EFFECTS OF CLIMATE THRESHOLD ON MAIZE PRODUCTION IN GUINEA-SAVANNAH, NIGERIA

Abstract

Agriculture is inherently risky. Farmers usually lack knowledge of the precise output at the time of their production and input decisions. This is because agriculture in general has a relatively long production cycle and is affected by a large number of endogenous or exogenous uncertainty factors. Climatic factors such as temperature, rainfall or sunlight are characterized by inter-annual variability To investigate the required climatic conditions that encourage maximum yield of maize and the causes of variability in the study area, cross-sectional and time series data were used. Climate data were obtained from Nigeria Meteorological Station (NIMET) while the maize yield data were collected from Nigerian Bureau of Statistics (NBS) and state Ministry ofAgriculture. Just -Pope Production Model was used to analyze the objectives and well-structured questionnaire was used to obtain data from respondents. The result from Just-Pope Production Model indicates that the quantity of maize seed, quantity of fertilizer, proportion of family labor on farm activity, and farm size increased the
yield variance of the maize farmers. The quantity of seed and fertilizer were also observed to increase maize farmers' yield risk in the study area. Maize yield had a positive growth rate of 3.8% in the period considered. The results of the climate variables revealed that a rise in temperature increased the yield risk of maize by  5 percent, although the effect was not too severe. There was deceleration in maize growth. The Growing Degree Day (GDD) was observed to reduce yield risk for maize. Thus, an increase of one GDD unit induced yield increase of about 8 percent in the states under consideration. As expected, however, the effect on maize yield resulting from increased extreme temperature measured with Harmful Degree Day (HDD) was negative. The long-run estimates showed that rainfall had a negative effect on maize yield.