Responses of yield and water use efficiency to the interaction between water supply and plastic film mulch in winter wheat-summer fallow system

Abstract

Plastic film mulch (FM) can significantly improve crop yield and water use efficiency (WUE), but the interaction between water supply (pre-sowing soil water, season) and FM has not been clearly elucidated. In this study, a four-year field experiment was conducted on the Loess Plateau of China to investigate the interactive effects of pre-sowing soil water, season, and mulch (FM and bare ground, CK) on winter wheat yield, water use, and WUE. The yield of wheat ranged from 1646 to 7955 kg ha−1, evapotranspiration (ET) was from 193 and 405 mm, and WUE varied from 8.5 to 19.9 kg ha−1 mm−1. In relation to bare ground, plastic mulch increased yield by 19% and WUE by 26%. The interaction between water supply and FM significantly affected ET, but not yield and WUE. Besides conserving more water, increases in yield and WUE under FM were ascribed to the increase in soil temperatures at 10–50 cm soil layers by 0.28–0.53 °C, on average, during the wheat-growing period, which promoted root growth, enhanced the use of soil water at deep layers, increased post-anthesis ET, and total ET, especially in average and dry seasons. Biodegradable films are needed to avoid the environmental impact of residual plastic mulch with current materials.