Komba, Martin Emmanuel2026-01-202026-01-202024https://www.suaire.sua.ac.tz/handle/20.500.14820/7238DisertationGrowing rice in Tanzania’s major basins is threatened by climate change impacts. It is projected that rice yield will fall by 7.6% in these major basins in aggregate. Climate change impacts in Tanzania’s major basins including Kilombero sub-basin (KSB) which is the biggest feeder of Rufiji basin is attributed to increasing temperature which accelerates surface evaporation. There is also increased water demand due expanding agriculture, influx of livestock and water for hydropower generation. Climate change impacts and increasing water demand in the sub-basin have called for planned and sustainable use of water. One of the implemented techniques is the new adaptive rice growing technologies. Irrigation technologies like traditional flooding irrigation technology (TFIT) for rice farming that exposes water to surface evaporation is no longer a viable adaptation technology for growing rice under stressed water availability from scientific point of view. Alternatively, the system of rice intensification (SRI) irrigation has recently been encouraged in KSB by the Ministry of Agriculture (MoA) to reduce water loss through surface evaporation through controlled water usage. However, 90% of rice irrigable land in KSB is still under flooding irrigation which is inefficient in use of water. From literature there is enough evidence in agronomic point of view that SRI irrigation is more water use efficient than TFIT but information on their economic efficiency at household level especially in KSB is not readily available. This study was conducted in Kilombero district to evaluate the profitability of TFIT and SRI irrigation technologies and the determinants of profitability of the two irrigation technologies and; factors that determine the choice of rice irrigation technology in KSB. Data were collected through Focus Group Discussions (FGDs), Key Informant Interview (KIIs) and household survey that involved 100 households. The study used farm budget method to evaluate profitability (Net Revenue) of rice produced under SRI and TFIT. From Net Revenue (NR) obtained, profitability determinants were evaluated using multiple linear regressions. This represented first published paper on the economics of the irrigation technologies. Furthermore, this study used the reduced household model to evaluate factors that motivate farming households to decide on the type of rice irrigation technology and allocation of production resources between the two technologies in situ SRI and TFIT which is the second published paper. The findings from first published paper (on economics of SRI irrigation and TFIT) have shown that on average rice production costs per acre are TZS 471 572.5 and 248 939.9 for SRI and TFIT respectively. Also, the study found that on average farming households practicing SRI and TFIT produce 1268 and 608 Kgs of threshed rice respectively per acre. Adding on that the average NR per acre under TFIT and SRI were TZS 902 236 and 1 276 841 respectively, indicating that SRI irrigation was more profitable than TFIT. Despite being more profitable, the findings have shown that SRI is more labour intensive than TFIT; a farming household practicing SRI needs to supply an average of 23 man-days per acre per season while a household practicing TFIT has to supply 14 man-days per acre per season. On one hand, the study found that farming experience, farm size, fertilizer application, agricultural supporting services like capital assistance and high frequency of extension visits positively and statistically influenced the profitability of both SRI and TFIT but differed in magnitudes for example each increment in extension visit caused a TZS 169 000 increase in SRI compared to TZS 101 000 in TFIT ceteris paribus. One of the notable recommendations from the findings is that the subsidization to industrial fertilizers is the viable option by the MoA to benefit rice farmers who irrigate using SRI principles and traditionally. Also increasing extension officers is important especially in areas found with inadequacy like Sululu.enSub-BasinIrrigation TechnologiesKilombero and Farming HouseholdsGrowing riceClimate change impactsThesis