Asian Journal of Soil Science and Plant Nutrition

The sustainable management of coconut biomass waste is a critical challenge in Kerala's agricultural sector, where systematic replanting generates substantial residues. This study evaluates the efficacy of converting this waste into nutrient-enriched coco-briquettes for use as a slow-release fertilizer (SRF) in chilli (Capsicum annuum L., variety Ujwala) production. the briquettes were produced from powdered coconut shell, husk, leaf, and wood waste and enriched with chemical fertilizers at 100% (T₅) and 75% (T₆) of the recommended primary nutrients.

A field experiment compared these briquette treatments against standard strategies, including the Kerala Agricultural University (KAU) Package of Practices (T₂) and soil test-based recommendations (T₄). Chemical analysis revealed that the coco-briquettes possess a nutrient-rich organic substrate with high organic carbon (51.50%) and lignin (25.65%), suggesting a slow decomposition rate beneficial for long-term soil structure. Results indicated that while soil test-based recommendations (T₄) achieved the highest total yield (1543.25 kg/ha) and capsaicin content (0.77%), the 100% nutrient-enriched briquettes (T₅) performed competitively, yielding the third best biometric observations and second-highest ascorbic acid content (32.89 mg/100g). Furthermore, briquette-amended soils showed high organic carbon levels (up to 1.22%) compared to traditional inorganic treatments. However, the application of briquettes also led to a slight reduction in soil pH and increased electrical conductivity (EC) due to high salt and lignin concentrations. The study concludes that nutrient-enriched coco-briquettes serve as an effective delivery system, combining immediate nutrient availability with the structural benefits of organic matter. Future applications should involve pre-treatment of biomass to mitigate soil acidification and high salinity issues.