Dryland Soil Carbon and Nitrogen Stocks in Response to Cropping System and Nitrogen Fertilization

Authors: Sainju, Upendra

Submitted to: Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2024
Publication Date: 4/2/2024
Citation: Sainju, U.M. 2024. Dryland Soil Carbon and Nitrogen Stocks in Response to Cropping System and Nitrogen Fertilization. Environments. 11:70-85. https://doi.org/10.3390/environments11040070.
DOI: https://doi.org/10.3390/environments11040070

Interpretive Summary: Improved management strategies are needed to enhance soil carbon and nitrogen sequestration and reduce greenhouse gas emissions from agriculture. ARS scientist from Sidney, MT evaluated the effect of cropping systems and nitrogen fertilization rates on soil carbon and nitrogen stocks in dryland cropping systems for seven years in the US northern Great Plains. He reported that no-till spring wheat-pea rotation with reduced nitrogen fertilization rate enhanced soil carbon and nitrogen sequestrations compared to conventional till or no-till spring wheat-fallow and continuous spring wheat with recommended nitrogen fertilization rate. Producers, industrialists, extension personnel, students,scientists, policy-makers can use the information for increasing carbon and nitrogen sequestrations, reduce greenhouse gas emissions, and obtain carbon credits in dryland cropping systems in the semiarid regions of the US northern Great Plains.

Technical Abstract: Innovative management practices are needed to mitigate greenhouse gas (GHG) emissions from the agricultural sector by enhancing soil carbon (C) and nitrogen (N) stocks which serve as major reservoirs of C and N in the terrestrial ecosystem. The effect of cropping systems and N fertilization rates were examined on soil organic C (SOC) and soil total N (STN) stocks at the 0-120 cm depth from 2012 to 2018 in a dryland farm in the US northern Great Plains. Cropping systems were no-till continuous spring wheat (Triticum aestivum L.) (NTCW), no-till spring wheat-pea (Pisum sativum L.) (NTWP), no-till spring wheat-fallow (NTWF), and conventional till spring wheat-fallow (CTWF) and N fertilization rates were 0, 50, 100, and 150 kg N ha-1 applied to spring wheat. The SOC and STN were greater for NTWP than other cropping systems at most N fertilization rates and depth layers. Increasing N fertilization rate increased SOC at 0-30 cm for NTWP and NTCW, but had a variable effect on STN for various cropping systems and soil depths. The NTWP with 50-100 kg N ha-1 can enhance SOC and STN at 0-30 cm compared to other cropping systems and N fertilization rates in the US northern Great Plains.