The effect of climate change on sorghum yield in the Teso farming system.

Abstract

Climate change is a serious environmental and livelihood challenge in Uganda, with the poor agro-based communities in the semi-arid areas being particularly more vulnerable. However, there is paucity of knowledge and information on the climate change impact on yields of major and key food security crops in the semi-arid zones of Uganda. Yet, this information is important in designing appropriate adaptive and coping practices to climate change. The thrust of this study was to assess the climate change impact on the yields of sorghum in the Teso farming system of Uganda. This study entailed a multiplicity of methods; first, a Regional Climate Model, PRECIS was used to downscale a Global Climate Model, ECHAM, and elicit projected future climate conditions for the study area. A crop model, AquaCrop, was then used to simulate sorghum yields under the projected climate regimes. The AquaCrop model was validated using observed sorghum yields of the Edeidei and Serena varieties based on the current climatic conditions. In addition to the simulations, household interviews and focus group discussions were undertaken to find out the farmers’ perceptions of climate change, impact of climate change on crop production, and to analyze the coping and adaptive practices of the communities. The results from the study revealed that climate change, by the year 2040, will generally result in; 1) average increase in annual rainfall of 5%, and in terms of seasonal distribution, rainfall is expected to reduce for the first season (MAM), and increase for season the second season (SON); 2) average drop in annual minimum/maximum temperatures of 0.3oC /1.0oC respectively. These changes are expected to result in average increase in sorghum grain yield in the study area of 25% to 35% by the year 2040. Grain yield will increase for both seasons of the year except for season 1 of the year 2019, when the seasonal rainfall is expected to reduce by over 6%. Thus, climate change generally presents benefits to sorghum grain yields in this area, rather than risks as reported for most parts of the world, according to the climate models and climate change scenario used. Therefore, efforts/policies should be put in place to ensure maximum exploitation of this expected benefit. The results of the socio-economic survey showed that 100% of the respondents think the climate is changing, with change in seasons being one of the greatest indicators cited. High crop failure, reduction in yields and destruction of crops by unpredictable weather were the major impacts of climate change on crop production mentioned. The existing adaptation practices in the Teso farming system were found to be effective, although requiring external support such as climate information and free/subsidized improved seed. However, some coping practices employed are ineffective and/or have negative effects on the people’s well-being ,and thus, can not be relied on to help members cope with the possible negative effects of climate change. Therefore, development projects, such as provision of micro-credit, to help farmers come up with alternative livelihood sources, should be conducted in this area to improve the farmers’ resilience.

Key words: Climate change, sorghum yields, Teso farming system