Effects of no-till on upland crop yield and soil organic carbon: a global meta-analysis.

Aims: No tillage (No-till, NT), a form of conservation agricultural management, can improve food security and alleviate world climate change by influencing crop yield and soil organic carbon (SOC), but the effects of NT on crop yields and SOC and the major factors which influence these effects remain poorly understood. Methods: We conducted a global meta-analysis using 5230 paired observations from 446 studies to evaluate the effects of NT on upland crop yield and SOC and to explore the associated influencing factors. Results: Generally, NT decreased upland crop yields by 5% (P < 0.05) and increased SOC sequestration by 9.9% (P < 0.05). Specifically, wheat and maize yields decreased by 7.7% and 2.3%, respectively. Our analyses indicate that NT combined with crop residue return and crop rotation reduced the negative effect of NT on crop yield from 5% to 2.44% and increased SOC up to 12.77%. The effects of NT on yield and SOC varied depending on the regulating factors. No-till increased yields in relatively arid areas, but reduced yields in more humid areas, whereas SOC is more likely to increase in humid regions. Soil organic carbon sequestration increased with temperature, but yield losses also increased in warmer regions. Conclusions: Our study suggests that NT combined with crop residue return and crop rotation could enhance SOC sequestration under moist and warm conditions without compromising crop yield. It may also improve soil quality and help alleviate global food security and climate change. [ABSTRACT FROM AUTHOR]