Browsing by Author "Kahimba, F.C."

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Climate change and food security in Tanzania: Analysis of current knowledge and research gaps
(2015) Kahimba, F.C.; Sife, A.; Maliondo, S.M.S.; Mpeta, E.J.; Olson, J.
A review of literature was conducted in order to identify knowledge gaps in climate change and food security research in Tanzania. The review focused on published literature covering the past 20 years addressing climate change effects on various components of the food security. The review of literature reveals, among other things, that the current agricultural practices cannot ensure food security due to the fact that they heavily rely on the increasingly erratic and unreliable rainfall. Food systems in Tanzania are highly vulnerable to climate change and variability due to poor adaptive capacity of the socio-economic systems and limited community resilience to cope with climate variability and change. Response to climate change impacts is affected by multiple factors at different scales, ranging from the individual to the household and landscape, which in turn affects food security. Quality climate change science research in Tanzania is limited by few, scattered, unevenly distributed, and ill-equipped meteorological stations. This calls for research that is geared towards combining mitigation and adaptation strategies against the impacts of climate change, focusing on adaptation strategies that build climate resilience, reduce greenhouse gas emissions, and increase food security. Multidisciplinary research is required to provide a science-based analysis of potential coping and adaptation strategies and their economic and social effects.
How much nitrogen would move down? Evaluating the effect of water application regimes on n leaching in the soil
(Research Journal of Agriculture and Environmental Management, 2015) Mthandi, J.; Salim, B.A; Kahimba, F.C.; Tarimo, A.K.P.R; Lowole, M.W.
Nitrogen is the nutrient most often deficient for crop production and its use can result in substantial economic return to farmers. However, when N inputs exceed crop needs, excess N may contaminate water. N Management is therefore important to achieve a balance between profitable crop production and environmentally tolerable levels. The aim of this paper is to evaluate the impact of water application regimes on the leaching of nitrogen. The research study was conducted at Nkango Irrigation Scheme in Kasungu district. Maize (SC 407) planted on Julian day of 2012152 and harvested Julian day of 2012250 was used as test crop in the study. The water regimes were full (100%) water requirement regime (FWRR) of maize plant; 60% of FWRR; and 40% of FWRR. The nitrogen application regime used was 92 N kg/ha which was constant.. The EU-Rotate_N model was run to quantify nitrogen leached below 90cm of the soil profile. The study found out that water application regime has a large influence on N leaching. The study concluded that applied water in the soil should not exceed field capacity of the soil and in such way leaching of nitrogen will be minimised.
Influence of irrigation water quality on soil salinization in semi-arid areas: A case study of Makutopora, Dodoma-Tanzania
(International Journal of Scientific & Engineering Research, 2013) Batakanwa, F.J.; Mahoo, H.F.; Kahimba, F.C.
This research was carried out in Dodoma, at Makutopora Agricultural Research Institute. The main objective was to determine the influence of irrigation water on soil salinization in semi-arid areas. A total of 80 representative soil samples were randomly collected from study area. Two water samples were also collected from the study area. The samples were treated and analyzed for physical and chemical related indices. The results are grouped into general quality parameters, which included salinity and salt inducing cations and anions. The findings indicated that the mean pH was 7.53 while the mean EC value was 944.5 µS/cm. The mean cations in the water were 3.97, 4.32, 2.57, and 11.39 meq/l for Ca2+, Mg2+, K+, and Na+, respectively. The Sodium Adsorption Ratio (SAR) was 5.60. The mean carbonates concentration detected in the irrigation water was 9.05 meq/l, while the mean chloride and sulfide were 17.20 and 3.6 meq/l, respectively. Soil samples were grouped into three major groups namely non-irrigated, half irrigated, and full irrigated soils. For the nonirrigated, half irrigated, and full irrigated soils: the mean pH in the soil was 6.59, 6.89 and 7.04, respectively; the mean ECe were 94.35, 338.5, and 344.72, mS/cm, respectively; SAR was 0.76, 2.64, and 4.82, respectively; exchangeable cations and anions as shown in Table 4, 6 and 8. The results reveal that water may have the potential to be hazardous to the soil as well as to the crop grown because most parameters were above safe limits. The linear regression model showed high correlation of soil salinity with exchangeable bases with R2 =0.776 and significant at p≤0.04 for non-irrigated soil, R2=0.627 at p≤0.001 for half irrigated soil, and R2=0.597 at p≤0.003 for full irrigated soil. For all soil samples the linear regression model shows strong relationships that exist between the soil salinity and exchangeable bases present in the soil. It is recommended that adequate drainage with emphasis on surface drainage should be provided and salt and sodium build up should be monitored regularly.
Land cover transition in Northern Tanzania
(2016-10-10) Tumbo, S. D.; Kahimba, F.C.; Ouedraogo, I.; Barron, J.
Land conversion in sub-Saharan Africa has profound biophysical, ecological, political and social consequences for human well-being and ecosystem services. Understanding the process of land cover changes and transitions is essential for good ecosystem management policy that would lead to improved agricultural production, human well-being and ecosystems health. This study aimed to assess land cover transitions in a typical semi-arid degraded agro-ecosystems environment within the Pangani river basin in northern Tanzania. Three Landsat images spanning over 30 years were used to detect random and systematic patterns of land cover transition in a landscape dominated by crop and livestock farming. Results revealed that current land cover transition is driven by a systematic process of change dominated by the following: (i) transition from degraded land to sparse bushland (10·8%); (ii) conversion from sparse bushland to dense bushland in lowland areas (6·0%); (iii) conversion from bushland to forest (4·8%); and (iv) conversion from dense bushland to cropland in the highlands (4·5%). Agricultural lands under water harvesting technology adoption show a high degree of persistence (60–80%) between time slices. This suggests that there is a trend in land-use change towards vegetation improvement in the catchment with a continuous increase in the adoption of water harvesting technologies for crop and livestock farming. This can be interpreted as a sign of agricultural intensification and vegetation regrowth in the catchment.
Using EU-rotate_N model to determine effects of nitrogen application dosage on N leaching
(International Journal of Research in Agricultural Sciences (IJRAS), 2015) Mthandi, J.; Kahimba, F.C.; Tarimo, A.K. P.R.; Salim, B.A.; Lowole, M.W
Nitrogen losses by leaching only occur when the capacity of the ecosystem to accumulate nitrogen has been saturated (which may take considerable time if the rate of nitrogen input is low). The research study was conducted at Nkango Irrigation Scheme in Kasungu district to determine the impact of nitrogen application regime on N leaching. Maize (SC 407) was a test crop. The planting and harvest were done on Julian day of 2012152 and 2012250 respectively. Water regime was kept constant at 100% of maize full water requirement regime (FWRR) while N application varied from 92 kg N/ha which represents Typical Nitrogen Placement Rate in the area (TNPRA), 125% of TNPRA (115 N kg/ha); 75% of TNPRA (69 N kg/ha); to 50% of TNPRA (46 N kg/ha). The EU-Rotate_N model was used to run the field data. The paper concluded that treatments that received high amount of inorganic N fertilizer lost more nitrogen through N leaching. Plant roots will only absorb nitrogen it requires leaving excess to be leached by water below the active rooting zone. The study also concluded that EU-Rotate_N model to perfectly predict N leaching from irrigated maize production. The study also found out that applying N fertilizers at once increase its susceptibility to leaching and therefore the study recommended that to apply N fertilizer in several small applications during the cropping season.