Abstract: Clarifying the effects of different mulching modes on dry matter accumulation and distribution of spring wheat in dryland and their relationship with yield formation can provide a basis for high-yield wheat production in dryland. In this study, we examined the effects of three mulching methods, including straw strip mulching (SM), full plastic mulching and bunch-seeding (PM), and no mulching (CK), on the accumulation and distribution of dry matter and yield formation of spring wheat in the rain-fed agricultural region of the Loess Plateau in northwest China. The results showed that mulching significantly increased shoot dry matter content of wheat at different stages. Compared with CK, PM increased dry matter accumulation by 7.5%-33.3% and SM increased by 15.4%-25.3%, mainly from jointing to flowering stage. Both PM and SM significantly increased dry matter distribution to leaf, stem+sheath, and spike axis+grain husk at flowering and maturity stages. Mulching significantly increased the post anthesis redistribution of dry matter accumulated in leaves, stem+sheath, and spike axis+grain husk, with that of stem+sheath and spike axis+grain husk being the highest in SM (3.9% and 29.2%). Moreover, mulching significantly increased grain yield by 13.8% and 14.1% under PM and SM treatments, respectively. In conclusion, mul-ching can promote the accumulation, distribution, and transport of dry matter in spring wheat, and thus promote wheat yield. In the rain-fed agricultural area of northwest China Loess Plateau, straw strip mulching, as a sustainable and protective mulching measure, is conducive to the improvement of cropland ecological environment and the development of green agriculture.

Key words: spring wheat, plastic film mulching, straw strip mulching, dry matter accumulation and distribution, yield.