Optimizing water and phosphorus management to improve hay yield and water‐ and phosphorus‐use efficiency in alfalfa under drip irrigation

Abstract

Abstract Alfalfa (Medicago sativa L.) is an important forage legume in arid areas, but limited water resources and low fertilizer utilization have restricted its agricultural development. Meanwhile, studies on the effects of integrated water and phosphorus on production performance and water‐use efficiency and phosphorus‐use efficiency of alfalfa, especially on hay yield, phosphorus accumulation, and total phosphorus uptake are rarely reported under drip irrigation. The treatments were a factorial combination of three irrigation rates (5,250, 6,000, and 6,750 m3/ha per year) and four P rates (0, 50, 100, and 150 kg/ha per year) and consisted of 12 treatments for water and P management, arranged in a randomized complete block design with three replicates. Total hay yield and water‐use efficiency and phosphorus‐use efficiency of alfalfa in P2 treatment were significantly greater than those in the P1 and P3 treatments (p W3P2 > W1P2. Therefore, an irrigation rate of 6,000 m3/ha and a phosphorus application rate of 100 kg/ha per year should be considered as the best management for both high yield and water‐use efficiency and phosphorus‐use efficiency of alfalfa.

Keywords

• alfalfa
• available phosphorus
• drip irrigation
• hay yield
• total phosphorus
• water‐ and phosphorus‐use efficiency