关键词: 绿肥, 氮肥, 玉米, 产量, 籽粒品质, 氮素积累

Abstract:

【Objective】 In order to seek a reasonable nitrogen application system suitable for high-yield and high-quality production of maize in arid areas, this study focused on the effects of reducing nitrogen application under the condition of returning green manure to the field on maize grain yield and quality, with a view to providing a theoretical basis for the regional development of nitrogen-saving, efficiency-enhancing, high-yield and high-quality agricultural production models. 【Method】 Field experiment were conducted at the Wuwei Oasis Agricultural Experiment Station from 2020 to 2022, and different nitrogen reduction rates were investigated under the condition of green manure returned to the field (Green manure retention with nitrogen reduction 0%, N100, 360 kg N·hm^-2; Green manure retention with nitrogen reduction 10%, N90, 324 kg N·hm^-2; Green manure retention with nitrogen reduction 20%, N80, 288 kg N·hm^-2; Green manure retention with nitrogen reduction 30%, N70, 252 kg N·hm^-2; and Green manure retention with nitrogen reduction 40%, N60, 216 kg N·hm^-2) on maize agronomic traits, yield components and grain quality. 【Result】 Compared with the N100 treatment, the N80 treatment ensured that maize plant height, stem diameters, and dry weight did not decrease, while the N70 treatment reduced them by 8.8%, 11.3%, and 16.4%, respectively, and the N60 treatment reduced them by 10.6%, 12.9%, and 21.3%, respectively. Among the yield components, there was no significant difference in maize bare top length among treatments; ear length, row number per ear, kernel number per row, and ear numbers under N100, N90, and N80 treatments were no significant difference too, but they were all significantly higher than those under N70 and N60 treatments. In addition, N80 treatment had the advantage of ensuring that the maize grain protein content was not reduced and fat content was increased while ensuring that maize yield was not reduced. And this system helped to reduce the amount of nitrogen accumulation in maize stems and leaves, and increased the amount of nitrogen accumulation in maize grain. Mantel test analysis revealed that maize grain yield, protein content, and fat content exhibited significant positive correlations (P<0.05, Mantel’s r>0.25) with nitrogen application rate, grain nitrogen accumulation, plant height, stem diameter, dry weight, ear length, and row number per ear. However, no significant correlations were observed with ear height, bare top length, or kernels number per row. Grey correlation analysis further showed that the ear numbers, plant dry weight and row number per ear were the key factors affecting maize kernel yield. 【Conclusion】 In the context of sustainable agriculture, reducing nitrogen by 20% under the condition of returning green manure to the field (288 kg N·hm^-2) could be used as a reasonable nitrogen management system for developing nitrogen-saving and input-reducing, high-yield and high-quality agriculture in arid areas.

Key words: green manure, nitrogen fertilizer, maize, yield, grain quality, nitrogen accumulation