Effect of Biochar Application on Soil Properties and Nutrient Uptake of Lettuces (Lactuca sativa) Grown in Chromium Polluted Soils

Abstract

The leather industry sector is one of the leading industries playing a significant role in the generation of foreign currency in Ethiopia. However, the environmental management for this industry is generally ignored. As a result, chromium (Cr) accumulates in vegetable tissues at toxic concentrations. The present pot experiment was therefore conducted to investigate the effect of biochar application on the selected properties of chromium polluted soils and uptake of lettuces grown in polluted soils. Biochar produced from maize stalk was applied at the rates of 0, 5 and 10t/ha on soils artificially polluted with Cr at the levels of 0, 10 and 20ppm. The study showed a significant (P<0.01) increase in pH, electrical conductivity, organic carbon, total nitrogen, available phosphorous, cation exchange capacity and exchangeable bases due to application of biochar. Moreover, uptake of nitrogen, phosphorous and potassium were significantly (P<0.01) increased by addition of biochar. A significant (P<0.01) reduction in the uptake of Cr due to application of biochar was also observed in heavily Cr polluted soils (20ppm). Therefore, application biochar is very imperative to increase soil fertility, enhance nutrient uptake, ameliorate Cr polluted soils and reduce the amount of carbon produced due to biomass burning.