Impact of Climate Variability on Smallholder Maize Yields: An Econometric Field Study

Thesis Abstract

The study addresses the adverse impacts of climate variability on maize yields among smallholder farmers in a major maize-producing region, where erratic rainfall, temperature fluctuations, and increased frequency of extreme weather events undermine farm productivity and income stability. The aim is to quantify the relationship between climate variability and maize yield outcomes and to identify adaptation strategies that enhance resilience. Specific objectives are (i) to quantify the influence of rainfall variability, temperature deviations, and growing-season length on maize yields; (ii) to evaluate the role of farm-level inputs (fertilizer use, improved seeds, irrigation) and agronomic practices in mediating climate impacts; (iii) to examine the socio-economic determinants of adaptive capacity, including access to credit, extension services, and information sources; and (iv) to develop evidence-based policy and farm-level recommendations for climate-resilient maize production. The methodology adopts a mixed-methods design, integrating quantitative and qualitative components to provide a comprehensive assessment. The population comprises maize-producing smallholders in three districts with diverse agro-ecologies. A stratified random sample of 600 farm households will be selected to obtain sufficient statistical power for econometric analyses, alongside 30 key informants from extension services, input suppliers, and agricultural cooperatives for contextual insights. Data collection instruments include a structured household survey capturing plot-level yields, input use, cropping patterns, and socio-economic characteristics; retrospective meteorological data (precipitation, temperature) aligned to each farming season; and in-depth interviews with a sub-sample of 60 farmers to explore perceptions and adaptive strategies. Secondary data on historical weather trends and policy interventions will be drawn from national meteorological archives and agricultural databases. Analytical methods combine econometric modeling with qualitative synthesis. The primary quantitative model will be a panel data regression (fixed effects and random effects specifications) to estimate the impact of climate variables on maize yields while controlling for input usage and household characteristics. Instrumental variable techniques will address potential endogeneity between input adoption and yield outcomes. A difference-in-differences approach will be applied where appropriate to identify the effect of specific adaptation interventions (e.g., drought-tolerant seeds, micro-irrigation trials) introduced during the study period. Descriptive statistics and correlation analyses will outline variable distributions and bivariate relationships. Model diagnostics will include tests for heteroskedasticity, autocorrelation, multicollinearity, and stationarity. The qualitative component will employ thematic analysis of interview transcripts to triangulate quantitative results and to illuminate barriers to adaptation, information gaps, and farmer decision-making processes. Key expected findings include (a) quantification of the elasticities of maize yields to rainfall anomalies, temperature deviations, and growing-season duration; (b) evidence on the mitigating effects of fertilizer optimization, improved seeds, and localized irrigation under climate stress; (c) identification of socio-economic determinants shaping adaptive capacity, such as credit access, farm size, and extension reach; and (d) nuanced understanding of farmers’ perceptions of climate risks and preferred adaptation pathways. The study anticipates that climate variability will significantly depress yields in drought-prone periods, while targeted agronomic practices and timely information can partially offset losses. The study contributes to knowledge by linking micro-level farm decisions to macro-level climate trends, refining econometric approaches to isolate climate-yield relationships in smallholder contexts, and providing context-specific evidence on effective adaptation strategies. It advances theoretical understanding by integrating climate risk literature with behavioral decision-making under resource constraints, referencing relevant theories such as the Climate Adaptation Theory and the Theory of Planned Behavior in interpreting farmer choices. Policy relevance is enhanced through actionable recommendations for extension services, credit facilities, seed systems, and irrigation investment to bolster resilience. The conclusion will synthesize quantified impacts and practical implications, asserting that climate-resilient maize production requires a combination of agronomic optimization and improved access to risk-cushioning resources. Recommendations include scaling drought-tolerant seed varieties, promoting efficient fertilizer use, expanding water-conserving irrigation technologies, enhancing climate information services, and strengthening credit and input supply networks to support adaptive capacity among smallholder maize producers.