Soil hydro-thermal characteristics, maize yield and water use efficiency as affected by different biodegradable film mulching patterns in a rain-fed semi-arid area of China

The farming practice of fully mulched double ridge-furrow with polyethylene (PE) film has been widely used to improve productivity of many staple crops in arid and semi-arid regions of northwest China. However, the residual PE film has caused many environmental problems such as "white pollution" and land degradation. Biodegradable film might be a good substitute for PE film in agriculture production, but the evidence for the appropriate biodegradable film mulching pattern for maize is lacking. A 2-year field experiment was carried out to identify a suitable biodegradable film mulching pattern for maize at a typical rain-fed semi-arid site on the Loess Plateau. The local widely cultivated maize variety 'Luodan 9' was sown in five planting patterns: 1) conventional flat planting without film mulching (CK); 2) flat planting with full mulching with biodegradable film (FB); 3) ridge-furrow planting with biodegradable film mulching on ridges (RFB); 4) double ridge-furrow planting with full biodegradable film mulching (DRFB) and with full transparent PE film mulching (DRFP). The results indicated that biodegradable film mulching patterns (including FB, RFB and DRFB) significantly increased soil hydrothermal conditions, improved leaf area index, shoot and mot biomass, and thus enhanced maize yield and water use efficiency (WUE) in comparison to CK (P < 0.05). Among the three biodegradable film mulching patterns, maize yield and WUE in DRFB (average across two growing seasons) were 9.7% and 11.7% significantly greater than FB, and were 9.9% and 12.2% significantly greater than RFB. In addition, maize yield and WUE in DRFB did not differ significantly from those in DRFP, except that the maize yield was 5.2% (P < 0.05) lower than DRFP in 2013 (a warm and dry season). Present field demonstration clearly indicated that DRFB could serve as a promising option to ameliorate soil hydrothermal conditions, improve maize growth and yield performance, boost WUE, and simultaneously reduce environmental risks such as "white pollution" in rain-fed semi-arid regions of northwest China.