Straw Strip Mulching: A Sustainable Technology for Saving Water and Improving Efficiency in Dryland Winter Wheat Production

An improved straw mulching model may be a sustainable agricultural production technology due to its improvements in soil water and the fertilizer environment by the recycling of waste straw resources. A four-year field experiment was conducted in a randomized block design on the Loess Plateau of northwestern China in 2015–2019, which aimed to study the effects of straw strip mulching (SSM) and conventional flat planting without mulching (CK) on soil water storage, water consumption characteristics, water use efficiency, precipitation use efficiency, winter wheat growth, economic benefits, and nutrient benefits. The results obtained for the four years showed that the SSM treatment improved soil water storage in the 0–180 cm soil layer over the whole growth period, which was especially obvious in the 0–60 cm soil layer at the jointing and blooming stages. Compared with CK, SSM increased the contribution rate of precipitation to total evapotranspiration and increased it quite significantly by 20.4 percentage points in the earlier growth period. SSM significantly reduced soil water storage consumption in the 0–180 cm soil layer and ultimately reduced evapotranspiration by 11.2 mm during the whole period. In the 0–180 cm soil layer, SSM decreased evapotranspiration by 33.1 mm from the sowing to the jointing stages, but increased it by 19.5 mm from the jointing to the blooming stages. In addition, SSM improved the water use efficiency of grain yield by 21.6% and improved the precipitation use efficiency of grain yield by 18.6%, and it ultimately increased grain yield by 16.5% through improving spike number by 9.5% and kernel number per spike by 8.9%. SSM improved the water use efficiency of biomass yield by 13.5% and the precipitation use efficiency of biomass yield by 9.9%, and it ultimately increased biomass yield by 8.7% and plant height by 6.5%. Furthermore, SSM increased net income by 413 CNY ha–1 and the total amount of straw returned to the field after harvest by 8 876–9 619 kg ha–1. After returning straw to the field, SSM significantly increased the soil nutrient contents, which could significantly reduce the burden of fertilization by farmers after a few years. Therefore, straw strip mulching technology could probably be a sustainable and potentially useful practice, which could save water and increase efficiency in rainfed winter wheat production.