Comparative analysis of nutrients composition in biochar produced from different feedstocks at varying pyrolysis temperature

Abstract

Biochar has proved to be effective in improving soil fertility and it is important to know its nutrients variability asinfluenced by pyrolysis temperature and feedstock type for optimum agricultural productivity. In this experiment fourdifferent feedstocks from animal and plant sources were selected and pyrolysed at four different temperatures of 300,400, 500 and 600 ˚C for 3 hours at a heating rate of 10 ˚C $min^{-1}$. The feedstocks were Corn cob (CC), Poultry litter (PL),Cow dung (CD) and Peanut shell (PS). The results showed that increase in pyrolysis temperature led to decrease in theconcentration of many of the parameters analysed in the biochar. At the lowest temperature of 300 ˚C the highestcontents of (0.62 %) N in CD, (66.4 mg $g^{-1}$) P in CC, (8.38 mg $g^{-1}$) K in CD, (16.2 mg $g^{-1}$) Ca in CC, (4 21 mg $g^{-1}$) Mg in CC,(0.28 %) S in CC, were observed. On the other hand, increase in temperature resulted to increase in C, pH, Ash contentand the highest pH value of 10.17 was found in CD. From this study, it can be deduced that feedstocks from animalsource shows a high range of nutrient when compared to feedstocks from plant source and likewise increase intemperatures led to decrease in some essential nutrient needed by plant for growth and stability in the soil.