Regulating effect of deep tillage and delamination fertilization on the yield formation of summer maize[

 In the Huang-Huai-Hai Plain, the hard stubble seeding of summer maize has caused a shallowed top soil layer, which in\u0002duced decreasing of use efficiencies of sources, such as light, heat, water, and fertilizers of summer maize. Therefore, this experiment applied a new tillage-fertilization technology, deep tillage and delamination fertilization (DTDF), to solve the above problem. In the experiment, two treatments were set: DTDF+seeding (DTDF) and hard stubble seeding and fertilization (HSSF); the soil bulk density,soil moisture content, and soil nutrients contents were investigated at the big trumpet, tasseling, silking, late filling stages of summer maize. In addition, the growth and development traits, dry matter accumulation traits, and yield components of summer maize were investigated too. Finally, the water use efficiency and partial nitrogen productivity of summer maize were analyzed. The results showed that the soil bulk density was significantly reduced, soil water content was increased. Soil contents of nitrogen, phosphorus, and potassium at 20–40 cm were higher than those at 0–20 cm under DTDF treatment, indicating a mitigating effect on surface accu\u0002mulation of nutrients. The plant height and leaf area per plant of summer maize during the big horn to silking stages, the dry leaf weight during the big horn to tasseling stages, and the dry ear weight during the silking to late filling stages under DTDF treatment were significantly higher than those under HSSF treatment. Ear diameter, grain number per row, 100-grain weight, cob weight, grain weight per plant, straw weight per plant, and yield under DTDF treatment were also higher than those under HSSF treatment. The DTDF treatment significantly increased water use efficiency, partial nitrogen productivity, and maize yield compared with the HSSF treatment. Therefore, the DTDF optimized the soil bulk density, water and nutrient distribution, regulated maize growth and develop\u0002ment, and increased yield, water use efficiency, and partial nitrogen productivity of summer maize. This study provides a theoreticalbasis and technical support for the high-quality development of farmland and sustainable green improvement of maize production in the Huang-Huai-Hai Plain.