Characterization of Biochars Derived from Different Organic Wastes

Abstract

Biochar is widely recognized as an efficient tool for soil fertility and carbon sequestration. The understanding of its physical and chemical properties is strongly related to the type of used material, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes (e.g., rice straw, rice husk and saw dust) with different characteristics were pyrolyzed at 350 0C in order to optimize the physical and chemical properties of biochar as a soil amendment. Bulk density of biochar samples in this study varied from 0.18 mg/m3 to 0.22 mg/m3. Moisture content was in the order of saw dust (8.41%) > rice straw (7.21%) > rice husk (6.74%). Rice straw biochar had highest pH (8.80) and electrical conductivity, EC (3.45 ds/m). The organic carbon was highest in rice straw biochar (46.50%) followed by with rice husk (39.3%) and saw dust (25.3%). The total nitrogen contents of the rice straw, rice husk and saw dust were 1.78%, 1.59% and 1.11%, respectively. The rice straw biochar contents higher available P, as compared to rice husk and saw dust biochar. The rice straw biochar had higher exchangeable Ca (5.60 meq/100 g), Mg (1.70 meq/100 g). This study suggested that the rice straw biochar has a great potential as soil amendment among the three biochars for sustainable soil management.