青藏高原氮磷钾肥施用对‘青引1号’燕麦生物量积累的影响

探讨高寒地区氮、磷、钾肥及其施肥水平对‘青引1号’燕麦（Avena sativa L.）生长和产量的影响，为青藏高原高寒区燕麦饲草生产合理施肥提供理论依据。以‘青引1号’燕麦为试验材料，采用完全随机区组设计，分别设置N（0、30、45、60、75、90、105 kg·hm^-2）、P（0、15、30、45、60、75、90 kg·hm^-2）和K（0、10、20、30、40、50、60 kg·hm^-2）各7个水平，研究氮、磷、钾肥不同肥料水平对‘青引1号’燕麦饲草产量和根系发育的影响并获得最适施肥水平。结果表明，N、P和K肥的添加均显著提高了燕麦干草产量 （P＜0.05）；N、P和K肥处理下分别以纯N 75 kg·hm^-2、P₂O₅ 60 kg·hm^-2和K₂O 40 kg·hm^-2下干草产量最高，分别达到31 803.3 kg·hm^-2、29 855.0 kg·hm^-2和28 308.3 kg·hm^-2。K肥处理下，燕麦株高、分蘖数、茎粗、根量、根长和根数表现优于N和P肥处理；N肥促进了燕麦地上生物量的形成；P肥有利于燕麦地下根系发育，而K肥对燕麦地上生物量和地下根系发育均影响较大；P、K单施量小于60 kg·hm^-2和40 kg·hm^-2时，其肥料农学利用率及偏生产力均优于N肥；而单施量高于60 kg·hm^-2时，N农学利用率及偏生产力表现最佳。利用TOPSIS 模型对燕麦饲草生长和经济效益等进行综合评价，结果表明，N 75 kg·hm^-2、P₂O₅ 60 kg·hm^-2和K₂O 40 kg·hm^-2为最适宜燕麦饲草的施肥模式组合。因此，在本试验土壤肥力水平下，少量施肥时，P和K肥对干草产量增加的效果优于N肥，高量施肥时，N肥效果较优；相对于N和P肥，K肥具有协调燕麦地上和地下部分发育优势，青海地区少量施K肥能有效增加饲用燕麦产量，提高肥料利用率。

Effects of Nitrogen, Phosphorus and Potassium Fertilizer Application on Biomass Accumulation of Aats ‘Qingyin No.1’ on Qinghai-Tibet Plateau

To investigate the effects of nitrogen, phosphorus and potassium fertilizers and their fertilization levels on the growth and yield of ‘Qingyin No.1’ oats (Avena sativa L.),the aim is to provide a theoretical guideline for the fertilization management of oat forage grass production in alpine areas of Tibetan Plateau.Using a completely random block design, effects of the three fertilizers on forage grass productivity and root system development of ‘Qingyin No.1’ oats were assessed under seven fertilization levels: N(0, 30, 45, 60, 75, 90, 105 kg·hm^-2), P (0, 15, 30, 45, 60, 75, 90 kg·hm^-2) and K (0, 10, 20, 30, 40, 50, 60 kg·hm^-2), respectively.The results showed a significant increase in oat hay yield with the application of N, P and K fertilizer (P<0.05).When only one of the fertilizers was applied, the highest hay yield was observed with 75 kg·hm^-2 of N, 60 kg·hm^-2 of P₂O₅, or 40 kg·hm^-2 of K₂O, resulting in hay yields of 31 803.3 kg·hm^-2, 29 855.0 kg·hm^-2, and 28 308.3 kg·hm^-2.Under K fertilizer treatment, oat plant height, tiller number, stem thickness, root amount, root length and root number were higher than that under N and P fertilizer treatment.For the oats under examination, N fertilizer enhanced aboveground biomass formation ; P fertilizer proved to be beneficial for development of their underground root system, and K fertilizer made a significant positive contribution to both aboveground biomass for mation and the development of underground root system.When the application rate of P and K was below than 60 kg·hm^-2 and 40 kg·hm^-2, respectively, the agronomic utilization rate and partial productivity of fertilizer were higher compared to N fertilizer.However, when the application rate of any one of the fertilizers was higher than 60kg·hm^-2, the agronomic utilization rate and partial productivity were the highest when N fertilizer was applied.The TOPSIS model was used to comprehensively evaluate the growth and economic benefits of oat forage grass.The results showed that 75 kg·hm^-2 of N, 60 kg·hm^-2 of P₂O₅, and 40 kg·hm^-2 of K₂O were the optimal fertilization combinations for the oat forage grass production.Therefore, when applying a small amount of fertilization,P and K fertilizers exhibite a higher effect on the increase in forage grass yield compared to N fertilizer.N fertilizer has a higher effect on forage grass yield when applied in larger quantities.Compared with N and P fertilizer, K fertilizer holds an advantage in promoting the development of aboveground and underground parts of oats.In Qinghai, even a modest application of K fertilizeri can effectively increase the yield of forage grass from oats and improve the fertilizer efficiency.