Indian Journal of Agricultural Research

This study evaluates the potential of local agricultural residues namely longkong peel, cajeput bark and oil palm bunches-as sustainable alternatives for fertilizer production in Narathiwat Province, Thailand. The use of compost made from these residues can offer a cost-effective and environmentally friendly solution to improve soil fertility and reduce dependency on chemical fertilizers.

The raw residues and their corresponding composts were chemically analyzed for their nutrient content. Fertilizer equivalence was calculated to estimate their potential contribution to soil nutrient supply. A plant growth experiment was conducted involving treatments comprising of longkong peel, cajeput bark and oil palm bunch composts, as well as a control group and standard fertilization to assess the influence of these composts on plant height and fresh weight.

The chemical analysis showed that longkong peel compost had the highest nutrient content, with (2.59% N; 1.41% P₂O₅ and 2.96% K₂O). Cajeput bark compost having a higher carbon-to-nitrogen (C/N) ratio, resulted in slower decomposition and nutrient release. Oil palm bunch compost displayed moderate nutrient levels. Fertilizer equivalence analysis indicated that longkong peel compost provided the highest nutrient equivalence, with an estimated annual contribution of 610 tons of nitrogen, 332 tons of phosphorus and 698 tons of potassium. Plant growth experiments with maize showed that longkong peel and oil palm bunch composts (145.75 cm in height and 80.75 g in fresh weight) being highest with oil palm bunch. significantly improved plant height and fresh weight. Cajeput bark compost also enhanced plant growth, but to a lesser degree.