VALORIZATION OF AGRICULTURAL WASTES INTO DENSIFIED BIOCHAR PELLETS: IMPLICATIONS FOR SOIL HEALTH AND SUSTAINABLE CROP PRODUCTION

Abstract

The increasing accumulation of agricultural residues presents significant environmental
challenges while simultaneously offering opportunities for sustainable resource utilization. This
study investigated the valorization of locally available agricultural wastes into densified biochar
pellets and evaluated their implications for soil health and sustainable crop production.
Specifically, the study developed and characterized biochar pellets produced from rice hulls, corn
cobs, coconut husks, sugarcane bagasse, and peanut shells through pyrolysis and pelletization;
assessed their effects on soil chemical properties, organic matter dynamics, and nutrient
availability; and examined their influence on the growth and yield performance of major cereal,
legume, vegetable, and root crops. A laboratory-experimental and field research approach was
employed using pyrolysis for biochar production, greenhouse incubation experiments, and field
trials arranged in a Randomized Complete Block Design (RCBD) with three replications. Soil and
biochar samples were analyzed for pH, organic matter, organic carbon, nitrogen, phosphorus,
potassium, and selected micronutrients using standard laboratory procedures. Results revealed
that all biochar formulations possessed alkaline properties and contained appreciable levels of
essential macro- and micronutrients. Peanut shell biochar exhibited the highest organic matter,
organic carbon, nitrogen, phosphorus, and iron contents, whereas corn cob biochar contained the
highest potassium, zinc, and manganese concentrations. Application of pelleted biochar
significantly improved soil pH, organic matter, nutrient availability, and soil fertility, with
sugarcane bagasse and corn cob biochars demonstrating superior performance in enhancing soil
chemical properties. Crop evaluation further showed that biochar treatments improved yields
across various crops, while combining pelleted biochar with recommended or reduced rates of
inorganic fertilizer consistently produced the highest yields, indicating improved nutrient-use
efficiency and reduced dependence on synthetic fertilizers. Overall, the findings demonstrate that
densified biochar pellets derived from agricultural wastes represent an effective and sustainable
soil amendment capable of enhancing soil quality, increasing crop productivity, promoting
agricultural waste valorization, and supporting climate-resilient organic farming systems. The
study highlights the potential of integrating biochar technology into sustainable agricultural
management strategies to improve long-term soil health and food production while contributing
to environmental conservation.