IMPACT OF CLIMATE VARIABILITY ON CEREAL CROP PRODUCTION IN NORTH CENTRAL STATES, NIGERIA

Abstract

Climate variability, its impacts and the associated vulnerabilities is a growing concern across the globe. It is believed to be one of the greatest impediments for achieving food security and sustainable crop production globally. The study investigated the impact of climate variability on cereal crop production in the North Central States of Nigeria. The specific objectives were examination of the trend and spatio-temporal variability in climatic variables (rainfall, temperature and relative humidity); examination of the trend in yield of the selected crops (Rice, Maize and Guinea corn); examination of the relationship between climatic variables and yield of the selected crops; analysis of the effect of daily extreme climatic indices on yield of the selected crops and identification of the adaptation and mitigation strategies to climate variability on crop yield. The study utilized climatic and crop yield data from Climate Prediction Center, Merged Analysis of Precipitation (CMAP) and Agricultural Development Projects (ADPs) and personal interview and questionnaire administration. Non-parametric test, Mann-Kendall test and Theil-Sen slope estimator (β) approach was used to analyse the spatio-temporal trend in climatic variables (Rainfall, Maximum Temperature, Minimum Temperature and Relative Humidity) and crop yield (Rice, Maize and Guinea corn) during the study period (1989 – 2018). Pearson Product Moment Correlation and Multiple Regression analysis were utilized in the examination of the strength of association between climatic variables and crop yield. Standardised extreme climatic indicators developed by Expert Team on Climate Change Detection and Indices (ETCCDI) under the World Meteorological Organization (WMO) were used to assess the effect of extreme climatic indices on crop yield. Descriptive statistics was used to analyse the questionnaires administered and interview schedule data. The results indicated that a downward trend existed in the monthly rainfall distribution in the study area especially at the onset of the rain in the month of May and an upward trend towards the cessation period in the month of October. On annual basis, there existed downward trend in rainfall in all the study locations except in Lafia where significant upward trend at alpha value of 0.001 was detected. It is evident that maximum 1-day rainfall (R1D) and maximum 5-day rainfall (R5D) correlated insignificantly with the three crops across the study areas. The variation in rainfall is between 0.09 mm yr-1 and 6.06 mm yr-1 within the rainy season months of May to October. The result of the crop-climate relationship indicated that rice yield at Abuja and Lafia was strong at 56 % and 54 %, respectively, while it was weak at Minna, Lokoja and Ilorin at 23 %, 27 % and 10 % respectively. For Maize, the result indicated weak relationship in all the study locations except at Lafia which was strong at 57 %. Guinea corn yield response to climate variability was weak over the study locations, it indicated 37 %, 40 %, 27 %, 24 % and 47 % in Minna, Lokoja, Abuja, Ilorin and Lafi stations, respectively; this is attributable to the fact that it is more tolerant to climatic extremes with much longer growing period than other crops studied. Conclusively, it is established that susceptibility of the yield of the selected cereal crop to the impact of climate variability occurred in the study area and each of the climatic variables impacted on the yield of the crops at different scales and level. It is therefore recommended that smart climate technologies and innovative practices for sustainability of yield of cereal crop be adopted in the face of current challenges of climate variability in the study area. i