Effects of mulching on water saving, yield increase and emission reduction for maize in China

Abstract

Mulching, an agricultural management measure widely used in arid and semi-arid regions of China, can effectively improve the hydrothermal environment of farmland and increase crop yield and crop water productivity (WPc). However, previous studies on the effects of mulching on water saving, yield increase and emission reduction of maize have provided inconsistent results. Therefore, a meta-analysis was used in this study to (1) evaluate the effect of mulching types [plastic film (PM), straw (SM) and degradable film (DM)] on maize yield, evapotranspiration, WPc and greenhouse gas emissions; and (2) determine the effects of mulching measures on water saving, yield increase and emission reduction in maize farmland under different climatic conditions. Compared with the no-mulching control, mulching significantly raised maize yield, WPc and carbon dioxide (CO2) and nitrous oxide (N2O) emissions. The PM, SM and DM increased maize yield by 27.31 %, 6.98 % and 16.55 % compared with no-mulching, respectively, and correspondingly WPc by 34.08 %, 11.48 % and 24.20 %. The PM and SM significantly increased CO2 emissions by 39.91 % and 16.43 %, respectively, and N2O emissions by 51.1 % and 30.12 %, but had no significant effect on methane absorption. For maize planting, in areas with altitudes < 500 and > 1000 m, average annual rainfall < 1000 mm, average annual air temperature of 5–15 °C and average annual evaporation < 1500 mm, a combination of PM and ridge–furrow planting can achieve the best effect of increasing production and saving water. In areas with an altitude of 1000–1500 m and average annual evaporation of 1500–2000 mm, the DM had the greatest effect of improving yield (by 16.17 %) and saving water, with a decrease in evapotranspiration of 8.82 % and an increase in WPc of 24.71 %. The local level of mechanization and labor costs should be considered when choosing a maize mulching pattern.