Cover Crops: Improving Soil Quality and Productivity
Annual legume and non-legume cover crops are usually grown after the harvest of main crops to cover soil and reduce erosion. Cover crops can have many benefits in improving soil and environmental qualities. They use residual soil N and can reduce N leaching to the groundwater. Depending on management, they can increase soil organic matter and improve soil physical, chemical, and biological properties. Legume cover crops fix N from the atmosphere, supplying some N to the succeeding crops that reduces the rate and cost of N fertilization. As a result, legume cover crops increase crop yields when compared with non-legume or no cover crops. They may help control many weeds, pests, and diseases, and they can be used for winter grazing. Cover crops also sequester additional atmospheric C and N in the plant biomass and soil and help to reduce global warming. The challenge is to find suitable cover crops and cropping practices that will allow them to fit in and flourish in the short growing season, very cold winters, and low rainfall.
Long-term use of conventional till and wheat-fallow systems in Northern Plains have reduced soil quality by increasing soil erosion and organic matter mineralization and decreasing crop yields. Improved soil and crop management practices are needed to reduce soil erosion, increase soil quality and productivity, conserve soil moisture, and sustain crop yields. Long-term studies are being conducted on the effects of legume and nonlegume cover crops for their N supplying ability for the succeeding crops, moisture conservation, and soil quality and productivity in no-till system in drylands. The N supplying capacity of cover crops will be compared with N fertilization rates on the yields of succeeding malt barley in till and no-till systems. The additional residue provided by cover crops accumulated at the soil surface in no-till system will be used to examine moisture conservation as compared with malt barley-fallow in conventional till system. The overall aim of cover crops is to replace the fallow system in drylands, thereby resulting in reduced rate of N fertilization, increased moisture conservation, improved soil quality and productivity, reduced soil erosion and weed infection, and sustained crop production.
Contributing Scientists: UpendraSainju (Soil Scientist) and JayJabro (Soil Scientist) Latest Research Findings/Reports Tillage, Cover Crops, and Nitrogen Fertilization Effects on Cotton and Sorghum Yields and Nitrogen Uptake Carbon Supply and Storage in Tilled and Non-tilled Soils as Influenced by Cover Crops and Nitrogen Fertilization
By: U.M. Sainju, W.F. Whitehead, & B.P. Singh
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Sustainable management practices, such as conservation tillage and cover cropping, that reduce soil erosion and N leaching and increase soil organic matter, still remain a challenge for cotton and sorghum production in southeastern USA. While no-till or reduced till can reduce soil erosion and increase organic matter compared with conventional till, cover crops can reduce N leaching, improve soil organic matter and N supply, and increase succeeding crop yields compared with no cover crops.
By: U.M. Sainju, B.P. Singh, W.F. Whitehead, & S. Wang
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Cover cropping can provide additional residues that not only reduce soil erosion but also improve soil quality and productivity by increasing soil organic carbon (SOC). Similarly, N fertilization can increase SOC by increasing crop biomass production and amount of residue returned to the soil. The increase in SOC due to these management practices can, however, be different in tilled and non-tilled soils due to differences in mineralization rates of plant residues.
Latest Research Findings/Reports
Tillage, Cover Crops, and Nitrogen Fertilization Effects on Cotton and Sorghum Yields and Nitrogen Uptake
Carbon Supply and Storage in Tilled and Non-tilled Soils as Influenced by Cover Crops and Nitrogen Fertilization