Cover crops are an ancient way to help farmers improve their soil, increase their harvests and, these days, save money on chemicals.
Scientists like Aref Abdul-Baki search for new and better cover crops. Mister Abdul-Baki is with the Agricultural Research Service of the United States Department of Agriculture. He works at the Sustainable Agricultural Systems Laboratory in Beltsville, Maryland.
Mister Abdul-Baki has found some cover crops to resist groundworms that attack the roots of tomatoes.
Sunn hemp, cowpea and velvet bean are good for warm, humid areas. The soil is plowed to plant the cover crops during the summer months. In the fall, the cover crops are turned over in the soil, then the tomatoes are planted.
In states with moderate climates, like Maryland and Virginia, the cover crops are planted in the fall to grow during early spring. Mister Abdul-Baki tells us that good cover crops are hairy vetch and rye.
To avoid soil loss, the seeds are planted without the use of plowing. In May, the cover crops are cut and the remains are left on the surface. The same method can be used for other summer crops like peppers, sweet corn, green beans and some melons.
After the cover crop is cut, the result is a layer of organic material. This will help the new crop grow and suppress unwanted plants. The cover crop provides extra nutrients to the soil. It also keeps the soil from drying out, and helps prevent the loss of soil.
In hot, dry areas, like in Southern California, cover crops help reduce soil temperatures. They also reduce water loss and erosion. Lana vetch is a good cover crop. It is planted in the fall and breaks down without any assistance. It releases its seeds back into the soil.
Mister Abdul-Baki says farmers who use cover crops no longer need to treat their soil with methyl bromide before they plant tomatoes. Methyl bromide kills many kinds of organisms. But Mister Abdul-Baki notes that the poison also damages the environment and is a health danger. The government restricts the use of methyl bromide. And countries have agreed to a treaty to ban it.
Aref Abdul-Baki says farmers who use cover crops produce as many, or more, tomatoes per hectare as compared to no use of cover crops.
This VOA Special English Agriculture Report was written by Mario Ritter. Our reports are online at voaspecialenglish.com. I'm Gwen Outen.