Effects of salinity and Ca:Mg ratio of irrigation water on pistachio seedlings phosphorus planted under greenhouse conditions.

Phosphorus (P) is a key element in many biological processes of plants and animals. We aimed to investigate the effect of different salinity levels and Ca:Mg ratios of irrigation water arid lands on soil available P, soluble P, and P absorbed by the pistachio plant. For this purpose, a greenhouse experiment was conducted by sowing the seeds of pistachio in a factorial randomized block design with four soil salinity levels (S1 (6 dS.m-1irrigation water salinity, leaching fraction (LF) = 50), S2, S3, and S4 (9 dS.m-1 irrigation water salinity, LF = 50, 30 and 20, respectively)) and three Ca:Mg ratios (M1, M2, and M3 equal to 1, 0.5, and 0.25, respectively). After harvesting the plants, the amount of soil available P (Po), water-soluble P (Pw), and total P (Pt) at soil depths of 0-5, 5-25, 25-50, and 50-75 cm, and P concentration in the leaves of Pistachio seedlings were measured.The results showed that the salinity of soil saturated extract had no significant effect on Po, Pw, and Pt. The reduction in Ca:Mg ratio increased Po and Pw in soil surface but it did not affect Pt. Increasing salinity from S1 to S2 augmented plant P uptake but at higher salinity levels, P uptake was reduced. The decrease in Ca:Mg ratio had no significant effect on plant P contents.