Impact of Climate Variability and Change on Irish Potato Production in Kigezi Highlands of Uganda

Abstract

East Africa has seen a warming trend of about 0.5 ºC and has become wetter on average by around 10-20% over the past years. Crop production tends to decline with rising temperatures, erratic and uncertain rainfall regimes. This situation is exacerbated by other factors such as soil erosion. This affects crop productivity in many highland areas of East Africa including the fragile highlands of Kigezi in Southwestern Uganda. This study was intended to; determine the spatial extent of the Irish Potato crop in relation to its suitability; examine the historical trends of climate and Irish Potato production in Kigezi highlands and assess the impact of climate change on Irish Potato production in the Kigezi highlands. This study was conducted in the Kigezi highlands, a landscape which is highly dominated with fragile fragmented land parcels. Irish Potato is a dominant crop in these highlands but has been declining in the recent past due to climate change impacts. A GIS-based Multi‐Criteria Evaluation method using Linear Combinations in ArcGIS version 10.2 was one of the methods employed. A Mann-Kendall Test, Sen’s Slope Method and Linear Regression Analysis were performed for trend determination. APSIM model simulations were conducted for both Historical and Future time periods. Four GCMs, which were selected on the basis of Hotness, Coolness, Dryness and Wetness, were used with RCP 4.5 and 8.5 to obtain future climate projection. Yield Deviations and Future Changes in rainfall and temperature were obtained. The results show that Irish potato production covers 71.50% of the agricultural area. 5.3% of that area was not suitable for Irish potato cultivation, 25.9% was marginally suitable, 66.8% was moderately suitable and 1.9% was highly suitable. In the MAM and SON season, minimum and maximum temperature had a significant increasing trend (P<0.05). The results indicate a decreasing and not significant (P>0.05) trend in rainfall for the MAM season and an increasing trend in the SON season. The yield trends are decreasing but not significant (P>0.05) in both seasons. Regression Analysis revealed that temperature and rainfall contribute significantly (P<0.05) to the variations in Irish potato yield in MAM season whereas in the SON season only rainfall contributes significantly (P<0.05). The GCMs projected an average increase in temperature and an average decrease in rainfall. Conclusively, the projected change in the climate will have a negative impact on Irish potato production in the Kigezi Highlands. This study recommends the development of adaptive technologies such as conservation agriculture approaches to improve soil health and fertility management; planting of Irish potato varieties tolerant to heat and water stresses in Kigezi Highlands of Uganda.