South Carolina farmers can reduce input costs, rejuvenate farm soil and help conserve the state’s water supply by including cover crops in their crop rotations.
This was the message Clemson experts gave farmers during an Oct. 19 workshop designed to extoll the virtues of the cover cropping.
Following a morning of indoor sessions, workshop participants traveled to Jason Carter’s farm to learn more about how using this technique is helping his bottom line.
Carter has been growing cover crops for seven years. He’s seen an increase in cash crop yields and a decrease in his input costs. Carter grows corn, cotton and soybeans on his farm near Eastover.
“I had read about legumes and how much nitrogen could be gotten from growing these crops,” Carter said. “Then I read more and found out about benefits that could be achieved by growing other cover crops. So I planted cover crops and have seen an actual increase in soil pH even though I have decreased the amount of lime I use.”
Carter uses mixes of clover, radish, rye and vetch for cover crops. He plants his crops using a seed drill and rolls them down with a roller-crimper.
“The rolling process flattens the cover crop, producing a mulch mat,” Carter said. “Seeds for the cash crop are planted no-till into the mulch and the mulch helps increase soil organic matter and fertility.”
Cover crops are planted between periods of cash crop production to help soils stay healthy and productive. In South Carolina, cover crops typically are planted from October to November through April to May.
Organic matter is one of the most important indicators of soil health. High organic matter means healthy soil. Planting cover crops can increase soil organic matter in fields where cash crops are grown. Bhupinder Farmaha, a soil nutrient management specialist housed at Clemson’s Edisto Research and Education Center, said farmers can plant rye, clovers, vetches, peas and radishes as cover crops, either as single species or multi-species to get multiple benefits. Determining which cover crop or cover crop mixture to grow depends on a farmer’s goals.
“Cover crops can be planted to improve soil health as well as provide insect control, weed control and conserve moisture in the soil,” Farmaha said. “Before a cover crop is planted, farmers must decide what they want to achieve.”
Planting a mixture of multiple cover crops is more beneficial than single species but can substantially increase the cover crop seed costs and on chemicals to terminate them.
In addition to setting goals, farmers should conduct soil tests on their fields prior to planting cover crops. Samples from cultivated areas should be taken from the top 6 to 8 inches. Samples from pasture or turf should be taken from a depth of 2 to 4 inches. Each soil sample should be taken from approximately the same depth. Around 12 soil cores should be pulled randomly from each homogenous zone of the field to make one composite sample to send to the soil testing lab for analysis. The advantage of taking composite soil samples by homogenous zone is that this is helpful when making fertilizer decisions.
Mulch produced by roller-crimping cover crops also can help improve soil structure, promote water infiltration and limit pest and disease outbreaks. Cover crops also can be used in weed suppression. Michael Marshall, Clemson Extension weed specialist at the Edisto REC, said growing cover crops can help slow herbicide resistance in some weeds.
Just as with any crop, it takes time to grow cover crops. Rachel Vann, North Carolina State University Extension soybean specialist, said farmers can save time by including cover crops in their crop rotation plans.
“Plant cover crops so that as soon as these crops are terminated, the cash crops can be planted,” Vann said. “By doing this, you can optimize nitrogen release from the cover crop to benefit the cash crop.”
To give growers more to choose from, there may soon be another cover crop to add to the current list of rye, clovers, vetches, peas, radishes and sorghum. This cover crop is grain peas. Clemson researcher Julie Carl Ureta said these peas can be planted in January. Grain peas produce a “tremendous amount” of biomass before being terminated in April, he said.
For more information on collecting soil samples, visit https://tinyurl.com/ClemsonSoilSamples. Soil samples can be dropped off at any Clemson Cooperative Extension Service county office or mailed directly to the Clemson Agricultural Service Laboratory. To order soil sample mailers or for more information, visit https://tinyurl.com/ClemsonAgLab.