Biochar Application: An effective Measure in Improving the Fertility Status, Carbon Stock and Aggregate Stability of Eroded Soil

Abstract

In search for an efficient means of building up the carbon stock, improving the fertility levels and aggregate stability of tropical soils for optimum crop yield, a field study was carried using different biochars and comparing the effects with inorganic fertilizer. The biochars were palm bunch biochar (PBB), saw dust biochar (SDM) and rice mill husk biochar (RMHB). Treatments consisted of 10 t/ha palm bunch biochar + 0.25t/ha poultry manure (T1), 10 t/ha rice mill husk biochar + 0.25t/ha poultry manure (T2), 10 t/ha saw dust biochar + 0.25t/ha poultry manure (T3), 500kg/ha N.P.K 15:15:15 fertilizer + 0.25t/ha poultry manure (T4) and plot without biochar + 0.25t/ha poultry manure (T5) (control plot). These were replicated five times on experimental plots of 4m2 in a randomized complete block design. Maize (Zea mays) was used as a test crop and data obtained were statistically analyzed using analysis of variance and correlation. Soils amended with biochars significantly improved soil pH, organic carbon, exchangeable bases and base saturation than non biochar fertilized soils. Saw dust biochar increased soil carbon stock by 95.1% against NPK fertilizer plots and control. There was 19% decrease in soil bulk density and 17% increase in soil pH with application of palm bunch biochar. Amending soils with palm bunch biochar increased soil organic carbon by 51.5%. The biochars increased the values of critical level of soil organic matter, modifies clay ratio and reduced the value of clay flocculation index more than NPK fertilized soils or control. Among the treatments, rice mill husk biochar recorded the highest maize cob weight though not significant with palm bunch biochar. Therefore, applying biochars on eroded soil is an effective measure of improving the stability, soil carbon stock as well as enhancing higher maize yield than inorganic fertilizer.