Effects of different film mulching methods on soil water productivity and maize yield in a semiarid area of China

Film mulching has been used widely to improve field productivity in rainfed agricultural ecosystems in semiarid areas of China. During 2013–2016, we evaluated the effects of different film mulching methods on soil water, water productivity, crop yield, and economic benefits in a semiarid area of southern Ningxia, China. Five treatments were tested: (i) a control method consisting of conventional flat planting without mulching (CK); (ii) alternate mulching and bare rows without ridges and planting in mulched rows (P); (iii) maize planted in furrows separated by consecutive plastic film-mulched ridges (S); (iv) maize planted in furrows separated by alternating large and small plastic film-mulched ridges (D); and (v) maize, planted in furrows with large plastic film-mulched ridges alternating with flat plastic film-mulched spaces (R). After four years of continuous treatment, the results indicated that D and S treatments significantly increased soil water content at depths of 0–200 cm during the early growth stage, but the increases in the soil water content were lower later in the maize growth process. The grain yield increases were affected by the different hydrothermal conditions in various years. On average, mulching increased grain yield by 31.33 %, and biomass accumulation by 22.48 %. Across four seasons, film mulching significantly (P < 0.05) increased water use efficiency and precipitation use efficiency, especially in D by 34.56 % and 43.09 %, and S by 35.25 % and 42.79 %, respectively. Mulching changed the crop water consumption characteristics, and resulted in higher crop water productivity due to an improved hydro-thermal balance, especially during the vegetative (30–90 days) and pre-reproductive (90–120 days) growth stages, which may account for yield increase effects in this system. In addition, the results suggested that the mulching system achieves higher economic returns than CK, especially the S treatment (7538 ¥ ha⁻¹, representing an average of 29.19 % higher than CK.). The S treatment could serve as a promising adaptive management method for increasing maize productivity to cope with food security and climate change in this semi-arid area with limited and erratic precipitation.