Farm states urged to promote more cover crop usage

Widespread adoption of cover crops would counter many of the ill effects of climate change while improving soil health, protecting soil from erosion and reducing nutrient pollution, according to a study released Thursday by the Natural Resources Defense Council.

'Extreme weather conditions such as drought and flooding are already having major impacts on farms, and they are only expected to become more common and more severe in coming years,” said Ben Chou, report co-author and NRDC water policy analyst specializing in climate science.

During the past five years, farmers in the top 10 agricultural states have lost more than $25 billion worth of crops due to drought, heat, hot wind, extreme rainfall, flooding and other climate-related impacts that are expected to worsen, according to the report titled 'Climate-Ready Soil.”

In Iowa alone, insured weather-related crop losses came to nearly $4.5 billion from 2010 to 2014, according to the study.

Cover crops - typically small grains or legumes grown between cash crop seasons - keep a living cover on the soil, increasing its resilience to adverse weather.

Planting cover crops on half the corn and soybean acres in Iowa and nine other leading agricultural states could sequester more than 19 million metric tons of carbon each year - the equivalent of taking more than 4 million cars off the road, according to the report titled 'Climate-Ready Soil.”

The study determined that using cover crops and other soil stewardship practices to increase soil organic matter by 1 percent on half the corn and soybean acres in the top 10 agriculture states could help the soil hold an additional trillion gallons of water, enough to meet the annual needs of nearly 33 million people.

Iowa, which ranks second among the 10 leading agricultural states based on the market value of its products, has by far the greatest potential for capturing carbon pollution and storing water, according to the study.

With cover crops planted on 50 percent of its corn and soybean fields, Iowa could capture 4.3 million metric tons of carbon and store 234 billion gallons of water. The corresponding figures for Illinois, the state with the second-greatest potential, are 4 million metric tons and 214 billion gallons.

Of course, Iowa and the other leading agricultural states have a long way to go reach 50 percent use of cover crops.

Citing 2012 statistics, the study said about 380,000 acres of Iowa cropland employed cover crops.

Nathan Katzer, a spokesman for the Iowa Department of Agriculture and Land Stewardship, said Iowa has more than 225,000 acres in obligations for cover crops through state programs and about 100,000 acres through the U.S. Natural Resources Conservation Service.

The cover crop acreage unsupported by state or federal programs is unknown, but most estimates put Iowa's total cover crop acreage at 500,000, which would constitute about 2.1 percent of the state's 23 million row crop acres.