Valorization of Lac Processing Waste as an Organic Soil Amendment for Tomato (Solanum lycopersicum) Growth

Abstract

The lac industry generates substantial waste during the scraping, washing, and processing of raw lac, which is often discarded or burned, causing environmental pollution and resource loss. Considering its rich organic and resinous composition, lac waste holds potential as a sustainable soil amendment. This study explores the eco-friendly conversion of lac processing waste from Lac Processing Industry into a nutrient-enriched organic sustenance, promoting circular economy principles in lac-based industries. Lac processing waste (lac mud) was subjected to controlled composting and nutrient fortification using rice husk ash (RHA), and fly ash. Seven treatments were prepared, including control soil and chemical fertilizers. Physico-chemical parameters (pH, EC, organic carbon), NPK content, and micronutrients were analyzed. Pot culture experiments were conducted using Solanum lycopersicum to evaluate germination percentage, plant height, root length, leaf number, chlorophyll content, and biomass. Statistical analysis (ANOVA) assessed treatment significance. Among all treatments, T4 (Lac Mud + RHA) showed superior performance. It recorded the highest mean soil pH (8.04 ± 1.25), moderate EC (2.50 dS m⁻¹), and elevated organic carbon (1.12%). Nutrient enhancement was significant (N: 0.091%, P: 0.041%, K: 0.52%). Germination rate was highest (mean 90%), with maximum leaf number (140.66) and plant height (9 cm). Compared to chemical fertilizers, T4 significantly improved soil fertility, microbial activity, and plant growth parameters. Lac processing waste can be effectively converted into a nutrient-rich bio-organic fertilizer. The integrated application of lac mud and rice husk ash (T4) demonstrated superior soil conditioning and crop growth performance over chemical fertilizers. This approach offers a cost-effective, eco-friendly alternative for sustainable agriculture while reducing industrial waste and promoting circular economy practices.