Greenhouse gas emissions in a spring wheat-field pea sequence under different tillage practices in semi-arid Northwest China

Greenhouse gas emissions from agriculture production are predicted to increase as the world's population and demand for food increases. This research assessed the influence of tillage systems on CO2, N2O and CH4 fluxes and soil properties in spring wheat-field pea sequence in a rain-fed semi-arid environment. The tillage practices included; conventional tillage with straw removed (T), no-till with straw removed (NT), no-till with straw retention on the soil surface (NTS) and conventional tillage with straw incorporated (TS). Greenhouse gas emissions were monitored during the 2013, 2014 and 2015 cropping seasons using a carbon dioxide analyzer and static chamber-gas chromatography. Although the results showed that all treatments served as sources of atmospheric CO2 and N2O, and a sink of atmospheric CH4, CO2 and N2O emissions significantly decreased by 21 and 34 % in NTS sites, and CH4 uptake increased by 22 % compared with T fields. Soil organic carbon (0-30 cm) increased by 24, 19 and 7 % in NTS compared to T, NT and TS respectively. In addition, the contribution to increase soil organic carbon was much higher under straw retention treatments. T plots significantly increased global warming potential by 37 and 30 % in N2O and CH4 versus NTS soils. NTS increased straw and grain yield compared with straw removal treatments (NT and T), but that had no effect compared with TS treatment. NTS farming practices demonstrated increases in crop productivity and reduced greenhouse gas under dryland cropping systems.