Optimization of organic fertilizer production using the co-composting process of cow manure and chicken manure with the addition of plant organic waste

The rising volume of agricultural waste underscores the need for efficient organic fertiliser production. This study assessed co-composting of cow, sheep and chicken manure with sugarcane leaves, bamboo leaves and banana residues, with and without EM4 microbial activation. Fermentation remained stable across treatments, with alkaline pH (7.7–8.6), curing-phase temperatures (25–27 °C) and moisture levels of 35–49%. Final compost nutrients showed wide variation: nitrogen 0.88–2.28%, phosphorus 1,100–2,478 ppm and potassium 2,360–5,801 ppm, with EM4-activated, manure-rich mixtures achieving the highest nutrient densities. Ash content (7–28%) confirmed advanced organic-matter decomposition in several treatments. Cucumber bioassays demonstrated strong fertiliser efficacy, with the best composts supporting plant heights of 190– 205 cm and more than 30 leaves by Week 8, outperforming lower-nutrient formulations. These findings show that co-composting diverse animal and plant wastes especially with microbial activation produces nutrient-rich, mature compost capable of significantly enhancing vegetable growth, offering a scalable and sustainable strategy for agricultural waste valorisation.