Articles, Conference and Workshop Papers Collection

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Adaptations in water harvesting technologies for enhancing food security and livelihood: A multi-country study in Sub-Saharan Africa
(Springer, 2018) Snelder, D; Kahimba, F.C; Korodjouma, O; Abebe, A; Oughton, E; Bunclark, L; Lasage, R
The objective of this paper was to examine farmer-directed technology adaptation of selected water harvesting technologies (WHTs) in order to enhance their potential contribution to food security and livelihood improvement in sub-Saharan Africa. The selected WHTs included micro- and meso-scale reservoirs that store water in the soil (in situ) or in a reservoir, respectively: household ponds in Ethiopia, ndiva systems in Tanzania and combinations of mechanized zaï, grass strips and bunds in Burkina Faso. The impact of non-adapted WHTs was below expectation. Although WHTs improved yields, most families were unable to meet their (nutritional) food needs every year and experienced limited or no long-term effects on sustainable livelihood. The lining of household ponds and conveyance canals with durable materials gave promising results, yet needs economic consideration; a minimum investment may form a barrier particularly to resource-poor farmers. Incorporation of the location-specific nature of farming and livelihoods into WHT interventions is recommended, along with incentive measures to support farmers including the provision of access to credits and inputs for agricultural production.
Adaption of the traditional coffee pulping machine to soybean dehulling
(2008-06) Silayo, V.C.K.; Laswai, H.S.; Ballegu, W.R.W; Mpagalile, J.J.; Kulwa, K.; Yuda, B.
Processing of soybean for human consumption requires wet heat treatment of the beans in order to inactivate anti-nutritional factors. After hot water treatment or steaming, dehulling of the bean has always been an uphill task for household processors in Tanzania. Dehulling is done by hand rubbing, which is tedious and time consuming. The traditional coffee pulping machine was adapted to dehull boiled soybean. Seven soybean varieties namely TGX-1876-2E, Bossier, Kaleya, TGX 1805-8E, Sable, Songea and Duicker were tried. This was a development process whereby three consecutively improved versions of dehulling machines were tested. The machines were branded Ml, M2 and M3, implying first, second and third generation, respectively. Bean recovery as a measure of performance was 74.3, 77.4 and 91.8% for Ml, M2 and M3, respectively compared with 89.7% for manual dehullingfrubbing. The respective throughput was 8, 10 and 28.2 kg/h compared with 0.43 kg/h for manual dehulling. The mean dehulling efficiency of the M3 dehuller was 82.4% which was the highest. The M3 dehuller's best performance was due to use of ball bearings to support the rasping roller axle instead of sleeves and its ergonomically suitable height. The M3 dehuller could be adopted for soybean dehulling under rural livelihood conditions but the economics for owning and running it needs to be explored. Its improvement to make it moiorised is recommended to increase throughput and increase chances for adoption in medium scale soybean processing.
Adoption and scaling-up of conservation agriculture in Tanzania: Case of Arusha and Dodoma regions
(Scientific Research, 2014-02-21) Kahimba, F. C.; Mutabazi, K. D.; Tumbo, S. D.; Masuki, K. F.; Mbungu, W. B.
A study was conducted to assess the adoption and scaling-up of Conservation Agriculture in Arumeru district, Arusha region, northern Tanzania and Chamwino and Dodoma Urban districts in Dodoma region, Central Tanzania. The study employed structured questionnaire survey and key informant interviews as the main data collection methods. Data analysis was done descriptively to determine factors that influence the adoption. Results showed that farmers in Arusha have highly adopted terraces, minimum tillage and cover cropping whereas their counterparts in Dodoma have highly adopted large planting pits, minimum tillage, and rippers. The intensity of adoption in Arusha is higher for the wealthy compared to the poor while in Dodoma the wealth status was not a factor that influenced adoption of the Conservation Agriculture (CA) technologies. The process of technology adoption should include the use of various participatory methods including farmer field schools, experimental plots, farmer exchange visits, and training of trainers among others. Use of farmer groups, incentives, and support instruments such as Savings and Credit Co-operative Society (SACCOS) or warehouse receipts systems are also important to ensure that farmers realize some acceptable profits from their efforts. Involvement of various stakeholders is also very important including local governments and agricultural change agents at national, regional, district, ward and village levels. Hence, the intention to promote CA technologies should not only look at the economic importance, but also its socio-economic importance to the local people in the area. Their desire to adopt and out-scale a technology should be among the most important investment factors that the government and development partners should consider.
Agricultural drought analysis for sustainable smallholder maize production in semi-arid areas: A case study of the lower Moshi irrigation scheme, Tanzania
(2015) Patrick, B.; Kimaro, D.; Lal, R.
Rainfed maize (Zea mays) in semi-arid Sub-Saharan Africa is subject to many climate-related risks—including agricultural dry spells and droughts. Effectively selecting appropriate agricultural water management strategies must first begin with evaluation of the potential climate-related risks. This article evaluates dry spell occurrence in the Mabogini Village—located within a semiarid area in Tanzania—using a water balance approach with nineteen years of historical daily precipitation data. The water balance equation was related to crop water requirements to evaluate both the prevalence of agricultural dry spells as well as estimate the water deficits throughout the same time period. Only four of the nineteen seasons did not experience a dry spell of at least five consecutive days. 37% of the seasons had at least one dry spell of 6-10 days while 63% had at least one dry spell of greater than 15 days. Soil water deficit in relation to crop production ranged from 0-140 mm. This study concludes that dry spells lasting greater than 15 days throughout 63% of the past 19 growing seasons represent a high risk to smallholder farmers in the area. The high prevalence of long dry spells suggests that rainfed maize production is not sustainable in the region without interventions. However, relatively small water deficits suggest that proper water capture, storage, and supplemental irrigation methods could help to bridge the gap between dry spells. It is therefore recommended that water management practices be put in place immediately to support productive and sustainable maize production in the area.
Agriculture is the main driver of deforestation in Tanzania
(Environmental Research Letters, 2020-02-26) Doggart, N.; Morgan-Brown, T.; Lyimo, E.; Mbilinyi, B.; Meshack, C. K.; Sallu, S. M.; Spracklen, D. V.
Reducing deforestation can generate multiple economic, social and ecological benefits by safeguarding the climate and other ecosystem services provided by forests. Understanding the relative contribution of different drivers of deforestation is needed to guide policies seeking to maintain natural forest cover. We assessed 119 randomly selected plots from areas deforested between 2010 and 2017, in Tanzania. Through ground surveys and stakeholder interviews we assessed the proximate deforestation drivers at each point. Crop cultivation was the most commonly observed driver occurring in 89% of plots, compared to livestock grazing (69%) and charcoal (35%). There was evidence of fire in 77% of plots. Most deforestation events involved multiple drivers, with 83% of plots showing signs of two or more drivers. Stakeholder interviews identified agriculture as the primary deforestation driver in 81% of plots, substantially more than charcoal production (12%), timber harvesting (1%) and livestock (1%). Policy-makers in Tanzania have sought to reduce deforestation by reducing demand for charcoal. However, our work demonstrates that agriculture, not charcoal, is the main driver of deforestation in Tanzania. Beyond protected areas, there is no clear policy limiting the conversion of forests to agricultural land. Reducing deforestation in Tanzania requires greater inter-sectoral coordination between the agriculture, livestock, land, energy and forest sectors.
Analysis of Intra and Interseasonal Rainfall Variability and Its Effects on Pearl Millet Yield in a Semiarid Agroclimate: Significance of Scattered Fields and Tied Ridges
(Water, 2019-03) Silungwe, F.R; Graef, F; Bellingrath-Kimura, S.D; Tumbo, S.D; Kahimba, F.C; Lana, M.A
Establishing food security in sub-Saharan African countries requires a comprehensive and high resolution understanding of the driving factors of crop production. Poor soil and adverse climate conditions are among the major drivers of poor regional crop production. Drought and rainfall variability challenges are not fully being addressed by rainfed producers in semiarid areas. In this study, we analysed the spatiotemporal rainfall variability (STRV) and its effects on pearl millet yield using two seasons of data collected from 38 rain gauge stations scattered randomly in farm plots within a 1500 ha area of semiarid central Tanzania. The STRV effects on pearl millet yield under flat and tied ridge management were analysed. Our results show that seasonal rainfall can vary significantly for neighboring fields at distances of less than 200 m, which impacts yield. The STRV for daily rainfall was found to be more critical than for total seasonal rainfall amounts. Scattering fields can help farmers avoid total harvest loss by obtaining at least some yield from the areas that received adequate rain. The use of tied ridges is recommended to conserve soil moisture and improve yields more than flat cultivation in semiarid areas.
Application of self-organizing-maps technique in downscaling GCMs climate change projections for Same, Tanzania
(2010) Tumbo, S. D.; Mpeta, E.; Mbillinyi, B. P.; Kahimba, F. C.; Mahoo, H. F.; Tadross, M.
High resolution surface climate variables are required for end-users in climate change impact studies; however, information provided by Global Climate Models (GCMs) has a coarser resolution. Downscaling techniques such as that developed at the University of Cape Town, which is based on Self-Organizing Maps (SOMs) technique, can be used to downscale the coarse-scale GCM climate change projections into finer spatial resolutions; but that must be combined with verification. The SOM downscaling technique was employed to project rainfall and temperature changes for 2046-2065 and 2080-2100 periods for Same, Tanzania. This model was initially verified using downscaled NCEP reanalysis and observed climate data set between 1979 and 2004, and between NCEP reanalysis and GCM controls (1979 - 2000). After verification, the model was then used to downscale climate change projections of four GCMs for 2046-2065 (future-A) and 2080-2100 (future-B) periods. These projections were then used to compute changes in the climate variables by comparing future-A and B to the control period (1961-2000). Verification results indicated that the NCEP downscaled climate data compared well with the observed data. Also, comparison between NCEP downscaled and GCM downscaled showed that all the four GCM models (CGCM, CNRM, IPSL, and ECHAM) compared well with the NCEP downscaled temperature and rainfall data. Future projections (2046-2065) indicated 56 mm and 42 mm increase in seasonal total rainfall amounts for March-April-May (MAM) and October-November-December (OND) (23% and 26% increase), respectively; and a temperature increase of about 2°C for both seasons. Furthermore, it was found that during MAM there will be a decrease in dry spells by 2 days, and an increase in seasonal length by 8 days, while for OND, there will be also 2 days decrease in dry spells, and 40 days increase in the seasonal length. The results for future-B shows a 4°C rise in temperature, and 46.5% and 35.8% increase in rainfall for MAM and OND, respectively. The results imply a better climatic future for the area because of the increase in the amount of rainfall and decrease in dry spells. However, it is suggested that further investigations are required to see if the projected changes will have real positive effects in agricultural production and also identify better agronomic practices that will take advantage of the opportunities.
Assessing the Impacts of Land Use and Land Cover Changes on Hydrology of the Mbarali River Sub-Catchment. The Case of Upper Great Ruaha Sub-Basin, Tanzania.
(Scientific Research Publishing Inc., 2018) Mutayoba, E; Kashaigili, J.J; Kahimba, F.C; Mbungu, W; Chilagane, N.A
Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha Sub basin, Tanzania. This has affected the magnitude of the surface runoff, total water yield and the groundwater flow. This study assesses the impacts of the land cover and land use changes on the stream flows and hydrological water balance components (surface runoff, water yield, percolation and actual evapotranspiration). The land use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and 2017 were created from Landsat TM and OLI_TIRS with the help of QGIS version 2.6. Supervised classification was used to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics for assessment of accuracy. SWAT was set up and run to simulate stream flows and hydrological water balance components. The assessment of the impacts of land use and land cover changes on stream flows and hydrological water balance component was performed by comparing hydrological parameters simulated by SWAT using land use scenarios of 2006 and 2017 against the baseline land use scenario of 1990. Accuracy of LULC classification was good with Kappa statistics ranging between 0.9 and 0.99. There was a drastic increase in areal coverage of cultivated land, for periods 1990-2006 (5.84%) and 2006-2017 (12.05%) compared to other LULC. During 2006 and 2017 surface runoff increased by 4% and 9% respectively; however, water yield increased by only 0.5% compared to 1990 baseline period. This was attributed to increased proportion of cultivated land in the sub-catchment which has a high curve number (59.60) that indicates a higher runoff response and low infiltration rate.
Assessment of improved ladder terraces in controlling soil erosion on Uluguru Mountains-Tanzania
(Canadian Center of Science and Education, 2016-06-15) Materu, S. T.
This study assesses effectiveness of improved ladder terraces in controlling soil erosion on steep slopes of Uluguru Mountains in Morogoro Region, where runoff collection tanks were located downstream of the divisor system were all runoff from the catchment upstream where improved ladder terraces were located. The soil properties percentage weight for sand, silt and clay were average 40, 10 and 50 respectively. Half of the terraces were left barely and half were planted with maize crop. Runoff and soil loss generated during every rainstorm was collected from six field plots of improved ladder terraces to the tanks. There was statistically significant different between reductions of soil loss in bare improved ladder terrace and cropped improved ladder terrace. The amount of runoff on the bare soil was high by 15% to 18% compare to runoff on cropped soils. It was found that cropped improved ladder terrace reduced soil loss by 74% while bare improved ladder terrace reduced soil loss only by 41%. Simple linear regression shows runoff water generated from rainfall amount with soil losses from different land cover. Bare soils behave with linear relationship (r² = 0.85) unlike cropped soil were r² = 0.36 because of gradual increase of crop canopy at every crop stage hence less impact to the soil. Soils losses from the bare soil ladder terrace and that of cropped soil ladder terrace was significantly difference with correlation coefficient of 0.863 at vegetative stage and 0.928 at the full booting stage.
Assessment of the Impacts of Climate Change on Hydrological Characteristics of the Mbarali River Sub Catchment Using High Resolution Climate Simulations from CORDEX Regional Climate Models
(Canadian Center of Science and Education, 2018) Mutayoba, E; Kashaigili, J.J; Kahimba, F.C; Mbungu, W; Chilagane, N.A
This study assesses the impacts of climate change on water resources over Mbarali River sub-catchment using high resolution climate simulations from the Coordinated Regional Climate Downscaling Experiment Regional Climate Models (CORDEX_RCMs). Daily rainfall, minimum and maximum temperatures for historical climate (1971-2000) and for the future climate projection (2011-2100) under two Representative Concentration Pathways RCP 8.5 and RCP 4.5 were used as input into the Soil and Water Assessment Tool (SWAT) hydrological model to simulate stream flows and water balance components for the Mbarali River sub-catchment. The impacts of climate change on hydrological conditions over Mbarali river catchment were assessed by comparing the mean values of stream flows and water balance components during the present (2011-2040), mid (2041-2070) and end (2071-2100) centuries with their respective mean values in the baseline (1971-2000) climate condition. The results of the study indicate that, in the future, under both RCP 4.5 and RCP 8.5 emission scenarios, the four main components that determine change in catchment water balance (rainfall, ground water recharge, evaporation and surface runoff) over Mbarali river catchment are projected to increase. While the stream flows are projected to decline in the future by 13.33% under RCP 4.5 and 13.67% under RCP 8.5 emission scenarios, it is important to note that simulated surface runoff under RCP8.5 emission scenario is higher than that which is obtained under the RCP4.5 emission scenario.
Assessment of upgrading strategies to improve regional food systems in Tanzania: Food processing, waste management and bioenergy, and income generation
(SAGE, 2015) Graef, F; Schneider, I; Fasse, A; Germer, J.U; Gevorgyan, E; Haule, F; Hoffmann, H; Kahimba, F.C; Kashaga, L; Kashaga, L; Lambert, C; Lana, M; Mahoo, H.F; Makoko, B; Mbaga, S.H; Mmbughu, A; Mmbughu, S; Mrosso, L; Mutabazi, K.D; Mwinuka, L; Ngazi, H; Nkonya, E; Said, S; Schaffert, A; Schäfer, M.P; Schindler, J; Sieber, S; Swamila, M; Welp, H.M; William, L; Yustas, Y.M
Food security is one of the main goals of rural poor people. To enhance food security in this context, participatory action research can help to ensure sustained success while considering entire food value chains (FVC). This paper assesses the feasibility and potential success of upgrading strategies (UPS) as well as their assessment criteria as developed by German and Tanzanian agricultural scientists. The results form part of a larger participatory research project conducted in two climatically representative regions of Tanzania: semi-arid Dodoma and subhumid Morogoro. This paper presents the findings with respect to food processing, waste management and bioenergy, along with income generation and market participation. Assessments on other components of the FVC, including natural resource management, crop production and consumption, are reported by Graef et al (2015). The assessments for food processing revealed preferences for preservation techniques, oil extraction processes and food storage devices for the semi-arid region. In contrast, in the subhumid region, the experts favoured food storage devices and preservation techniques. Assessments of waste management and bioenergy UPS for both regions indicated the importance of animal feed from crop residues, crop residues as mulch and compost from food waste, although with somewhat different priorities. Assessments on income generation and markets in both regions revealed preferences for savings and credit cooperatives and communication techniques, but also indicated that warehouse receipt systems and guarantee systems had a high impact. Assessments differed between the two different climatic regions, and to some extent also between the nationality of experts and their gender. The authors therefore attach importance to integrating different South–North and female–male awareness in assessments among scientists. Moreover, local and/or regional stakeholders and experts should be involved in developing site-adapted UPS for enhancing FVCs.
Assesssment of the Perfomance of sun drying of maize grains on perforated surfaces
(1998) Silayo, V.C.K.; Kajuna, S.T.A.R.; Omari, B.
Sun drying of maize grains on different mesh sizes ofperjorated trays using different heights from the ground was investigated. The mesh sizes used were 1.5 mm and 3 mm at the elevations of 30, 60 and 90 cm. The results show that both mesh size and height from the ground affect the drying rate and seed viability. The combination of90 cm elevation and 3mm mesh size gave the highest drying rates and lowest seed viability loss.
Cassava Sun Drying Performance on Various Surfaces and Drying Bed Depths
(2013) Silayo, V.C.K; Lazaro, E.L.; Yustas, Y.; Laswai, H.S.
Processing of cassava (Manihot esculenta Crantz) to obtain flour is faced with a lot of technical constraints including inefficient drying. The traditional sun drying method is very inefficient as the product can take 2- 3 days to dry. Mould growth and other problems such as contamination of the product are likely and therefore necessitate intervention. Among the interventions was sun drying on a platform raised 1 m above ground in comparison with drying in a direct box solar dryer; by using trays with various bottom surfaces. The experiments were done using kiroba cassava variety obtained from the University farm, which was peeled and sliced into thin chips (2-3 mm) then sun dried on wire mesh, black polythene, white polythene and woven mat for three days. The material was dried for 8 hours daily after which it was kept indoors overnight. The surface with highest sun drying performance was wire mesh while white polythene was the least. The 10 mm bed depth attained constant weight in just about six hours of drying while for 20 and 30 mm bed depth it was about 16 hours and 40 mm bed depth for about 24 hours. There was moisture adsorption which was at 10, 22 and 28 hours for the 10 mm bed depth, 10, 20, 26 and 28 hours for 20 and 30 mm bed depths, and 28 hours for the 40 mm bed depth. The time 0,10 and 20 hours marked the beginning of drying whereas 8, 18 and 28 hours marked the end of drying. The best performance was therefore obtained on wire mesh and 10 mm bed depth and recommended for sun drying of cassava. However; there is need to investigate on whether there is significant quality difference between cassava sun dried at different bed depths investigated in this study
Cassava sun drying performance onvarious surfaces and drying bed depths
(2013) Silayo, V.C.K; Lazaro, E.L.; Yustas, Y.; Laswai, H.S.
Processing of cassava (Manihot esculenta Crantz) to obtain flour is faced with a lot of technical constraints including inefficient drying. The traditional sun drying method is very inefficient as the product can take 2- 3 days to dry. Mould growth and other problems such as contamination of the product are likely and therefore necessitate intervention. Among the interventions was sun drying on a platform raised 1 m above ground in comparison with drying in a direct box solar dryer; by using trays with various bottom surfaces. The experiments were done using kiroba cassava variety obtained from the University farm, which was peeled and sliced into thin chips (2-3 mm) then sun dried on wire mesh, black polythene, white polythene and woven mat for three days. The material was dried for 8 hours daily after which it was kept indoors overnight. The surface with highest sun drying performance was wire mesh while white polythene was the least. The 10 mm bed depth attained constant weight in just about six hours of drying while for 20 and 30 mm bed depth it was about 16 hours and 40 mm bed depth for about 24 hours. There was moisture adsorption which was at 10, 22 and 28 hours for the 10 mm bed depth, 10, 20, 26 and 28 hours for 20 and 30 mm bed depths, and 28 hours for the 40 mm bed depth. The time 0,10 and 20 hours marked the beginning of drying whereas 8, 18 and 28 hours marked the end of drying. The best performance was therefore obtained on wire mesh and 10 mm bed depth and recommended for sun drying of cassava. However; there is need to investigate on whether there is significant quality difference between cassava sun dried at different bed depths investigated in this study.
Characterization of sounds in maize produced by internally feeding insects: Investigations to develop inexpensive devices for detection of prostephanus truncatus (Coleoptera: Bostrichidae) and sitophilus zeamais (Coleoptera: Curculionidae) in small-scale storage facilities in Sub-Saharan Africa
(Florida Entomological Society, 2015) Kiobia, D. O.; Tumbo, S. D.; Cantillo, J.; Rohde, B. B.; Mallikarjunan, P. K.; Mankin, R. W.
Infestations by Prostephanus truncatus Horn (Coleoptera: Bostrichidae) and Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) are prevalent in small-scale Zea mays L. storage facilities in Tanzania and other regions of sub-Saharan Africa. It is especially difficult to detect these species’ larvae, which feed unseen inside the grain kernels. An electronic device that acoustically detects and reliably indicates the presence of such larvae could assist pest managers in maintaining the quality of the stored maize. A study was conducted in a sound- and vibration-controlled environment to estimate the amplitudes and spectral ranges of signals that an inexpensive electronic system would encounter while detecting insects in maize storage facilities. Larva-infested wheat kernels from a laboratory colony of Sitophilus oryzae (L.), a species similar in size and behavior to S. zeamais, were placed in a pouch and inserted near the side or the bottom of a bag of maize. An acoustic probe was inserted into the bag, and recordings were made at multiple positions, 5–35 cm from the pouch. Numerous sounds of 4 different types were detected over a range of frequencies extending to 7 kHz, well within the signal-processing capabilities of currently available low-cost microcontroller platforms. Larval sound impulses were detected frequently within 25 cm from the pouch, but not at 35 cm. However, adjustable-length probes could be used to reach within 30 cm of all maize kernels in the types of containers commonly used in regional storage facilities. Thus, there is considerable potential to develop an inexpensive sensor/ microcontroller system useful for managing stored product insect pests in sub-Saharan Africa.
Combined effects of biochar and fertilizer application on maize production in dependence on the cultivation method in a sub-humid climate
(Taylor and Francis, 2018) Graef, H; Kiobia, D; Saidia, P; Kahimba, F; Graef, F; Eichler-Lobermann, B
Low, erratic rainfall amounts and restricted accessibility of chemical fertilizer for rural farmers in developing countries may have negative effects on crop production. Agricultural methods like biochar applications, fertilizer microdosing and tied ridging can help to mitigate these constraints, but have rarely been studied in combination and under varying water availability. A field trial was conducted in split-plot design over two contrasting cropping seasons in 2016 and 2017 in Tanzania to study the effect of these agricultural methods on maize grain yield, biomass, leaf area index, plant height and soil moisture content. In both seasons each with contrasting irrigation frequencies, fertilizer microdosing increased the grain yield of maize. Biochar alone affected the yield only at high application rates (10 t/ha) and low irrigation frequency. However, when combined with fertilizer microdosing the yield effect of biochar was more pronounced. For example, combining 5 t/ha biochar with fertilizer microdosing under flat tillage increased yield by 170% compared to the control without biochar and fertilizers. Tied ridges increased soil moisture content and tended to increase maize yield compared to flat tillage, whereas biochar application resulted in significantly higher soil moisture contents. Fertilizer microdosing with biochar application can be recommended to improve maize yields mainly under flat tillage.
Comparison of silicon status in rice grown under the system of rice intensification and flooding regime in Mkindo Irrigation Scheme, Morogoro, Tanzania
(TAJAS, 2020) Gowele, G. E.; Mahoo, H. F.; Kahimba, Frederick C.
Silicon (Si) is the second most abundant element available in the earth's crust, and is considered as a benefcial element for crop growth especially rice. A study was conducted in Mkindo irrigation scheme, Mvomero District, Morogoro, Tanzania to assess the Silicon status in rice grown under the System of Rice Intensifcation and continuous ﬂooding at various growth stages. The experiment was laid out in a randomized complete block design (RCBD) with two treatments which were two water application regimes: T1 was alternate wetting and drying using SRI technology and T2 was continuous ﬂooding. The treatments were replicated three times and the rice variety used was SARO 5 (TXD 306). The experiment was conducted in two seasons from October 2019 to January 2020 and from March 2020 to June 2020. Si status in rice seeds and grains as well as rice plant leaves at various growth stages were evaluated according to elemental analysis based on Energy Dispersive X- Ray Fluorescence and results were analyzed using GENSTAT software. Si content in rice seeds observed prior to the experiment was 6.76%. Si content in rice grains was gradually increasing during reproductive stage and later drops during harvest. Si content in rice plant leaves increased signifcantly from vegetative to ripening stage whereby the highest Si content was recorded in T 1 (12.37%) while T2 recorded the lowest value (10.15%). It was concluded that, the alternate wetting and drying feld conditions enhances adequate uptake of Si compared to continuous ﬂooding practices.
Crop Upgrading Strategies and Modelling for Rainfed Cereals in a Semi-Arid Climate—A Review
(Water, 2018-03) Silungwe, F.R; Graef, F; Bellingrath-Kimura, S.D; Tumbo, S.D; Kahimba, F.C; Lana, M.A
Spatiotemporal rainfall variability and low soil fertility are the primary crop production challenges facing poor farmers in semi-arid environments. However, there are few solutions for addressing these challenges. The literature provides several crop upgrading strategies (UPS) for improving crop yields, and biophysical models are used to simulate these strategies. However, the suitability of UPS is limited by systemization of their areas of application and the need to cope with the challenges faced by poor farmers. In this study, we reviewed 187 papers from peer-reviewed journals, conferences and reports that discuss UPS suitable for cereals and biophysical models used to assist in the selection of UPS in semi-arid areas. We found that four UPS were the most suitable, namely tied ridges, microdose fertilization, varying sowing dates, and field scattering. The DSSAT, APSIM and AquaCrop models adequately simulate these UPS. This work provides a systemization of crop UPS and models in semi-arid areas that can be applied by scientists and p
Crop water productivity of an irrigated maize crop in Mkoji sub-catchment of the Great Ruaha River Basin, Tanzania
(Elsevier, 2006-09-16) Igbadun, Henry E; Mahoo, Henry F; Salim, Baanda A; Tarimo, Andrew K. P. R.
Crop water productivity (CWP) is a quantitative term used to define the relationship between crop produced and the amount of water involved in crop production. It is a useful indicator for quantifying the impact of irrigation scheduling decisions with regard to water management. This paper presents CWP quantified from field experimental data. Three fields were cultivated to maize under irrigation during the 2004 dry season in a traditional irrigation scheme in Tanzania. The maize crop was irrigated at eight different seasonal water application depths: 400, 490, 500, 510, 590, 600, 610 and 700 mm, in two of the three fields, and at five water application depths: 400, 590, 600, 610 and 700 mm in the third field. The variation in seasonal water application depth was achieved by skipping the weekly irrigation once after every other irrigation at some pre-defined stages of the crop growth. CWP were computed in terms of …
Determinants of farm-level adoption of water systems innovations in dryland areas: The case of Makanya watershed in Pangani river basin, Tanzania
(2005) Masuki, K.F. G.; Mutabazi, K. D; Tumbo, S. D.; Rwehumbiza, F. B.; Mattee, A. Z.; Hatibu, N.
Water system innovations such as rainwater harvesting involve abstraction of water in the upper catchments. Increasing adoption of rainwater harvesting in the riparian catchments could have hydrological impacts on downstream flows in the river basin, but it is assumed to have overall gains and synergies when efficient use of rainwater is optimized at farm-level. This paper examines the main determinants of adoption of water system innovations with specific emphasis on the intensity of adoption and adoption lag, using a cross-sectional sample of 234 farmers in the Makanya watershed. Censored Tobit models were used to estimate the coefficients of intensity of adoption and adoption lag of water system innovations. Group networking, years spent in formal education, age of respondent, location and agricultural information pathways were found to be major determinants of intensity of adoption at farm-level. It was also found that intensity of adoption and frequency of attendance to collective action are strong determinants of adoption lag of water system innovation in Makanya watershed. Empirical knowledge of the determinants of adoption of water system innovations is critical for an effective scaling out of best practices of water harvesting in the Basin.

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