氮磷添加对藏北人工牧草生产性能和品质的评价

采用田间实验，随机区组设计，选用禾本科牧草绿麦、燕麦，豆科牧草箭筈豌豆、藏豌豆为试验材料，设置不施肥（CK）、尿素75 kg·hm^-2（N）、磷酸二铵375 kg·hm^-2（NP）、有机肥22500 kg·hm^-2（OM），尿素75 kg·hm^-2+磷酸二铵375 kg·hm^-2+有机肥22500 kg·hm^-2（NPOM）5种处理，应用相关分析和4种评价模型对藏北人工牧草的生产性能和营养品质进行关联性分析和综合评价。结果表明：1）与未施肥（CK）相比，氮磷添加均提高了牧草的生产性能和营养价值，使牧草的主要物候期提前1~12 d。2）简单相关和偏相关分析表明对藏北人工草地的产量影响最大的是株高和出苗率，其次也应关注牧草的茎叶比、分蘖/枝数和盖度。3）主成分分析法、隶属函数分析法、灰色关联分析法、相似优先比法综合评价表明以NPOM处理的绿麦与藏豌豆，NP处理的燕麦、绿麦与藏豌豆，NP和NPOM处理的人工牧草综合评价最佳。因此，藏北人工草地建设过程中应适当地提高株高及出苗率，选用绿麦与藏豌豆混播进行NP、NPOM处理对提高草地生产性能，改善牧草品质效果最好，适宜在藏北地区大面积种植。

Effects of nitrogen and phosphorus addition on production performance and nutritive value of pasture species in Northern Tibet

The development of snow pastures is an effective means to relieve rangeland degradation and improve grassland productivity. Rational fertilization is a key measure for ensuring the sustainable development of degraded alpine meadows. Therefore， we conducted field experiments and laboratory analyses to evaluate the effects of different fertilization treatments on the main agronomic traits， nutritional value， and total outputs of cultivated pasture species. This study was conducted at Namache， in the North Tibetan Autonomous Region of Naqu Prefecture. We focused on the effects of the nitrogen（N） and phosphorus（P） fertilizers on the production performance and nutritive value of pasture species to for provide a theoretical basis for the establishment of artificial grassland. The experiment had an orthogonal design with three factors （plant variety， fertilization and mixture of plant varieties）. The four pasture species were Secal cereale， Avena sativa， Vicia sativa and Vicia tibetica， five fertilization treatments were no fertilizer （CK）； 75 kg·ha^-1 urea （N）；375 kg·ha^-1 NH₄H₂PO₄（P）； 22500 kg·ha^-1 organic manure （OM） and 75 kg·ha^-1 urea+375 kg·ha^-1 NH₄H₂PO₄+22500 kg·ha^-1 organic manure （NPOM）. Data for the sown pastures were evaluated by grey associative analysis， membership function analysis， and similar priority ratio analysis， principal component analysis. The four models and their evaluation results were subjected to a weighted analysis. We analyzed 16 main traits： plant height， growth rate， fresh-dry weight ratio， stem-leaf ratio， number of tillers/branches， sowing rate， stem diameter， total vegetation cover， crude protein content， crude fat content， crude fiber content， ash content， water content， non-nitrogenous components content， calcium content， phosphorus content and dry yield on sown pasture to explore the effects of main traits on dry yield. Then， we used simple correlation analysis and partial correlation analysis to determine which traits were most closely related to dry yield. The results showed that： 1） Compared with CK， the N， P， OM and NPOM fertilization treatments significantly affected the production performance and nutritive value of pasture species. In general， N and P addition advanced the phenological development of pasture species by 1 to 12 days. 2） Plant height， sowing rate， stem-leaf ratio， number of tillers/branches， total vegetation cover and yield showed positive partial correlations with dry yield. 3）The highest dry weight of pasture species was under the N and NPOM treatments. The optimal fertilization schemes were NP and NPOM. The top four pasture species/fertilization combinations were ranked， from highest productivity to lowest， S. cereale +V. tibetica （NOPM）>A. sativa （NP）>S. cereale +V. tibetica （NP）>A. sativa+V. sativa （NOPM）. Therefore， at an appropriate planting density， these pasture species are suitable for the development of high-yielding artificial grassland in Northern Tibet. The results indicated excellent performance of A.sativa+ V. tibeticaunder NPOM and S. cereale +V. tibetica NP， the multivariate evaluation indicated that their yield was stable and that they are suitable for wide utilization in Tibet.