Space-Time Oscillations in Rainfall Onsets and Their Implications on Sustainable Staple Crop Production in Imo State, Nigeria

This study investigates the influence of space-time oscillations in rainfall onsets on sustainable staple crop production in agro-ecological zones from 1981 to 2023 in Imo State. The study area was stratified into three agro-ecological zones, comprising Imo East, Imo West and Imo North using stratified sampling techniques to ease data extraction. Data on rainfall onsets were obtained from NASA native resolution daily data PRECTOTCORR MERRA-2 using a gridded method 43 climatic years and analyzed using SPSS. The descriptive assessments of the monthly mean distributive patterns reveal that Imo East recorded the highest mean value of 369.2 mm in September, while Imo North recorded the lowest value of 15.19 mm in December. Also, the highest annual mean value of 68.419 mm is associated with Imo North, while the most dominant standard deviation and variance scores of 13.159 mm and 173.169 mm occur in Imo West agro-ecological zone. The time series with regression models of oscillations in rainfall onsets offered the generalized negative trends, but at varying rates. Comparatively, Imo West gives the highest predictive power of −0.244x + 70.59 and a corresponding highest R2 value of 0.054 in the sequence, while the ANOVA model gives a low value of 0.466. The results led to a conclusion that variations in agro-ecological zones have no statistically significant effects on rainfall onsets. This study recommends an urgent need to boost farmers’ adaptation capacity through proactive climate change education and training by agro-extension officers to increase crop production and sustainable food security in Imo State.