Efficiency of Biochar and Bio-Fertilizers Derived from Maize Debris as Soil Amendments

Abstract

Unsuitable handling of crop residues can result in many environmental problems such as air pollution and soil degradation. In the northern parts of Thailand, such problems are partly caused by the burning of agricultural debris after harvesting. The use of maize debris as an amendment for degraded soil can reduce such problems. The aims of this research were twofold. Firstly, to produce biochar and bio-fertilizer from maize debris to improve the quality of degraded agricultural soil. Secondly, to study the efficiency of biochar and bio-fertilizer in Chinese kale (Brassica alboglabra) cultivation with two different water regimes. From the study, it was found that 2.8 kg of dry maize debris could produce 1 kg of biochar and could store 13.6% organic carbon, while 0.5 kg of dry maize debris mixed with 1.1 kg of cow dung could produce 1 kg bio-fertilizer and could store 16.4% organic carbon. Watering once a day resulted in an increase in the yield which was comparatively greater than watering twice a day. By adding bio-fertilizer at 25% (w/w) in soil, the fresh weight of the kale plants was found to be about six times greater than those grown in an untreated soil. A suitable amount of bio-fertilizer to be added to soil for Chinese kale cultivation ranged between 15-30% (w/w), while a maximum of 25-30% (w/w) bio-fertilizer in soil was sufficient for plant growth and it was not necessary to add biochar to the soil.