Ameliorating Effects of Leucaena Biochar on Soil Acidity and Exchangeable Ions

Abstract

The amendment effect of Leucaena biochar was investigated in incubation study in acidic soil (pH (water (H2O)) = 4.5) of northwest India. The biochar (BC) was mixed at 2%, 4%, and 6% with soil and change in soil pH, electrical conductivity (EC), ammonium () and nitrate nitrogen (), exchangeable bases (calcium + magnesium, potassium, sodium) (Ca + Mg, K, Na), aluminum (Al), and Bray’s phosphorus (P) were measured periodically. The mean increase in soil pH was 0.65, 1.35, and 2.0 unit at 2%, 4%, and 6% (w/w) of biochar incorporation, respectively. Application of biochar significantly (P < 0.01) reduced ammonium () content of soil, whereas NO3-N concentration increased by threefold and fivefold by application of 2% and 4% (w/w) of biochar, respectively. Exchangeable soil potassium (K) and Ca + Mg concentrations increased with the application of biochar. Application of biochar above 2% (w/w) reduced exchangeable Al concentration to nondetectable limit. The study suggests Leucaena biochar may serve as an amendment for N transformation in highly acidic soil.