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Empty fruit brunch compost: processing and utilities

Siregar F.A., Salètes S., Caliman J.P., Liwang T., Raham D.. 2002. In : Poeloengan Zulkarnain (ed.), Guritno Purboyo (ed.), Darnoko D. (ed.), Buana Lalang (ed.), Purba Abdul Razak (ed.), Darmosarkoro W. (ed.), Sudharto Ps (ed.), Haryati Tri (ed.), Elisabeth Jenny (ed.), Siahaan Donald (ed.), Wahyono Teguh (ed.). Enhancing oil palm industry development through environmentally friendly technology : Proceedings of agriculture conference, 2002 International Oil Palm Conference, Nusa Dua, Bali, July 8 - 12 2002. Medan : IOPRI, p. 225-234. International Oil Palm Conference, 2002-07-08/2002-07-12, Bali (Indonésie).

Empty fruit bunches (EFB) are available in large quantities in oil palm factories. Every tonne of crude palm oil produced generates also one tonne of EFB. This represents huge quantities of organic matter that can be used to sustain physical, chemical and biological soil fertility. There are specific situations where field application of fresh EFB is not feasible due either to particular ecological situations (peat soil, low-land areas) or to specific organization scheme (independent factories without plantations). In such cases, composting represents an interesting solution, by reducing both weigh and volume of the initial product, while keeping benefit of organic matter. In Indonesia, P.T. SMART Tbk. has carried out several trials since 1997. The results show that it is possible to reduce the initial volume and weigh of EFB by 80% and 55% respectively, after 14 weeks of composting. High initial C/N ratio of EFB can be decreased by addition of N content products like Urea or mature compost, which improve the activity of microorganisms for a faster process. Addition of mature compost at the initial stage of composting, followed by an application of urea 2 weeks later provide the highest beneficial effect. On the other hand several commercial products have been tested in order to activate the composting process. None of them has given significant results. One key parameter is the temperature of the compost during the process, which is related to the humidity and the aeration of the heaps. The results seem to confirm that optimum humidity is around 60% For that purpose natural rainfall should reach around 80 mm / week and be regularly distributed. Irrigation with mill effluent can be a very valuable substitute for water when rainfall is too low, or when composting in a covered area. A calendar of irrigation with effluent is proposed, with variable rates and frequencies depending on the composting phases. One of the points that still needs to be improved concerns the final balance of nutrient. A significant part of potassium, but also nitrogen, phosphate and magnesium seems to be lost through leaching. A specific composting scheme is proposed in order to overcome this problem. Mature compost can be used as a substitute for mineral fertilizer in nurseries. A trial shows that 7.5 kg of compost mixed with usual topsoil in polybags can replace standard mineral fertilization. Lower rates of compost can also be proposed, combined with reduced mineral fertilizer regime. (Résumé d'auteur)
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