Abstract:

Given the current problem of excessive nitrogen application in Northeast China, studying the effects of reduced nitrogen application on spring maize growth and development, yield, and grain quality were of great significance to optimizing scientific management techniques of nitrogen fertilizer and promoting the green and efficient development of spring maize production. In this study, the Danyu 405 was used as the experimental material, and the farmer's habitual nitrogen application rate was used as the control. Three levels of 11.1%, 55.5%, and 100% nitrogen reduction experiments were conducted. The response mechanisms of yield and grain quality to reduced nitrogen application were analyzed. The results showed that at the seedling stage of maize, nitrogen reduction results in the reduction of growth and development indicators (plant height, stem diameter, leaf area index, dry and fresh weights of biomass, leaf specific gravity, etc.), which is not conducive to the growth of shoots and the distribution of dry matter to leaves. As the amount of nitrogen reduction increases, the reduction rates increase. After the seedling stage, the appropriate amount of nitrogen reduction promotes the growth of maize shoots, and the biological characteristics such as plant height, stem thickness, leaf area index, biomass, and leaf proportion have an increasing trend. A moderate amount of nitrogen reduction results in an increase in ear length, ear thickness, 100-kernel weight, theoretical yield, grain water content, and starch content, and a decrease in grain fat content, as well as a first increase then decrease in amino acid and crude protein content. With the increase in nitrogen reduction, the increased amplitudes in ear length, ear thickness, 100-kernel weight, and theoretical yield all decrease, and those in grain water content and starch content increase, and the decreased amplitude in fat content decreases. When the nitrogen application rate is 240 kg·hm^-2 which is reduced by 11.1%, the increase rates of ear length, ear thickness, theoretical yield reach peak values which are 1.9%, 3.7%, and 11.5%, respectively, and the maize yield reaches the maximum i. e. 945.4 g·m^-2, while the fat content of the grain i. e. 2.4 g·100 g^-1 is the least, the amino acid content i. e. 83.9 μmol·g^-1 is the largest and the crude protein content i. e. 6.8% is the highest. The research results provide more complete fertilization management for local corn production and guidance for farmers to apply fertilizer scientifically.

Key words: Spring maize, Nitrogen fertilizer, Growth, Yield, Quality