Vermicasts produced from different culture media

The quality of vermicasts produced by African Night Crawler as influenced by different culture media was determined and its effect on 'pechay' (Brassica rapus) yield was assessed. The common/based materials utilized as culture media were fermented rice hull, sawdust, and rice bran, kakawate (Gliricidia sepium) and 'ipil-ipil' leaves. These materials were mixed following the recommended ratio and combined with carabao manure, cattle manure, sheep manure, goat manure and chicken manure represented as T1, T2, T3, T4, and T5, respectively. Harvesting of castings commenced 90 days after the stocking of worms. Watering of substrates was stopped for 1 week to make the separation of castings easier. Pechay was used as the experimental plants due to its high demand in the local market and ease in it culture. The color of the castings was described by visual observation and under moist condition. Based on the criteria, T1, T2, and T3 were described as dark brown, T4 which was described as black had the darkest color while T5 which was described as brown had the lightest color. The color of the soil tells much about its condition. Generally, the darker the color, the higher is its productivity. This is due to the OM [organic matter] content and the humic substances present in the soil (McCollum 1975). Among these five different culture media, T4 (base/common materials + goat manure) has the highest N content (1.76%), T5 (base/common materials + chicken dung) contained the highest P (4.20%) and T3 (base/common materials + sheep manure) has the highest percentage of exchangeable K content (1.76%). The pH values of the castings ranged from 6.4 for T4 and 7.6 for T3. The pH range can be described as nearly neutral. These data implied that there was not much accumulation of organic acids in the castings that can be detrimental to the plant. As to the OM content of the vermicasts, the highest value was observed in T4 at 30.4% and the lowest value was noted in T1 (12.6%). For the mean weight of pechay, T4 got the highest at 4.3 g and T1 had the lowest at 2.4 g. However, T4 and T3 did not differ significantly. JMoreover, T4 had the highest mean yield of 3.89 kg and T1 with 2.18 kg was the lowest. Further, DMRT [Duncan multiple range test] showed that T4 was comparably significant with T3. This implied that manures from small ruminants when used as culture media for African Night Crawler would result in increase in pechay weight and yield. Based on the price of P35/kg of pechay, the highest ROI [return on investment] was in T4 at 63.76% followed by T3 at 51.10%, and T2 at 18.07%. Treatments 1 and 5 provided negative ROI value. Based on the result, goat manure + base/common materials can be considered as the most effective culture media in vermicomposting despite the fact that the total NPK content of goat manure (6.69%) was lower than chicken manure (10.04%). Goat manure, however, has higher NPK value as compared with carabao manure with 3.15% NPK content.