Effect of straw return and rotary tillage on soil physical properties and me-chanical sowing quality of maize in Central Sichuan

With continuous development of agricultural science and technology and improvement of ecological and environmental awareness in China, rational use of crop straw has become an efficient and sustainable agricultural practice.With the rapid development of winter wheat-summer maize rotation system, concerns have grown about the processing of soil barrenness, wheat straw waste and other cultivation issues.Irrespectively, researches targeting purple clay soils have been limited.Therefore, an experiment was conducted to determine a suitable straw return and tillage method of mechanically sowed maize under wheat-maize double-cropping system in purple soils in hilly areas in Central Sichuan.The study also investigated the problems of soil fertility and viscosity, sowing conditions and plough layer quality for high yields.The experiment consisted of four treatments-rotary tillage with straw return (RTS), none-tillage with straw return (NTS), rotary tillage without straw return (RT) and none-tillage (NT).The aims of the experiment were to study the effects of tillage patterns with wheat straw return on physical properties of purple clay soils, and on quality of mechanically sowed summer maize in hilly areas in Central Sichuan.The results showed that compared with RT, RTS significantly increased capillary porosity in the 0-10 cm soil layer at elongation stage, increased water content in the 0-10 cm soil layer under no-tillage treatment for the entire growth period, and significantly reduced the rate of emergence, and uniformity of mechanical sowing and seedling quality of maize.Compared with NTS, RT reduced soil bulk density and water content in the 0-10 cm layer, but increased capillary porosity, emergence rate, seedling height, stem diameter, leaf area and dry mass of mziae.Under wheat straw return condition, rotary tillage reduced soil bulk density at the 0-10 cm layer by 2.0%-12.1% as compared to no-tillage, significantly improved emergence rate (by 17.9%), plants per hill and uniformity of mechanical sowing and seedling uniformity of maize.Emergence rate of maize was significantly positively correlated with soil water content of the 0-10 cm layer.Both mechanical sowing uniformity and seedlings uniformity were significantly negatively correlated with soil bulk density of the 0-10 cm layer.It was thus clear that rotary tillage with straw return improved soil structure, increased soil water content, benefited the quality of mechanical sowing and quality of seedlings of maize under winter wheat-summer maize cropping pattern in hilly areas in Central Sichuan, China.