Management Practice to Reduce Global Warming Potential and Increase Soil Quality and Malt Barley Yield.

Intensive management practices in the last several decades have increased crop yields but also reduced soil and environmental quality by increasing soil erosion, potential for N leaching, and greenhouse gas emissions. Improved management practices are needed to simultaneously increase soil quality, mitigate greenhouse gas emissions, and sustain crop yields and quality. We evaluated the effects of irrigation, tillage, cropping system, and N fertilization on soil C and N, global warming potential (GWP), greenhouse gas intensity (GHGI), and malt barley yield and quality from 2005 to 2011 in western North Dakota. Treatments were two irrigation practices (irrigated vs. non-irrigated) as the main plot and five cropping systems (conventional till malt with N fertilizer [CTBN], conventional till malt barley without N fertilizer [CTBO], no-till malt barley-pea with N fertilizer [NTB-P], no-till malt barley with N fertilizer [NTBN], and no-till malt barley without N fertilizer [NTBO]). Soil C sequestration rate at 0-10 cm and malt barley yield were higher but GWP and GHGI were lower in NTB-P than other cropping systems in both irrigated and non-irrigated practices. The amount of N fertilizer applied and soil residual inorganic N content at 0-85 cm were also lower in NTBP than the traditional system (CTBN). Estimated N balance was higher in irrigated practice but lower in the non-irrigated practice in NTB-P than other cropping systems. Malt barley grain protein concentration was similar between NTB-P and CTBN in both irrigated and non-irrigated practices, but plump kernel was lower in NTB-P than CTBN in the non-irrigated practice. Because of higher C sequestration rate and grain yield and lower GWP, GHGI, inorganic N, and N fertilizer requirement, no-till malt barley with adequate amount of N fertilizer may be recommended to improve soil quality, reduce the N fertilization rate and the potential for N leaching, mitigate greenhouse gas emissions, and sustain crop yield and quality in the irrigated and non-irrigated cropping systems in the northern Great Plains.