DENICH, M.

JONSSON, A.

VIELHAUER, K.

VLEK, P. L. G.

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No. 137Title: Energy balance of a traditional and a modifled land-use systemin the Eastern Amazon Basin, Brazil, as a case studyAuthors: Jõnsson, Axel, (1) Denich, Manfred (2), Vielhauer, Konrad (3) and Vlek, P.L.G. (2)Institutions: (I) Universitãt Gõttingen, Gõttingen, Deutschland (2) Zentrurn für Entwicklungsforschung,Universitãt Bonn, Deutschland (3) EMBRAPA Amazônia Oriental, Belém-PA, BrazilContent of Abstract:The comparative case study traces anthropogenous energy input into land-use systems in tropical Brazil, andoutput in terms of agricultural production with related CO2 emission into the atrnosphere in the instances ofgrowing passion fruit (Passiflora edulis Sims varo flavicarpa Degener) and cassava (Manihot esculenta Crantz).Introducing system sustainability in terms of nutrient preservation as a factor of balance, the traditional manualslash-and-bum system is compared to a mechanized, chop-and-rnulch system employing a tractor propelledmobile chopping unit. Assessment of anthropogenous energy fluxes is achieved by calculating all related on-farm production steps, including human manpower, machine utilization and inputs like fertilizer or plantprotection means. Chemical inputs, as well as machines and tools utilized are being calculated including indirectenergies consumed during their production on a primary energy level. Figures for energy consumption duringproduction of relevant means are adapted from state-of-the-art energy balances in terms of final energy,assurning compar~ble production conditions in Brazil. These values are then being recalculated to primaryenergy units, employing specific transformation factors for Brazilian conditions. Efficiency factors for primaryto final energy transformation, valid for the relevant sectors of cast iron and steel production, chemical industryand other industry, are being calculated from the national energy balance of Brazil. CO2 emission factors by fuelare adapted from literature and applied to the named sectors, due to lack of data, inconsistent or contradictoryquantification in literature they partly had to be estimated. CO2 emission from means production is beingassessed at primary energy level, assurning emission to be linearly related to primary energy consumption.Nutrient loss by slash-and-burn practices is quantified according to SHIFf findings in the study area, it is beingtranslated to energetic terms by calculating compensatory fertilization. CO2 emission from above- and below-ground biomass in the land-use systems compared is being estimated from literature and findings of SHIFfresearch in the study area. Field study was carried out to quantify time demand and tools utilization during thesteps of work necessary for the respective productive cycles, as they are commonly being performed in the studyarea. System scenarios for comparative calculation had to be set up based on non-chronological, thus virtual timesequences to be enabled to include the complete respective production period, which by far extended the periodavailable for observation. As is the nature of energy balances, the outcomes of the case study can only claim tobe estimating the true energy and CO2 tumover.Jõnsson, A., Universitat Gõttíngen, Institut fur Pflanzenbau und Tierproduktion in den Tropen und Subtropen, GrisebachstraBe 6, 37077Gõttingen, Gerrnany; a.joensson@gmx.net296 Poster section 7

Energy balance of a traditional and a modified land-use system in the Eastern Amazon basin, Brazil, as a case study.

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