Plastic mulch increases dryland wheat yield and water-use productivity, while straw mulch increases soil water storage

Amplifying drought stress and high precipitation variability impair dryland wheat production. These problems can potentially be minimized by using plastic mulch (PM) or straw mulch (SM). Therefore, wheat grain yield, soil water storage, soil temperature and water-use productivity (WUP) of PM and SM treatments were compared with no mulch (CK) treatment on dryland wheat over a period of eight seasons. Compared to the CK treatment, PM and SM treatments on average significantly increased grain yield by 12.6 and 10.5%, respectively. Compared to the CK treatment, SM treatment significantly decreased soil daily temperature by 0.57, 0.60 and 0.48°C for the whole seasons, growing periods and summer fallow periods, respectively. In contrast, compared to the CK treatment, PM treatment increased soil daily temperature by 0.44, 0.51 and 0.27°C for the whole seasons, growing periods and summer fallow periods, respectively. Lower soil temperature under SM allowed greater soil water storage than under PM. Pre-seeding soil water storage was 17% greater under the SM than under the PM treatment. Soil water storage post-harvest was similar for the PM and SM treatments, but evapotranspiration (ET) was 4.5% higher in the SM than in the PM treatment. Consequently, WUP was 6.6% greater under PM than under the SM treatment. Therefore, PM treatment increased dryland wheat yield and water-use productivity, while straw mulch increased soil water storage.