Theses and Dissertations Collection

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Assessment of environmental pollution by residues of copper fungicides used on coffee in Arusha Region, Tanzania
(Sokoine University of Agriculture, 2012) Mzimba, Sada Bakari
Bean bruchids Acanthoscelides obtectus (Say) and Zabrotes subfasciatus (Boheman) are the main storage pests of beans in Africa. Farmers in Tanzania have been using different pesticidal plants which were not uniform from different locations for many years to reduce damage in their produce. Laboratory studies were carried out to investigate the effectiveness of nine botanical extracts in controlling the two bruchid species. The study included plant species from Iringa, Kilimanjaro, Mbeya and Morogoro Regions. The insecticidal materials were extracted from Eucalyptus citriodora, Vernonia amygdalina, Telfairia pedata, Chenopodium ambrosioides. Neorautanenia mitis. Dolichos kilimandscharicus. Gnidia kraussiana, Zanha africana and Schinus mode. Powders of these plants were tested under the laboratory conditions, where doses commonly used by farmers were tested to identify plant species with superior characteristics. The experiment was set in a Completely Randomised Design to determine the optimum doses of five selected pesticidal plant formulations that can be recommended for protecting beans against bruchids. The effectiveness of the extracts was compared with Actellic Super Dust, a synthetic chemical commonly used for control of bean bruchids. The results show that, all plant species were potential in controlling A. obtectus. Two plant species namely N. mitis and C. ambrosioides, performed similar to synthetic Actellic Super Dust followed by Z. africana at the highest tested concentration (600 g/100 kg) to A. obtectus and Z. subfasciatus. Out of nine plant formulations evaluated on Z. subfasciatus only three were statistically different in their effectiveness compared to untreated beans. The study shows that C. ambrosioides and N. mitis have higher efficacy comparable to Actellic Super Dust followed by Z. africana. Hence, the plants can be used efficiently as the recommended insecticidal plants. However, further study is recommended to assess the insecticidal plants role in seed deterioration during storage, shelflife, pesticidal plant combination and toxicity to mammals.
The effect of variety, lulching and planting date on the grain yield and yield cohponents of bean (Phaseqlus Vulgaris L.)
(Sokoine University of Agriculture, 1984) Elia,Wilfred Martin
Kabanima (Kb), Canadian Wonder (CW) and Selian Wonder (SW) bean varieties were investigated on their growth and seed yield as influenced by variety, sowing date and mulching. Mulching promoted effective primary branches/plant, vegetative growth - plant height, leaf number, leaf area, leaf area index (LAI) but depressed plant uptake of Mg and K, shelling percentage, grain yield and water-use efficiency (WUE). Mulching appears undesirable under high soil moisture conditions, it should be encouraged only in arid conditions* CW gave 154, SW 124% higher grain yield than Kb. CW outyielded SW by 124%. Kb was taller, thicker, had more leaves at maturity, greater leaf area, LAI and total plant dry weight but lower N, K and Mg at blooming, lower pod dry weight, shelling percentage, grain yield and WUE than CW and SW. Mid-March planting gave the highest grain yield and WUE. Plant height at maturity increased with subsequent sowing date because of increased favourable moisture conditions. Mid-March planting appears the best date of planting beans under Morogoro conditions* White Mould outbreak in mid-March planting depressed(iv) leaf area and LAI but promoted grain yield. White Mould resistance was observed in two GW plants that exhibited the primitive trailing habit.. Bean leaf N, P, K decreased from seedling to flowering stage in respective values of 4.96 to 4.22%, 0.39 to 0.29% and 5.14 to 2.61%; Ca and Mg increased from. 0.72 to 1.37% and 0.60 to 0.63% in the same growth stages, respectively. Nutrient uptake by bean plant is influenced by variety, growth stage and directly or indirectly by soil moisture in different dates and mulches. Pod yield,shelling percentage, 100 grain weight and seed number/pod and pod length exerted positive influence on grain yield unlike plant height, LAI, leaf number and days to 50% flowering.
Improvement of rangelands by oversowing with leguminous plant species in Shinyanga Region, Tanzania
(Sokoine University of Agriculture, 2020) Sokoine University of Agriculture
Four herbaceous legumes (C. pubescence, C. ternatea, M. atropurpureum and S. hamata) were oversown in 1992 in Shinyanga, Tanzania to assess their effect on forage production quality and soil fertility. Forage and soil samples were taken in the seventh year of the experiment during the dry and wet season. Oversowing improved soil characteristics of Cation Exchange Capacity, organic matter content and available P. C. ternatea, M. atropurpureum and S. hamata persisted in the sword while C. pubescence virtually disappeared. In the dry season the CP content of the treatments in g/kg DM was 44.4, 37.6, 36.5, 35.0 and 29.7 for C. ternatea, S. hamata, M. atropurpureum, and C. pubescence oversown and the control treatments respectively. The DMD of the oversown treatments in g/kg DM was 384.4, 366.8, and 321.0 for treatments oversown with C. ternatea, S. hamata and M. atropurpureum in that order. OMD of the treatments in g/kg DM ranged from 304.4 to 425.2 for the control and C. ternatea oversown treatments respectively. The potential degradability of the treatments in g/ kg DM was 600.6, 585.1, 577.7, 572.9 and 492.0 for C. ternatea, M. atropurpureum, S. hamata, and C. pubescence oversown and the control treatments respectively. Biomass production results in t/ha were 1.75, 1.69, 1.66 and 1.62 t/ha for treatments oversown with S. hamata, M atropurpureum, C. ternatea and C. pubescence oversown treatments respectively. The control plots were significantly lower (P<0.01) in CP, potential degradability, DMD, OMD and biomass production than the oversown treatments. In the wet season, natural pasture from the oversown treatments had significantly higher (P<0.05) CP content than the natural pasture of the control treatment. Naturaliii pasture associated with C. ternatea, S. hamata and M. atropurpureum had CP content pasture associated with C. ternatea, S. hamata and M. atropurpureum had CP content of 55.3, 55.4 and 49.1 g/kg DM respectively. The control plots had 43.0 g/ kg DM. It was also found that mixed samples had better nutritional quality over the control. C. ternatea, M atropurpureum and S. hamata mixed samples had CP content of 68.8, 65.6, and 59.7 g/kg DM respectively. The control plots had CP content of 43.0 g/kg DM. The treatments had DMD of 478.3, 478.2, 447.3, 426.8 and 419.9 g/kg DM for C. ternatea, M. atropurpureum, S. hamata and C. pubescence over sown treatments and the control plots respectively. The OMD of the oversown treatments was 506.6, 493.9, 485.9 and 456.0 for M. atropurpureum, C. ternatea, S. hamata and C. pubescence respectively. The biomass production of the oversown treatments was 1.79, 1.70 and 1.62 for S. hamata, M. atropurpureum and C. ternatea oversown treatments respectively. The control treatment was significantly lower (P<0.05) in CP OMD and biomass production than the oversown treatments. The CP content of the oversown legumes in g/kg DM was 151.9, 142.1 and 104.4 for C. ternatea, M. atropurpureum, and S. hamata respectively. The DMD of the oversown legumes was 534, 484 and 460 g/kg DM for S. hamata, M. atropurpureum and C. ternatea respectively. The OMD was 572.2, 547.8 and 512 g/kg DM for S. hamata M. atropurpureum and C. ternatea in that order. The potential degradability of the oversown legumes in g/kg DM was 570 for S. hamata, 718 for M atropurpureum and 707 for C. ternatea. C. ternatea, S. hamata and M. atropurpureum oversown treatments performed better than the other treatments in both the dry and wet seasons. S', hamata had excelled the other legumes in degradability and degradation characteristics. From the results obtained it was concluded that oversowing legumes had improved soil fertility, biomass yield, nutritional quality and species composition of the rangeland.
Effect of plant density and types of seedbed on the growth and grain yield of bambaranuts (vigna subterranea (l.) verde.)
(Sokoine University of Agriculture, 1996) Mkandawire, Frackson Lameck
A field experiment was laid out during the short (October to February) and long (March to June) rain seasons to evaluate the effects of population density and types of seedbed on the growth and grain yield of bambaranuts [Vigna subterranea (L.) Verde.). The experimental design was a split plot laid out in a randomized complete block with three replications. Types of seedbed (flat, ridge and furrow) were the main plot factors while population densities T, =■ (94 444), T2 - (133 333), T3 - (222 222) and T« - (666 666) plants ha'1 achieved by intra-row and inter-row spacings of 35 x 30, 25 x 30, 15 x 30 and 5 x 30 cm were sub plots, respectively. During both seasons, bambaranuts planted on the ridge across all population densities were slowest to emerge. Generally, emergence rates decreased with increase in plant population densities. During the short rain season, bambaranuts planted on the ridge were the tallest (38.2 cm) at 66 ' plants m'2, had the highest leaf area plant'1 (4460.6 cm2), highest leaf area index and highest root: shoot ratio at 9 plants m'2. Bambaranuts planted in the furrow had the highest number of flowers plant'1 (26.0) at 9 plants m'2, highest number of pegs plant'1 (57.8) and highest number of pods plant'1 (18.2 and 18.7) at 9 and 13 plants m'2, respectively. The crop planted in the furrow or ridge resulted into higher values for root dry matter plant'1 (6.7 g) at 13 plants m'2, number of plants at harvest (63), highest grain yield (519.2 kg ha'1 at 13 plants m'2 and highest harvest index (62.5) at 13 plants m'2. Bambaranuts recorded significantly (PX0.05) higher values for shelling percentage at 13 plants m'2 across all types of seedbed. During the long rain season, planting on the flat or in the furrow resulted into the tallest plants, highest leaf area plant'1 (1343.69) at 13 plants m' -2 2, highest shoot dry matter plant'1 (10.9 g and 10.1 g) at 13 and 22 plants m'2, respectively. The crop planted in the furrow resulted into the highest number of plants (66) at harvest at 66 plants m'2 and highest above ground dry matter (1271.6 kg ha'1) at 13 plants m'2. Bambaranuts planted on the ridge or flat recorded significantly (P<_0.05) high values for shelling percentage (85.5 and 80.6) at 22 plants m'2. The crop planted on the flat resulted into the highest number of flowers (31.6) and pegs (72.9) ijiant'1 at 22 plants m'2, highest number of pods (14.4 and 14.7) at 13 and 22 plants m'2, respectively, highest root dry matter (4.10) at 22 plants m'2, highest root : shoot ratio (0.45) at 22 plants m'2, highest pod yield (1065.3 kg ha'1), highest grain yield (746.6 kg ha'1) at 22 plants m'2, highest 100-seed weight (36.6 g) at 9 plants m'2 and highest harvest index (95.8) at 22 plants m'2. Generally, leaf area plant'1 for both seasons decreased with increase in population density while LAI increased. Flower, peg, pod, shoot and root dry matter decreased with increase in population density during the short rain season but were variable for the long rain season. Bambaranut yield was positively correlated with the number of flowers, pegs, pods, pod dry matter and kernel dry matter during the short rain season. Positive correlations for the number of pods, leaves, pod dry matter, kernel dry matter, stem dry matter with grain yield were also observed during the long rain season. On the basis of coefficient of determination (R2) values, pod dry matter, number of pods and kernel dry matter were the most important factors that determine
The response of tea to foliar and soil applied copper: a case study of Luiga and Lugoda tea estates in Mufindi tea growing areas.
(Sokoine University of Agriculture, 2002) Mhagama, John Patrick
A study was conducted in Mufindi district to determine the response of tea to copper application. Low levels of copper in the soils and in tea leaves in Mufindi which has been reported previously prompted this study to be carried out to determine the effect of foliar and soil copper application on quality and yield of tea. Five levels of copper; 0, 1.5, 3.0, 4.5 and 6.0 kg Cu/ha as copper sulphate (25% copper) applied on the foliage and 0, 2.5, 5.0, 7.5 and 10.0 kg Cu/ha applied to the soil were used to test the effect of copper application on tea quality and yield. Copper application generally improved the fermentation of tea leaves and quality of made tea. Improvement of both fermentation and quality of made lea increased with increasing foliar and soil copper application rates. The effect of foliar copper application on fermentation and quality of made tea lasted for about three months. While that of soil application was found to last longer. The highest quality score was obtained at application rate of 6.0 and 5.0 kg Cu/ha for foliar and soil application of copper. respectively. Foliar copper application generally decreased tea yield non significantly at site one and two except at application rate of 4.5 kg Cu/ha which increased tea yield non significantly at site one by 5.41 percent. The decrease in yield was probably due to difference in the size of tea plants, different pruning intensities and application rates that could have not been uniform..Soil application of copper increased tea yield by up to 26.89 and 15.45 % for site one and two, respectively. At site two application of 5.0 kg Cu/ha gave the highest response. Foliar and soil application of copper significantly (P < 0.05) increased leaf copper concentration in both third leaf and shoots when compared to the control. Soil application of copper sulphate at a rate of 5.0 kg Cu/ha is recommended to correct copper deficiency at both sites.
Assessment of residual effects of long-term use of NPK: B formulation on tobacco meld and quality in Tabora Region
(Sokoine University of Agriculture, 2011) Mapunda, Hugo Gido
The assessment of residual effect of long term use of NPK plus B formulation on tobacco yield and quality involved soil sampling from four districts; Urambo, Uyui, Tabora and Sikongc. There were two experiments each one with six treatments: pot experiment at ARI Tumbi had three replications while Held experiment al Ntalikwa village had four replications. Data collected were; leaf length, green and dry weights grade index and nutrients concentration in plant leaves. The results showed that; total nitrogen was very' low (0.03 to 0.18%). Phosphorus was low to medium (5.62 to 60.83 mg/kg soil). Exchangeable potassium was. low to very' high (0.06 to 0.81), exchangeable calcium was very' low to high (0.01 to 4.4). The cation exchange capacity (CEC) of the soils was low; 6.4 to medium 23.33 me/100 g soil. Tobacco grown in Isenga soils (sandy soils) and Kikungu soils (Alfisols) had good performance in T2 (40.5 mg N kg’1 ) while Tobacco grown in Mbuga soils (Vertisols) had good performance in T3 (recommended rate 300 mg N kg’1, 238 mg P kg’1, 598 mg K kg’1 and 3 mg B kg’1 soil). The increase in rates of NPK+B and CAN, Mg, Zn caused death of tobacco in treatments 4, 5 and 6 possibly due to B toxicity. In the field experiment the current formulation, T3 (NPK + B (10:18:24 +0.1 and 5 g CAN) produced below treatment 4, 5, and 6. Dry' weight yield and quality' increased in treatments with higher rates of NPK+ B formulation with Zn and Mg than the current recommendation. The highest yield was from T6 (2488.12 kg ha’1). Residual nutrients T1 yielded 1411.89 kg ha’1 of dry leaf of tobacco. In general, low residual nutrients in Tabora soils need new formulations which include Mg and Zn to improve yield and quality of tobacco.
Effects of growth media and mineral nutrients on the growth of rose flower plants at Kiliflora flower farm, Arusha, Tanzania.
(Sokoine University of Agriculture, 2001) Nnko, Anathe Moses Isaack
A glasshouse pot study was undertaken to investigate the effects of three growth media namely soil, gravel and coconut coir dust (CD) and decreasing concentrations of the essential nutrients in complete plant nutrient culture solution currently in use at Kiliflora -Arusha, Tanzania, on the quality and growth performance of rose flower plants. The objectives of the study were to identify the best growth media for raising rose flower plants and the optimal levels of nutrient concentrations in the complete plant nutrient culture solution for optimal rose plant growth, yield and quality of the rose flowers. Appropriate amounts of the three growth media to fill 4 litre plastic pots to 3/4 of their capacities were put into the pots with holes at the bottom, plugged loosely with cotton wool fordrainage purposes and prevent loss of the growth media. Five levels/rates of the essential nutrient elements in the complete plant nutrient culture solution currently in use at Kiliflora farm (coded as lx), that is lx, 0.5x, 0.25x, 0.125x and 0.0625x were applied to each growth media, and replicated three times. Rose plant cuttings raised in a propagation unit at Kiliflora farm were then transplanted to the growth media in the plastic pots. Half a litre of each of the five concentrations of the complete plant nutrient culture solution was added once to each pot for the soil growth medium per day and the same amounts were added nine times to each of the pots for the CD and gravel medium, respectively everyday, for the whole duration of the study (3 months). Appropriate measures were taken to control all diseases and plant pests during the growth period of the rose plants. Assessment of the rose flowers quality was done at the end of the sixth week from the date of transplanting. At the end of the 3-month growth period the rose plants were harvested by cutting the whole plant just above the first internode from the surface of the growth media in the pots. Immediately after harvesting, the stem length, stem thickness, flower bud width and heights were determined. The stems were then trimmed to 45cm, dried to constant weights for dry matter determinations. The stems and leaves were mixed together after they had been separated from the flower buds, ground into a fine powder and used for the determination of N, P, K, Mg, Ca, S, Fe, Mn, Zn, B and Cu. From the data obtained, the growth media at various levels/concentrations of the complete plant nutrient culture solution, had no effect on the stem lengths, stem thickness, bud widths and bud heights. However, the levels of concentrations of the nutrients in the culture solution had significant effect on the above plant parameters. The effects of levels of nutrient concentrations in the rose plants did not follow well defined trends. However, based on the assessment of the quality of the rose flowers, the mean nutrient contents of the nutrients in the rose plants, the CD was found to be the best growth medium, followed by gravel and then soil. The optimal level of nutrient concentrations in the complete culture solution currently in use at Kiliflora was the 0.25x (25%). It is therefore, suggested that CD be used as the growth medium and the concentrations of the nutrients in the current complete plant nutrient culture solution be reduced by 75% and this would undoubtedly be very economical for the rose flower production at Kiliflora, Arusha, Tanzania.
Evaluation of pesticide effects on bean and sesbania rhizobia and their symbiotic relationship
(Sokoine Univesirty of Agriculture, 1996) Baijukya, Frederick Philbert
Laboratory and glasshouse experiments were conducted at the Sokoine University of Agriculture, Morogoro, to evaluate the effects of kocide 101 (77% cupric hydroxide) a fungicide and oxadiazon [3-(2,4-dichloro-5(l- methylethoxyphenyl)-5-(1 ,1 -dimethylethyl-1,3,4-oxadiazol-2(3 H)-one] a herbicide, on the growth and symbiotic performance of bean (Phaseolus vulgaris L.) and Sesbania rostrata rhizobia, respectively. The growth of the rhizobial strains in the presence of the pesticides was evaluated in Yeast Mannitol Broth (YMB). The \eg\i.vne-Rhizobium symbiosis was evaluated in the glasshouse using a sandy loam soil (Typic Rhodustalf) for beans and a clay soil (Udic Ustifluvent) for Sesbania. Kocide 101 in the broth medium inhibited growth of rhizobia. Of the three strains tested for sensitivity to kocide 101, the local isolate was most tolerant followed by the PV] strain, and the strain CI AT 899 was least tolerant. The growth of Sesbania rhizobia in broth medium was unaffected by the addition of oxadiazon. The application of kocide 101 at the recommended application rate (equivalent to 1.7 mg/kg soil) had no harmful effect on growth, nodulation and nitrogen fixation of bean plants. Kocide 101 applied at 2x and 4x the recommended application rate (equivalent to 3.4, and 6.8 mg/kg soil) was detrimental to the growth, nodulation and N2 fixation. The inhibition of nodulationiii and N2 fixation in the presence of kocide 101 was mainly due to the direct effect of the fungicide on the bean plants. The application of oxadiazon at the recommended application rate, at 2x and at 4x the recommended application rate (equivalent to 0.75, 1.50, and 3 mg/kg soil, respectively) adversely affected the growth, nodulation and N2 fixation by Sesbania rostrata plants, the inhibition increasing with increase in oxadiazon concentration. The inhibition in nodulation and N, fixation in the presence of oxadiazon was, to a large extent, due to adverse effects of the herbicide on plant growth and development rather than on rhizobial viability. Nodule formation and plant growth of both beans and Sesbania continued to be curtailed by the pesticides residues four months after they were first applied to the soil.
Effect of genotype x environment interactions on yield and grain qualities of rice (oryza sativa, l.) in Morogoro region.
(Sokoine University of Agriculture, 2001) Kibanda, Nkori John Maregesi
Three experiments were conducted in the 1999/2000 season at Lumemo (rainfied lowland), Tanganyika Agricultural Cooperation (TAC) (irrigated) and Sokoine University of Agriculture (SUA) Farm (upland). The aim of the study was to determine the relative contributions of the newly obtained genotypes, environments and their interaction to the variations of grain yield, yield components and grain quality characteristics. Ten genotypes obtained from SUA and Kilombero Agricultural Training and Research Institute (KATRIN) were used in the experiments which were laid down in a Randomized Complete Block Design (RCBD) with thiee replications. The plot size was 4m x2m in which the plants were spaced at 20cm x 20cm. Data collected included the agronomic and grain quality characteristics, which were subjected to the analysis of variance, Correlation, Path coefficient and Stability analyses. The analysis of variance revealed that there were significant variations in the genotypes tested for most of the traits tested. Although there was significant genotype x environment interactions for most of the traits tested, early maturing lines SSD1, SSD3 and SSD5 performed better in all three environments. However, the late maturing genotypes performed better under supplementary irrigation at TAC. The results from correlation and path coefficient analyses revealed that the number of panicles/plant and percent spikelet fertility could be important characters that influence grain yield. Since these two characters also showed high heritability estimates, they could be used as indirect selection criteria for grain yield during early generations of rice breeding. Similarly for grain quality, estimates of heritability and genetic advance were high for gel consistency. From the results of this study, it can be provisionally concluded that early maturing genotypes may be grown in all three ecosystems in Morogoro region, while the late maturing genotypes are suitable in irrigated conditions or under rainfed with supplemental irrigation. Based on the overall performance and grain quality analysis, lines SSD1, SSD3 and SSD5 can be recommended fbr further evaluation in farmers fields.
Occurrence of some heavy metals in sewage sludge in some Urban Areas and their uptake by amaranthus (amaranthus hybridus}
(SUA, 2001) Matemba, Lameck Eliawony
A study was conducted to determine the occurrence of some heavy metals in sewage sludges from Morogoro and Dar es Salaam urban areas and their uptake by Amaranthus hybridus. A field study was conducted at the Horticultural Unit, Sokoine University of Agriculture Morogoro whereby, the soil was characterised for its physical and chemical properties prior to planting of the test crop. The analytical data showed that the experimental soil was texture mildly-alkaline with a pH value of 7.6, very low % O.C. The textural class of the soil was sandy clay loam. Available and total Cu, Zn, Mn. Cd and Pb ranged from medium to high as compared to established critical levels. The sewage sludge was collected from the disposing sites in Morogoro and Dar es Salaam. Prior to incorporation into the soil the sewage sludge was air dried and characterised for its chemical properties . The results showed that the available and total Cd, Mn, Cu, Zn and Pb ranged from medium to high as compared to established critical ranges. A field study was conducted to study the uptake of some heavy metals and other plants nutrients. In the field studies a Randomised Complete Block Design (RCBD) was used. The rates of sewage sludge application on air dry basis were 0, 10, 20, 40, and 60 tons/ha. Amaranthus seeds were measured by using 35 cm3 container and sowed in 1 m2 plots which were separated by 0.5 m strips while the blocks were separated by 1 m strips. The uptake of N, P, K, Mg, Ca and heavy metals (Cu, Zn, Mn, Cd, Pb) were determined. Application of sewage sludge resulted in a marked increase in metal content in Amaranthus plant especially for the highest rates of application during the first and second plantings. The uptake of other essential plant elements increased with increasing rate of sewage sludge application. No adverse effects due to application of sewage sludge were observed. At the end of the first growing season, the soil was analysed to evaluate the residual effects of sewage sludge on soil chemical properties. The results showed that sewage sludge application resulted in a marked increase in total and extractable metals as well as essential elements in the soil, except for total and extractable Mn. The application of sewage sludge resulted in a significant increase (p < 0.05) in the concentrations of Cd, Zn, Cu, and Pb. However, the metal content in the soil was below the limits generally accepted as toxic for most agricultural soils. A second planting was done in the same plots without further application of sewage sludge in order to determine the residual concentration of heavy metals in the soil from the previously applied sewage sludge. The results indicated that, the residual metal concentration in the soil had significantly increased. Plant dry matter yield of Amaranthus was determined for the first and second harvests. The application of sewage sludge from Dar es Salaam increased dry matter yield significantly (P < 0.05) at 60 tons/ha. The maximum yields obtained were 3.66 and 2.4 tons/ha for the first and second harvests respectively. The Dry matter yield as the result of application of Morogoro sewage sludge reached a maximum of 2.16 and 1.79 tons/ha at 60 tons/ha for the first and second crop respectively. Generally, the increase in the
Heavy metal uptake by some vegetables grown on sewage sludge-treated soils
(Sokoine University of Agriculture, 2003) Msongaleli, barnabas
A glasshouse pot experiment was conducted to determine the uptake of heavy metals by Chinese cabbage (Brassica chniensis), lettuce (Lactuca sativa L.) and cowpea {Vigiza unguiculatd) from sewage sludge-treated soils. A sandy loam (pH 6.9) and a loamy sand (pH 7.1) were amended with sewage sludge at rates of 0, 10, 20 and 30 ton/ha (oven-dry weight basis). Total and extractable heavy metals in soils and sludge, plant materials, vegetable heavy metals concentrations and uptake, were determined. Results on characterization of the soils and the sludge indicated that the soils contained small amounts of heavy metals, thus having a low potential for causing pollution and the sludge had elevated levels of heavy metals. Amendment with sewage sludge significantly (P=0.05) increased the yields of all vegetables. ry.y • 1 ; —F Chinese cabbage dry matter yields ranged from 3.34 to 15.89 and 9.83 to 17.09 g/plant for Msimbazi and Mjimpya soils, respectively. For lettuce they ranged from 3.43 to 14.29 and 6.69 to 13.63 g/plant for Msimbazi and Mjimpya soils, respectively, while for cowpea they ranged from 5.89 to 15.74 and 13.77 to 19.94 g/plant for Msimbazi and Mjimpya soils, respectively. The highest yields were observed with applications of sewage sludge at 30 ton/ha. The analysis of the edible parts of vegetables for heavy metals revealed higher uptake of Cd, Cu and Zn by all vegetable species with increased rates of sewage sludge application. The uptake of Pb and Cr by the vegetables was low and not consistent with the rates of sewage sludge application. There were, significant differences between the uptake of heavy metals by the different vegetable species. DTPA-extractable Cu and Zn concentrations in post-harvest soil increased significantly with sewage sludge application rate. However, the increase of DTPA-extractable Pb and Cd was not consistent with the rates of application of sewage sludge. Chromium was not detected in the post harvest soil. Vegetables grown in amended soils showed higher N and P concentrations than control plants. The results indicate that there should be close monitoring over the use of the sludge for edible crop production.
Isolation and evaluation of antibiosis by streptomyces from soils of different levels of salinity
(Sokoine University of Agriculture, 2001) Senkondo, Yasin Hassan
This study was undertaken to isolate and screen for antibiosis Streptomyces from soils of different levels of salinity. Soil samples for the study were obtained from the Coast region (Chalinze Mzee) and Morogoro region (near Catholic Capuchin Seminary, Kikundi Primary School, Mkata Ranch and SUA farm). Soil samples were analysed for pH, EC, exchangeable bases, % organic carbon, total nitrogen and texture using appropriate methods.Enumeration of Streptomyces was done by the plate count method using starch casein agar. Isolation to obtain pure isolates was done on oatmeal agar. Antibiosis testing was carried out on nutrient agar, against Clavibacter michiganensis sub sp. Michiganensis, Xanthomonasphaseoli, Xanthomonasvasicatoria, Xanthomonas Xanthomonas phaseolicoli oryzae pv var fuscoris, oryzae and Acidovorax avenae. Colour of aerial mycelium and morphology of spore chains were determined.S/rep/o»zyces population ranged from (logio) 2.0 to 4.9 per gram of soil. The study revealed that soil characteristics such as exchangeable bases, extractable phosphorus, organic carbon, and clay content had no significant effect on the number of Streptomyces, while ntotal nitrogen and salinity (electrical conductivity) had significant effects.The Streptomyces isolates from different levels of salinity were of various colours such as blue, brown, red, white and their colour inlergrades. The spore chains’ morphologies of the Streptomyces isolates from different soils of different levels of salinity ranged from flexuous. Straight, open spirals, open loops and monoverticillate.All the Streptomyces isolates were able to grow on media of salt concentration of less than 2%. Some were able to grow on media of salt concentrations between 2% and 8%. No isolate grew on media of 10% salt concentration. The Streptomyces showed different degree of antibiosis. Some isolates had strong antibiosis against the test plant pathogenic bacteria, while some had moderate and others had weak antibiosis. Some isolates did not show antibiosis.
Occurrence of streptomyces antagonistic to plant pathogens in pathogen-infested soils of Morogoro, Tanzania
(Sokoine University of Agriculture, 2002) Peter, Deusdedit
This study was carried out to investigate the occurrence of Streptomyces antagonistic to plant pathogens in pathogen-infested soils. Soils were sampled from the Horticultural Unit of Sokoine University of Agriculture (SUA) and from Mlali in Morogoro district, Tanzania. Isolation of Streptomyces was done using starch-casein agar. Fungi were isolated using Potato Dextrose Agar (PDA) amended with Rose Bengal. Plant pathogenic fungi were identified using culture and microscopic characteristics. There were significant (p=0.05) differences in populations of Streptomyces in soils obtained from rhizosphere of different tomato varieties/lines with different disease severity levels. The populations were lowest in soils associated with tomato line 2 from Horticultural Unit and highest in soils of the other tomato varieties/lines. There were significant (p=0.05) differences in populations obtained from soils sampled under different disease severity. The populations of fungi showed significant (p=0.05) differences between the two locations, being lower at Mlali and higher at SUA Horticultural Unit. There were significant (p=0.05) differences in populations of fungi isolated under rhizospheres of tomato plants with varying levels of disease. Numbers of pathogenic fungi identified varied not only from one site to another but also one tomato variety/line to another, and also among different disease severity levels. About 73% of Streptomyces isolates produced antibiotic to various levels against plant pathogenic fungi which were identified as Phytopthora sp. 1 and 2, Aspergillus sp. 1 and 2, Phoma sp. 1 and 2, Pythium sp., Penicillium sp. And Botrytis sp. Other isolates (27.0% of all isolates) did not produce antibiotic against any of the tested plant pathogenic fungi.
Effects of some amendments on soil properties and maize yield grown in sodic soil: a case study of Mto wa Mbu, Arusha, Tanzania
(Sokoine University of Agriculture, 2003) Gwasso, Nestory Charles Warioba
A study was conducted at Mto wa Mbu, Arusha, Tanzania to evaluate the effects of some amendments on soil properties and yield of maize grown in sodic soils. The soil of Mto wa Mbu was classified as sodic with a clay loam texture. The soil was characterized in this study for its physical and chemical properties prior to planting maize as a test crop. The soil laboratory analytical data showed that the soil was alkaline, clay loam textured and compact (bulk density ranging from 1.39 to 1.45 gem'3). The soil pH ranged from 9.80 to10.45, ECe from 1.6 to 3.57 dSm'1 and ESP ranged from 92 to 99%. Total N, available P, % OC, exchangeable Ca, Mg, CEC, and DTPA extractable Cu, Zn, Fe and Mn were in the low range while exchangeable K and Na were high. In the field a randomized complete block design was used to evaluate the effects of the amendments using maize as a test crop. Gypsum was applied at 0, 7.5, 15, 22.5 and 30 tha’1 and sulphur at 0, 1.4, 2.9, 4.3 and 5.7 tha'1, corresponding to 0, 25, 50, 75, and 100% of laboratory gypsum requirement. The amendments were surface mixed at 0-15 cm depth. The rates of farmyard manure were 0 and 20 tha’1. Prior to soil incorporation, the amendments (FYM and gypsum) were analyzed for their chemical properties. In gypsum treated plots maize grain yields ranged from 0 (control) to 1.32 tha’1. The maize grain yields in sulphur amended plots ranged from 0 to 0.32 tha’1 and that of FYM treated plots ranged from 0 to 0.35 tha’1. When gypsum and sulphur were combined with FYM the maize grain yields ranged from 0 to 1.42 and 0 to 0.53 tha’1 respectively. Therefore, maize grain yield was significantly higher in gypsum and FYM when applied alone than in sulphur amended plots. But it was much higher when gypsum and sulphur were mixed with FYM. Application of sulphur caused only slight yield increases, but was more effective when combined with FYM. The economic analysis showed that the application of amendments was uneconomical due to low maize grain yield. At the end of growing season the soil was analyzed to evaluate the residual effect of the amendments on soil properties. Available P, ECe, % OC, total N exchangeable bases, CEC in the plots amended with gypsum, sulphur and FYM increased in the top 15 cm of soil relative to the control. Soil pH and ESP in all treated plots was significantly reduced except in S25 and S50 treatments. Bulk density in all amended plots was not significantly different to the control. DTPA extractable Zn, Fe, Cu and Mn increased slightly following the application of amendments. Regression analysis between soil variables and maize grain yield showed that soil pH and Ca were significantly affected the yield (P<0.05). ECe was slightly correlated with the yield. The rest of the variables (P, % OC, Total N, excahngeable bases and DTPA extractable Zn, Fe, Cu, Mn) were notlinearly correlated with the yield. Though maize grain yields from the treated plots were low compared to that of normal soils which range from 1.2 to 2.4 tha'1, the results from the field suggested that, the amendments especially G100 + FYM can ameliorate sodicity and produce satisfactory plant growth and yields.
Seed vigor measurements and their use in predicting field establishment of grain pearl millet (pennisetum americanum)
(Kansas State University, 1978) Mwageni, Gallus Joseph
The aim of the experiment was to measure vigor in grain millet varieties. Seed vigor is very critical for millet field establishment. Also, the purpose of the experiment was to evaluate the several methods used to determine seed vigor in other cereals and select the one most appropriate for pearl millet. Several criteria were used to select the best test e.g. correlations, ranking, rank means, and the Kendall coefficients of concordance. In the laboratory, standard germination consistently was higher than germination following the stress tests because the non-vigorous seeds were killed during the harsh treatment. It was also noted that the vigorous varieties performed well in both laboratory stress tests and in the field. The opposite was true for non-vigorous seeds. Therefore, highly significant differences in vigor were observed among varieties. Each vigor test was then evaluated for its ability to predict field establishment of millet. Criteria included: 1. Correlation with field establishment 2. Ability to rank millet varieties according to field performance. The vigor test having the lowest rank means coupled with high correlations with field establishment was selected as the best to predict field establishment. Based on these criteria the NaOH treatment appeared to be the best vigor test although all vigor tests were similar in ranking the varieties as vigorous, non-vigorous or between the two. The biggest problem in millet establishment even for vigorous seeds lies in the inability of seedlings to break through the soil crust after it has rained heavily or silting over or wash-out during early stages of field establishment (first week after planting). Any or a combination of the above factors will adversely affect their establishment.
Effects of residual tied ridges on soil physical factors and sorghum yield in semi-arid central Tanzania.
(Sokoine University of Agriculture, 2001) Mwaliko, Ramadhani Bakari Msilagi
With the increasing use of conservation tillage, many questions have been raised on many at harvest respectively. Tillage significantly (p=0.05) affected the soil surface the viability of using residual tied-ridging system. The reported field study was conducted in semi-arid central Tanzania on a continuing three year old tillage trial comprising No-till (Tl), Shallow tied ridges (T2) and deep tied ridges (T3) to study the effect of residual tied-ridges on soil physical and hydrological properties as well as sorghum grain yield. Land preparation involved the removal of crop residues from the previous season and a minimum maintenance of residual ridges. The test crop was sorghum cultivar Tegemeo. Investigated parameters include dry bulk density and cumulative infiltration which were determined before planting, at mid season and after harvest. Gravimetric soil moisture determinations at different soil depth were made on weekly basis. Measurements on soil surface roughness were made before and after every field operation and after every heavy rainstorm. Bulk densities were significantly (p=0.05) different between Tl and other treatments only at mid season within 0-10 cm soil layer. Total porosity values were not significantly different among tillage treatments during the study period. Weekly gravimetric soil profile moisture content (mm) in 0-50 cm soil layer was significantly (p=0.05) different between treatments on the 4th, 8th, and 17th week after planting. Profile moisture content variations of between 40.4 to 59.4 mm, 48.4 to 77.7 mm and 57.5 to 85.5 mm for Tl, T2 and T3 respectively were observed during the growing season. However, Tl had significantly (p=0.05) higher cumulative infiltration than T2 and T3 by 134.8 and 172.8 mm before planting, 764 and 845.5 mm at mid season and by 355 and 437 With the increasing use of conservation tillage, mm at harvest respectively. Tillage significantly (p=0.05) affected the soil surface roughness indices (SSRI) among treatments. SSRI variations of between 68.7 to 106.3 for Tl, 152.8 to 169.2 for T2 and 173.2 to 180.0 for T3 were observed. Moreover the SSRI decreased during the growing season. Percentage seedling emergence was significantly (p=0.05) higher in Tl by 5.7 and 14.2% than in T2 and T3 respectively. Nevertheless the crop stand at harvest was lower in Tl by 15.1 and 4.1% than in T2 and T3 respectively. T2 and T3 had significantly (p=0.05) higher grain yield by about 0.85 and 1.06 t/ha respectively. Grain yield was more than doubled by residual tied-ridges compared to the control which had a yield of 0.64t/ha. Residual tied ridges are thus a viable tillage system which can reduce tillage and ridging cost as well as increase sorghum grain yield in semi-arid areas.
Rice yields as influenced by nitrogen from azolla-anabaena association supplemented with inorganic fertiliser nitrogen in the lower Moshi irrigation project, Tanzania
(Sokoine University of Agriculture, 1999) Mvukiye, Ndimubandi Egidius
A field study was conducted in the Lower Moshi Irrigation green-manurial Project, quantify Tanzania, the to potential of Azolla grown as a dual crop with irrigated rice. Parallel studies on the in situ decomposition rate of Azolla and the effect of the rice canopy on Azolla N accumulation were also undertaken. Azolla alone and in combination with 40 and 80 kg N/ha as urea (45% N) was compared with untreated control or, 160 kg N/ha as urea. These treatments were tested on Wahiwahi (indigenous) (improved)and IR54 rice varieties in a split-plot design with 3 replications. Each plot received a basal phosphate dose of 20 kg P/ha as TSP. Rice leaf chlorophyll plant content, height, tiller number, flowering and maturation time, panicle excertion, panicle number per unit area, grain number per panicle, panicle fertility, grain weight and the ultimate grain yield were recorded. An inoculation rate of 3 t/ha yielded 19.63 t/ha of fresh Azolla in 15 days and contained about 26 kg N/ha. The Azolla decomposed very fast, loosing 90% of its weight in 3 weeks of incorporation into soil. Azolla alone significantly (P = 0.05) improved rice leaf chlorophyll and most of the other parameters cited above, the improvement being comparable to that obtained with Azolla supplemented with successive amounts of urea or, 160 kg N/ha Despite itsalone. low Nas urea contribution, Azolla demonstrated considerable potential in promoting rice performance under conditions of the Lower Moshi Irrigation Project. Given the low amounts of N contributed by Azolla, studies to identify furthe rother possible rice growth-promoting in Azolla factors are suggested at the study site and in other rice growing areas in Tanzania.
Assessment of soil fertility status of selected paddy growing areas of Tanzania
(Sokoine University of Agriculture, 1997) Mnguu, Youze Orgeness
Nitrogen, phosphorus, zinc and iron deficiency or limited availability are the main soil fertility constraints limiting rice yield worldwide. The objective of this study was diagnostic to develop criteria for assessing the fertility status of the selected rice growing areas of Tanzania in terms of the availability of the above nutrients. Soil samples were collected from 10 different areas where rice is grown for both laboratory analyses and a glasshouse experiment. The laboratory analyses included the screening of suitable indices for available N, P, Zn and Fe total N, P, Zn Nitrogen availability was assessed by in soils. OC and the alkaline-KMnO4 indices, P by Bray-1, Olsen and the filter paper strip methods while available Zn and Fe were assessed by 0 . IN HC1, 0.005M DTPA at pH 7.3 and 0.01M EDTA-(NH4) 2CO3 at pH 8.6. (Oryza sativa L). The response of rice variety Super India to these nutrients was assessed in a glasshouse experiment where plants were grown for 51 days. The results showed that all the soils used in this study were deficient in N and hence required fertilization with N while 60% of the soils responded to P application. All the soils had adequate levels of K and Zn although three of the soils appeared to be borderline cases between adequate and deficient. The extractable Fe content was very high in all soils. Of the nutrient availability indices tested, OC correlated significantly with the DM yield while Olsen extractable P was found suitable for P assessment with a critical level of 20 mg/kg soil. None of the indices tested was found for suitable Zn and Fe assessment. Basing on these results, OC and Olsen methods were recommended for use in assessing N and P availability in the soils, respectively. No reliable extractant for micronutrients Zn and Fe was obtained in this study. Field experiments are recommended to confirm these findings.
Localization of mineralizable organic carbon using X-Ray CT
(Ghent University Vrije Universiteit Brussel, 2010) Sanga, Hilda Gerald
The sensitivity of organic C (OC) to decomposition depends not only upon its chemical composition but also on its location within the soil matrix. However, the precise location of OC mineralization is not clearly known. This Master thesis research's objective was to investigate the role of soil pore structure on the organic matter (OM) decomposability in a model sandy loam soil. To achieve this, the influence of different artificial operations (compaction, artificial change in texture, acidification, and OM application) on soil pore size distribution, decomposer group community (assessed by the fungal: bacteria ratio) and C mineralization was studied. Two major experiments were included. In the first one, manipulated soil samples were incubated in larger tubes for five weeks. A second incubation experiment was set up to follow C mineralization of added C-sources (grinded sawdust or grass particles) in artificially manipulated soil with differing pore size distribution and decomposer community. Soil samples were incubated in small tubes (1cm diameter* 1cm height) for five weeks and the evolving CO2 gas was analyzed by a Gas chromatography method. Samples were then scanned after incubation by X-ray computed tomography (CT) and following image processing, the total pore volume and % volume of different pore size classes were calculated. Correlation analysis was used to investigate the relation between the % pore volume of five pore classes (10-200, 210-400, 410-600, 610-800 and >800 pm equivalent sphere diameter) and the cumulative C mineralization after 5 weeks. Artificial manipulation of the sandy loam soil, through compaction at BD 1.6 g cm -3 and artificial change in texture from coarse sand: fine sand: silt and clay (CS: FS: S&C) ratio of 10:40:50 to 15:50:35 and 20:60:20 was found to reduce the total soil porosity. Soil compaction at BD 1.6 g cm'3 reduced the proportion of macropores (pores with pore neck diameter 30-300 pm) while artificial change in soil texture found to affect mainly the distribution of micropores (pores with pore neck diameter 0.2-15pm) and to a lesser extent the macropores. Soil amendment with grass material found to increases the total soil porosity. Artificial change in soil texture, soil acidification to pH 4.3 and additions of sawdust material compared to grass changed the microbial community towards more fungi oriented. This suggests these artificial soil operations to be usable for manipulation of soil pore structure and the microbial community. In the second experiment, very pronounced interaction effects on C mineralization between substrate type and the artificial changes in soil pore structure were found. First an interaction effect between soil compaction at BD 1.6 g cm'3 compared to BD 1.3 g cm'3 and substrate type was present as the reduction on C mineralization was more pronounced in grass amended soil than in sawdust amended soil. Similarly, a very pronounced interaction effect between artificial change in texture and substrate type was also noted as addition of sawdust strongly reduced the net substrate derived C mineralization, while grass addition did not. C mineralization from native SOM positively correlated to % pore volume of the 200-600 pm, class implying the dominance of mineralization in intermediate sized pores. On the other hand, a positive correlation between C mineralization and % volume of 610-800 pm pores with both grass and sawdust addition demonstrates the importance of larger pores for substrate decomposition. An inhibiting effect of soil compaction on C mineralization was observed from pF and X-ray CT data and this was likely related to the effect of macropore reduction and probably aeration. The negative influence on C mineralization of artificial change in soil texture and the associated reduction in the microporosity only with addition of sawdust but not with grass seems to be related to observed differences in microbial community involved in decomposition of both substrates. Interestingly but complex interactions between soil pore structure and substrate type were demonstrated in this thesis. Pronounced negative or positive correlations between individual pore size class volumes and C mineralization could be established and this indicates their role in the OM decomposition process.
Assessment of residual tied ridges and farm yard manure application on sorghum yield in semi-arid areas of Hombolo Dodoma, Tanzania
(Sokoine University of Agriculture, 2003) Kabanza, Andrew Kaggwa
Soil physical management involves better understanding of the dynamics of soil physical properties. The reported field study was conducted in semi-arid central Tanzania on a continuing five years old tillage trial comprising No-till (NT), shallow tied ridges (STR), deep tied ridges (DTR) and annually made tied ridges (ADTR) to study the effect of residual unmanured and manured tied ridges on soil physical and hydrological properties as well as sorghum grain yield. Land preparation involved the removal of crop residues from the previous season and a minimum maintenance of the residual tied ridges. The test crop was sorghum variety Tegemeo. Investigated parameters included average residual organic matter (OM) content of the experimental site at different depths. Soil surface roughness before and after field operations and after every heavy rainstorm. Dry bulk density was determined before planting, at mid season and at harvest. Cumulative infiltration was determined before planting and at harvest. Gravimetric moisture content determinations at different depths were made on weekly basis. There was no significant (P<0.05) difference in residual OM content among tillage treatments. The results were that tillage significantly (P<0.05) affected soil surface roughness indices (SSRI) among tillage treatments (NT, STR and DTR). It was 185% high in the residual tied ridges compared to the control. Cumulative infiltration was significantly (P<0.05) higher in NT treatments than in all other six treatments. It was 285.66 mm/hr before planting and 412.83 mm/hr at harvest. STR, DTR and ADTR had intermediate values. Weekly gravimetric soil profile moisture content (mm) in 0-50 cm soil layer were significantly (P<0.05) influenced by treatments throughout the season. It was high in the residual tied ridges compared to the control. Dry bulk density in the surface layer was not significantly (P<0.05) different among treatments. A significant difference in bulk density was observed between treatments only at harvest and within 30-50 cm-soil layer. Farmyard manure had no effect on bulk density. Total porosity values were not significantly different among tillage treatments during the study period. Percentage seedlings emergence and the number of plants at harvest were significantly (P<0.05) higher in DTR. than the other treatments. Sorghum grain yield was significantly (P<0.05) affected by tillage methods. The annually made tied ridges had higher grain yield of 2.17 tons/ha than only 0.42 tons/ha in the control. Grain yield of 1.92 tons/ha under residual tied ridges after five seasons was statistically comparable to the yield from annually made tied ridges. Residual tied ridges can thus be utilized for up to five seasons. The reduced tillage and ridging cost as well as the increased sorghum grain yield under the residual tied ridges is likely to now make the system attractive to farmers in semi-arid areas.

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