Abstract
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.
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