Growth, yield and arsenic accumulation by wheat grown in a pressmud amended salt-affected soil irrigated with arsenic contaminated water
Muhammad Imran, Muhammad Ashraf, Abdul Rasul Awan
Abstract
The study assessed the influence of pressmud (PM) application on soil available phosphorus (P) content, growth, yield, and arsenic (As) accumulation in wheat grains on a salt-affected soil receiving irrigation of As-contaminated water. Wheat seeds (cv. Faisalabad-2008) were sown in pots containing saline soil (EC 11.72 dS m−1; pH 8.07; SAR 31.3 mmol1/2 L−1/2) amended with PM (0, 2.5, 10 and 15 g kg−1) and irrigated with As-contaminated water (0, 25 and 100 µg L−1). The pot experiments had two sets, one was harvested after 30-days of germination while the other at crop maturity. Pressmud application at 2.5, 10 and 15 g kg−1 improved biomass of 30-days old wheat seedlings by 44%, 86% and 90%, respectively compared to unamended soil. Irrigation with As-contaminated waters did not affect seedling biomass or grain yield of wheat. Plant height, fertile tillers, straw biomass and grain yield increased from 57-62 cm, 3–5 no. plant−1, 2.93–5.31 g plant−1 and 3.93–7.11 g plant−1, respectively by 15 g PM kg−1 soil. Moreover, PM application resulted in an 8-fold increase in soil available P content, which resulted in higher grain P uptake. Irrigation with water of 25 and 100 µg As L−1 increased soil available P by 7.6% and 11%, respectively, but its influence on the grain P concentration was non-significant. Pressmud application in combination with As-contaminated water increased accumulation of As in grains. By applying water of 25 and 100 µg L−1 As, accumulation of As in wheat grains increased from 3.12-42.4 and 49.58–91.85 µg kg−1, respectively compared with normal water. However, these concentrations of As in wheat grains were still below the permissible limit of 430 µg kg−1 prescribed for agronomic crops. In conclusion, PM is very effective in improving wheat productivity on salt-affected soils but it can aggravate As accumulation in wheat grains if applied in combination with As polluted water.