Climate variability and impacts on maize (Zea mays) yield in Ghana, West Africa

Abstract

AbstractRain‐fed agriculture is predominantly the primary source of livelihood in sub‐Saharan Africa. In Ghana, it employs over 60% of the population and contributes to about 30% of the Gross Domestic Product (GDP). Despite the relevance of rain‐fed agriculture to the socioe‐conomic development of the country, studies investigating the impacts of climate variability on crop yield in the region are limited. This prevents the growth of relevant policy frameworks to address the threats posed by climate variability on crop production. As a contribution to guide policy planning and food security in Ghana, the present study seeks to analyze the vulnerability of maize yield to rainfall, soil moisture, and minimum and maximum temperature variability in Ghana. Moreover, the study assesses the impact of below‐normal and above‐normal rainfall conditions on maize yield in the country. The results show a decreasing trend in rainfall and soil moisture and an increasing trend in the maize yield and minimum and maximum temperature in Ghana. The individual climate variables (rainfall, soil moisture, minimum and maximum temperature) account for approximately 4.2, 22.5, 39.2, and 23.1%, respectively, of the annual maize yield variations throughout the study period. Multivariate regression analysis revealed that soil moisture and minimum and maximum temperature account for approximately 75% of the variation of maize yield under wetter‐than‐normal conditions in Ghana. This implies that, under wetter‐than‐normal rainfall conditions, 25% of the variation in maize yield could be attributable to non‐climatic conditions or practices. In like manner, climatic parameters account for 40.8% of maize yield under drier‐than‐normal rainfall conditions in the country. This study, therefore, recommends investment in climate‐smart agronomic technologies such as access to improved seed, extension and mechanization services, and other farm management practices to maximize maize yield in the country.