Exploring soil nutrient management and production performances to support building smallholder farms’ resilience to climate change: case of South-Western Burkina Faso

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Sub-Saharan Africa remains the most affected region by food insecurity and poverty. Unsustainable soil nutrient management undermines crop production. Also, climate change impacts on farming by disrupting nutrient cycles which are key to farm production. Studies revealed large negative nutrient balances in many farming systems. Population’s livelihood is at stake. There is a need to build resilient farming systems capable of improving soil nutrient closeness while ensuring efficient and profitable food production in climate change context. Farm resilience arises from internal decision making and from external decision making through policies and intervention measures. The main objective of this research is to contribute to building African smallholder farms’ resilience to climate change by analysing farms nutrient management use behaviour (decision making), soil nutrient balances and related production and economic performances, and identifying promising options for closing soil nutrient gaps. In a first step a multi-dimensional dataset was collected from 360 households-farms sampled in six villages of Ioba province in South-Western Burkina Faso. The Sustainable Livelihood Framework was used to analyse farms heterogeneity. Multiple linear and bi-logit regressions were run to analyse determinants of mineral fertilizer use intensity, separate adoption of mineral and organic fertilizer, and combined mineral-organic fertilizer adoption for different farm types. In a second step, the NUTMON framework was used to analyse farm nutrient management and economic performances. Five farm types for a total number of 15 farms were monitored for one year. Farms’ agronomic and economic performances were evaluated. Whole farm and soil subsystem nutrient (N, P and K) balances of the farm types were calculated and their linkages with farm economic performances were investigated. The research finally discussed scenarios for closing soil nutrient gaps.Findings revealed five socio-economic and ecological farm-types with different soil nutrient management strategies. Beside common determinants of fertilizer use and adoption, type-specific determinants and behaviour were unveiled. Farm and soil nutrient balance and economic performances analyses revealed two main cases: (1) farms with ’negative soil nutrient balance and low margin’, and (2) farms with ’negative soil nutrient balance with better margin’. The first case faces the convergent problem of depleted soil resources, poor productivity and profitability. The second case, currently profitable, will become problematic as soon as the negative soil nutrient balance trend depicts nutrient stock depletion in near future. Balancing soil nutrient with only mineral fertilizers is likely unaffordable as the current fertilizer uses are not efficient with high rates of net soil nutrient loss. In this scenario the required amount of fertilizer to fill nutrient gaps will cost up to 72% of crop marginal revenue drawn per hectare. If crop residues are fully recycled, soil nutrient balance will be improved by 40-90%. The integration livestock-cropping was found to be the most promising option for sustainable smallholder farming. The research recommends that, rather than uniform interventions decision makers should distinguish between farming systems using relevant socio-ecological criteria in designing policies to promote sustainable soil nutrient management. Policy interventions and farm design should focus on the subsidiary linkages between livestock and crop production. Capacity building of smallholders’ farms in agro meteorology is required to lay the basis for efficient adaptation and building resilience to climate change. From a methodological perspective, the research demonstrated the relationship between structural and functional typologies and the importance for considering both in regional farming system studies. The results also provide an empirical framework for scaling-out studies
A Thesis submitted to the Department of Civil Engineering, College of Engineering in partial fulfilment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Climate Change and Land Use April, 2015