Applying Cassava Stems Biochar Produced from Agronomical Waste to Enhance the Yield and Productivity of Maize in Unfertile Soil

Abstract

Many agronomical wastes are produced annually in significant amounts after cultivation, especially in agricultural countries. This study applied biochar produced from the pyrolysis of cassava stems to improve soil with low fertility for maize cultivation. The effect of soil biochar incorporation on maize yield and productivity was also investigated. Eight experimental plots, each with four replicates, were applied with cassava stem biochar (CSB) at different rates of 0.5 kg/m2 (TB0.5), 2.5 kg/m2 (TB2.5) and 3.0 kg/m2 (TB3.0), fertilizer at 0.56 kg/m2 (TM), fertilizer at 0.56 kg/m2 mixed with CSB at 0.5 kg/m2 (TMB0.5), 2.5 kg/m2 (TMB2.5), 3.0 kg/m2 (TMB3.0) and untreated soil (TC). Pyrolysis of cassava stems at 450–500 °C produced strongly alkaline CSB with pH 9.6 and increased nutrient contents. Specific surface area and total pore volume increased, and pores were classified as mesoporous, while average pore diameter decreased. CSB had a highly stable carbon content of 58.46%, with high aromaticity and polarity obtained from O/C and H/C ratios. Results indicated that CSB enhanced and supported maize growth by improving soil physicochemical properties to suit cultivation. Applying CSB into the soil gave higher maize yield and productivity than cultivation using fertilizer. The highest yield and nutrition contents were obtained in seed from cultivation using fertilizer mixed with biochar at 3.0 kg/m2. Biochar production from cassava stems generated a useful commodity from waste material.

Keywords

• biochar
• cassava stems
• agricultural wastes
• maize yields
• soil amendment
• resilient agricultural