage alone, not counting the cost of planting and combining. I tell them I can give them a Cadillac cover including planting for $25-$40 an acre. If they are farming 1,000-acres, that means they are saving about $60,000 a year,” he said.

Bevis has been spending a lot of time staging demonstrations and hosting events on his farm in recent years to show visitors what he discovered.

“We have experienced a lot of bumps and bruises and mistakes along the way, and we share that with other farmers so they don’t have to discover it on their own. They can discover, as we did, that they can improve their soil, their yields and their farm by going to a no-till, cover crop system.”

Bevis recommends a mix of cover crops that will almost always include a cereal, a grass and, generally, vetch. If the cover is going in ahead of corn, he will add winter pea and clover into the mix to get added nitrogen benefit.

He says he likes to rotate soybeans and corn from year to year on his farm to further add diversity to soil health.

“I have soil tested each fall season for the last three years just to monitor my soil nutrients and the need for fertility. Sometimes I will add a little when I have to, but mostly my cover crops and no-till practice controls the balance across my farm.”

He says one of the major benefits to his farming system is the control of weeds. If he has good growth with his cover crop, his weed suppression is ‘phenomenal,’ and the control of pests is so good that he usually can depend entirely on the beneficials that live in his soil.

The Arkansas Soil Health Alliance is a non-profit organization promoting sustainable agriculture with the intent of benefiting growers in the Delta region. Bevis encourages interested farmers to contact him at rbevis77@gmail.com with their questions or for a demonstration or tour of his farm.

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