Organic fertilizer production from solid wastes and its utilization in vegetable production

De la Cruz et al. (CLSU) developed and improved a technology on producing organic fertilizer from solid wastes. Also, the researchers, through field experiments, determine the efficacy of organic fertilizer product and by-product like composts leachate in vegetables like lettuce, tomato and pechay. Composting procedure is presented. Findings of the study revealed the following: Organic materials. For lettuce production under greenhouse condition, the incorporation of 16 t/ha of composted household wastes (CHW) yielded almost the same as the incorporation of combined CHW and coco coir dust (CCD), soil-less CHW and soil-less combined CHW and CCD. Yield ranged from 5.6 kg/sq m to 6.2 kg/sq m plot. Residual effects of organic materials such as CHW, CCD, and CCD + CHW previously used as growth media for lettuce production were observed. The bulk density decreased with the porosity and water-holding capacity increased. Also, the soil organic matter, total nitrogen, exchangeable potassium, and available phosphorus were higher compared with plots without the organic material. Yield of grafted tomatoes (Maxima variety) grown in plots previously used for lettuce production varied significantly among treatments. Results, however, indicated the potential of the cited organic materials as growth media in the greenhouse production of lettuce as the first crop followed by grafted tomato. Organic Fertilizer. Yields of lettuce and pechay grown in open fields were comparable in all treatments (application of 26 t/ha organic fertilizer, 140-90-90 kg NPK, and 50% organic + 50% inorganic fertilizer). However, yields in the third cropping were lower than the first two cropping because of high temperature during the period and the high damage due to insect. Analysis of soil N and P using the soil test kit showed improvements from the initial value of low to medium and high. The decreasing trend in the soil bulk density value indicated improvements in soil porosity. Compost leachate. The use of compost leachate or compost tea as nutrient source for eggplant and lettuce was evaluated by comparing it with two commercial foliar fertilizers and granular fertilizer. The application of 1/2 L leachate per hill + 1/2 recommended rate (RR) of 120-60-60 kg NPK/ha, effected better yield over the RR, registering a 55.39% yield increase in eggplant. The application of 1 L/hill compost leachate in lettuce yielded almost the same as the application of 90-30-30 kg NPK/ha from granular fertilizer, but an 89% yield increase was observed, when compared with the application of inorganic fertilizer alone. A positive net benefit was obtained in all treatments. Net benefit from household compost leachate was close to the net benefit from recommended rate of granular fertilizer. Household compost leachate could be a potential plant nutrient source for lettuce production. Economic analysis of producing 1,200 bags of organic fertilizer for 12 cycles (27-30 days/ cycle) revealed gross sales of P180,000 and net income of P49,750. Production of organic fertilizer from solid wastes and its use in crop production is recommended. This would further improve the soil condition and at the sane time enable recycling of solid wastes.