Smaller fields, higher yields? Rethinking intervention strategies across field sizes in Nigerian rice production

"Context Rice is a staple crop in Nigeria, yet significant yield gaps continue to limit national production. While numerous efforts have focused on improving on-farm rice yields, the role of field size in limiting productivity has received little attention. This is particularly important in Nigeria’s smallholder rice production systems, where fragmented and variable-sized fields may hinder effective crop management. Objective This study investigates how the size of the main rice field of farmers and crop management practices contribute to yield variation across major rice-growing regions of Nigeria. Methods During the 2022–2023 wet and dry seasons, 1440 irrigated and rainfed rice fields were surveyed across 24 Local Government Areas in Kano, Jigawa, and Nasarawa states. Descriptive statistics were used for farm and farmer characterization. Yield and yield variability was assessed using random forest and multiple regression analysis on pooled and season-specific data to quantify the relative importance of field size and agronomic management factors to rice yield variability. Results Farmer reported rice field size ranged from 0.14 to 6.0 ha with Jigawa having the largest average field size (1.1 ha) and Kano the smallest (0.7 ha). Rice yields and yield gaps, defined as the difference between attainable and actual yields, varied widely by state, season, and production system. In irrigated systems, Kano recorded the highest dry season yield (5.6 t ha−1, 29 % yield gap), while Jigawa had the lowest wet season yield (2.0 t ha−1, 69 % gap). Rainfed yields were also lowest in Jigawa and Nasarawa (2.1 and 2.0 t ha−1) compared to Kano (4.7 t ha−1). Yield variation was significantly influenced by field size, residue management, land leveling, nutrient application (N, P, K), seed quantity, and bird control. In Kano, the estimated boundary yields exceeded 8 t ha⁻¹ in the smallest field size classes but declined progressively as field size increased. In contrast, Jigawa and Nasarawa showed lower maximum boundary yields at around 6 t ha⁻¹ , and similarly exhibited a negative relationship between field size and yield. Conclusion and implications Smaller fields had higher yields, likely due to better land preparation and more efficient input use. Improving yields in larger fields will require targeted agronomic support and better access to mechanization."