Characterization of Pyrolysis-Mediated Biochar from the Petiole of Cocos nucifera (L.) and its Effect on Soils from Diverse Agroecosystems of Kerala, South India

Crop residue burning is a major environmental concern all over the world. Agricultural leftovers can be pyrolyzed to biochar and used in the soil as a sustainable means of carbon sequestration. In this study, pyrolysis-assisted biochar was produced from the petiole of Coconut palm (Cocos nucifera, L,) under experimental conditions. The coconut petiole was pyrolyzed at an optimum temperature of 350degree celsius for 90 min (as per standardization studies) and the physicochemical properties of the resultant biochar were assessed. In addition to this, elemental analysis, specific surface area assessment, Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) studies were also performed. The study also attempted to analyze the short-term effect of biochar on the physicochemical properties of soil from three agroecosystems of Kerala, representing highland, midland, and lowland. Coconut petiole biochar (CPB) application significantly enhanced soil pH, electrical conductivity (EC), soil organic matter (SOM), water holding capacity (WHC), and Total heterotrophic bacteria (THB), but significantly reduced the resistivity and Total heterotrophic fungi (THF). Principal component analysis (PCA) showed that the first component (PC1) explains 93.01%, 72.71%, and 92.42% of the total variability in the data corresponding to lowland, midland, and highland regions, respectively. Superior increments in the soil properties were observed while increasing the biochar concentration from 0.5 to 1.5%. The biochar characterization by SEM, FTIR, and XRD studies confirm the quality of coconut petiole biochar, viz., surface area, pore volume and size, oxygenated groups, amorphous nature, and carbon content, which have a substantial impact on its ability to adsorb water and thereby retain bacterial load in the soil.