QUALITY IMPROVEMENT OF ORGANIC COMPOST USING GREEN BIOMASS

An experimental study following the completely randomized design (CRD) was conducted to address the low nutrient content of compost product from crop residues. Rice straw and corn stalks which were the locally available crop residue were used as the main compost material, while succulent stems plus green leaves of Ipil-ipil (Leucaena leucocephala) and wild sunflower (Tithonia diversifolia) were used as the green biomass material. Treatments were crop residue and green biomass combinations at 3:0, 3:1, 3:2 and 3:3 ratios subjected to rapid composting method with the aid of Trichoderma harziamum as activator. Using the compost products mixed with pure soil at 1:1 ratio, pot experiment was conducted to test the effect of green biomass-enriched compost on the early growth of eggplant (Solanum melongena) and green pepper (Capsicum annuum). The results indicated that, gradual enrichment of crop residue compost with green biomass especially those prepared at 3:3 and 3:2 crop residue-green biomass combinations gave significant increase in the Nitrogen, Phosphorous and Potassium contents of the compost. It also showed significant improvement on the percent organic matter, pH level, and weight of the compost product. The results further revealed that the use of green biomass-enriched crop residue compost significantly stimulated plant growth in terms of plant height, number of leaves, size of leaves, number of buds, and total weight of fresh plant biomass. The overall findings of the study indicated that gradual application of green biomass during composting of crop residue produced better quality of compost that can be used to stimulate plant growth