Yield- and efficiency-increasing effect of new tillage-fertilization-sowing method on wheat in the North China Plain

The North China Plain is the main production area of summer corn-winter wheat in China; however, the long-term large area management of no-tillage sowing corn and rotating tillage sowing wheat leads to shallow tillage layers and poor yield and efficiency. The North China Plain is also an area with serious groundwater overexploitation and a key area for the development of modern water-saving agriculture. To break the hardpan, improve water and nutrients use efficiencies, reduce the frequency of farming operations and production costs, we conducted an experiment on a comprehensive technology of tillage-fertilization-seeding of corn and wheat. A split-plot design was used in this study. In the main plot, two treatments were set up: 1) no-tillage seeding of corn in the front stubble and 2) deep tillage-delamination fertilization and sowing of corn. In the main plot of no-tillage corn seeding, two sub-zones were set up: artificial fertilization-rotary tillage and drill sowing of wheat (T1) and artificial fertilization-rotary tillage-deep loosening and drill sowing of wheat (T2). In the main plot of the treatment with deep tillage-delamination fertilization and sowing of corn, two sub-zones were set up: artificial fertilization-rotary tillage-strip seeding of wheat (T3) and rotary tillage-deep loosening-delamination fertilization-wide uniform seeding of wheat (T4). At the tillering, jointing, flowering, and maturing stages, wheat growth, dry matter accumulation, and yield traits were investigated and compared, and the water use efficiency and partial factor nitrogen productivity of wheat, annual total yield of corn and wheat, and output/input ratio were analyzed. The results showed that the T4 treatment significantly reduced soil bulk density in the 0–40 cm layer, increased soil moisture content in the deep layer, optimized nutrient distribution in soil layer, and increased plant height, tillers number, dry matter weight of shoot and root in the 0−40 cm layer, thus increasing spike number per unit area and grain number per spike, leading to water saving and high yield. The grain yield was in the order of T4 (8333.75 kg∙hm⁻²) > T3 (8222.63 kg∙hm⁻²) > T2 (7778.17 kg∙hm⁻²) > T1 (7000.35 kg∙hm⁻²); T4, T3 and T2 treatments significantly increased production by 19.05%, 17.46% and 11.1% compared with T1 treatment, respectively. Water use efficiency and partial factor nitrogen productivity were improved. In T4 treatment, the total annual grain yield reached 19 469.7 kg∙hm⁻², which was higher than the tonnage of a grain field (15000 kg∙hm⁻²), and the output/input ratio reached 3.76. Thus, T4 was a water-saving, green, quality improving, yield increasing, and efficiency enhancing tillage model for maize and wheat in the North China Plain. Accelerating the demonstration and popularization of the technique of “deep tillage-delamination fertilization and sowing of corn, and rotary tillage-deep loosening-delamination fertilization and wide uniform seeding of wheat” in the North China Plain is thus suggested.