Continuous No-Till and Cover Crops – Boosting Soil Organic Matter, Carbon, and Crop Yields
Since 1969, select farm plots at the University of Illinois have been in continuous no-till. In that time, the measure of organic matter has been boosted three-fold – from about 1 percent to 3.2 percent, without use of cover crops. In the same period, rotating between corn and soybean crops, the stored carbon in that soil has risen from 25,200 lbs per acre to 99,300 lbs.
It’s said that agriculture is a significant contributor to the carbon load in the atmosphere (estimated at about 8%) and that conventional tillage is largely to blame. Mike Plumer, a University of Illinois Extension educator who has done extensive no-till research, believes farms are a potential ally in lowering the release of carbon dioxide into the atmosphere. Plumer has also been an avid promoter of cover crops as a companion to no-till.
“Conventional tillage burns carbon and decreases organic matter,” he said. “Cover crops essentially speed the recapture of organic matter and carbon in the soil.” He points to annual ryegrass as an example. “Its network of deep roots sequester carbon over the winter while increasing organic matter, rebuilding soil structure more quickly than by no-till alone.” Cover crops also reduce erosion, store nitrogen, mine deeper minerals and, particularly in the case of annual ryegrass, produce channels for subsequent corn and soybean crops to follow, allowing them access to deeper moisture in dry years.
In a 2 year, replicated study on a southern Illinois farm where corn yields were compared with conventional, no-till and no-till with annual ryegrass, Plumer found that crop productivity increased substantially with annual ryegrass. Moreover, the yield increased as the years in no-till and cover crops increased. Here’s a brief look at the data, collected during 2006 and 2007 seasons.
Type of tillage / Ave. yield in bushels/acre
Conventional - 52.5
Conventional (1st yr), No-till (2nd) - 61.5
No-till - 79.0
No-till w/annual ryegrass cover crop - 121.0
In 2006 and 2007, the weather was exceptionally dry. In 2008, a more normal rainfall year, average yield on the no-till with cover crop land was 169 bu/ac.
Note, the soil at this farm has a layer of fragipan. Annual ryegrass excels at eliminating compaction. Yield differences between conventional and no-till with cover crop would less dramatic in a normal year.
Positive results like these have encouraged farmers throughout the Midwest to adopt no-till and cover crops. Government agencies including the USDA/NRCS (Natural Resources Conservation Service) are incentivizing and advising farmers, helping with conservation plans and practices to sequester carbon.
For more information: www.ryegrasscovercrop.com
Tags: all cover crops, Annual ryegrass, annual ryegrass as a cover crop, carbon sequestration, crop yield, Mike Plumer, No-Till, No-Till corn and soybean, No-Till farming, organic matter, soil compaction, soil-based carbon, sustainable agriculture, University of Illinois
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