Tillage does not impact soil greenhouse gas emissions in a Central Texas rainfed maize–cotton system
Dorothy Menefee, Hal Collins, Doug SmithAbstract
Agricultural soils are a significant source of greenhouse gas (GHG) emissions, primarily as N 2 O. Monitoring how management practices impact soil gas fluxes (CO 2 , CH 4 , and N 2 O) is useful for making sure conservation practices (e.g., no‐till) are sustainable with regards to all potential environmental impacts. Static chambers were used to collect soil gases from a rainfed maize–maize–cotton rotation ( Zea mays and Gossypium hirsutum ) with three tillage treatments (conventional till, strip‐till, and no‐till) in Temple, TX, at a USDA Long‐Term Agroecosystem Research network site. Soil available nitrogen (ammonia and nitrate), soil moisture, and soil temperature were also collected alongside gas measurements. Measurements were conducted over three growing seasons to capture the full rotation cycle in each plot. CH 4 fluxes were small and largely net uptake with some influence of soil temperature and crop selection. Soil CO 2 fluxes were primarily influenced by soil moisture ( p < 0.0001) and temperature ( p < 0.0001). Soil N 2 O emissions were primarily correlated with soil moisture ( p < 0.0001), temperature ( p < 0.0001), and nitrate availability ( p < 0.001). Tillage practices had no significant effect on soil GHG fluxes, including N 2 O, in this agricultural system.