Grass clippings to biochar: A promising soil amendment for sustainable agriculture under drip irrigation

Soil fertilization is commonly used to improve soil quality for enhanced agricultural production. Biochar has attracted attention due to its ability to improve soil fertility and decrease the requirements of multinutrient inorganic fertilizers that contribute to greenhouse gas emissions. This work assesses the effect of pyrolysis conditions on the physical and chemical properties of biochar derived from green waste, specifically St. Augustine grass (Stenotaphrum secundatum). The biochar has varying surface areas ranging from 24 to 187 m²/g and surface chemistry with a greater content of the basic groups. The results indicate that potassium and phosphorus can leach from biochar via different mechanisms, confirming that biochar has the potential to be used as fertilizer. Biochar loaded with NPK fertilizer changed the leachate mechanism and improved some chemical properties. Finally, the drip irrigation experimental setup proposed for evaluating ion leachate in biochar approximates an actual agricultural system.