Effect of organic amendments on phytoavailability of nickel and growth of berseem (Trifolium alexandrinum) under nickel contaminated soil conditions

Abstract

The use of organic amendments is a common practice in Pakistan to improve soil fertility. Organic amendments affect the chemical speciation and thus the bioavailability of heavy metals and their uptake and toxicity to plants. The present study evaluates the influence of organic amendments viz. farm yard manure (FM), poultry manure (PM), press mud (PrM) and activated carbon (AC) on nickel (Ni) bioavailability in soil, as well as its uptake into, and growth responses of, Trifolium alexandrinum. Pot experiments were conducted where T. alexandrinum was exposed to three different concentrations of Ni i.e., 30, 60 and 90 mg kg−1 in the form of NiCl2 solution in the presence and absence of organic amendments each applied at 15 g kg−1 soil. The results showed that the effect of organic amendments on Ni bioavailability and uptake by T. alexandrinum depended on the Ni concentration in the soil and the amendment type. Application of organic amendments generally increased Ni phytoavailability in soil and Ni uptake by plants at low Ni levels (Ni-0 and Ni-30) but decreased at higher levels (Ni-60 and Ni-90).