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Sokoine University of Agriculture  Institutional Repository (SUA IR). This repository was built and is maintained by the university library  (Sokoine National Agricultural Library-SNAL) , in order to collect, preserve and disseminate scholarly output generated by University research community (staff and students) members.

This repository hosts a variety of openly accessible materials including: scholarly articles and books, theses and dissertations, conference proceedings and technical reports. For assistance about depositing your research output in the repository click here. SUA IR Policy  click here or any queries contact us at snal@sua.ac.tz.

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Now showing 1 - 5 of 16

Recent Submissions

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Relaxing credit and information constraints: five-year experimental evidence from Tanzanian agriculture
(The University of Chicago Press, 2025-04) Abdulrazzak Tamim; Aurélie P. Harou; Marshall Burke; David Lobell; Malgosia Madajewicz; Christopher Magomba; Hope Michelson; Cheryl A. Palm; Jiani Xue
Although many regions of the world have achieved dramatic increases in agri- cultural productivity since the Green Revolution, staple cereal yields remain low throughout sub-Saharan Africa (SSA). One important contributor to this low productivity is limited use of mineral fertilizer (Duflo, Kremer, and Rob- inson 2008; Xu et al. 2009; Harou, Walker, and Barrett 2017; Harou et al. 2022). Researchers have studied a range of explanations for low investment in mineral fertilizer, including unresponsive soils, high transaction costs, farm- ers’ time preferences, nonadoption among peers, uncertainty, and absence of in- formation about the suitability of fertilizer types and specific quantities for a far- mer’s soils (Marenya and Barrett 2009; Duflo, Kremer, and Robinson 2011; BenYishay and Mobarak 2018; Emerick and Dar 2021; Harou et al. 2022).1
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Assessing improved sorghum seed adoption and market participation under contract farming in Dodoma region, Tanzania: an endogenous switching regression approach
(COGENT ECONOMICS & FINANCE, 2026-03) Thedy Kimbi; Fulgence Mishili; Christopher Magomba; Essegbemon Akpo; Stefan Sieber
Sorghum farming is vital due to its resilience and suitability in the marginal lands of Africa, playing a key role in food security and economic stability. This paper analyzed the effect of Contract Farming (CF) on the adoption of improved seeds and market participation among sorghum farmers in Tanzania. Data were collected from 400 sor- ghum households across three districts in Dodoma: Kongwa, Mpwapwa and Chamwino. Using an Endogenous Switching Regression model, the results show that contract farming significantly increases both improved seed adoption and market par- ticipation. Additionally, the study identifies key determinants of contract farming involvement, including location, age, gender, household size, off-farm activities, experi- ence, sorghum demonstrations, labor, land type, leadership position, bulking distance, contract farming trust and the number of groups per village. Therefore, it is recom- mended that policymakers and stakeholders promote and facilitate targeted contract farming programs that strongly enhance input availability, financial services and extension services, as these improvements are crucial for boosting seed adoption and market participation. Targeted efforts in these areas are likely to yield significant improvements in sorghum production and enhance the economic stability of the farmers.
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Assessing the effect of contract farming on sorghum land productivity: an endogenous switching regression approach
(Elsevier, 2025-11) Thedy Kimbi; Stefan Sieber; Essegbemon Akpo; Christopher Magomba; Fulgence Mishili
In low-and middle-income countries, contract farming handles agricultural problems facing small-scale growers. This study analyzes the extent to which sorghum productivity can be enhanced under contract farming in Tanzania. Using cross-sectional data from 400 sorghum growers in Tanzania and an endogenous switching regression model, we observed that contract farming significantly improves the productivity of contract farmers compared to non-contract farmers. The findings show a 12 % increase in productivity for contract farmers, while non- contract farmers could potentially increase their productivity by 28 % if they participated in contract farming. Moreover, the study identifies significant variables such as age, off-farm in­ come, location, hired labor, the mix of owned-hired labor, farm size, financial services, household size, gender, experience, and the number of groups as determinants of contract farming partici­ pation among sorghum farmers. The results call for policies emphasizing contract farming as a viable approach to improve sorghum productivity, especially for small-scale farmers. Further­ more, policy adjustments matching the specific requirements of farmers in the target area are needed to maximize the positive impact of contract farming, factoring in the heterogeneity among producers.
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Effects of herbicides on weeds, sugar content and yield of sugarcane (saccharuh officinarum l.' at low and high application volumes
(1990) Fute, Jonas Louis
Results are presented of two field experiments conducted under rainfed and irrigated conditions to evaluate the effects herbicides, on weeds, sugarcane (Saccharu» o-f-ficirtarum L. ) cv NCo 376 yield and quality. The herbicides were Dimepax (3.0 and 2.0 kg a.i./ha) containing 507. dimethametryn C4-C1,2-di methyl—n-propy1ami no)-2-ethylamino- 6-methylthio-s—triazinel; Gesapax Plus (2.75 and 1.65 kg a.i./ha) containing 10.3'Z ametryn C2--(ethylamino)-4- (isopropylamino)-6-methylthio--s-triazine3 and 36. 77. MSMA (Monosodium methane arsonate); Gesapax H (2.50 and 1.50 kg a.i./ha) containing 21‘Z ametryn and 29‘Z 2,4—D C(2,4-dichloro phenoxy) serfi acid3; and Gesapax Combi <4.0 and 2.5 kg a.i./ha) containing 25X ametryn and 257. atrazine C2—chloro— 4- (ethyl ami no) -6- (i sopropylainino) -s—tr i azinel. Each experiment was laid down as split-plot in a randomised complete block design replicated four times with main plots assigned to high (213.0 1/ha) and low (26.5 1/ha) carrier water volumes. Herbicides dosage rates were assigned to the sub—plots with the lower rate receiving a supplementary handweeding 6 weeks after spraying. In the irrigated experiment, where broadleaf weeds were the main species, Gesapax H at 2.50 and 1.50 kg a.i./ha provided the best control pf greater than SOX at 6 weeks after treatment (WAT). Grass weeds, which were dominant at the rainfed site, were best controlled by Gesapax Plus at2.75 and 1.65 kg a.i./ha which provided a control greater than 907. during the same period. In both cases, supplementary handweeding improved duration of weed control. Reduction of carrier water volume had no biological advantage but reduced manday requirements for spraying by 69.47.. All herbicides induced recognizable but temporal phytotoxic symptoms to sugarcane. Most severe symptoms were shown at the rainfed experiment by Dimepax (3.00 kg) when applied in 26.5 1/ha carrier volume. Best sugarcane yields were obtained where effective herbicide treatment was supplemented by a handweeding. In the irrigated crop the weedfree treatments yielded significantly higher than all herbicide treatments in sugarcane yields but in the rainfed crop it yielded statistically similar to Dimepax (2.00 kg), Gesapax Plus at 2.75 and 1.65 kg in sugarcane yields. Sugarcane quality was not significantly (P<0.05) influenced by either herbicide treatments or application volume. Economic -analysis showed that Gesapax Plus at 1.65 kg a.i./ha applied in 26.5 1 /’ha had the highest returns of Sh 49.92 and Sh 12.36 per each shilling invested for rainfed and irrigated crops respectively.
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Seed health status of rice and onion under the quality declared seed system: the case of Morogoro, Iringa and Dodoma Regions
(Sokoine University of Agriculture, 2006) William, Magdalena Nchagwa Magere
A study was conducted to determine the seed health status of rice and onion produced under the quality declared seed (QDS) system in Tanzania. Using a purposeful sampling technique, a total of 34 QDS farmers from Morogoro, Iringa and Dodoma regions were interviewed using a structured questionnaire. Seventeen QDS samples each of rice and onion were collected from the interviewed farmers from respective regions. The Blotter method was used to detect the fungal pathogens. Identification of the detected fungi was done based on growth habit and morphological characters of fruiting bodies and spores/conidia. The cassette holder and direct plating methods were used to detect and isolate bacterial pathogens. The isolated bacteria were characterized based on physiological tests, Biolog and pathogenicity tests. All QDS onion and rice seed samples tested were infected by fungal pathogens. Aspergillus niger and A. flavus were common detected fungal pathogens in all onion seed samples. In rice seed samples, Phoma sp., Bipolar is oryzae and Fusarium pallidoroseum were common detected fungal pathogens. Bacterial pathogens were identified in 41.2 % and 52.9 % of onion and rice seed samples, respectively. Pantoea agglomerans, P. dispersa, Ralstonia pickettii and Enterobacter cloacae were identified as new pathogens on onion in Tanzania while P. agglomerans, Flavimonas oryzihabitans, Pseudomonas resinovorans, P. maculicola and E. aerogenes emerged as the new bacterial pathogens of rice. Insect pests were found to be of major importance in producing good quality and healthy seed under the QDS production system. The results stress the importance of checking the seed health status of QDS in order to ensure the production and use of healthy seed. Future studies should be conducted on the importance of such detected organisms under field and onion storage conditions. Insect pests should also be taken up as a problem to be addressed by the QDS system.