Doctoral thesis
This study aimed at assessing the impact of climate change on traditional irrigation farming systems and adaptation strategies was conducted in Lushoto District. The specific objectives were to establish the trend and magnitude of climate change in the study area for the past 30 years (1985-2014), to assess the impact of climate change on crop yield in Ndiwa and Chamazi traditional irrigation farming systems, to analyse the way traditional irrigation farmers adapt to climate change and to develop decision guide for adaptation to climate change in traditional irrigation farming systems. A cross-sectional explanatory research design encompassing both purposive and systematic random sampling was adopted for this study. The study sample comprised of 380 households, 48 members of Focus Group Discussion (FGD) and 15 key informants. Primary data from household heads and key informants were collected through a questionnaire survey, FGDs, interviews and the researcher‘s observations while secondary data were collected through documents reviews including annual reports from District Agriculture Irrigation and Cooperative Offices and weather reports of the study area for the past 30 years from Tanzania Meteorological Agency (TMA). Descriptive statistics such as mean, frequency and percentages were computed to establish the trends and magnitude of climate change using SPSS and MS-Excel programs. Cross-tabulation between rainfall and crop yield trends was used to establish the impact of climate change on crop yields. Descriptive statistics such as mean, frequency, percentages and Analytic Hierarchy Process (AHP) analysis were performed to identify the most feasible adaptation strategies and adaptive capacity of farmers. Decision guide for adaptation to climate in traditional irrigation farming systems was developed in order to integrate the challenges of climate change and those related to the adaptive capacity to enhance adaptation actions.
The results show that for the past 30 years (1985-2014) climate variables such as annual mean (minimum and maximum) temperature and annual mean rainfall have been increasing and decreasing respectively in fluctuating patterns. For the past 30 years, annual mean (minimum and maximum temperature) have increased by 0.83Oc and 2.4oC respectively and annual mean rainfall has decreased by 803mm. Climate change has affected crop yield in Ndiwa and Chamazi traditional irrigation systems through decrease amount of water for irrigation, an outbreak of crop diseases, pests and insects. Farmers engaged in Ndiwa and Chamazi irrigation systems adopted different adaptation strategies to combat the impact of climate change. These include cultivating near water sources, crop diversification, digging of shallow wells and application of pesticides. However, the adaptive capacity to climate change for Ndiwa farmers was 41.6% indicating moderate adaptive capacity while that of Chamazi farmers was 23.6% indicating low adaptive capacity. The decision guide for adaptation to climate change for traditional irrigation farming systems was finally proposed with the intention of facilitating Ndiwa and Chamazi farmers to select appropriate adaption actions to the impact of climate change.
It has been recommended that the government and other stakeholders should extend their efforts more to help the farmers engaged in Ndiwa and Chamazi irrigation systems to improve their adaptative capacity to climate change. They should especially help farmers to access the following; climate information, land and security of tenure, water sources, and financial resources, agricultural inputs, agricultural extension services and improved transport and irrigation infrastructures.
The government, particularly the local government authority of Lushoto, should also sensitize farmers to establish and strengthen the farmer-based organizations. The central government and other stakeholders should further help in improving irrigation farming and the coordination between crop research centres, extension and farmers.