Conservation agriculture Tanzania_casestudy.pdf - Sokoine ...

Case study project background and methodBernard Triomphe, Josef Kienzle, Martin Bwalya, Soren Damgaard-LarsenThis case study presents the status of conservation agriculture in Ghana. It is onein a series of eight case studies about conservation agriculture in Africa, whichwere developed within the framework of a collaboration between CIRAD (FrenchAgricultural Research Centre for International Development), FAO (Food andAgriculture Organization of the United Nations), RELMA-in-ICRAF (RegionalLand Management Unit of the World Agroforestry Centre) and ACT (AfricanConservation Tillage Network).This introductory section outlines the overall background of the conservationagriculture case study project and the key methodological choices made. It alsogives a brief overview of major results and observations across all case studies. Thisbroad perspective allows the reader to appreciate both the commonalities amongthe eight case studies and the specifics of the thee being presented here.Conservation agriculture: a working definition‘Conservation agriculture’ has been defined differently by different authors. Perhapsthe most generic definition is the one provided by FAO: 1CA is a concept for resource-saving agricultural crop production that strives to achieveacceptable profi ts together with high and sustained production levels while concurrentlyconserving the environment. CA is based on enhancing natural biological processes aboveand below the ground. Interventions such as mechanical soil tillage are reduced to anabsolute minimum, and the use of external inputs such as agrochemicals and nutrients ofmineral or organic origin are applied at an optimum level and in a way and quantity thatdoes not interfere with, or disrupt, the biological processes.From this definition, we can infer that conservation agriculture is not an actualtechnology; rather, it refers to a wide array of specific technologies that are basedon applying one or more of the three main conservation agriculture principles(IIRR and ACT 2005):• reduce the intensity of soil tillage, or suppress it altogether• cover the soil surface adequately—if possible completely and continuouslythroughout the year• diversify crop rotationsIdeally, what we call ‘conservation agriculture systems’ comprise a specific set ofcomponents or individual practices that, combined in a coherent, locally adaptedsequence, allow these three principles to be applied simultaneously (Erenstein2003). When such a situation is achieved consistently, we speak of ‘full conservationagriculture’, as illustrated by the practices of many farmers in southern Brazil (doPrado Wildner 2004; Bolliger et al. 2006) and other Latin American countries(Scopel et al. 2004; KASSA 2006).1 FAO conservation agriculture website: http://www.fao.org/ag/ca/index.htmlviiiShetto, Owenya