Studies On Effects Of Crop Residues Incorporation And N-fertilizer Usage On The Growth And Yield Of Summer Maize

In this paper, employed two factors randomized blocks design, effects of crop residues incorporation and N-fertilizer on the growth, development, seed formation, yield formation and NUE(Nitrogen Use Efficiency) of summer maize were studied. We discussed the effects of different managements on height of summer maize, number of nodal root, leaf area, plant stem width and chlorophyll content etc. We analyzed grain filling rate and transference rate of (14)^C-assimilate, through which, we understood the effects of crop residues incorporation and N-fertilizer on seed formation, final yield and NUE. The results showed as follows:(1) Crop residues incorporation and N-fertilizer promoted the growth of summer maize, especially in the treatments of the optimized fertilization with crop residues and the traditional fertilization with crop residues. At the same time, nutrition growth of summer maize was enhanced, the "source" of summer maize was enlarged and senility was delayed.(2) Crop residues incorporation and N-fertilizer accelerated the filling rate of summer maize, prolonged maximum filling continuous period and promoted assimilate transference from the ear leaf to grain.(3) Crop residues incorporation and N-fertilizer benefited the production of dry matter of summer maize. Compared with the treatment without straw and without N-fertilizer, the production of dry matte was raised 17.76% in the treatment of crop residues incorporation and optimized N-fertilization. And its final seed production was 7385.1kg/hm², the biggest in the whole six treatments, which raised 58.94%, compared with the treatment of without straw -without N-fertilizer.(4) Using of straw and N-fertilizer, NUE was raised in some degree. The results indicated that optimized N-fertilizer enhanced the crops' NUE by 3.12-7.39kg/ kg.hm² .(5) Analyzing crop yield, economically net income and environmental aspects, "crop residues incorporation + optimized N-fertilization" is the best model in our experiment and is worth popularizing in suburban district of Peking.