Conservation Tillage Methods and Key Techniques for Two-crop Annual Rotation in Semi-arid Regions inNorth China

摘要

The conservation tillage based on straw residue coverage, minimum tillage and no-tillage, ar,d oest control is a sustainable tillage system suitable for dryland farming in North China. This study was conducted at the demonstration zone for mechanizedconservation tillage techniques and machinery in Yangling, Shaanxi, with the goal of increasing resource use efficiency, crop yield, production efficiency, and agricultural sustainability. On the basis of testing and field experiments, different mechanization methods were investigated and the soil physical, chemical and biological Properties as well as the economic returns were compared among different tillage methods for wheat-corn annual rotation in a semi-arid region in North China. The effects of key conservation Wtoge technical factors, including fertilizer rate, fertilization spacing, time intervals of deep soil loosening, amount of crop residue coverage, were tested and analyzed. The results from sever years' experiments showed that: 1) leavingwheat residue for mechanized corn production could improve soil structure and soil fertility and lower soil volumetric density; 2) tall straw residue wa better than low straw residue for planting corn using either rotary tillage or deep loosening tiliaQand 3) based three soil deep loosening methods, deep loosening had certain effects on weed ' control, and weed infestations reduced with the decreasing interval of deep loosening. The best interval for deep loosening without residue was one year, and thedeep loosening with straw resid for no-till planting could replace traditional plowing and deep loosening without residue for no-till planting. Fertilizer rate and fertilizer spacing experiments showed that applying fertilizer with seeds had relativelylower yield than applying fertilizer at a distance from the seed row. These results provide a basis for the implementation of conservation tillage for wheat-corn annual rotation in the semi-arid regions in North China.