Rainfall variability and crop production in northern Ghana: thw case of Lawra district

Type Working Paper
Title Rainfall variability and crop production in northern Ghana: thw case of Lawra district
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Abstract
Though agriculture is the predominant occupation in Northern Ghana, the relationship between rainfall variability and crop production appears not to have been adequately investigated in the area. Crop production is largely characterized by smallholder subsistence farmers who depend solely on highly unpredictable and irregular seasonal rainfall. In recent times, rainfall variability has led to numerous incidences of drought and floods. This phenomenon has the potential to adversely affect crop production and food security in the area. This study analyses inter- and intra-annual variability of rainfall so as to identify the relationship between rainfall variability and crop production in a representative district of Northern Ghana. Available monthly rainfall data for 33 years (1980 - 2012) recorded at Babile station of the district was analyzed for seasonal and annual variability using the coefficient of variation (CV) and the precipitation concentration index (PCI). Total annual quantity of crop production data on main crops (i.e. maize, millet, sorghum, groundnut and cowpea) was used. The available data covered a period of 21 years (1992 - 2012). To verify the influence of rainfall variability on crop production, correlation analysis was conducted. Although the results showed moderate seasonal rainfall distribution, (i.e. PCI>11), the inter-seasonal and inter-annual rainfall variability (CV=0.19 and C=0.18 respectively) were moderate/less erratic. The results point to a negative correlation between annual rainfall and crop production for maize, millet, sorghum, groundnut and cowpea. At seasonal level sorghum, millet and groundnut showed negative correlation while maize and cowpea showed positive correlation. These results also point to a need for further studies to determine the influence of rainfall on arable land use and the periods of occurrence of drought in the study
area. The results of this study would enable farmers to improve their crop production strategies.

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