Effect of partial root-zone drying irrigation (PRDI) on alfalfa available soil P

ABSTRACT This study focused on alfalfa (Medicago sativa) to investigate the effect of partial root-zone drying irrigation (PRDI) on N-fixing crops available soil P. A three-year field experiment was designed with two irrigation methods and four irrigation volumes. Two irrigation methods consisted of PRDI and conventional furrow irrigation (CFI), and four irrigation volumes were set as 70% ETc (alfalfa water requirement), 85% ETc, 100% ETc and 115% ETc. This study showed that the PRDI had no effect on alfalfa seasonal forage yield but increased alfalfa P uptake. The PRDI decreased the soil available P content and stock but had no effect on the total P content and stock, which demonstrates that effect of PRDI on crop available soil P was different when different P forms were used to estimate crop available soil P. This study also showed that the variation in the coefficient was below 3% between soil P (available or total P) contents and soil P stocks, indicating that soil P contents and stocks were similar when estimating alfalfa available soil P under PRDI conditions. The findings of this study present a pattern of estimating the N-fixing crops available soil P in relation to PRDI.