Theses and Dissertations Collection

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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.
Comparative assessment of land suitability evaluation based on land mapping units and agroecological zones: a case study of Morogoro rural district, Tanzania
(Sokoine University of Agriculture, 2003) Mathew, Laurent
A study was conducted in Morogoro rural District to compare land evaluation based on land mapping units (LMUs) and Agro ecological zones (AEZs) as a land unit criterion for land suitability classification and evaluates their effectiveness for land evaluation at district level in Tanzania. The study comprised of Agro economic survey using semi-structured questionnaires, compilation of land resource and Agro economic databases, and physical and Agro economic land suitability evaluation of LMUs and AEZs for maize, paddy and sesame as the main land utilization types (LUTs) using Automated Land Evaluation System (ALES). The results showed that parts of land units Vai (50%), Va2 (50%), AEZ IX (50%), MO21 (35%), AEZ V (35%), AEZ VI (35%), Pe3 (30%), AEZ III (20%) and AEZ VII (5%) are moderately of yields and gross margins by ALES were better (P<0.05) when AEZs were used as a land unit criterion for land suitability evaluation than when were based on LMUs. The study has demonstrated that land suitability evaluations using Agroecological zones criteria as a unit for land evaluation is much better and more effective (P< 0.5) than LMUs criterion particularly when working on small scale surveys for land use planning at District level. Similar studies should be carried out elsewhere in Tanzania in areas with similar environmental conditions to verify the applicability of AEZs as an evaluation land unit in land evaluation in favour of the LMUs. Further research to assess on-farm land evaluation methodologies taking into consideration climatic variability over a long time is also recommended. suitable for maize production. The rest are either marginally or currently not suitable for maize production. Parts of land units Vai (50%) and AEZ VII (45%) are highly suitable for paddy production. While land unit Va2 and, parts of the land units Pel (55%) and AEZ IV (75%) are moderately suitable for paddy production. The rest are either marginally or currently not suitable for paddy production. Also the results indicates that parts of land units AEZ IX (50%), AEZ V (35%), Pe3 (30%), AEZ VI (5%) and AEZ VII (5%) are moderately suitable for sesame production. The rest are either marginally or currently not suitable for sesame cultivation. The major limiting factors for production of these LUTs are erosion hazards, oxygen availability to root zones, rooting condition, moisture availability, nutrient availability and nutrient retention. The study also revealed that there is positive correlation between ALES predictions and farmers’ reported yields and gross margins with correlation ranging from 0.3 to 0.7 and 0.2 to 0.8 for yields and gross margins respectively. Predictions
Soils of Mtibwa sugar estate: some physical and chemical properties and their effect on crop performance under sprinkler irrigation
(Sokoine University of Agriculture, 1995) Tarimo, John Emanuel Rai
A study was conducted in Mtibwa Sugar Estate, Morogoro, to causes production. This for involved in sugarcane soil physical decline observed detailed characterization of affected areas and that of a bare area. Quality of water for irrigation was also studied. The results showed that the salt affected blocks have sandy loam topsoil overlying sandy clay subsoil of low permeability (0.5 - 0.9 m/day) . The electrical conductivity of saturation extract is low to medium (1.15 3.7 dS/m); the level of sodium is very high throughout the profiles of affected blocks (above 2.0 cmol( + )/kg); the calcium content is very low to low (1.10 - 3.39 cmol( + )/kg) while that of magnesium is moderate (1.5 - 2.39 cmol(+)/kg). j.t was Gleyic concluded that the soil of the affected fields is Cambisol Classification. It according was to classified FAO-UNESCO as Typic (1989) Tropaquept according to United States Department of Agriculture Soil Classification System (Soil Survey Staff, 1990). The soil of the non affected field was found to be in the subgroup Typic Ustipsamment (USDA Soil Taxonomy) . It wasclassified as Umbric Regosol (FAO-UNESCO Classification) . According to FAO (1976) land suitability classification, the affected fields studied are marginally suitable while the non affected field is moderately suitable. The electrical conductivity of the irrigation water is low (0.09 dS/m) and that of the groundwater of field 10E is medium (0.55 dS/m). The sodium content in irrigation water is low (0.2 meq/1) but very high (56.35 - 71.04 meq/1) in the groundwater of the affected fields. It was also noted that the chloride content of the groundwater of the affected fields is very high (145.0 - 236.0 meq/1). It was concluded that salinity, sodium and chloride toxicity are the main problems responsible for the declining sugarcane production at Mtibwa Sugar Estate. The Mtibwa Sugar Company is thus urged to look for means of correcting the observed problems for example by establishing a drainage system for the Estate. The adoption of this suggestion will of course be determined by the economics involved as will be reflected in the drainage plans and designs.
The influence of selected cropping systems on soil properties in Kwalel Village, Lushoto, Tanzania
(Sokoine Univesity of Agriculture, 2001) Mwinuka, Clement T.K.G.
A study was conducted in Kwalei village. Lushoto district to evaluate the influence of selected cropping systems on soil properties. The following cropping systems were identified through a transect walk, cropping systems on the slopes (monoculture tea. coffee/banana and maize/beans intercropping systems) and vegetable cropping systems in valley bottoms. Other cropping systems were woodlot systems (Eucalyptus. Grevillea. Wattle in a mixture of tree species) and fallows. Three soil profiles representing summits. slope and footslope areas were dug. According to World Resource Base (WR.B) (FAO. 1998) classification system three soil levels were identified namely Lixisols (summit). Fluvisols (slope) and Lixisols (footslope). The corresponding USDA-soil classification at soil order levels were Alfisols (summits). Entisols (slopes) and Mollisols (footslopes). Soil samples were taken at a depth of 0-20 cm from each identified cropping system for physical and chemical analysis. Core samples from the same cropping systems were taken for bulk density determination. The results from cropping systems on the slopes showed that soils from monoculture tea had low levels of plant nutrients compared to coffee/banana and maize/beans cropping systems. However, the soil physical properties in all three cropping systems on the slopes were suitable for crop production. Soil pH was conducive for tea production. The DTPA extractable Fe was significantly higher (P=0.05) in monoculture tea than in other cropping systems and the opposite was true for DTPA extractable Mn. DTPA extractable Zn did not differ significantly (P=0.05) between theiii cropping systems while DTPA extractable Cu was higher in coffee/banana cropping system. Most of the plant nutrients in soils from vegetable growing area were adequate for vegetable production except for available P. DTPA extractable Fe and Zn were within the acceptable range while DTPA extractable Cu and Mn were above the critical level for vegetable production. Soil properties in four woodlot systems were variable. Except for Eucalyptus, other tree species showed superiority in one or more properties. Eucalyptus had the least effect on soil properties, which suggest that the tree have low potential for amelioration of soil fertility compared to other tree species. From the study it can be concluded that fallow systems did not improve the soil fertility of degraded soils in Kwalei village. This is possibly due to the young age of the fallow systems. It takes long time to restore soil fertility. It can be recommended from this study that, for optimum crop production, farmers should control soil erosion, use cover crops and organic fertilisers like composts, crop residues and farm yard manures.
Phosphate retention and the effects of retained phosphate on the pH, CEC, AEC and ZPC of soils with high contents of variable charge soil minerals from Tanga, Tanzania
(Sokoine University of Agriculture, 1993) Assenga, Rufini Hassan
A laboratory study was undertaken to investigate on the phosphate retention and the effects of retained phosphate on the pH, CEC, AEC and ZPC of three soils, namely Rhodic Kandiustox, Rhodic Haplustox and Typic Haplustox from Tanga, Tanzania. These highly weathered and leached soils have high contents of variable charge soil colloids (VCS) dominated by kaolinite and iron and aluminium oxides and hydrous oxides, with low to very low pH (< 5.5), low CEC (< 10 c.mole/kg soil) and aluminium saturation between 15 to 25%. The phosphate retention capacities of the soils ranged from 1000-1400 mg P/kg in the order Rhodic Kandiustox Rhodic Haplustox < Typic Haplustox. There were high and positive correlations between the amounts of phosphate retained and the contents of iron and aluminium oxides and the 1:1 layer silicates. The phosphate adsorption data did not conform to the linear transformations of the Langmuir and Freundlich equation models. Additions of up to 1600 mg P/kg to the soils significantly increased the pH of the Rhodic Kandiustox, Typic Haplustox and Rhodic Haplustox by 0.1, 0.4 and 0.05 pH units, and the CEC by 103%. 66% and 61%, respectively. Phosphate retention by the soils at 1600 mg P/kg soil reduced the AEC and lowered the ZPC of the Rhodic Kandiustox, Rhodic Haplustox andTypic Haplustox by 1.S0, 1.10 and 0.55 pH units, respectively. The effects of added and retained phosphate on the pH, CEC, AEC and ZPC of the soils could be attributed mostly to the charge reversal through specific ligand exchange reactions between the phosphate ions and the aquo and hydroxo groups on the VCS colloids. The resultant increases in pH and CEC with phosphate retention appears to be very small in relation to the large amounts of phosphate added to the soils. However, the amounts of P fertilizers required to effect such changes in pH and CEC could be minimized if the P fertilizer materials are banded.
Soil water status, maize growth and yield under traditional farming practices at Bvumbwe -Malawi.
(Sokoine University of Agriculture, 1996) Kayira, Kondwani Kenton Mwachilinda
An experiment was conducted at Bvumbwe Research Station in Malawi with the objective of characterizing the soil water status and maize (Zea mays) growth and yield under traditional tillage practices. Four tillage practices namely Open Ridge (OR), Residual Ridge (RR), Basin Ridge (BR) and Tie Ridge (TR) systems were used as treatments. Instantaneous soil water content was determined in situ by using tensiometers (Model 2900F1) set in the field within 0 - 45 cm depth on rows, interrows, and 2/3 distance from interrows. Weekly gravimetric determinations of soil water at 0 - 45 cm depth were used to assess the profile soil water distribution characteristics at different maize development stages. Infiltration measurements soon after cultivation and after harvesting were determined by the double ring method. Runoff collection tanks were installed at the edge of each plot to collect runoff discharges from respective plots. Plant performance was assessed on a complete randomised block design (CRBD). Treatment BR maintained the highest profile soil water content on rows, interrows and 2/3 distance from interrows during the greater part of the season, RR had the lowest whereas TR and OR had an intermediate profile soil water content. Row soil water readings were normally lower than interrows with a mean differrence of about 4.5 mm in OR and RR, 6.3 mm in BR and 5.4 mm in TR. The differential patterns of recharge and drying within the profile created spatial variations in soil water content at different depths. There was significant correlation between spatial variations and the mean soil water content. Subsurface recharge from interrows to rows, narrowed the spatial variations in soil water content in BR by about 0.0021 and a minimal rate of0.00065 in RR. Temporal variances in soil water content ranged from 0.0086 in BR and TR to 0.0053 in RR with intermediate temporal variance for OR treatment. The soil water behaviour showed a temporal dependence on spatial variations and a spatial dependence on temporal variations. Higher soil water content in BR was attributed to basin storage which promoted in situ water retention allowing longer periods for infiltration process ■ to take place leading to the low runoff coefficient of 10% in BR, 18% in TR, 29% in OR and 47% in RR. Maize performance was significantly related to the soil water content with the highest growth rate in BR treatment of 2.11 cm/day, TR 1.93 cm/day in TR, 1.84 cm/day in OR and 1.39 cm/day in RR at 59 DAP. Tasselling rate, leaf area Index, dry matter yield responded positively to the soil water variations in the treatments.
Evaluation of banding methods and organic matter addition for improving dissolution and availability of phosphorus from Mijingu phosphate rock in two soils on contrasting characteristics
(Sokoine University of Agriculture, 2003) Mhagama, Joseph
A study was conducted under pot and field conditions to evaluate the effects of Minjingu Phosphate Rock (MPR) banding and some manipulations within the band, on maize yields. The treatments were: varying depth of incorporating MPR, and organic materials (plant residues). They were evaluated for their effects on enhancement of dissolution and consequently availability of P from banded MPR in two soils with contrasting characteristics. The treatments tested were 20-cm MPR + O.M band, incorporated down to the 10 or 20cm depth, 20-cm MPR alone band, in corporated to the 10 or 20cm depth, 2-5cm width strip banded MPR, broadcasting MPR (only for field) and control, giving seven treatments for field and six treatments for pot experiment. The experiment was laid using Randomized Complete Block Design with four replications. Extractable P in soils, DM yields, plant P concentration, P uptake and grain yields were used to assess the effects of these treatments. The results of this study showed that some banding treatments significantly (P=0.05) increased dissolution and availability of P from MPR. For example, in the pot experiment, Minjingu PR plus organic matter increased DM yields from 3.17 to 56.32 g/pot and 7.13 to 76.24 g/pot, and P uptake from 2.75 to 83.24 mg/pot and 4.72 to 118.40 mg/pot for Sasanda and Magadu soil, respectively. Under field conditions, MPR + O.M treatments increased extractable P in the soil from 4.0 to 18.45 mg/kg and 5.39 to 79.84 mg/kg, and grain yields from 0.16 to 2.27 t/ha and 0.32 to 2.59 t/ha for Sasanda.and Magadu sites, respectively. This study *shows that banding of MPR can be a good method of MPR application in acid and high P fixing soils, especially when MPR is incorporated together with organic residues
Isolation, enumeration and evaluation of antimicrobial potential of streptomyces isolated from some acid and alkaline soils of Tanzania
(Sokoine Univerisity of Agriculture, 2000) Mvungi, Mussa Faraji
The study reported herein was conducted to enumerate and evaluate the antimicrobial potential of Streptomyces from acid and alkaline soils. The soils were sampled from Morogoro, Coast and Iringa regions in Tanzania. Streptomyces were enumerated us ing starch-casein agar. Colour of aerial mycelium and morphology of spore chains were determined. The isolates were evaluated for tolerance to pH changes and as sessed for antibiosis against selected plant pathogenic bacteria. There were signifi cant (P=0.05) differences in populations of Streptomyces in soils of different pH lev- respectively) and were highest at pH 7.2, with a population of 5.4. Regressions analy sis revealed that only % clay was significantly (0.05) correlated with Streptomyces populations. The regression of Streptomyces on all soil pH values was not significant in the entire range. However, the relationship was significant (P=0.05) when Strep tomyces populations were regressed on pH levels ranging from 4.5 to 7.2. The Strep tomyces isolates displayed the following morphologies of spore chains: flexuous (60.9%), straight (12.4%), open spirals (13.3%), closed spirals (2.86%), open loops (7.62%), hooks (1.9%) and monoverticillate (0.95%). The colours of mature colonies of Streptomyces isolates were white (20%), gray (58.1%), pink (1.9%), red (1.9%), yellow (1.9%) and cream (16.2%). All isolates from acidic soils (pH 4.5 and 5.95) were able to proliferate at high pH up to 7.8 while those from alkalinity conditions (pH 7.85, 8.2 and 10.0) could not do well when tested on the acidic side (pH 4.5 and 5.95). els. The populations were lowest at pH 4.5 and at pH 10 (log io values of 3.2 and 3.5, About 84% of the strains produced antibiotics against Ciavibacter michiganensis sub sp michiganensis, Xanlhotnonas phaseoli, X. vascatoria, X. oryzae pv oryzae and Acidovorax avenae. Six isolates (about 16.2% of all isolates) did not produce antibio sis against any of the tested plant pathogens. Xanthamonas phaseolicoli var fuscoris was not inhibited by any of the isolates. The Acidovorax avenae was inhibited by the least number of isolates, mainly those from acidic soils.
Land suitability assessment of the Wami plains in Morogoro,Tanzania with respect to the production of the main food crops and extensive grazing.
(Sokoine University of Agriculture, 2000) Kileo,Emmanuel P.
ABSTRACT A study was conducted at Wami Plains in Morogoro to assess the suitability of land for the production of the main food crops and for extensive grazing. Field land resources survey was conducted covering an area of 35,810 hectares. Soil profiles were excavated, studied and sampled for laboratory analysis. Soils of Wami Plains are mostly well drained, sandy clay loams, except on the valley bottoms, floodplains and mbuga where they are poorly drained. They have low to medium available water capacity (83 - 135 mm/m) except profile NYN-P7 which has high available water capacity (164 mm/m). The soils are generally poor in chemical fertility. The levels of nitrogen range from very low (0.04%) to low (0.17%) while those of organic carbon are between low (0.66%) to medium (1.46%). Available phosphorus contents range between low to medium (0.96- 16 0 mg/kg) The level of micronutrients in these soils is adequate except for Zn which is rated as inadequate for most crops. The soils were classified according to both FAO- World Reference Base and USDA Soil Taxonomy systems. The FAO-WRB soil names with their mapping units in brackets are as follows: Chromi-Rhodic Cambisols and Hapli- Hypocalcic Calcisols (Alluvial fan); Rhodi-Profondic Lixisols (Ridge summits); Rhodi- Profondic Lixisols (Ridge slopes with red soils); Hypereutri-Ferralic Cambisols (Ridge slopes with sandy soils); Hypereutri-Mollic Fluvisols and Calcari-Mollic Cambisols (Valley bottoms); Chromi-Profondic Lixisols and Hapli-I-Iypocalcic Calcisols (Flats with red soils); Calcari-Mollic Fluvisols (Flats with sandy soils); Hypocalci-Endosodic Calcisols (Floodplains) and Endosodi-Pellic Vertisols (Mbuga) Three land utilisation types (LUTs) (maize, rice and extensive grazing) were selected for land suitability evaluation and the results of physical suitability evaluation are as follows: About 38% of the area was classified as moderately suitable, 44% marginally suitable and 18% physically not suitable for maize production. As for rice production, about 55% of the area was classified as marginally suitable and 45% is physically not suitable for the LUT. About 84% of the area was classified as moderately suitable for extensive grazing while only 16% is marginally suitable for the LUT. Major limitations in these soils are: nutrient availability and retention, moisture availability, flooding hazards, oxygen availability to roots and biological hazards.

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