关键词: 青稞（Hordeum vulgare var. coeleste Linnaeus）, 生长发育, 磷肥, 过量施用, 肥料利用率

Abstract: To explore the upper limit of phosphorus fertilizer application for the main highland barley varieties and new highland barley strains, and find out the characteristics of growth, development, and nutrient absorption and utilization of new highland barley varieties （lines） under excessive phosphorus application, five treatments were set up, including control without phosphorus application （CK）, conventional phosphorus application treatment （P1）, and excessive phosphorus application treatments （P2, P3, P4）, to study the changes in growth and phosphorus absorption and utilization of highland barley under excessive phosphorus application. The application rates of P₂O₅ in the five treatments were 0, 56.2, 138.5, 220.8 and 277.0 kg/hm², respectively. The results showed that the highest tillering number of highland barley increased with the increase of phosphorus fertilizer application amount. Applying phosphorus could increase the number of mature ears of highland barley, but excessive phosphorus application could reduce the number of mature ears of highland barley. Applying phosphorus fertilizer could increase the plant height of highland barley, but when the amount of phosphorus fertilizer increased to a certain extent, the increase in plant height of highland barley was not significant. Applying phosphorus fertilizer could increase the average and maximum filling rates of highland barley, and with the increase of phosphorus application rate, they first increased and then decreased. The phosphorus fertilizer utilization efficiency, phosphorus fertilizer agronomic utilization efficiency, phosphorus fertilizer partial productivity, and yield of the two highland barley varieties （lines） showed a decreasing trend with the increase of phosphorus application amount. The above analysis showed that excessive application of phosphorus fertilizer would lead to a decrease in the number of ears of highland barley and a significant decrease in phosphorus fertilizer utilization efficiency.

Key words: highland barley（Hordeum vulgare var. coeleste Linnaeus）, growth and development, phosphorus fertilizer, excessive application, fertilizer utilization rate