关键词: 青贮玉米, 品质, 产量, 有机无机肥配施, 减量灌水

Abstract:

【Objective】In terms of the issues of yield instability and quality deterioration caused by improper water and fertilizer application, the effects of reduced irrigation combined with organic and inorganic nitrogen fertilization on the yield and quality of silage maize in arid irrigated regions of Northwest China were investigated, so as to identify optimal water and fertilizer management practices for achieving high yield and superior quality in silage maize cultivation in the irrigated areas. 【Method】 From 2021 to 2022, a field experiment based on two-factor split-plot design was carried out at the Oasis Agricultural Experimental Base of Gansu Agricultural University. The main factor was two irrigation levels, respectively, including I1 conventional irrigation reduction 20 % irrigation was 324 mm, and I2 conventional irrigation is 405 mm, and drip irrigation was used. The sub-factor included five different fertilization regimes: F1, 100% chemical nitrogen fertilizer; F2, 75% chemical nitrogen fertilizer+25% organic fertilizer; F3, 50% chemical nitrogen fertilizer+50% organic fertilizer; F4, 25% chemical nitrogen fertilizer+75% organic fertilizer; and F5, 100% organic fertilizer. The effects of different water and fertilizer management practices on the yield, grain quality, and stalk quality of silage maize were analyzed, and the comprehensive evaluation of the yield and quality of silage maize was performed using factor analysis.【Result】Reducing irrigation alone led to a decrease in the yield and quality of silage maize. However, the combined application of organic-inorganic nitrogen fertilizers helped to enhance the potential for simultaneously improving both yield and quality under reduced irrigation conditions. Notably, the combination of reduced 20% irrigation with 75% chemical nitrogen fertilizer+25% organic fertilizer (I1F2) demonstrated significant advantages. The I1F2 treatment significantly increased fresh and hay yields of silage maize, with fresh and dry grass yields improving by 9.9% and 12.7% over conventional irrigation combined with 100% chemical nitrogen fertilization (the control treatment, I2F1), respectively. Meantime, the I1F2 treatment was able to maintain a relatively high grain and stover quality of silage maize. Compared with I2F1, the I1F2 treatment increased protein and fat contents of grain by 17.4% and 20.5%, and increased essential amino acids content too, with phenylalanine, valine, leucine, isoleucine, tryptophan, threonine, lysine, and methionine rose by 17.4%, 13.9%, 19.4%, 17.9%, 23.1%, 30.0%, 44.5%, and 22.0%, respectively. The I1F2 treatment increased crude protein, crude fat, and soluble sugar contents in the stover by 13.9%, 19.1%, and 15.6% over I2F1, respectively, while decreasing neutral detergent fiber content by 13.5%, thereby improving relative feed value by 14.0%. Factor analysis also revealed that the I1F2 treatment had the highest composite applicability index, which was beneficial for increasing both the yield and quality of silage maize.【Conclusion】The combination of 20% reduced irrigation with 75% chemical nitrogen fertilizer+25% organic nitrogen fertilizer was the optimal water and nitrogen management practice for simultaneously enhancing both the yield and quality of silage maize in the Northwest irrigation areas.

Key words: silage maize, quality, yield, combined organic and inorganic fertilization, reduced irrigation