Received: 29 March, 2011. Accepted: 15 August, 2011. Original Research Paper Dynamic Soil, Dynamic Plant ©2012 Global Science Books Vermicomposting of Coffee Processing Wastes Kulandaivelu Velmourougane 1,2* • Kurian Raphael 3 1 Post Harvest Technology Lab, Coffee Research Substation, Chettali Post, North-Coorg, Karnataka, India 2 Present address: Central Institute for Cotton Research, Indian Council of Agricultural Research, Nagpur- 440010, Maharashtra, India 3 Division of Entomology, Coffee Research Substation, Chettali Post, North-Coorg, Karnataka, India Corresponding author: * velicar@gmail.com ABSTRACT In India, nearly 80% of arabica and 20% of robusta coffee are prepared by wet method. One tonne of coffee pulp is generated for every tonne of clean coffee (coffee beans) processed. Coffee wastes are lignocellulosic enriched residues that can be used as soil fertilizers; however, the direct application of these residues to coffee plants can cause serious environmental problems. Therefore, it is necessary to find a suitable methodological alternative to reduce the environmental problems associated with their management. Considering the significance of the situation and shortage of organic manure in coffee plantations, a case study was conducted in Coorg District of Karnataka in three coffee growers farms to evaluate the efficiency of an exotic (Eudrilus eugeniae) and a native earthworm (Perionyx ceylanensis) for bioconversion of coffee pulp into valuable vermicompost. The analysis revealed that exotic earthworms were faster in degrading coffee pulp (112 days) as compared to the native worms (165 days). The vermicomposting efficiency (77.9%) and vermicom- post yield (389 kg) were found to significantly higher with native worms, while the multiplication rate of earthworms (280%) and worm yield (3.78 kg) recorded significantly higher with the exotic earthworms. The plant nutrients, nitrogen and phosphorus content found to increase significantly in the vermicompost produced using native earthworms. Vermicompost and vermicasts from native earthworms recorded significantly higher functional microbial group’s population as compared to the exotic worms. The study reveals that coffee pulp can be very well used as substrate for vermicomposting using exotic (Eudrilus eugeniae) and native earthworm (Perionyx ceylanensis). _____________________________________________________________________________________________________________ Keywords: coffee pulp, Eudrilus eugeniae, Perionyx ceylanensis, microflora, nutrients Abbreviations: ANOVA, analysis of variance; Cfu, colony forming units; FYM, farm yard manure; PSM, phosphorus solubilizing microbes INTRODUCTION Among the various commercial plantation crops, coffee forms an important export commodity that fetches conside- rable foreign exchange to the producing countries. In India, coffee is cultivated mainly in Southern states of Karnataka (58% of area and 72% of production), Kerala (25% of area and 20% of production) and Tamil Nadu (9% of area and 7% of production) (Velmourougane et al. 2010). In India, nearly 80% of arabica and 20% of robusta coffee are pre- pared by wet (parchment coffee: removal of fruit skin fol- lowed by fermentation, washing and drying) and dry method (cherry coffee: fruits are directly sun dried) respectively (Velmourougane et al. 2011). Coffee is a perennial crop and is mostly confined to hilly tracts of Western Ghats. In general, coffee requires higher nutrients for its growth and productivity compared to other crops. The availability of organic manures particularly the farm yard manure (FYM) is a major problem in coffee plantations because of non- availability of cattle’s, but the FYM can be substituted by application of composts if composting is practiced at on- farm level in coffee farms (Muralidhara et al. 2006). In the present low price situation, coffee growers are unable to invest on chemical fertilizers for their plants, though reduc- tion of chemical fertilizers seems to be positive in environ- mental view but the required quantity of nutrients removed should be replenished with alternative source. In coffee plantations, coffee pulp and cherry husk are the major solid wastes obtained during coffee processing (Table 1). About one ton of husks are generated during dry processing, whereas for wet and semi-wet processing this residue amounts to more than 2 tonnes (Aranda and Barois 2000). Coffee pulp and cherry husk are lignocellulose-en- riched residues that can be used as soil fertilizers, providing a high content of macro- and micronutrients for crop growth and represent a low-cost alternative to mineral fertilizers, but coffee pulp also contains little amount of caffeine, tan- nins and polyphenols making them toxic and anti-nutri- tional resulting in the disposal problem, the direct and in- appropriately-timed application of these residues to agricul- tural fields can cause serious environmental problems, in- cluding the release of excessive amounts of tannins and phenols in soils, which could inhibit root growth in coffee (Nagaraja et al. 2000). Due to the presence of anti-phy- siological and anti-nutritional factors, coffee pulp and husk is not considered as an adequate substrate for the bioconver- sion process. Several authors have worked on detoxification of coffee pulp and husk through various means viz., phy- sical, chemical and microbiological (Muralidhara et al. ® Table 1 Coffee processing wastes and its composition. Processing methods Weight (kg) Wet processing (for 100 kg of coffee cherries) Beans with mucilage 60-62 Pulp/fruit skin 38-42 Wet parchment 43-46 Mucilage 17-20 Dry processing (for 100 kg of dry cherries) Cherry husk 46-48 Constituents (coffee pulp) % by weight Moisture content 12.7 Ash 8.30 Crude protein 9.30 Ether extracts 11.7 Soluble carbohydrates 56.0