Development of Organic Fertilizer Products and Systems to Improve Soil Fertility of Organic Vegetable Production of Cabbage in Benguet, Philippines

Abstract

Formulation of organic fertilizers were studied to support organic vegetable production in Benguet, Philippines. The formulated liquid organic fertilizers based on farmers’ concoctions showed very low nutrient contents. New formulations using legume seeds were done which resulted to higher nutrient contents. Likewise, solid organic fertilizers were formulated using locally available raw materials. A combination of 50% chicken manure, 20% sawdust, 20% sunflower leaves, 10% Alnus compost and Trichoderma gave the highest nutrient contents. The solid and reformulated organic liquid fertilizers and Trichoderma were tested on cabbage grown in farm under conversion to organic production. Lower yields were observed during the early part of conversion. However, after three years of conversion, the yields of cabbage had significantly increased which were comparable to the yield in conventional farms. The recommended rates of solid and liquid formulated organic fertilizers found effective for both cabbage are 10t/ha of formulated solid fertilizer and 60 ml/L of liquid fertilizer, respectively. The nutrient management system found effective for organic production of cabbage was the application of Trichoderma two weeks before planting and split application of solid organic fertilizers three times during the growing period, that is, before planting, 15 days after planting and 30 days after planting at the rate of 2.5, 2.5 and 5.0 t/ha, respectively. The organic liquid fertilizer was applied at the rate of 60 ml per liter of water 15 days after planting and every two weeks thereafter until cabbage heads have formed. This nutrient management system provided the crops the essential nutrients during the critical growth and reproductive stages which resulted to higher yields comparable to those produced in conventional farms.