Effects of optimized subsoiling tillage on field water conservation and summer maize (Zea mays L.) yield in the North China Plain

Abstract

Farmland water management includes improving soil properties, optimizing root distribution, promoting rainfall and irrigation infiltration, reducing soil water evaporation, increasing water storage, and utilizing precipitation and irrigation efficiently through appropriate tillage methods. These factors are important for summer maize planting systems in areas of extreme water deficiency and hot rainy seasons, such as the North China Plain (NCP). A four-season field experiment was conducted on summer maize to compare the influences and mechanisms of two tillage methods (no-tillage (NT) and subsoiling tillage (ST)) on the water conservation and yield. The ST treatment promoted irrigation and rainfall infiltration, and the water storage capacity in the 2 m soil layer increased by 18.3 mm in the ST treatment over the entire growth period compared to the NT treatment. The field evapotranspiration (ET) and soil evaporation (E) intensities of the ST treatment were 5.6% and 11.5% lower than those of the NT treatment, respectively. Compared to the NT treatment, the ST treatment increased the root width in the 20–40 cm soil layer by 17.8% (on average) and the proportion of root activity by 36.7%. The root dry matter accumulation ratio, root active absorption area, and diameters of the vascular bundle and xylem vessels increased significantly. The average yield of summer maize under the ST treatment was 11.2% higher than that of the NT treatment over the four study years. The water use efficiency was also 16.5% higher in the ST treatment. These results demonstrate that the ST treatment of summer maize improved the infiltration of precipitation and irrigation into the soil, reduced the E, promoted root growth, and increased the maize kernel weight, thereby collectively achieving improved water use efficiency and summer maize yields.