Soil Carbon Sequestration, Nitrogen Cycling and Greenhouse Gas Emissions
Global warming due to increased concentrations of greenhouse gases, such as carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4), in the atmosphere is a major concern. Agricultural practices contribute a significant source of greenhouse gases. Intensive cultivation and high rates of fertilization to increase crop yields in the past few decades have not only reduced soil and water qualities by increasing soil erosion, organic matter mineralization, and N leaching but also increased the emissions of greenhouse gases. To reduce the deleterious effects of global warming, the emission of greenhouse gases from agricultural practices have to be reduced and sequestration of atmospheric C and N in the soil have to be increased. Studies have shown that sequestration of atmospheric C in the soil can be increased by using improved soil and crop management practices, such as no-till, diverse crop rotation, increased cropping intensity, cover cropping, and improved N fertilization. Such management practices also help to increase soil and water qualities by increasing soil organic matter, recycling organic N sources and mineralization, microbial activities, and aggregation, and reducing the potential for N leaching.
In collaboration with other ARS Laboratories and Montana State Unviersity, long-term studies are being conducted to measure greenhouse gas emissions, C sequestration, and N cycling and mineralization using different tillage, crop rotations, cover cropping, and N fertilization practices in irrigated and drylands in the Mon-Dak region. The studies will help to determine best management practices that reduce greenhouse gas emissions, increase C sequestration and N cycling, improve soil and water qualities, and sustain crop yields. The studies will also create national data base for modeling greenhouse gas emissions and soil C sequestration for the national GRACENET model being developed by the ARS.
Contributing Scientists: UpendraSainju (Soil Scientist), JayJabro(Soil Scientist)andBartStevens (Agronomist) Latest Research Findings/Reports Carbon Sequestration in Dryland Soils and Plant Residue as Influenced by Tillage and Crop Rotation Irrigation System Effects on Soil Carbon and Nitrogen Under Sugar Beet and Barley in Northern Great Plains
By: U.M. Sainju, A. Lenssen, T. Caesar, and J. Waddell
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Conventional tillage and wheat-fallow systems have resulted in a 30 to 50% loss of original soil organic carbon levels during the last 50 to 100 years in drylands of the Northern Great Plains. While cultivation is done to prepare seedbeds for planting crops and controlling weeds, fallowing is done to increase water storage and production of succeeding crops. Sustainable soil and crop management practices that reduce tillage intensity and increase the amount of crop residue returned to the soil are needed to conserve carbon in plant residue and soil and to sustain crop yields.
By: Upendra M. Sainju, Robert G. Evans, and William M. Iversen
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The semiarid MonDak region at the confluence of Yellowstone and Missouri rivers in eastern Montana and western North Dakota has an abundant supply of high quality water that can be used for irrigation to expand crop production. Because of increased competition of water use among municipalities, industries, and farm producers and decreased soil and water qualities due to increased erosion and chemical contamination, improved soil and water management practices are needed to use water efficiently, improve environmental quality, and sustain irrigated crop production.
Latest Research Findings/Reports
Carbon Sequestration in Dryland Soils and Plant Residue as Influenced by Tillage and Crop Rotation
Irrigation System Effects on Soil Carbon and Nitrogen Under Sugar Beet and Barley in Northern Great Plains