氮肥用量对粮饲兼用玉米产量和饲用品质形成的影响

Effects of nitrogen application on yield and forage quality of grain and forage maize

本研究分析了陇中黄土高原半干旱雨养农业区全膜双垄沟播模式下不同氮肥施用量(N1:0 kg·hm-2,N2:100 kg·hm-2,N3:200 kg·hm-2,N4:300 kg·hm-2)对粮饲兼用玉米(Zea mays)产量和品质形成的影响。结果表明,相同P、K肥条件下,在0~300 kg·hm-2纯N用量范围内,粮饲兼用玉米叶面积指数(LAI),叶片、叶鞘和茎秆的干物质量,持绿性,以及籽粒产量和生物产量都随施氮量的增加而增加;中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量随着施氮量的升高而降低,随生育进程增加;粗蛋白含量随着施氮量的升高而增加,随生育进程降低;相同施氮量处理下的叶片中NDF和ADF含量在不同时期均低于叶鞘;高的施氮量也有利于籽粒饲用品质的改善。因此,适量增施氮肥能明显提高粮饲兼用玉米产量,改善其品质。建议陇中旱农区采用全膜双垄沟播技术种植粮饲兼用玉米时氮肥用量为纯N 300 kg·hm-2,既能提高生物产量和籽粒产量,又能改善青贮和饲用品质。

Influences of different nitrogen application rates( N1: 0 kg · ha- 1,N2: 100 kg · ha- 1,N3: 200kg·ha- 1,N4: 400 kg·ha- 1) on yield and forage quality of grain-forage maize which were planted in furrows of completely mulched in rainfed agriculture regions in the Loess plateau were investigated.The results showed that leaf area index( LAI),dry weight of leaf,leaf sheath and stalk,grain yield and biomass increased with the increasing of nitrogen application rate with the same rates of phosphorus( P) and potassium( K) applications.Contents of neutral detergent fiber( NDF) and acid detergent fiber( ADF) decreased with the increasing of nitrogen application rate,but increased with crop development.Content of crude protein performed increased with the increasing of nitrogen application rate,but decreased with the crop growth development.Content of NDF and ADF in the leaves were lower than those of leaf sheath under the same nitrogen rate.The quality of grains was also benefited from higher nitrogen application rates.Therefore,it can be concluded that optimum nitrogen fertilizer application can improve yield and quality of grain-forage maize and 300 kg·ha- 1of N was the optimum rate for maize growth in furrows of completely mulched alternating narrow and wide ridges systems,in semiarid areas in the Loess Plateau.