Spatiotemporal variability and trends of rainfall and temperature in the tropical moist montane ecosystem: Implications to climate-smart agriculture in Geshy watershed, Southwest Ethiopia

Abstract

This paper examines the spatio-temporal trends and variability of temperature and rainfall in Geshi Watershed of South Western Ethiopia. The available gridded daily rainfall and temperature data managed by Ethiopian National Meteorological Agency (NMA) for 1986–2020 was used. Spatial variability and temporal trends of temperature and rainfall were analyzed using XLSTAT and ArcGIS 10.8 software. The Mann-Kendall test was used for trend analysis. Variability analysis was also done using the coefficient of variation and precipitation concentration index. The study reveals constant increasing trends in rainfall; and insignificant and high variability but increasing trends of temperature. The variabilities and trends justify the spatio-temporal differences along different seasons (spring locally known as ‘belg’, summer locally known as ‘kiremt’, and annual). The watershed is characterized by high to moderate rainfall coefficient of variation, significant years of high concentration of rainfall, and substantial negative annual rainfall anomalies; that severe variability was found in the summerseason. These variabilities and trends, especially late onset and early cessation of rainfall and increase in temperature created favorable conditions for insect and disease proliferation that eventually reduces agricultural productivity. Household income, which is solely based on agricultural production, declines which in turn affects household resilience. Maladaptation in the form of deforestation, fuelwood and charcoal selling, agricultural land expansion, and practicing input-intensive agriculture that contributes to greenhouse gas (GHG) emissionsare taken as an alternative livelihood strategy. In conclusion, spatiotemporal variabilities and trends of rainfall and temperature affect agricultural productivity, reduced household resilience leading to low adaptive capacity, and increased GHG emissions, which are known to be major pillars of climate-smart agriculture (CSA). In response, area-specific CSA technologies such as small-scale irrigation, improved animal husbandry, efficient inorganic fertilizer use, using manure, crop residue management, using high-yielding improved crop varieties, and using disease-resistant varieties are recommended.