Browsing by Author "Tumbo, Siza D."
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Item A Decision Support System for Enhancing Crop Productivity of Smallholder Farmers in Semi-Arid Agriculture(College of Business Education) Casmir, Respickius; Churi, Ayubu J.; Mlozi, Malongo R. S.; Mahoo, Henry; Tumbo, Siza D.Item A Decision Support System for Enhancing Crop Productivity of Smallholder Farmers in Semi-Arid Agriculture(College of Business Education) Casmir, Respickius; Churi, Ayubu J.; Mlozi, Malongo R. S.; Mahoo, Henry; Tumbo, Siza D.Item A Decision Support System for Enhancing Crop Productivity of Smallholder Farmers in Semi-Arid Agriculture(College of Business Education) Casmir, Respickius; Churi, Ayubu J.; Mlozi, Malongo R. S.; Mahoo, Henry; Tumbo, Siza D.Item Agronomic management strategies for adaptation to the current climate variability: the case of North-Eastern Tanzania(2014) Tumbo, Siza D.; Rwehumbiza, Filbert B.; Kahimba, Frederick C.; Enfors, Elin; Mahoo, Henry F.; Mbilinyi, Boniface P.; Mkoga, Zacharia; Churi, AyubuRainfed agriculture in semi-arid areas of sub-Saharan Africa faces a great challenge due to increasingly high variability and unreliability of rainfall. Two of the effective adaptive responses to reduce the vulnerability to the changing climate are through use of soil and water conservation technologies and employment of improved agronomic practices. A study was conducted to quantify the risk and profitability of agronomic management strategies for maize using long-term climatic data and a crop simulation model. APSIM model was used to perform long-term simulations of different management strategies. Simulated maize grain yield for different cultivars and sets of management strategies were evaluated to establish the associated risks and benefits. Results indicate that planting Situka or SC401 during Masika season instead of Kito or other cultivars, gives a yield of more than 1 ton/ha under conventional methods. Maize yield increases to 2t/ha or even higher with the use of fertilizers and recommended management practices. The cost benefit analysis indicated that income greater than USD 700 per ha could be obtained when recommended practices are applied, with Situka and SC401 as the maize varieties planted. Based on the results of the study, it is recommended that farmers should employ improved agronomic management practices only when the seasonal forecast indicates above normal rainfall. The early availability of seasonal rainfall forecast is thus vital. Alternatively, farmers are much safer if they continue to employ their conventional approaches of farming because these have lower risks.Item ECAWsoft: A web based climate and weather data visualization for big data analysis(Global Journal of Computer Science and Technology: H Information & Technology) Tumbo, Siza D.; Kadeghe, Fue G.; Sanga, Camilius A.Item Experimenting open agricultural extension service in Tanzania: A case of Kilosa Open Data Initiative (KODI)(Journal of Scientific and Engineering Research) Sanga, Camilius A.; Masamaki, Joseph Phillipo; Fue, Kadeghe G.; Mlozi, Malongo R.; Tumbo, Siza D.Item Impacts of climate variability and change on rainfed sorghum and maize: implications for food security policy in Tanzania(Canadian Center of Science and Education) Msongaleli, Barnabas M.; Rwehumbiza, Filbert; Tumbo, Siza D.; Kihupi, NgangaItem Prediction of soil moisture-holding capacity with support vector machines in dry subhumid tropics(Hindawi) Kaingo, Jacob; Tumbo, Siza D.; Kihupi, Nganga I.; Mbilinyi, Boniface P.Item Prediction of soil moisture-holding capacity with support vector machines in dry subhumid tropics(Hindawi, 2018-07) Kaingo, Jacob; Tumbo, Siza D.; Kihupi, Nganga I.; Mbilinyi, Boniface P.Soil moisture-holding capacity data are required in modelling agrohydrological functions of dry subhumid environments for sustainable crop yields. However, they are hardly sufficient and costly to measure. Mathematical models called pedotransfer functions (PTFs) that use soil physicochemical properties as inputs to estimate soil moisture-holding capacity are an attractive alternative but limited by specificity to pedoenvironments and regression methods. This study explored the support vector machines method in the development of PTFs (SVR-PTFs) for dry subhumid tropics. Comparison with the multiple linear regression method (MLR-PTFs) was done using a soil dataset containing 296 samples of measured moisture content and soil physicochemical properties. Developed SVR-PTFs have a tendency to underestimate moisture content with the root-mean-square error between 0.037 and 0.042 cm 3 ·cm −3 and coefficients of determination (R 2 ) between 56.2% and 67.9%. The SVR-PTFs were marginally better than MLR-PTFs and had better accuracy than published SVR-PTFs. It is held that the adoption of the linear kernel in the calibration process of SVR-PTFs influenced their performance.Item Sorghum yield response to changing climatic conditions in semi-arid central Tanzania: evaluating crop simulation model applicabilityMsongaleli, Barnabas; Rwehumbiza, Filbert; Tumbo, Siza D.; Kihupi, Nganga I.Item Sorghum yield response to changing climatic conditions in semi-arid central Tanzania: evaluating crop simulation model applicability(Scientific Research Publishing) Msongaleli, Barnabas; Rwehumbiza, Filbert; Tumbo, Siza D.; Kihupi, NgangaItem Sorghum yield response to changing climatic conditions in semi-arid central Tanzania: evaluating crop simulation model applicability(2013) Msongaleli, Barnabas; Rwehumbiza, Filbert; Tumbo, Siza D.; Kihupi, Nganga I.Decision Support System for Agrotechnology Transfer (DSSAT) and Agricultural Production Systems Simulator (APSIM) were calibrated and evaluated to simulate sorghum (Sorghum Bicolor L. Moench) var. Tegemeo under current and future climate in central Tanzania. Simulations for both current and future periods were run assuming present technology, current varieties and current agronomy packages to investigate rain-fed sorghum yield response. Simulations by both crop models using downscaled weather data from eight General Circulation Models (GCMs) under the Coupled Model Intercomparison Project phase 5 (CMIP5) and Representative Concentration Pathway (RCP 4.5) by mid-century show a mixture of increase and decrease in median sorghum yields. Four GCMs project yields to increase by 5% - 23.0% and one GCM show a decrease by 2% - 9%. Model simulations under the remaining three GCMs give contrasting results of increase and decrease. Adjustment of crop duration to mimic the choice of growing local cultivars versus improved cultivars seems a feasible option under future climate scenarios. Our simulation results show that current open-pollinated sorghum cultivars would be resilient to projected changes in climate by 2050s but things seem better with long duration cultivars. We conclude that crop simulation models show their applicability as tools for assessing possible impacts of climate change on sorghum due to agreement in the direction of crop yield predictions in five out of eight selected GCMs under projected climate scenarios. The findings provide useful guidance and motivation to government authorities and development agencies dealing with food security issues to prioritize adaptations policies geared to ensuring increased and sustained sorghum productivity in Tanzania and elsewhere.Item Understanding Farmers Information Communication Strategies for Managing Climate Risks in Rural Semi-Arid Areas, Tanzania(College of Business Education) Casmir, Respickius; Churi, Ayubu J.; . Mlozi, Malongo R. S; Tumbo, Siza D.Item Understanding Farmers Information Communication Strategies for Managing Climate Risks in Rural Semi-Arid Areas, Tanzania(College of Business Education) Casmir, Respickius; Churi, Ayubu J.; . Mlozi, Malongo R. S; Tumbo, Siza D.Item Use of a hydrological model for environmental management of the usangu wetlands, Tanzania(IWMI Research) Kashaigili, Japhet J.; McCartney, Matthew P.; Mahoo, Henry F.; Lankford, Bruce A.; Mbilinyi, Boniface P.; Yawson, Daniel K.; Tumbo, Siza D.Item Use of a hydrological model for environmental management of the usangu wetlands, Tanzania(IWMI Research, 2016-05) Kashaigili, Japhet J.; McCartney, Matthew P.; Mahoo, Henry F.; Lankford, Bruce A.; Mbilinyi, Boniface P.; Yawson, Daniel K.; Tumbo, Siza D.This report presents the findings of a study to assess changes to flows into, and downstream of, the Usangu Wetlands, located in the headwaters of the Great Ruaha River, Tanzania. Hydrological data, in conjunction with remote sensing techniques, were used to provide insights into changes that have occurred to the Eastern Wetland. Results indicate that, between 1958 and 2004, inflows to the wetland declined by about 70 percent in the dry season months (July to November) as a consequence of increased human withdrawals, primarily for irrigation. This resulted in a decrease in the dry season area of the wetland of approximately 40 percent (i.e., from 160 km 2 to 93 km 2 ). In the last decade, outflows from the wetland have ceased for extended periods. An environmentalflow model indicates that a minimum dry season outflow of approximately 0.6 m 3 s -1 is essential to sustain the basic ecological condition of the river. To maintain this outflow from the wetland, a minimum average dry season inflow of approximately 7 m 3 s -1 (i.e., approximately double current dry season flows) is required. To achieve this, dry season flows in the perennial rivers discharging into the wetland would have to be apportioned so that 20 percent is used for anthropogenic purposes and the remaining 80 percent discharges into the wetland. There issignificant potential for improving water use efficiency. However, to ensure minimum downstream flow requirements, consideration should also be given to active water management within the wetland itself.