NUTRIENT LEACHING BEHAVIOUR OF AN ALFISOL AS AFFECTED BY TOBACCO STALK BIOCHAR AND SYNTHETIC ZEOLITE

Abstract

Organic soil amendment tobacco stalk biochar (TS Biochar) and inorganic soil amendment synthetic zeolite (SZ) application to light textured soils of tobacco in order to minimize the nutrient leaching losses was studied in a laboratory column experiment. The organic amendment TS Biochar was produced from tobacco stalk biomass under pyrolysis conditions of 500 0C temperature and 90 minutes holding time and synthetic zeolite was procured from zeolite and allied products, Mumbai. The two soil amendments alone and their combinations with recommended dose of nitrogen and potassium were tested in the present experiment. Each leaching event was performed with 5cm irrigation equivalent. 60 g of TS Biochar, 15 g of SZ, and their combinations with fertilizer (ammonium sulphate @ 7.1 g and potassium sulphate @ 6.72 g) and without fertilizer were mixed with 5cm soil layer of columns. Amount of water leached in each leaching event was measured and the leachate samples were analyzed for ammonium and potassium. The results indicated that on an average maximum retention of water was recorded in TS Biochar treated columns. The column that received fertilizer alone without any soil amendment has retained minimum amount of water. Cumulative ammonium (NH4+) and potassium (K+) leaching was measured in treated and control plots. Cumulative ammonium and potassium concentrations were higher in fertilizer alone without any amendment treated column. The TS Biochar has effectively inhibited the leaching of ammonium and potassium by 28.10 and 25.28 per cent, respectively. Whereas the SZ, inhibited leaching of 5.09 and 4.71 % of ammonium and potassium, respectively. The inhibition of ammonium and potassium leaching by TS Biochar could be attributed to appreciable cation exchange capacity and amount of increased water retention over fertilizer alone control and unamended unfertilized control.