利用方式与施氮对黄土高原无芒雀麦农艺性状、产量和品质的影响

放牧和刈割是草地利用的有效方式，为探究施氮对黄土高原不同利用方式下无芒雀麦草地的饲草产量和营养品质的影响效应，本研究在甘肃庆阳以无芒雀麦草地为研究对象，设置放牧(G)和刈割(M)两种利用方式，每种利用方式下设0(N₁),80(N₂)和160(N₃)kg·hm^-23个施氮水平。结果表明，放牧较刈割显著提高了无芒雀麦的株高累积量、相对叶绿素含量(SPAD)、干草产量以及粗蛋白、粗脂肪、粗灰分的含量，并降低了中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量。两种利用方式下，无芒雀麦的株高累积量和干草产量均随施氮量的增加而增高，相对饲用价值(RFV)显著提高。放牧条件下施氮160kg·hm^-2(G-N₃)处理获得最高的两年平均干草产量和RFV，分别为7.89kg·hm^-2和133.72，是一种适宜黄土高原地区无芒雀麦草地的管理措施。

Effects of Using Methods and Nitrogen Application on Agronomic Characters,Yield and Quality of Bromus Inermis in Loess Plateau

Grazing and haying are two effective ways of grassland utilization. In order to investigate the potential effect of nitrogen application on forage yield and nutritional quality of Bromus inermis grassland in the Loess Platea,an experiment was carried out in Qingyang,Gansu Province. The experiment included two utilization modes (grazing,G and mowing,M) and three N fertilizer levels of 0 (N₁),80 (N₂),and 160 (N₃)kg·ha^-1. The results showed that grazing was more effective than mowing. Grazing significantly increased the plant height accumulation,relative chlorophyll content (SPAD),hay yield,crude protein,crude fat,and crude ash content,and decreased the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of Bromus inermis compared with those under mowing. Under both utilization methods,the plant height accumulation and hay yield of Bromus inermis increased with the increase of N application,and the relative forage value (RFV) increased significantly. Among all the treatments,N application of 160 kg·ha^-1 (G-N₃) under grazing improved plant agronomic traits and resulted in the highest two-year average hay yield and RFV of 7.89 kg·ha^-1 and 133.72,respecyively. Therefore,the N application of 160 kg·ha^-1 (G-N₃) under grazing could be used as a suitable management practice for improving Bromus inermis grassland productivity in the Loess Plateau region.