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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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- The Agroforesty Community is a collaborative network dedicated to advancing sustainable land-use practices that integrate trees, crops, and livestock. It serves as a platform for knowledge exchange, research dissemination, and practical innovations in Agroforestry. By fostering connections among researchers, practitioners, policymakers, and local communities, the Agroforestry Community promotes environmental conservation, enhanced agricultural productivity, and resilient livelihoods.
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Recent Submissions
Evaluation of pedo-transfer functions for the estimation of hydraulic properties in some Morogoro soils, Tanzania
(Sokoine University of Agriculture, 2002) Mdemu, Makarius Victor Chogimembe
A study was conducted to evaluate some selected pedotransfer functions (PTFs) for soil water retention (SWR) and saturated hydraulic conductivity (Ks) using soils from Sokoine University of Agriculture (SUA) farm. Laboratory methods were used in analysis of collected samples for soil texture, organic carbon (OC), bulk density (BD), total porosity (p) and SWR characteristics (soil WRC). The Ks values were determined using the double ring and tension infiltrometer methods. Existing PTFs for soil WRC and Ks were selected from the literature for evaluation depending on their usability from the obtained soil data, easiness to apply them and their predictive capacity. Representative soil physical properties (RSPPs) for each soil profile studied were calculated using the ratios of individual soil profile horizons depths divided by the total depth of the soil profile. The RSPPs were used in evaluating PTFs for Ks estimation based on field measured Ks. The pedotransfer functions of Tomasella and Hodnett (1998), and PTFs of Ahuja et al. (1984), Campbell (1985), Vereecken, et al. (1990) and Jabro (1992) for SWR and or Ks were evaluated using obtained soil physical properties. Good estimates of SWR were obtained by Tomasella and Hodnett (1998) PTFs. Estimates of Ks proved unreliable by the evaluated PTFs. Simple linear multiple regression models were developed for SWR and Ks using determined soil physical properties following similar procedures to the evaluated PTFs. This was done for SWR so as to include important soil physical properties such as BD and OC, which were not included in evaluated PTFs. Soil texture, BD and OC contributed significantly (p < 0.05) to the developed regression equations for SWR characteristics at different matric potentials. Retained soil water contents significantly (p < 0.05) correlated to percentage clay, OC and BD in most developed regression equations. Estimates of AWC by the developed regression equation were not good enough compared to other estimated soil WRC. Only representative percentage clay had a significant (p < 0.05) contribution to the developed regression equation for Ks estimation. The correlation coefficient for the developed regression equation was high (r = 0.94). Generally, the Ks values estimated using the developed models matched measured values well with mean differences not significantly different from zero. The root of mean squared differences between measured and estimated SWR and Ks were 0.055 cm3cm'3 and 0.198 mm/h respectively. The developed PTFs for soil WRC and Ks gave good estimates compared to evaluated PTFs. It is recommended that more PTFs for soil hydraulic properties be developed using large soil samples under variable soil conditions for reliable estimations of the properties.
Measurement of soil water evaporation using microlysimeters of different sizes: effect of shade and soil texture
(Sokoine University of Agriculture, 1996) Maseko, Stephen Phuz’ukuvela
The effect of soil texture and shade on soil water evaporation using microlysimeters of different sizes was investigated. The rate of evaporation from the different sized microlysimeters was studied to see which evaporates the most. The days after irrigation were monitored to see if evaporation would increase or decrease. The effect of the depth of the microlysimeters was also studied to find out which depth evaporates more between the shallow depth microlysimeters (SDM) (10 cm), and the deeper depth microlysimeters (DDM) (20 cm). Two periods of the day, morning period (MP) and afternoon period (AP) were also studied to determine which one had more evaporation. The study, which was conducted from October to December 1994, was carried out in two sites with contrasting soils viz; (a) Ismani, in Iringa region selected for its clayey soils, and (b) Hombolo, in Dodoma region which had sandy soils. For the experiment, two plots were used, one shaded and the other unshaded. Shading was obtained by using a shade screen (a black net) which provided a shade of about 50 per cent. Sixty mm of irrigation water was applied on both plots at the same time. Results show that sandy soils evaporated significantly (P<0.05) more water, up to about 20 per cent, than clayey soils. Shading significantly (P<0.05) reduced evaporation by 5 to 10 per cent. The 10 cm diameter microlysimeters lost more water than the 5 cm diameter ones. This was prominent in clayey soils (P<0.05) than in the sandy soils, at the initiation of the experiment. However, towards the end of the study the difference was reduced. It was also observed that evaporation significantly decreased as the soil progressively dried after irrigation. The second day’s evaporation was reduced by almost 50 per cent. The rest of the days’ evaporation was steady at about 10 to 20 percent of the first day. There was no significant difference between the SDM and DDM. It seems depth (10-20 cm) does not significantly affect evaporation. The periods of the day showed some significant difference. In clayey soils significantly (P<0.05) more water was lost in the MP than in the AP. However, the reverse was true for the sandy soils.
Measurement of soil water evaporation using microlysimeters of different sizes: effect of shade and soil texture
(Sokoine University of Agriculture, 1996) Maseko, Stephen Phuz’ukuvela
The effect of soil texture and shade on soil water evaporation using microlysimeters of different sizes was investigated. The rate of evaporation from the different sized microlysimeters was studied to see which evaporates the most. The days after irrigation were monitored to see if evaporation would increase or decrease. The effect of the depth of the microlysimeters was also studied to find out which depth evaporates more between the shallow depth microlysimeters (SDM) (10 cm), and the deeper depth microlysimeters (DDM) (20 cm). Two periods of the day, morning period (MP) and afternoon period (AP) were also studied to determine which one had more evaporation. The study, which was conducted from October to December 1994, was carried out in two sites with contrasting soils viz; (a) Ismani, in Iringa region selected for its clayey soils, and (b) Hombolo, in Dodoma region which had sandy soils. For the experiment, two plots were used, one shaded and the other unshaded. Shading was obtained by using a shade screen (a black net) which provided a shade of about 50 per cent. Sixty mm of irrigation water was applied on both plots at the same time. Results show that sandy soils evaporated significantly (P<0.05) more water, up to about 20 per cent, than clayey soils. Shading significantly (P<0.05) reduced evaporation by 5 to 10 per cent. The 10 cm diameter microlysimeters lost more water than the 5 cm diameter ones. This was prominent in clayey soils (P<0.05) than in the sandy soils, at the initiation of the experiment. However, towards the end of the study the difference was reduced. It was also observed that evaporation significantly decreased as the soil progressively dried after irrigation. The second day’s evaporation was reduced by almost 50 per cent. The rest of the days’ evaporation was steady at about 10 to 20 percent of the first day. There was no significant difference between the SDM and DDM. It seems depth (10-20 cm) does not significantly affect evaporation. The periods of the day showed some significant difference. In clayey soils significantly (P<0.05) more water was lost in the MP than in the AP. However, the reverse was true for the sandy soils.
Assessment of uranium levels in selected soils and its uptake by rice, maize and millet in Bahi district, Tanzania
(Sokoine University of Agriculture, 2014) Makoti, Clavery Atiianas
This research aimed to determine levels of uranium (U) contamination in selected agricultural soils of Bahi District and its uptake by food crops in order to enhance public awareness and safety. The research involved determination of spatial distribution of U in agricultural soils, its uptake and translocation in plant/crop tissues. Soil, plant and water samples were collected randomly from farmers' fields and water sources, respectively. Laboratory sample analysis was done at the Government Chief Chemist Laboratory in Dar es Salaam and Soil Science Laboratory at the Sokoine University of Agriculture. Substantial differences of U concentrations in soils, plants and water were determined. The highest U level in soil profiles was 74.8 pg kg’1 at Mpamantwa and the lowest was18.3 pg kg’1 at Hindi. Along the studied transects, the highest U level was 743 pg kg’1 at Bahi and lowest was 13.6 pg kg’1 at Hindi. Uranium concentrations in maize and rice were below detectable limit (<10 pg L"1) except for finger millet where U accumulation levels ranged from 10.4 to 32.0 pg kg‘l. The concentration of U in water differed from village tovillage. The highest U level of 1233 pg L’1 was found in Hindi village at Hindi Playa Lake whereas in Bahi the highest U concentration was 62.9 pg L’1 found in one of the Bubu tributaries under the bridge. The concentrations of U in water in Hindi and Bahi villages were more than 30 pg L’1 the tolerable limit set by WHO for human and animal consumption. The levels of U in soils and crops were within the tolerable limit for agricultural use and the environment. Further studies should be carried out for other types of crops that are grown in the Bahi District villages to assess their safety for human consumption.
Crop production for household consumption and food security: a case study of Musoma rural district
(Sokoine University of Agriculture, 2010) Maijo, Elias Lugane
This study was carried out to assess food crop production for household consumption and food security in Musoma Rural district. A multistage random sampling procedure was employed to select 120 households from Musoma rural district. The study used a Gross Margin (GM) model to test the hypothesis that the selected major food crops production for household consumption is not economically profitable. When the GMs of the major crops were compared it was apparent that maize had the highest gross margin of Tsh 421352.10 than other crops. In’general, the results of this study revealed the existence of considerable economic profitability in producing the major crops. Furthermore, the study conducted a comparison of gross margin across different size categories of farms sizes using the Analysis of Variance (ANOVA) technique. The ANOVA indicated the existence of a significant difference in the level of GM for the different farm size categories. Binary Logistic model was estimated to establish factors influencing food security in the study area. The results revealed that 48.3% of the populations were food secure and 51.7% were food insecure. The results indicate that food security was positively influenced by farm size, wealth, off-farm employment, access to credit and market. Furthermore, the results revealed that food security was negatively influenced by the household size. However, strategies for sustainable agriculture to enhance food security, like the use of improved inputs and seed and expanding the farm size are recommended. The general conclusion from the research is that policies that would intensify food production and improve off farm employment would enhance food security in the study area.