Rice husk is the hard outer shell of rice grains, separated during the milling process. Abundantly available in Vietnam, it is an eco-friendly and versatile by-product widely used as animal bedding, organic fertilizer, soil conditioner, biomass fuel, and raw material for construction and industrial applications. With high absorbency, good aeration properties, and natural silica content, rice husk helps improve soil structure, retain moisture, promote root growth, and support sustainable agriculture and environmental solutions.