Results are in from the first year of the Southwestern Colorado Research Center’s study on cover crops, and they are less than encouraging for dryland farmers.
In 2015, the research center, which is an extension of Colorado State University, received a grant from the U.S. Department of Agriculture to study the effect of cover crops on soil health for dryland, no-till farmers. At a soil health workshop in Dove Creek last week, researcher Abdel Berrada reported that results are mixed so far. He said the research center hopes to spend a few more years on the study to come to a firm conclusion, but that depends on the uncertain fate of federal grants.
Cover crops are often touted as a way to improve productivity for dryland and no-till farmers. Many scientists believe that planting certain cover crops between cash crop harvests, instead of letting the fields lie fallow, adds nutrients to the soil and helps it retain moisture. Five farmers in Southwest Colorado and Southeast Utah planted cover crops in test fields in 2015 as part of a planned three-year study to see whether that theory would work in the dry, high-altitude conditions of the Four Corners.
Berrada said that after the first year, which included two growing seasons for most farmers, some of the fields with cover crops showed slightly healthier soil, but others showed the reverse. Soil with cover crops generally had more biomass and nitrogen content than fallow soil, as expected, but in some fields, it had less – and the change wasn’t always very significant. It was the same with moisture levels. Berrada noted that conditions varied wildly even among the five test farms in the project, and many different factors can affect soil health – such as rainfall, weeds and whether or not the farmer has grazing animals. One thing early results do seem to show is that cover crops are more effective when they’re planted in the fall, and certain species of crops are more effective than others.
“I’d say probably around August ... get rid of as many weeds as you can, and then plant the cover crops,” he said. “You also want species that grow in winter.”
Each field in the study used a different mix of cover crops. Some of the species planted included spring peas, oats, barley and safflower – plants designed to put nutrients into the soil as well as taking them out. But so far, the farmers in the study aren’t convinced the method will pay off.
Blaine Nebeker, owner of Crowley Farms in Utah, said that when he planted cover crops in fall 2015, they didn’t grow very well, and they cost him twice as much to plant as his cash crop, winter wheat.
“When we went out to look at it, it was like, ‘Did you plant anything here?’” he said. “But we planted organic safflower last year, and I’d say we had a better-than-average safflower crop this year. But as far as yield, I didn’t see a huge difference where the cover crop was versus where it wasn’t.”
Fortunately for the test farmers, the USDA grant allows the research center to reimburse them for the cost of all cover crops. But that grant money will only last until spring of 2018, and Berrada said it’s not certain the project will be funded after that. That’s bad news for his research.
“We need a minimum of five years to really see concrete results,” he said.
The research center is in the process of applying for another grant, but researchers won’t know until spring if the money will come through. For now, another growing season is in progress for the test fields, and Berrada hopes to find some definite trends in cover crop effectiveness by next year.