施氮与刈割对陇东地区高羊茅产量、品质及氮肥利用的影响

为探究陇东地区高羊茅(Festuca arundinacea L.)草地高产、优质和氮肥高效利用的种植方式，本研究设置0kg·hm^-2(N1),80kg·hm^-2(N2)和160kg·hm^-2(N3)3个施氮量，每个施氮量下设置25 d(M1),50d(M2)和75d(M3)3个刈割频率。结果表明：N2和N3处理的全年干草产量、粗蛋白产量和氮吸收量显著高于N1，两年平均干草产量较N1分别增加13.5%和15.5%，两年平均粗蛋白产量分别增加21.34%和25.25%，并且N2较N3显著提高了氮肥利用效率。两年M2处理的干草产量和粗蛋白产量显著高于M3，而各营养成分含量与M3无显著差异。两年M1处理较M2，M3降低了酸性洗涤纤维(Acid detergent fiber,ADF)和中性洗涤纤维(Neutral detergent fiber,NDF)含量，显著提高相对饲用价值。两年M2处理较M3显著提高了氮吸收量和氮肥利用效率。所有处理中，N3M2处理的营养品质综合评价最优，是一种提升牧草品质的管理措施，而N2M2处理获得了较高的干草产量和氮肥利用效率，是一种氮肥高效利用的管理策略。

Effects of Nitrogen Application and Mowing on Yield,Quality and Nitrogen Utilization of Tall Fescue in the Longdong Area

To explore the planting methods of high yield and quality with efficient use of nitrogen fertilizer in tall fescue (Festuca arundinacea L.) in the Longdong area,two years field trials were conducted by using three nitrogen application rates of 0 kg·hm^-2(N1),80 kg·hm^-2(N2)and 160 kg·hm^-2(N3). In addition,three mowing frequencies including mowing every 25 days (M1),every 50 days (M2),and every 75 days (M3) were set under each nitrogen rate. The results showed that the annual hay yield,crude protein yield,and nitrogen uptake was significantly higher for N2 and N3 treatments than that of N1 in both years. Compared to N1,the average hay yield of N2 and N3 treatments was increased by 13.5% and 15.5%,and the average crude protein yield increased by 21.34% and 25.25%. The N2 treatment significantly improved nitrogen use efficiency compared to N3 treatment. Moreover,the hay yield and crude protein yield of M2 treatment were higher than that of M3 treatment,but the difference between the two treatments was not significant. Compared to M2 and M3 treatments,M1 significantly decreased the content of acid detergent fiber and neutral detergent fiber,which obviously increased the relative feed value. Compared to M3 treatment,M2 significantly improved the nitrogen uptake and nitrogen use efficiency. Among all the treatments,N3M2 treatment has the best comprehensive evaluation of nutritional quality and can be considered as a best management measure for improved forage quality in tall fescue,while N2M2 treatment obtained higher hay yield and nitrogen use efficiency,and can be adopted as a suitable management strategy for efficient use of nitrogen fertilizers.