Articles, Conference and Workshop Papers Collection

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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, Ayubu
Rainfed 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.
Assessing drivers of soil properties and classification in the West Usambara mountains, Tanzania
(Elsevier, 2017-10-16) Massawe, B. H. J.; Winowiecki, L.; Meliyo, J. L.; Mbogoni, J. D. J.; Msanya, B. M.; Kimaro, D.; Deckersf, J.; Gulinck, H.; Lyamchai, C.; Sayula, G.; Msokah, E.; Vagen, T.; Brush, G.; Jelinskii, N. A.
Improved soil information in tropical montane regions is critical for conservation, sustainable agricultural management, and land use planning, but is often challenged by topographic and land-use heterogeneity. The West Usambara mountains are a part of the Eastern Arc chain of mountains of Tanzania and Kenya, a globally important tropical montane ecoregion made up of isolated fault-block mountain complexes characterized by high biological endemism, population density, and agronomic productivity. We synthesized novel and legacy soil data from published and unpublished studies to better understand the drivers of soil property distributions and soil diversity in the West Usambaras, and to serve as a foundation for improved soil mapping efforts across the Eastern Arc. Analysis of the resulting dataset of 468 sites (ranging in elevation from 1040 to 2230 m.a.s.l.) revealed that soil properties varied more significantly by land use and topography than by soil type, suggesting that future mapping efforts in the region should focus primarily on soil property prediction and secondarily on soil classification. Sites under cultivated land uses had the lowest topsoil soil organic carbon (SOC) concentrations and highest pH values, and SOC generally increased with increasing elevation. Valley soils had significantly lower surface SOC concentrations but higher exchangeable bases and pH values than all other landscape positions. Soil pH decreased by an average of 3.5 units across the entire elevation gradient and decreased by 1 unit with elevation even after SOC, land use and landscape position were included in multiple regression models. The relationship of cation exchange capacity (CEC) to SOC and clay content varied by landscape position. Therefore, particularly in montane regions where soils can vary significantly over short distances, multiple functions may be necessary to produce improved estimates of parameters such as CEC. Soil classification was driven most strongly by topography, with Acrisols (WRB Reference Group) and Ultisols (U.S. Soil Taxonomy (ST)) as the dominant soil types, located primarily on mid slope, upper slope and crest landscape positions, making up 47% and 75% of observed profiles, respectively. However, five ST Orders and seven WRB Reference Groups were present in the dataset, with the highest soil diversity occurring at lower slope landscape positions. Conclusions drawn from this large dataset support previous work in the West Usambaras and provide a conceptual foundation from which to build improved soil maps across the Eastern Arc and in other tropical montane systems throughout the world.
Assessment of soil fertility status for Bambara Groundnut Production in South-eastern Tanzania
(IJPSS, 2018-09-13) Tenga, J. J.; Semoka, J. M. R.; Msanya, B. M.
Intensive farming practised in the agro-ecological zones of Makonde plateau (C2) and Inland plain (E5) of south-eastern Tanzania without proper soil management has led to nutrient depletion. The objective of the study was to assess the fertility status of soils in Bambara groundnut growing areas of south-eastern Tanzania. Twenty-two farmers' field sites were sampled and composite samples of top soil at 0 – 20 cm depth were collected for physical and chemical analysis. The results indicate that the soils in the study area are sandy loam (64%), loamy sand (27%) and sandy clay loam (9%). About 28% of the soils in the study area had very low CEC values (< 6 cmol (+) kg soil). Soil pH was strongly acidic to moderately acidic (≤ 5.5) and slightly acidic (≥ 6.0) in the C2 and E5 agro- ecological zones, respectively. Total N was very low (< 0.1%) and organic carbon was very low to low (< 0.6%). Low levels of available P (<10 mg/kg), inadequate S (SO 4 -S) levels (< 10 mg/kg) were observed. The exchangeable K in the C2 zone was very low to low (< 0.05 cmol(+)/kg) while E5 zone had medium K level. The calcium level of C2 was low to medium (0.2 – 2.5 cmol(+)/kg) 2+ whereas that of E5 was medium to high (0.6 – 5.0 cmol(+)/kg). The exchangeable Mg levels were + very low to low (< 0.2 cmol(+)/kg) while Na was < 0.30 cmol(+)/kg soil indicating no sodicity problem. For > 90% of the studied soils extractable Zn was below critical level of 0.6 mg/kg. All soils had adequate extractable Fe whereas > 70% of the soils had high (> 5 mg/kg) extractable Mn. The study area generally indicated low fertility status in terms of N, P, K, S, Mg and Zn, calling for proper management for improving crop production.
Assessment of soil N, P, and K status of selected paddy growing areas of Tanzania
(2000) Semoka, J.M.R.; Mnguu, Y.O.
Suitable diagnostic criteria to assess the N, P and K status of rice growing areas particularly in developing countries like Tanzania are required. The objective of this study was to develop such criteria in selected rice growing areas of Tanzania and relate nutrient levels to rice response to fertilizer appli cation; Soil samples from 10 paddy growing areas of Tanzania were testedfor N, P and K using selected indices. Nitrogen supply was assessed by organic carbon (OC), total Nand alkaline-KMn04-N while P was assessed by Olsen, Bray-1 and the iron oxide coated-filter paper strip (Pi) methods. Potassium was extracted by neutral 1 N NH40Ac. Extractable nutrients were correlated with DM Yields and nutrient uptakefrom a glasshouse experiment which was also used to assess response of rice to these nutrients. OJ the three Nindices evaluated, only OC correlated significantly (r = 0.73, P< 0.05) with n'ce DMyield thus serving as a good index of N supply. Asfor P indices, Olsen P gave a highly significant correlation with rice DM yield (r = 0.85, P < 0.01) while the relationships with the other two methods gave lower correlation coefficients. All the soils tested were deficient in N and thus no criticallevelfor N could be established while six soils out of 10 were deficient in P. The critical soil P level for Olsen method was estimated to be 20 mg Ikg. The extracted K values were all found to be higher than critical values established elsewhere. Therefore; Nand P are important constraints to rice production in Tanzania and appropriate recommendations should be drawn and demonstrated to farmers.
Available technologies to replenish soil fertility in East Africa
(Springer, 2006) Semoka, J. R. M; Okalebo, J. R; Othieno, C. O; Woomer, P. L; Karanja, N. K; Bekunda, M. A; Mugendi, D. N; Muasya, R. M; Bationo, A; Mukhwana, E. J
Low inherent soil fertility in the highly weathered and leached soils largely accounts for low and unsu- stained crop yields in most African countries. But in particular, the major nutrients, nitrogen (N) and phosphorus (P), are commonly deficient in these soils. This scenario of nutrient depletion is reflected in food deficits and hence the food aid received continuously, specifically in sub-Saharan Africa. Undoubtedly, substantial efforts have been made in the continent to replenish the fertility of degraded soils in attempts to raise crop yields, towards self-sufficiency and export. Such efforts consist of applications of both organic and inorganic resources to improve the nutrient status of soils and enhanced nutrient uptake by crops, provided that soil moisture is adequate. Overall, positive crop responses to these materials have been obtained. Thus in the East African region, maize (staple) yields have been raised in one growing season from below 0.5 t/ha without nutrient inputs, to 3–5 t/ha from various nutrient amendments at the small- hold farm level. However, in spite of the positive crop responses to nutrient inputs, farmers are generally slow to adopt the soil fertility management technologies. In this paper we review the impact of some technologies, focussing the use of nutrient resources of different characteristics (qualities) in relation to improved crop yields, with an overall goal to enhance technology adoption. Thus, inorganic resources or fertilizers often give immediate crop responses, but their use or adoption is rather restricted to large-scale farmers who can afford to buy these materials. Organic resources, which include crop residues, water hyacinth and agroforestry shrubs and trees, are widely distributed, but they are generally of low quality, reflecting the need to apply large quantities to meet crop nutrient demands. Moreover, most organics will add N mainly to soils. On the other hand, phosphate rocks of varying reactivity are found widely in Africa and are refined elsewhere to supply soluble P sources. The recently developed soil fertility management options in East Africa have targeted the efficient use of N and P by crops and the integrated nutrient management approach. Some people have also felt that the repackaging of inputs in small, affordable quantities, such as the PREP-PAC described in this paper, may be an avenue to attract smallhold farmers to use nutrient inputs. Nonetheless, crop responses to nutrient inputs vary widely within and across agroecozones (AEZs), suggesting specificity in recommendations. We highlight this observation in a case study whereby eight soil fertility management options, developed independently, are being tested side-154 by-side at on-farm level. Farmers will be empoweredby-side at on-farm level. Farmers will be empowered to identify technologies from their own choices that are agronomically effective and economically friendly. This approach of technology testing and subsequent adoption is recommended for technology development in future
Bean Nodulation Patterns in Soils of Different Texture at Morogoro, Tanzania
(1998) Msumali, G.P.; Judith, A.K.
system in three soils of varying texture and % recovery of rhizobia I cells immediately after inoculation into such soils. Effects of inoculation methods (seed pelleting versus soil inoculation) on nodulation and plant growth were investigated in the three soils using a serologically- marked Rhizobium strain (ClAT 899) which was subsequently monitored in the nodules by the enzyme-linked immunosorbent assay (ELISA) technique. When the major soil chemical factors affecting nodulation were standardized, bean nodulation patterns continued to be closely related to soil texture, being higher in the sandy and loamy soils than in the fine-textured clay. Soil inoculation consistently gave better nodulation than seed pelleting.According to the ELISA procedure however, percent nodule occupancy by ClAT 899 showed patterns completely the opposite of the nodulation trends outlined above, being 100% in the clay but only 10% in the sandy soil. Thus, nodulation success by the inoculum was total in the clay but only dismal in the sandy soil. The unexpected discrepancy between inoculum success on the one hand and nodulation plus plant growth response on the other, is discussed.
Bean nodulation patterns in soils of different texture at Morogoro, Tanzania
(1998) Msumali, G.P.; Judith, A.K.
This study was designed to examine the, relationship between nodulation in a bean-Rhizobium system in three soils of varying texture and % recovery of rhizobia I cells immediately after inoculation into such soils. Effects of inoculation methods (seed pelleting versus soil inoculation) on nodulation and plant growth were investigated in the three soils using a serologically- marked Rhizobium strain (ClAT 899) which was subsequently monitored in the nodules by the enzyme-linked immunosorbent assay (ELISA) technique. When the major soil chemical factors affecting nodulation were standardized, bean nodulation patterns continued to be closely related to soil texture, being higher in the sandy and loamy soils than in the fine-textured clay. Soil inoculation consistently gave better nodulation than seed pelleting.According to the ELISA procedure however, percent nodule occupancy by ClAT 899 showed patterns completely the opposite of the nodulation trends outlined above, being 100% in the clay but only 10% in the sandy soil. Thus, nodulation success by the inoculum was total in the clay but only dismal in the sandy soil. The unexpected discrepancy between inoculum success on the one hand and nodulation plus plant growth response on the other, is discussed.
Bringing evidence to bear for negotiating tradeoffs in sustainable agricultural intensification using a structured stakeholder engagement process
(Taylor & Francis, 2021) Winowiecki, Leigh Ann; Bourne, Mieke; Magaju, Christine; Neely, Constance; Massawe, Boniface; Masikati, Patricia; Vågen, Tor-Gunnar; Musili, Faith; Nabi, Muhammad; Nguyo, Anthony; Seid, Hadia; Hadgu, Kiros; Shoo, Aikande; Tembo, Howard; Chipatela, Floyd; Chesterman, Sabrina; Hughes, Karl; Temu, Emmanuel; Kimaro, Anthony Anderson; Sinclair, Fergus
Sustainable agricultural intensification (SAI) has the potential to increase food security without detrimental effects on ecosystem services. However, adoption of SAI practices across sub-Saharan Africa has not reached transformational numbers to date. It is often hampered by lack of context-specific practices, sub-optimal understanding of tradeoffs and synergies among stakeholders, and lack of approaches that bring diverse evidence sources together with stakeholders to collectively tackle complex problems. In this study, we asked three interconnected questions: (i) What is the accessibility and use of evidence for SAI decision making; (ii) What tools could enhance access and interaction with evidence for tradeoff analysis; and (iii) Which stakeholders must be included? This study employed a range of research and engagement methods including surveys, stakeholder analysis, participatory trade-off assessments and co-design of decision dashboards to better support evidence-based decision making in Zambia, Tanzania and Ethiopia. At the inception, SAI evidence was accessible and used by less than half of the decision makers across the three countries and online dashboards hold promise to enhance access. Many of the stakeholders working on SAI were not collaborating and tradeoff analysis was an under-utilized tool. Structured engagement across multiple stakeholder groups with evidence is critical.
Building resilient crop production systems for drought-prone areas—a Case for Bambara Groundnut (Vigna subterranea L. Verdc) and Groundnut (Arachis hypogaea L.)
(MDPI, 2022) Kundy, Aloyce Callist; Mayes, Sean; Msanya, Balthazar; Ndakidem, Patrick; Massawe, Festo
Drought is a major crop production constraint worldwide. Some legume crops are known for their ability to resist water deficit stress. This study evaluated the responses of bambara groundnut (Vigna subterranea (L.) Verdc) and groundnut (Arachis hypogaea (L.) to soil water deficit stress. The experiment was set as a split-plot randomized complete block design. Three bambara groundnut landraces: viz DodR, NALBAM 4 and S19-3, and one groundnut variety, MNANJE, were assigned to subplots with three water regimes assigned to main plots (regime one: irrigated throughout the growing period, regime two: water deficit stress was imposed at the start of flowering to the end of first flush flowering, regime three: water was withheld during the pod development). Water deficit stress increased proline content by 123% in stressed plots. The highest (174%) and lowest (89%) proline increases were evident in the genotypes MNANJE and NALBAM 4, respectively. Water deficit decreased stomatal conductance, transpiration rate and photosynthetic rate, with MNANJE and S19-3 showing the smallest percentage decrease in most of the traits. This suggests that the two genotypes are drought resistant. The variations observed among landraces could be exploited to breed resilient varieties for cultivation in drought-prone areas, ultimately improving food security.
Challenges facing effective use of bat guano as organic fertilizer in crop production: a review
(International Journal of Engineering and Applied Sciences, 2021) Marwa, Ernest Melkiory; Andrew, Twisege; Hatibu, Asha Ally
Bat guano is excrements of bats and it is commonly used in agriculture as a soil amendment and sometimes as a pesticide in organic farming. Small-scale farmers nearby guano deposits use it for indoor and outdoor plants as well as for hydroponic crop production. Guano in soils acts as a source of carbon (C) and energy to drive microbial activities as well as a precursor to soil organic matter fractions. With all these benefits, bat guano should be used in crop production with some precautions. Chemical composition and properties of bat guano are not fixed and are changing with time depending on the maturity, reaction with the country rock and bat diet. The pH of guano changes from alkaline to strongly acid with maturity. Similarly, guano loses some essential plant nutrients on decomposition and sometimes acquires potentially toxic elements as it reacts with the host rocks. Amounts added to the soil also vary with maturity and composition of guano. Thus, utilization of bat guano as organic fertilizer requires a thorough and regular characterization at the time of using it as soil amendment for crop production
Characterization of soil depth to coral bedrock and bedrock roughness in Jozani Groundwater Forest, Zanzibar, Tanzania.
(International Journal of Scientific & Engineering Research, 2017) Said, M. S.; Msanya, B. M.; Semoka, J. R.; Maliondo, S. M.S.
Soils formed on coral terrain have a wide range of depths to coral bedrock and percentage of coral outcrops. Cliffs and other featuresof seawater abrasion, limited root zone, habitation and distribution of specific plant species are among the common conditions on Zanzibar coral landscapes.The current study was intended to characterize the relationship between soil depth to coral bedrock (SDCB) and bedrock roughness (BR) and determine features which are related to seawater abrasion at Jozani Groundwater Forest (JGWF). Such conditions and features have varying spatial distribution and magnitude which are likely to affect plant growth and species distribution in JGWF. The study area was divided into 320 grid points that were used as probing points for determining SDCB and BR. Global positioning system (GPS) model GARMIN etrex 10 was used to locate grid points, while a long graduated stick was used to measure depths from soil surface to coral bedrock at each point. SDCB was calculated as an arithmetic mean of measured depths and BR as standard deviation of measured depths. ArcGIS 10.1 was used to map SDCB and BR of JGWF. Kichangani in Tumbatu Islet was visited to gather information related to abrasion that took place on coastal coral bedrock. Minimum values of SDCB and BR obtained from JGWF grassland were used to rank and categorize SDCB and BR in JGWF. Results from probes on the 302 grid points showed that JGWF has range of SDCB of about 0.35 - 1.4 m and above (>1.4 m) and BR of 0.1 - 0.4 m and above (>0.4 m).Trends of SDCB and BR values in JGWF were complex, decreasing towards the cliff on the West and towards North-end, but increased in the opposite direction. It was concluded from this study that there are complex relationships between SDCB and BR on coral land and that the relationships can be captured, ranked, and mapped. Such relationships affect plant growth and species distribution. Again, flat platform which was found at Kichangani and grassland of JGWF is an evidence of seawater abrasion on coral bedrocks.
Characterization of soils on various planation surfaces in Tanzania
(Proceedings of the World Congress of Soil Science, 1998-08-26) Shigeru, Araki; Msanya, B. M.; Magoggo, Juvent P.; Kimaro, Didas N.; Kitagawa, Yasuo
Chemical properties of travertine from different sources in Rwanda with regards to their calcium oxide and magnesium oxide contents
(Sokoine University of Agriculture, Tanzania., 2012) Sirikare, N.S.; Naramabuye, F.X.; Marwa, E; Semu, E.
This study was conducted in the districts of Rusizi, Korongi and Musanze districts, Rwanda in areas where travertine is found. The objective of the study was to characterize the chemical compositions of travertine for use in amending soil acidity for crop production. Thirty two samples of travertine from different deposits at Mashyuza (Rusizi), Gishita (Karongi) and Mpenge and Rwaza (Musanze) were analysed to establish their CaO and MgO contents. Percentages by weight of CaO and MgO in samples were determined using X-ray fluorescence. Results revealed that travertine from Mashyuza and Rwaza has the highest CaO wt% content followed by Gishyita. Mpenge deposits had the lowest content CaO% . There was no significant difference among sites for MgO contin travertine. The tratio of CaO:MgO in Mpenge, Mashyuza and Gishita was within a range required to prevent deficiency of Ca and Mg in acid soils where maize and beans are grown.
Classification of soil profiles from alluvial plains of greece (thessaly and pelopennesos) according to the USDA and FAO soil taxonomy systems
(Sokoine University of Agriculture, 1986) Ala Loannis
Fifty profiles are studied for reclassification according to the USDA Soil Taxonomy System, The data come from soil surveys and investigations carried out since 1977 by the Institute of Soil Classification and Mapping of Larissa and by the Agriculture Faculty of Athens. According to the USDA Soil Taconomy Stystem (1975) the studied profiles are classified in five orders i.e. Mollisols, Entisols, Vertisols, Inceptisols and Alfisols, 7 suborders, 7 great groups, 20 subgroups. In the FAO-Unesco system they fall among the Gleysols, Fluvisols, Regosols, Luvisols, Vertisols, Cambisols and among 15 subunits. There were not sufficient data for the classification purposes and this as well for the chemical analyses (base saturation, cation exchange capacity, extractable cations, sulfidic material, C/N ratio, sometimes organic matter content and amorphous material) as for the particle size analysis (fine sand, fine clay), the physical analyses (bulk density, water retension capacity, n-value, Cole), the mineralogical analyses (clay mineralogy, amorphous minerals, weatherable minirals of 20-200 micron size) and the field observa tions (designation of organic matter, rubbed, dry and moist colour, colour, quantity and size of mottles, depth of cracking pattern, presence of pyroclas tic material, presence of ground water table, orientation, vegetation). Finally many of the chemical analysis should be considered as not accurate
Contents of heavy metals in coal and its by-products from the Songwe-Kiwira Mine, Tukuyu District, Tanzania
(SADC-ICART Project, 2010) Mndeme, U.M.; Semu, E.
Coals can be potent sources of heavy metal pollution upon their mining and utilisation. While Tanzania has many coal deposits, the coals have not been evaluated to determine their heavy metal contents and their potential to cause environmental pollution. Therefore, a study was undertaken to determine the heavy metal contents of the coal and its by-products from the Songwe-Kiwira mine, Tukuyu district, southern Tanzania. This is the area in the country where, currently, coal is being mined. The contents of lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), zinc (Zn), selenium (Se), and manganese (Mn) in different coal grades, in coal combustion by-products, and in various coal-derived sediments were determined by atomic absorption spectrophotometry (AAS) following aqua-regia digestion. The results showed the presence of heavy metals in the Kiwira coal. The highest levels of metals recorded in the different grades of coal were 6.8, 4.7, 7.9, 35.1, 72.4, 58.9, 59.5 and 801.1 mg/kg for Cr, Ni, Cd, Pb, Zn, Cu, Se and Mn, respectively. Long-term disposal of these coals will result in pollution of the surrounding environment. Some metal (Zn, Cr, Mn, Pb, Cd) levels in the coal indicated significant (p = 0.05) differences with coal sampling periods, an indication that the metal contents of the Kiwira coal were not uniform along the coal seams or layers. The highest levels in the solid ash were 6.4, 5.2, 9.4, 33.3 and 60.4 mg/kg for Cr, Ni, Cd, Pb and Se, respectively. The highest levels for the fly ash were 7.1, 4.5, 10.8, 90.9 and 45.4 mg/kg, for Cr, Ni, Cd, Pb and Se, respectively. Long term accumulation of these metals will cause environmental pollution. Results showed variations in metal contents between the coal grades, its combustion by-products as well as between the sampling periods.
Contents of heavy metals in coal and its by-products from the Songwe-Kiwira Mine, Tukuyu District, Tanzania
(SADC Project, 2010) Mndeme, U. M.; Semu, E
Coals can be potent sources of heavy metal pollution upon their mining and utilisation. While Tanzania has many coal deposits, the coals have not been evaluated to determine their heavy metal contents and their potential to cause environmental pollution. Therefore, a study was undertaken to determine the heavy metal contents of the coal and its by-products from the Songwe-Kiwira mine, Tukuyu district, southern Tanzania. This is the area in the country where, currently, coal is being mined. The contents of lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), zinc (Zn), selenium (Se), and manganese (Mn) in different coal grades, in coal combustion by-products, and in various coal-derived sediments were determined by atomic absorption spectrophotometry (AAS) following aqua-regia digestion. The results showed the presence of heavy metals in the Kiwira coal. The highest levels of metals recorded in the different grades of coal were 6.8, 4.7, 7.9, 35.1, 72.4, 58.9, 59.5 and 801.1 mg/kg for Cr, Ni, Cd, Pb, Zn, Cu, Se and Mn, respectively. Long-term disposal of these coals will result in pollution of the surrounding environment. Some metal (Zn, Cr, Mn, Pb, Cd) levels in the coal indicated significant (p = 0.05) differences with coal sampling periods, an indication that the metal contents of the Kiwira coal were not uniform along the coal seams or layers. The highest levels in the solid ash were 6.4, 5.2, 9.4, 33.3 and 60.4 mg/kg for Cr, Ni, Cd, Pb and Se, respectively. The highest levels for the fly ash were 7.1, 4.5, 10.8, 90.9 and 45.4 mg/kg, for Cr, Ni, Cd, Pb and Se, respectively. Long term accumulation of these metals will cause environmental pollution. Results showed variations in metal contents between the coal grades, its combustion by-products as well as between the sampling periods.
Contents of micronutrients in different vegetables grown in different locations in Tanzania: implications for soil fertility and nutrition potential of the vegetables
(Sokoine University of Agriculture, Tanzania., 2012) Semu, Ernest; Mlaki, J. S.
Samples of twenty two different vegetables were collected from different locations in Tanzania, in three replicates, with the objective of determining their micronutrient contents. The samples were washed, dried, ground, and asked in a muffle fiunace. The ash was dissolved in 10% nitric acid and the extracts made to volume in 25-m1 vohunetric flasks. Copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) were determined using atomic absorption spec trophotorrktry. The data were subjected to analysis of variance. Results showed that the different types of vegetables contained different quantities of the nutrients. For example, Cu ranged from3.75 ng/kg in egg plant to 8.26 Ingice in sweet potato leaves. Zinc ranged from 13.54 mg/kg in African egg plant to 49.89 mg/kg in cassava leaves (rubber type). Manganese ranged from 15.21 rug/kg in egg plant to 137.19 mg/kg in cassava leaves (cassava) and Fe ranged from 102.08 in African egg plant to 478.11 mg/kg in Chinese cabbage. Within a given type of vegetable, nutrient contents were different across locations of sampling. For example, Cu in amaranthus fiomMorogoro varied from 6.25 rraikg to 7.5 rag/kg, while that fiomMbeya varied from 5 ng/kg to 10.62 mg/kg. Zinc in amaranthus from Mbeya varied from 25.31 rrg/kg to 40 n-alg, while from Vumari- Sank Zn varied from30.31 ap-ika to 39.06 nalg. Manganese in amaranthus fiom Mbeya varied from 89.37 rig/kg to 110 ng/kg, while from Morogoro varied fiom31.25 ng/kg to 35.62 ng/kg. Iron in amaranthus from Vumari-Sane varied from 318.75 mg/kg to 409.37 nig/kg, while from Morogoro Fe varied from 425 mg/kg to 531.25 nvkg. Similar variations were observed in the other types of vegetables. Copper was rated as being low (for pregnant and lactating women). Zinc was generally rated as being low; the rest of the nutrients in the vegetables were deeded adequate for human nutrition.
Contribution of legume rotations to the nitrogen requirements of a subsequent maize crop on a rhodic ferralsol in Tanga, Tanzania
(2013) Marandu, A. E. T.; Semu, E.; Mrema, J. P.; Nyaki, A. S.
Industrial fertilizers are expensive for small-scale farmers who, as alternative, rely on legume crops for providing N for a subsequent maize crop. A legume-maize rotational experiment was carried out on a Rhodic Ferralsol at Mlingano Agricultural Research Institute in Muheza, Tanga, Tanzania, to evaluate the effects of legumes rotation in meeting the N fertilizer requirements of maize. The experimental site was located at 39o 52’E, 5o 10’S and 183 metres above sea level (m.a.s.l.). The experiment was conducted for two rotation cycles whereby cowpea, pigeonpea or greengram were grown during the short rains followed by maize during the long rains. The maize rotations were imposed on plots on which legumes had been grown during the previous legume rotation. Monoculture maize was grown with treatments of 0, 25, 50 and 100 kg N ha-1 imposed for purposes of plotting N fertilizer response curves. Based on the response curve lines, the effects of the legume rotation on maize yields were compared and translated as N fertilizer equivalency of the legumes in question. The grain and residue yields of the three legumes were significantly different (P<0.01), a fact which was attributed to the genetic differences of the legume species. The maize yields following rotation with each of the three legumes were significantly higher (P<0.05) than those under continuous maize. The effects of the rotations on increasing the maize yields were equivalent to application of 25, 19 and 16 kg N ha-1 for the cowpea, pigeonpea and greengram rotations, respectively. It was, however, concluded that the contributions of N by the legumes in the legume-maize rotations were not enough to satisfy the maize N requirements of 50 kg N/ha; hence supplementation with mineral N, in addition to the rotations, is necessary for increased yields.
Copper bioavailability to beans (phaseolus vulgaris) in long-term cu-contaminated soils, uncontaminated soils, and recently cu-spiked soils
(Taylor & Francis, 2015-01-13) Senkondo, Yasin H.; Semu, Ernest; Tack, Filipi M. G.
Copper solubility and its bioavailability to Phaseolus vulgaris in long-term coppercontaminated soils, uncontaminated soils, and copper-spiked soils were studied. The role of plant factors, total copper load in soils, and/or the aging effect on the uptake of copper was explored so as to assess health risks through contamination of the food chain associated with growing the crop on such soils. Contaminated soils and clean soils were collected from coffee-growing fields in Kilimanjaro and Arusha, Tanzania. Two bean seeds were sown per pot, replicated three times, and arranged in a randomized design in a glass house. Copper spiking significantly increased extractable copper, as expected. For all of the treatments except for the Mwanga and Arumeru control soils, the addition of CuSO4 did not significantly increase the humic-acid-bound copper, but it significantly increased the fulvic-acid-bound copper (p = 0.05). Moshi soils had significantly higher concentrations of copper in the bean shoots than was the case with other treatments (p = 0.05). For the respective soil types, there was no significant difference in the concentrations of copper in bean leaves between spiked and unspiked treatments (p =0.05). Bean shoots did not accumulate copper beyond the normal concentrations.
Critical analysis of synergies between Kilimo Kwanza resolution and sustainable Forest Management in Tanzania
(Sokoine University of Agriculture, 2015) Said, I.; Sangeda, A. Z.; Mahonge, C. P.
Like other agricultural development efforts in Tanzania, Kilimo Kwanza which was launched in 2009 that is literary translated as “agriculture first;” recognizes that the role of agriculture is to bring about social and economic development. Pillar number three of this resolution highlights in general terms, mainstreaming environmental conservation in Kilimo Kwanza activities. However, the term ‘environment’ is used broadly. Hence, there is no guarantee that forest conservation, a key component of environmental conservation, is being given due consideration when implementing Kilimo Kwanza activities. Besides, the Ministry of Natural Resources and Tourism, which is responsible for forest conservation is not included in the core team for Kilimo Kwanza implementation. It is therefore rational to anticipate possible negative consequences to forests in the operationalisation of the Kilimo Kwanza resolution. Agricultural development and sustainable forest management can hardly be separated, for successful achievement of objectives within the two sectors successfully, which calls for a holistic Kilimo Kwanza. This entails addressing soil and water conservation while adopting intensification and landscape conservation approaches including ecoagriculture. If this is not done, agricultural transformation through Kilimo Kwanza will not be sustainable. Using an intensive review of literature, this paper critically analyzed the synergies between objectives of agricultural transformation, using Kilimo Kwanza as a case study, and those of sustainable forestry management, in order to inform an integrated agricultural policy development in the country.

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