Effect of corn straw returned to soil and N application on growth, water and nitrogen use efficiency of winter wheat

Through field experiments, the effects of combined N and corn straw application on the growth, grain yield, nitrogen use efficiency (NFUE) and water use efficiency (WUE) of winter wheat in wheat-maize cropping systems were analyzed. At pre-winter and jointing stages, total stems and tillers per plant of wheat under combined N and corn straw application were lower than under application of the same rate of N only. At N application rate of 75~225 kg·hm^-2, the plant dry weight was higher under combined application of N and corn straw. At booting and maturity stages, dry matter, ears and yield components of wheat under combined corn straw and N application were higher than under N only. Grain yield and WUE under combined corn straw and N application were respectively 58.9~339.6 kg·hm^-2 and 0.026~0.083 kg·m^-3 higher than under N only. With 75 kg·hm^-2 N application, NFUE under combined N and corn straw application was lower than under N only, but it became higher with 150~300 kg·hm^-2 N application. Corn straw competed with wheat seedling for nitrogen at early growth stages, and soils provided more nitrogen at late growth stages in wheat-maize cropping systems in the Huanghuai Plain. Hence simultaneously incorporating corn straw into soil and applying 225 kg·hm^-2 of N increased both WUE and NFUE. This enhanced yield and winter wheat cultivation efficiency.