Evaluation of Manurial Value of Urban and Agricultural Waste Composts

The hygienic disposal of organic wastes by composting is an environmentally-sound and economically-viable technology resulting in the production of organic fertilizer which is a basic and valuable input in organic farming. Methods of composting for the production of organic manures of high quality were standardized. Composting methods with enrichment techniques were adopted with 2 methods (aerobic and anaerobic) and 7 treatments in each method. The samples of the aerobic compost were drawn after 30, 60, 90 and 120 days after composting and in anaerobic compost samples were drawn after 150 days of composting. Effect of bio-inoculum (Pleurotus sajorcaju), chemical amendments (0.88% P and 1% N) and method of composting on organic carbon (OC), chemical oxygen demand (COD), cation exchange capacity (CEC), C/N ratio, pH, EC and total nutrient status during composting was determined in aerobic and anaerobic composts. The OC, COD, C/N ratio decreased significantly during maturation of the compost irrespective of treatments and method of composting. High organic carbon was recorded in 100% urban solid waste (USW) compost in both the methods. It ranged from 20.15 to 24.0% in aerobic matured compost and from 21.5% to 23.25% in anaerobic matured compost. The 100% agricultural waste (AW) compost had lower C:N ratio (18.65 and 17.47 in aerobic and anaerobic composts, respectively) than 100% USW compost (19.20 to 18.02 in aerobic and anaerobic compost, respectively). Nitrogen content increased from 0.78 to 1.29% in 100% urban waste compost and from 0.75 to 1.23% in 100% agricultural compost. Rock phosphate treated composts in both the methods enhanced the total P content with maximum of 0.89% in both aerobic and anaerobic composts. There was a gradual increase in total K content from the initial status of 0.44 to 0.64%.