Farmer forecasts: Impacts of seasonal rainfall expectations on agricultural decision-making in Sub-Saharan Africa

Seasonal climate variability frequently undermines farm yields, reduces food availability, and lowers income. This is particularly evident among small-scale agricultural producers in both irrigated and non-irrigated agroecosystems in the Global South where maize cultivars constitute a critical component of food production. In these systems, farmers make climate-sensitive decisions that include the selection of lateand/or early-maturing seed varieties, the diversity of seed varieties sown, and when to plant. Farmers' expectations of future rainfall would therefore seem to be critical determinants of agricultural outcomes and foreshadow climate impacts. However, few studies have quantified the linkages between on-farm decisions and farmer seasonal predictions. We report on detailed household and phone surveys of 501 smallholder farmers in central Kenya based on the 2018 growing seasons and expectations for the 2019 March-April-May growing season. We show that farmers' expectations of the upcoming seasonal rainfall have important associations with selections of seed maturity varieties and the number of maturing varieties farmers expect to plant and less important associations with the seeds' planting dates. Furthermore, we show that 79% of the farmers form an expectation of the future seasonal climate and about two-thirds of them formed expectations based on a heuristic that connects the past climate to future seasonal conditions. More problematically, one-third of the farmers formed their rainfall expectation based on the prior season, and we show that no such correlation exists in observational data nor is correlation of seasonal rainfall supported by current understanding of climate variability. These results highlight the challenges farmers face in anticipating seasonal rainfall, which has implications for crop diversification and choices to adopt drought tolerant cultivars. The results suggest that farmers' expectations of upcoming seasonal climate are important measures of farm decision-making.