Table 19.2
Key conditions for four intervention strategies
Key conditionsRecapitalization of nutrient stocks (one-time)High external inputs (especially inorganic fertilizers)Low external inputs (especially organic matter management)Mixed strategy: integrated nutrient managementSoil type and limiting nutrientsAppropriate for P limited soils, less so when N limited.Any: fertilizer mix can be adapted to particular soil and plant needsMost effective for N limited soils, through build up of organic matterAnyBiomass availabilitynanaHighVariableLabour requirementsHigh initial inputLowHighVariableFinancial costs – credit or subsidy requirementsHighHighLowVariableFarmers’ skill levels required – requirements for extension supportLowLowMediumHighNeed for good infrastructural/market links for input supplyHighHighLowMediumPotentially negative environmental or health impactsYesYesNoLimitedIntervention focusInput importation; transport; implementation logistics; farmer and area targetingSoil testing; fertilizer manufacture, blending; demonstration plots; input prices and marketsAppropriate technology development; trainingLocal experimentation; researcher–farmer participation; skills training; ‘field schools’Source: Scoones and Toulmin, 1999