Mulching optimizes water consumption characteristics and improves crop water productivity on the semi-arid Loess Plateau of China

Water consumption is closely related to crop growth and development, and optimizing its characteristics will be beneficial to water saving and high yield of crops. To find out the more promising cultivation technology to optimize water consumption characteristics and improve crop water productivity for winter wheat, a four-year field experiment in 2015-2019 was conducted in a randomized and complete block design in the Loess Plateau of northwest China. The experimental treatments: (i) whole plastic-film mulching (PFM), coverage rate was approximately 100%, (ii) straw strips mulching (SSM), including the alternating straw strip (0.5 m) and plant strip (0.35 m), and the coverage rate was 59%, (iii) conventional flat planting without mulching (CK). The obtained results showed that PFM and SSM increased the contribution rate of precipitation to evapotranspiration; inhibited evaporation but promoted transpiration to a great extent; reduced soil water storage consumption in the 0-60 cm but promoted it in the 150-200 cm soil layer; reduced soil water storage consumption at the early growth stage but promoted it at the middle growth stage compared with CK. In 2015-2019, compared with CK, PFM and SSM respectively decreased soil water consumption by 12.4% and 10.6% in the 0-60 cm soil layer, but increased it by 46.6% and 27.7% in the 150-200 cm soil layer. PFM and SSM reduced evapotranspiration by 20.1% and 14.4% before the jointing stage due to the low water consumption intensity, but increased it by 26.8% and 11.1% from jointing to blooming stage due to the high water consumption intensity. Besides, PFM and SSM respectively improved crop water productivity by 20.1% and 19.1%, improved precipitation use efficiency by 20.0% and 18.6%, and eventually increased grain yield by 18.1% and 16.5%. SSM was less effective than PFM, but taking the friendly sustainability into consideration, SSM would probably be a potential practice to develop the rainfed agriculture.