Crop Rotation and Fallow Period Optimisation for Sustainable Groundnut Production in Katsina State

This study examines crop rotation and fallow period management for sustaining groundnut production in Katsina State, North West Nigeria. Groundnut production in Katsina State is constrained by progressive soil fertility decline, increased Rosette virus incidence, and nematode build-up under continuous monoculture. Crop rotation and managed fallow represent low-input strategies for addressing these constraints, but rotation system recommendations for Katsina State conditions are based on limited local evidence. This study uses a long-term field experiment at Umaru Musa Yaradua University Katsina, evaluating four rotation sequences over four years: continuous groundnut monoculture, groundnut-sorghum-groundnut-sorghum, groundnut-cowpea-sorghum-groundnut, and groundnut-fallow-groundnut-fallow. Soil nematode populations, Rosette disease incidence, soil organic nitrogen, and groundnut pod yields are measured annually. Economic analysis compares rotation system net returns. Findings reveal that the groundnut-cowpea-sorghum-groundnut rotation produces the highest average groundnut pod yield of 2.4 tonnes per hectare by year four, with Rosette incidence 64 percent lower than continuous monoculture. Nematode populations are significantly reduced under all rotation sequences compared to monoculture. Fallow rotation shows strong nematode suppression but lower economic returns than cowpea-inclusive rotations due to the opportunity cost of fallow. The study concludes that three-year rotation including cowpea and sorghum is the most productive and disease-suppressive system for groundnut in Katsina State. It recommends this rotation for ADP extension guidance.

Keywords: crop rotation, groundnut production, Katsina State, Rosette disease, nematode management.