Organic and Inorganic Amendments Immobilized Cadmium and Improved Maize Growth and Yield in Cd-Contaminated Soil

Abstract

In situ immobilization of contaminants by application of organic and inorganic amendments is one of the effective techniques to reduce availability of heavy metals to plant. A pot trial was carried out to evaluate the effects of inorganic (rock phosphate) and organic amendments (press mud compost) for Cd immobilization to improve maize growth and yield in Cd-contaminated soil. Cadmium chloride salt was used for spiking (0, 10 and 30 mg Cd kg−1 soil). Rock phosphate was applied at the rate of 1% and 2% alone and in combination of press mud compost 2%. These amendments were applied alone and in all possible combinations. Results indicated that Cd contamination negatively affected and the effect was more pronounced under 30 mg Cd kg−1 compared to lower levels of Cd stress. But the immobilization of Cd due to the combined application of rock phosphate and press mud compost improved the growth and yield of maize both in uncontaminated and Cd contaminated soil. Application of 1 and 2% rock phosphate and press mud compost alone and in combination improved the plant growth at all Cd stress levels. However, combined application of rock phosphate (2%) and press mud compost (2%) promoted plant height (1.21 times), root length (3.2 times), shoot dry mass (1.57 times) and root dry mass (5.3 times) at 30 mg kg−1 Cd stress level as compared to respective untreated stressed control plant. In conclusion, Cd stress was highly detrimental to maize plants under higher level of contamination. Moreover, combined application of rock phosphate and press mud compost immobilized Cd and ultimately improved the growth and yield of maize in Cd contaminated soil.