Cultivation and mulching materials strategies to enhance soil water status, net ecosystem and crop water productivity of winter wheat in semi-humid regions

Abstract

Different cultivation practices with mulching materials have been applied in the semi-arid areas of China. However, there is still insufficient systematic research on its eff ;ects on ecological indexes and crop water productivity. Therefore, a field trial was carried out in three consecutive study years (2015–2018) to evaluate ecological productivity, crop water productivity, and wheat production under six different treatments: CT: conventional flat tillage without mulching; TSM: conventional flat tillage with gravel mulching; TPM: conventional flat tillage with plastic film mulching; RP: ridges covered with plastic film and furrows without mulching; RSM: ridges covered with plastic film and furrows with gravel mulching; RPM: ridges and furrows covered with plastic film mulching. We found that different cultivation and mulching materials practices considerably improved soil moisture content, crop productivity, ecological eff ;ects and evapotranspiration (ET) rates. The RP cropping system with different mulching practices significantly increased soil moisture and ecosystem CO2 and NO2 emissions during the three consecutive study years. The RP cropping system with gravel or plastic film mulching on the furrows improved the dry matter per plant and LAI at the late growth stage, and it improved crop water productivity. Compared to the CT cultivation practice, the annual net primary productivity (NPP) and net ecosystem productivity (NEP) were significantly increased by 13% and 70%, respectively, with the RPM. In the RPM treatment, the CWPeco and CWPyield were significantly improved by 66% and 84%, respectively, relative to the CT cultivation practice. In addition, RPM treatment improved the spike partitioning index by 16%, maintained a fruiting efficiency that was 12% higher, increased water soluble carbohydrates (WSC) in the stem, increased apparent translocation (amount and ratio), and ultimately achieved an 89% higher grain yield. Taking into account the ecological eff ;ects, wheat production and ET rate, RPM treatment is an eff ;ective approach for saving water and improving CWP and production in semi-humid conditions.