Fine Root Turnover Characteristics of Alfalfa under Drip Irrigation at different Phosphorus Levels

摘要

The present study investigated fine roots turnover characteristics of alfalfa under drip irrigation when different phosphorus levels were applied (0, 50, 100, and 150 kg ha -1 ); including production and mortality were evaluated for two years (2017 and 2018). The results showed that the total hay yield of alfalfa at 100 kg P ha -1 was significantly higher than control and 50 kg P ha -1 treatments in two years (P < 0.05). There were two peaks of fine root standing crop and production, respectively, which reached the maximum at 100 kg P ha -1 . With the increase of soil depth, the fine root standing crop of alfalfa decreased gradually under different P treatments. Fine root production at 100 kg P ha -1 was significantly higher than control and 50 kg P ha -1 treatments. Fine root mortality at 100 and 150 kg P ha -1 treatments were significantly higher than control and 50 kg P ha -1. The turnover rate at 100 kg P ha -1 treatment reached the maximum in two years at 0.2134 yr -1 and 0.1814 yr -1 , respectively. Pearson correlation analysis showed that annual total hay yield of alfalfa and annual production of fine root had significant correlation (P < 0.01). At 100 kg P 2 O 5 ha -1 , the turnover rate of fine roots in alfalfa was improved, and fine root production of alfalfa significantly affected the above dry matter yield.