Soil respiration and net ecosystem production under different tillage practices in semi-arid Northwest China

In semi-arid areas, increasing CO2 emissions are threatening agricultural sustainability. It is unclear whether different tillage practices without residue returned could help alleviate these issues while increasing crop productivity. This study aimed to quantify soil respiration under conventional tillage (CT); rotary tillage (RT); subsoiling (SS) and no-till (NT), all without residue returned in the Western Loess Plateau. The results showed that SS and NT significantly decreased soil respiration compared to CT, but the effects of SS was the greatest. As a result, SS decreased carbon emission by 22% in 2014 and 19% in 2015 versus CT. The trends of net ecosystem production under different tillage systems were as follows: CT > RT > NT > SS. No-till increased net ecosystem production by 33% in 2014 and 12% in 2015 relative to CT. The SS treatment increased average grain yield by 27% and 23% over CT and RT, and enhanced water use efficiency by an average of 43%. On average, SS increased carbon emission efficiency by 60% and 43% compared to CT and RT, respectively. Thus, subsoiling management strategy is a promising option for the development of sustainable agriculture in semi-arid areas.