Theses and Dissertations Collection

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Tableland soil of North-Eastern Brazil:characterization, genesis and classification
(State University of Ghent, 1986) Barrera, Daniel
The coastal low level tablelands of the State of Alagoas are located in the north-eastern region of Brazil between 8° 25' and 10° 20' south latitude, and from 35° 10’ to 37° 15' west longitude of Greenwich. These surfaces formed by Tertiary Sediments are flat or slightly undulated with slopes rarely higher than 4%. It enjoys a tropical climate with a dry summer and a constant temperature throughout the year. The dominant vegetation is formed by the so-called "Atlantic Forest", presenting also minor areas of "Cerrado". Nine profiles corresponding to the soil types present in, a) the well drained surfaces of the tablelands - which classify as Oxisols, Ultisols and Oxisol-Ultisol intergrades -, and b) in poorly drained depressions - classified as Spodo-sols -, were selected for this work. The influence of the morphogenesis of the landscape and the topographical location on soil development is evident from the soils studied. The properties of the soils are strongly related to geomorphic processes. The soils were characterized in terms of their morphological, physico-chamical, mineralogical and micromorphological properties. The sedimentological analysis of the sand fraction(63 - 2000ym) was also carried out. The mineralogy of the sand fraction is similar in all profiles. The light minerals are dominant ( 91-98% ) and almost entirely composed of quartz grains and no more than traces of feldspars. In the heavy fraction the opaques are dominant, ( 84-92% ); among the transparent minerals zircon dominates, followed by tourmaline and rutile. The composition of the clay fraction is also very similar throughout the region, dominated by kaolinite and minoramounts of gibbsite and oxi-hydroxides of iron and aluminium. With the sole exception of profile 2, all the soils are developed from highly uniform parent materials. At the sametime the parent materials of the different soils are also mutually very similar from sedimentological point of view. " Selective erosion 11 of fine soil components as a consequence of run-off is throughout the plateaux the dominant morphogenetic process, which influences the physico-chemical properties, the classification and the distribution of the soils in the landscape. The micromorphological analysis indicates similar features among the dominant soils of the area; and that the illuviation of clay is present in all profiles, which however is not manifested as clay skins in the field as a result of poor structure development. The soils were classified according to Soil Taxonomy, FAO/UNESCO, the Brazilian System of Soil Classification and under the I.N.E.A.C. ( Zaire ) System.
Bodemkundige inventarissen : kwaliteit en evaluatie karakterizering, van hun geschiktheid voor specifiek landgebruik / Soil resource inventories : characterization, quality and evaluation of for their adequacy specific land use
(State University of Ghent, Belgium, 1987) Msanya, Balthazar M.
In many countries a lot of soil resource inventories (SRIs) particularly soil surveys have been made and are still being made. Their objectives are generally well stipulated and known, yet there are indications that these documents are not sufficiently being used both in developing and developed countries. It is against this background that the present study was started. The intention has been to look for ways of characterizing SRIs and to evaluate their adequacy for specified land uses. This way it was hoped that reasons behind the limited use of such documents could be identified and hence help to frame recommendations for future soil inventories. The data base in this study comprises (a) a total of 176 soil survey reports (including accompanying maps) from 46 countries, (b) 70 70 completed questionnaires from soil surveyors representing 40 countries and (c) 94 completed questionnaires from users of soil maps and reports representing 35 countries. Using the 176 SRIs, a general inventory of the documents was made as a first attempt to characterize them. Then indices to characterize the SRIs in terms of their cartographic attributes were developed. These indices were highly correlated with each other. Other observations on cartographic attributes indicated that (a) the concept of map linear reduction factors is not consistently used and (b) information on soil description sites is only rarely given in SRIs. In relation to the information content of map legends and soil reports it was observed that (a) most SRIs are produced by free survey method; (b) the most commonly used attributes in soil mapping are texture, drainage, landform, topography, parent material and soil depth; (c) information on density of field observations is often lacking in SRIs and is commonly vaguely presented; (d) USDA and FAO/Unesco classification systems are the most widely used internationally; (e) most SRIs contain interpretive data and (f) information on purity of mapping units is often not given in SRIs and in many cases only partly presented. Two methods are developd and described for estimating the utility of base maps. It was noted that many SRIs do not bear information about their compliance with specified base map accuracy standards. With regard to general legibility of SRIs, it was observed that (a) provision of instructions on how to use the SRIs is mostly neglected and (b) glossary of specialized terminology and ranges of soil properties of mapping units are commonly not provided in the documents. A method is developed and described for characterizing and systematically evaluating information given in map legends and soil reports about mapping units in function of specified land uses. Furthermore, a comprehensive method is also described for the assessment of the predictive adequacy of SRIs for three land uses in function of (a) cartographic attributes, (b) map legend and soil report attributes and (c) base map attributes. Guidelines outlining the assessment procedure are provided. This method was applied on 66 selected semi-detailed and detailed SRIs from 17 countries. Following strictly the stipulated criteria of adequacy it was found that only about 27 « of the documents are completely adequate for predicting performance of both corn and oil palm, and about 30 % can be considered adequate for predicting performance of Eucalyptus deglupta (forestry). A preliminary study on the adequacy for prediction of soil erosion hazards was done on 50 selected SRIs from 18 countries, Based on the adequacy criteria per se, it was found that most of the documents could be said to be adequate for the use in question, It was also noted that (a) although information on climate is given in all documents, winds are frequently not described; (b) information on topography is normally limited by the lack of contour lines printed with soils information or the lack of contour maps appended to the soil maps and (c) information on soil permeability is often not described. Analysis on the answers given by respondents of the questionnaire to soil surveyors shows that (a) soil surveyors to a great extent determine the nature of SRIs to be made and only occasionally do users have the opportunity to do so; (b) some terminologies and criteria used in soil survey eg. soil survey intensity, field soil mapping procedures and purity of mapping units are not conceived and used consistently; (c) most soil surveyors do not monitor utility of the SRIs they make; (d) soil maps are sometimes too complicated and (e) publicity about SRIs has not sufficiently been made. The results from the questionnaire to users of soil maps and reports indicate among other things that (a) soil surveys are still considered very important in development projects; (b) there are problems of knowing about the existence of soil maps, yet communication media such as radio, television and newspapers have not been used significantly to ameliorate the situation; (c) major problems encountered while using soil maps and reports include poor legibility, problems of location on the maps, use of vague and in some cases complicated terminology, A revised questionnaire to users of soil maps and reports has been proposed to accomodate changes that will take it more useful as a source of information. To put everything in a nutshell, it can be said that indeed, existing SRIs do present serious bottlenecks that need attention in future inventories. For this a series of recommendations has been suggested at various levels of the study.
Effect of method of terracing on some physical and chemical properties of soils of Mgeta, Morogoro, Tanzania
(Sokoine University of Agriculture, 1992) Kisanga, Danielson Ramoz
A field experiment was conducted on cultivated sandy clay loam Chromic Cambisols at Mgeta on the slopes of Uluguru mountains. The objectives were to study the effects of terracing methods on some soil physical and chemical properties and to relate the results to crop performance observed in the field. The main treatments consisted of bench and ladder terraces. The subtreatments were three positions on the slope, and five 10 cm interval soil depth sections. The physical properties assessed were particle size analysis, bulk and particle densities and available water capacity. The assessed chemical properties included pH, CEC, exchangeable cations, carbon, organic total nitrogen, and available phosphorus. There available were significant water capacity, increases in exchangeable clay, silt, calcium and magnesium contents and a decreasing trend in very coarse sand particles along the slope under ladder terraces. In the bench terraces, bulk density increased slightly while total porosity decreased significantly along the slope. Most of the soil physical and chemical properties from the bench terraces were significantly different along the slope, but lacked a defined trend, Exchangeable cations, total nitrogen, and organic carbon for the two main treatments showed a decreasing trend from surface to the bottom of the soil profile. Other soil physical and chemical properties lacked defined trends with depth. The causes of the observed trends in the bench and ladder terraces are respectively attributed to the mechanical movement of soil and gradual but continuous transportation of fine soil materials by water down the slope. The variations in soil physical and chemical properties within and between the two treatments were attributed to the nature of the soils and methods used in the construction of the terraces. Variations in the studied soil properties account for the observed crop performance. In order to improve crop performance and maintain a sustainable crop production at Mgeta, several soil management and conservation measures are proposed.
The role of microaggregation in physical edaphology
(Sokoine University of Agriculture, 1993) Mtakwa, Peter W
Soil type and the previous tensile strength and penetration resistance as a (PR) should allow the soil compared ranging fail to failure planes in between the microaggregates. function of easily along Five Tanzanian soil hardsetting Paleustalf from a extreme of strength behaviour, through a Paleudoll, Paleustult, both It was expected (the strength characteristics). that microaggregation types were can I characterized soil strength by measuring affect soil strength. matric potential cultivation history of one at Paleudalf and a to a strongly microaggregated Orthox expected to be at At each site soils that had a history of the weak end of the scale. 7 or more years of cultivation and cropping were compared with newly cultivated soils. The and Orthox Paleustult had the best PR characteristic for ease of root growth and the Paleustalf had the worst characteristic which suggested that it would not permit root growth at matric suctions exceeding 100 kPa. The Orthox also had much the most favourable tensile strength characteristic. At air dryness (100 MPa suction), the previously uncultivated and previously cultivated Orthox topsoils strength. compressive) Paleustalf topsoils. Paleustult) a previous had 3 and respectively, 9 times than less the tensile (and corresponding For three of the soils (Orthox, Paleudoll and history of cultivation was found to have significantly and substantially reduced the tensile strength of the topsoil at any given matric suction compared to the newly cultivated soil
Physico-chemical and biological properties of atrazine in soils
(Sokoine University of Agriculture, 1993) Natai, Roland Elisamia
The physico-chemical and biological properties of atrazine (2-chloro-4- ethylamino-6-isopropylamino-s-triazine) in soils were laboratory. investigated in the The batch suspension method was used to study the adsorption desorption properties of atrazine. The results revealed that the amount of atrazine adsorbed or desorbed varies with the soil properties. The adsorption data fitted the Freundlich model. Freundlich "K" values describing the adsorptive capacities of the soils varied with the inherent soil properties. Over 70% of the adsorbed atrazine was found to be desorbed after five desorption cycles. Microbial numbers were determined by dilution plate count technique, and the microbial processes by measuring the final products of the transformations carried out by the test organisms. All the test organisms in this study (i.e total bacteria, Azotobacter, Beijerinckia and nitrifiers) were tolerant to atrazine at the concentrations tested. The population and the activities of these organisms were only slightly and temporarily affected. The practical implications of these findings are discussed.
Distribution and characterisics of calcretes and calcrete-soil profiles on the Northern lower slopes of Uluguru mountains in Morogoro, Tanzania
(Sokoine University of Agriculture, 1997) Sentozi, Eliab
This study was conducted on the area extending northwards from the footslopes of the Uluguru mountains towards the Ngerengere river. Kihonda transect was selected for detailed characterization of different calcrete forms and the associated soils and regolith so as to understand the origin of calcretes, their characteristics and their influence on soil properties. Near Ngerengere river, the calcrete layer is considerably thinner (27.5 cm) than those on the lower slope (76 cm), midslope (135 cm), crest (106 cm) and neighbouring depression (142 cm) implying the influence of Ngerengere river on calcrete formation. Less developed calcretes occur near the river while the most developed calcretes occur at or near the crest. Nodular, honeycomb and massive calcretes are the major forms of calcretes occurring on the transect. Their proportions along the transect which reflect their lateral extension follows the order: nodular (94.9%), honeycomb (87.2%) and massive (51.3%). A considerable difference in purity exists among different calcrete forms ranging from 47.6% in nodular calcrete, 75.0% in honeycomb and 97.5% in massive form. This difference in purity is explained in terms of their difference in degree of development. A sharp di (Terence in average CaCO3 content ranging from 7.7% in soil solum to 65.0% in calcrete layer exists. The latter implies a lithological discontinuity at the soil-calcrete interface. The difference is gradual from 65.0 to 37.7% at the calcrete-regolith interface. The source of the CaCO3 in the calcretes is therefore the underlying parent material. The calcretes are mainly constituted of micritic calcite. Sparite occurs on top of massive calcrete, in fissures, voids and around the relic minerals implying a multi-phase precipitation of calcite. Minor minerals are quartz, opaline silica and feldspars. The studied calcretes were formed during the last glacial period, about 41,000 or more years ago. The gravel and soil layers are considerably younger.
Estimating unsaturated hydraulic conductivity of a sandy clay loam soil from Bulk density data
(Sokoine University of Agriculture, 1997) Natai, Shakwaanande Roland
The Gardner parameters field model, K Kgat/[1 + (bhj"] , with three (Ksat, b, n) , was calibrated and validated with dataforestimating conductivityfora the sandy clay unsaturatedhydraulic insemi-arid loam soil Dodoma, Tanzania. Calibration of the model was achieved by measuring the in situ saturated and unsaturated hydraulic conductivity at different levels of bulk density (1.43, 1.64, 1.85 Mg/m3) and matric suction (0.0, 0.2, 0.5, 0.8 and 1.0 kPa) using the Disc Permeameter method which is a surface technique. Ksat was obtained from the graph of log(K,sat) versus bulk density. The parameters b and n were obtained by solving the simultaneous equations obtained by measuring different soil matric suctions. K at For the sandy clay loam soil at Hombolo, Ksat was obtained from the linear equation, log(K3at ) = 5.644 2.164Qb and values of b and n are 0.66 and 1.32, respectively. The model was validated using the Disc Permeameter method by measuring the in situ unsaturated hydraulic conductivity at different bulk densities (ranging between 1.3 and 2.1 Mg/m3) and different matric suctions (0.2, 0.5, 0.8 and 1.0 kPa within the same range of bulk density) from the plots which initially were not used in the model measurements. calibration The unsaturated hydraulic conductivity was estimated from the same values of bulk densities used in measuring the in situ unsaturated hydraulic conductivity by using the calibrated Gardner model. A coefficient of determination (R2) = 0.997 was obtained when the estimated unsaturated hydraulic conductivity values against the ones measured in the field, were plotted indicating that easily measured soil characteristics such as bulk density for a particular soil, can be used to estimate hydraulic conductivity of that particular soil.
Influence of soil properties on the dissolution of Minjingu phosphate rock
(Sokoine University of Agriculture, 1999) Mwakisimba, John
Phosphorus is mostly supplied in the form of water soluble fertilisers which are very expensive. Thus resource poor farmers can not afford it. The price of Minjingu phosphate rock (MPR) is relatively lower and may substitute water soluble P fertilisers if found to be agronomically comparable to the traditional P sources. A study was conducted to investigate the extent of M'PR dissolution and extractability of P after dissolution of MPR and to determine soil factors controlling the dissolution of MPR and subsequent levels of extractable P in eleven Tanzanian soils. Also the adsorption characteristics of the experimental soils were determined. P adsorption maxima of the experimental soils ranged from 375.4 to 4110.2 mg P/kg and were directly influenced by A12O3. The amounts of P adsorbed at 0.2 pg P/ml ranged from 22 to 710 pg P/g. The soil with the highest P adsorption maximum had the highest P adsorbed at 0.2 pg P/ml. On the other hand, soils with substantial amount of P in equilibrium solution at zero added P had low P requirement. Some of the soils with high P adsorption maxima had low P requirement. The extent of MPR dissolution in the eleven soils tested ranged from 34 - 97 % of the applied P after 70 day (d) of incubation. High percentage (83%) of the variation in MPR dissolution was accounted for by three soil properties namely percent Ca saturation, OC and P retention capacity. Bray 1 P in the experimental soils ranged from 7.3 to 71.0 % of the dissolved P after 56 days of incubation, with an average of 29.6 % suggesting a high degree of fixation. Bray 1 P was also significantly related to exchangeable Al, Al saturation, soil pH, soil pH buffering capacity and OC. However none of these soil properties accounted for > 50 % of the variation in Bray 1 P. This implies that none of the independent variables tested adequately predicted the dependent variable. Results from this study indicate that MPR has high solubility in acid soils of pH < 5.8 and should thus be evaluated for direct application under field conditions.
Erosion hazard assessment in the upper ewaso Ng’lro basin of Kenya: application of GIS, USLE and EUROSEM
(Sokoine University of Agriculture, 1999-01-15) Mati, Bancy Mbura
A methodology was developed for assessing soil erosion hazard in the Upper Ewaso Ng’iro basin of Kenya, using Geographic Information Systems (GIS), the Universal Soil Loss Equation (USLE) and the European Soil Erosion Model (EUROSEM). The USLE was used in a GTS environment by creating thematic maps of R, K, L, S, C and P and then calculating soil loss by raster-grid modelling with Arc/Info GRID. The rainfall erosivity factor (R) was derived from relationships between rainfall amount and erosivity using erosion plot data from within the catchment. The nature of the relationship was found to be a function of agro-climatic zones of the region. Mean annual erosivities ranged from 145 to 990 J m"2 hr"1 For a given amount of rainfall, erosivity was higher in zone IV than in the wetter zones 11-111. The soil erodibility factor (K) was estimated using the USLE nomograph and data from laboratory analysis of field samples collected from representative major soil mapping units. The K-values were low to medium, ranging from 0.10 to 0.25 over 84 percent of the basin. The topographic factor (LS) was obtained by creating Digital Elevation Models (DEMs) of the basin with TOPOGRIDTOOL of Arc/Info. These were then used to determine the slope steepness and length factor values, calculated with raster-grid modelling. Although DEMs proved a useful tool, maximum values of both steepness and length had to be set in this reconnaissance study to achieve reasonable results. A finer resolution of input data and a smaller grid cell size are needed for accurate determination. The cover and management factors (C) were obtained by determining the land cover types within the basin using remotely sensed data (SPOT 1 colour composite prints) and ground truthing studies. The factor values were estimated from USLE guide tables and measurements of cover from plots and test sites. Some 70 percent of the basin is covered by rangelands. The conservation practice (P) factor values were estimated from USLE guide tables and then applied to areas where soil conservation had been introduced according to maps obtained from the Ministry of Agriculture. The USLE was validated using data from erosion plots. A value of R2 = 0.645 was obtained between predicted and measured values but the standard error was rather high (e = 5.745 t ha"1 yr"1). Using an annual soil loss of 9.0 t ha"1 yr"1 as tolerance level, some 36 percent of the basin was found to experience unacceptably high erosion rates. Most of this area was communal grazing land and cropland where soil conservation measures had not been applied. A critical land cover type within the grazing land is shrubland, where vegetation cover is less than 40 percent and high erosion risk was predicted and confirmed by field surveys. EUROSEM could not be integrated within a GIS in the time available for research. It was therefore simulated outside GIS environment, where it was applied to Embori and Mukogodo plot data using separate data sets for calibration and validation. Calibration was used to obtain input parameters for saturated hydraulic conductivity, cohesion and Manning’s roughness coefficients. Validation gave correlation coefficients of 0.907 and 0.840 for predictions of storm runoff and soil loss respectively at Embori; the corresponding values for bare soil plots at Mukogodo were 0.895 and 0.577. However, EUROSEM predicted runoff poorly (R2 = 0.570) and failed to predict soil loss at all the vegetated plots at Mukogodo. The model was applied to simulated vegetation covers of barley, maize, grass and forest for a 36.7 mm rainstorm at Embori. The simulated soil losses showed an exponential decrease with increasing cover. At a threshold cover of 70 percent, soil loss diminished to zero under grass and forest and decreased to a minimum value under barley and maize. These results support the USLE simulations, which showed that areas with more than 70 percent cover (such as forest) had a low erosion hazard, even with steep slopes and high rainfall erosivities. This research has demonstrated that GIS can be used with the USLE to assess and quantify erosion hazard, giving results that can be used for conservation planning. EUROSEM can be applied successfully to bare soil and cropland, but application to other land covers requires further investigation. Land cover and topography are the main factors controlling the spatial distribution of soil loss in the Upper Ewaso Ng’iro basin. Future conservation activities should be concentrated on the rangelands.
Automated land evaluation for alternative uses in south western part of the uluguru mountains in Morogoro Rural District, Tanzania
(Sokoine University of Agriculture, 2000) Mwango, Sibaway Bakari
An automated land evaluation was carried out in Mgeta Area, Morogoro Rural District, Tanzania to assess the potentials and constraints of the various land units for the production of low input rainfed cabbage, round potato and arabica coffee. A total area of 41,964 ha was covered in this study. Land resources database was established by conducting soil survey at semi-detailed level, whereas socio-economic data were collected using semi-structured questionnaires coupled with Participatory Rural Appraisal techniques (PRA). Soils were mapped at the scale of 1: 50,000 based on landforms, parent material and geology. According to the FAO World Reference Base (FAO, 1998), the soils of summits classify mostly as Umbrisols, Cambisols, Leptosols and Acrisols; those of the slopes and piedmonts classify mostly as Regosols, Phaeozems and Luvisols. In the river valley sides the soils are dominantly Fluvisols and Phaeozems. Mgeta soils have low to medium fertility status except those of the summits which have very low fertility status. The topsoil reaction ranges from strongly to slightly acid (pH 5.1 - 6.5). Organic carbon ranges from very low to very high (0.2 to 11.3% OC) while phosphorus is rated as low to medium (P < 7 to 20 mg/kg). Nitrogen content varies from very low to high (0.01 to 5.8 %). The values of CEC are medium to high (12.4 to 40 cmol (+)/kg). Base saturation levels range from very low to very high (1.5 to 95 %). About 80 % of Mgeta Area is both physically and economically moderately suitable for round potatoes, 74 % for cabbage and 71 % for arabica coffee production. The remainder of the area is either unsuitable or marginally suitable for the three crops, the main limitations being soil depth, nutrient availability, nutrient retention and soil erosion hazards.Improvement of soil fertility status is deemed necessary. This can be achieved through agro-forestry practices and appropriate fertiliser/manure application. Improvements of extension services, marketing and storage facilities are also recommended in order to encourage farmers to produce more on a sustainable basis under the prevailing socio-economic conditions.
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.
Agronomic evaluation of some industrial wastes as alternative sources of plant nutrients in Morogoro District, Tanzania
(Sokoine University of Agriculture, 2001) Ndaki, Stephen Mhoja Mashauri
A study’ was conducted at Magadu. Morogoro. Tanzania to evaluate the industrial wastes as alternative sources of plant nutrients and/or soil conditioners. The soil of Magadu was classified by Kaaya (1989) as Oxic Haplustult. The soil was characterised in this study for its physical and chemical properties prior to planting of the test crop. The analytical data showed that the soil was strongly acidic with a pH of 5.1. Total N. available P. %OC, exchangeable Ca and Na. CEC. and DTPA extractable Zn were in the low range. Exchangeable Mg was in the medium range, while exchangeable K. DTPA extractable Fe, Mn and Cu were high. In the field a randomised complete block design was used to evaluate the wastes using maize as test crop. The rate of waste application were 5.24 4.8, 4.25, 4.5 and 3.7 tonnes/ha of waste tea, wattle bark chippings, waste tobacco, wood ash and saw dust respectively. Prior to soil incorporation, the wastes were analysed for their chemical properties. Maize dry matter yields were significantly higher in plots which received 5.24 tonnes/ha of waste tea followed by plots which received 4.25 and 4.5 tonnes/ha of waste tobacco and wood ash respectively. Maize grain yields were significantly higher in waste tea and wattle bark chippings amended plots than in the other waste amended plots. At the end of the growing season the soil was analysed to evaluate the residual effect of wastes on soil properties. Soil pH, available water capacity, available P, % OC, total N, exchangeable bases, CEC, DTPA extractable Zn and Cu in waste amended plots increased in the top 15 cm of soil relative to the control plots. DTPA extractable Fe and Mn, exchangeable Al and acidity were significantly reduced in all waste treatments. Total N and % OC in wood ash and saw dust amended plots were at par with those found in control plots. The results from the field suggested that when applied at agronomic rates, industrial wastes can produce satisfactory plant growth and yields. The results revealed further that waste application on a long term basis will allow good build up of soil organic matter and plant nutrients which in turn will improve on soil productivity. It is recommended that N supplement to wood ash which is rich in almost all macro and micronutrients (except N) would balance its nutrient supply to plants. A glasshouse decomposition experiment was carried out with some wastes including sawdust and wattle bark chippings in perforated plastic litter bags. The wastes were either surface applied or buried to 10 cm depth in wooden troughs. The decomposition process which was monitored at 0. 3, 6, 9, and 12 weeks of incubation revealed that soil incorporated wastes decomposed and released nutrients faster than surface applied ones.
The use of mulberry (morus alba) dry leaves as a protein Supplement for Tanzania blended goats fed with low-quality roughage
(Sokoine University of Agriculture, 2001) Temu,Vitalis Wilbald Kisingo
A study was conducted to evaluate the effect of substituting Morns alba dry leaves (MDL) for sunflower seed cake (SSC) as a protein supplement on the performance of blended goats fed with poor quality roughages. In a growth study, 32 growing blended goats (4 to 7 months old) weighing 14±2.4 kg were randomly allocated to four dietary rations so formulated that MDL replaced 0, 50, 75 and 100% SSC as a source of supplementary nitrogen in treatments T, T, T3 and T4 respectively. There animal received an amount of its respective treatment ration estimated to meet its DCP requirements (adjusted fortnightly) for maintenance plus an allowance for 50 gd'1 live weight gain. Each animal was also given 10 and 2% of its estimated dry matter intake (DMI) as hominy meal (HM) and mineral mix respectively plus ad libitum fresh drinking water daily. After the 84 days of growth study, 3 males from each treatment were slaughtered for carcass yield and killing-out characteristics. Nutrient digestibilities and N utilization were measured in a digestibility trial with 4 treatment groups each with 3 mature males. Tj ration (100% SSC), was poorly accepted by the animals leading to slow growth rates and weight losses towards the end of the growth study. There were significant treatment effects on daily feed intakes with highest values in T3 and lowest in T,. Energy intakes were significantly (P<0.05) lower (2.6 MJ ME d'1) for T1 and higher for the other groups, which were not significantly (P>0.05) different. Tj animals showed poor growth but the other groups gained between 30 and 53 g d'1, the highest being for T4. Highest feed conversion ratio was in T, which differed significantly (P<0.05) from the rest of the were 8 animals (4 and 4 $) in each group. On top of the basal diet (hay) each iii treatments. Hot carcass weight (HCW) % of slaughter weight (SW), was highest in T, followed by T3, T4 and Tt in decreasing order. SW, empty body weight (EBW), HCW and gut fill were significantly (P<0.05) influenced by the treatments, the mean (P>0.05) treatment effects on gut fill. Yield of total edible non-carcass components was significantly (P<0.05) higher in T4 than T3, T2 and T,, the order being reversed when expressed as % of EBW. There were no significant (P>0.05) treatment effects proportions of lean in the sample joints from animals in all treatment groups. Sample joints from T, animals had the lowest fat and the highest bone proportions (P<0.05) than T2, T3 and T4 animals whose differences were generally small and insignificant (P>0.05). All treatment rations supported positive N balances, high in vivo feed digestibility with higher energy intakes being associated with rations containing higher levels of MDL. It was concluded that, MDL can substitute SSC as a protein supplement to growing meat goats without reduction in performance and that a better effect of CP supplementation is achieved when some SSC is offered together with M. alba preferably in the ratio of 25 : 75 (SSC : MDL) in terms of DCP contribution for meeting maintenance and a growth rate of 50 gd'1. The use of SSC as a sole protein supplement to growing goats on poor quality roughages is likely to cause low dietary energy intake leading to lower feed utilization efficiency.
Effect of ethylene dibromide on the control of white grubs and its impact on cordyceps in soils of the TPC sugarcane estate, Moshi, Tanzania
(Sokoine University of Agriculture, 2001) Kapama,Juma Tuwelango
The populations of white grub pest of sugarcane, and that of Cordyceps, a naturally occurring fungal pathogen of white grubs, were determined in the four fields of the TPC sugarcane estate. The effects of ethylene dibromide (EDB), a commercially Cordyceps. Also the contribution of Cordyceps as the biocontrol agent of white grubs was evaluated both in fields and in the laboratory. White grubs populations (in the four fields) varied significantly among four selected Fields with grub densities varying from 25 000 to 93 000 grubs per hectare. These variations were possibly due to differences in field location and soil types and also the number of crop ratoons. Similarly the populations of Cordyceps differed significantly between fields ranging from 600 to 4000 Cordyceps clavac per hectare. The variations were attributed by initial population of white grubs, and soil properties. Ethylene dibromide significantly reduced the populations of both white grubs and Cordyceps in the treated plots, with maximum impacts al the third week after EDB application. In the laboratory, reduction in the population of white grubs by EDB was consistent to the sliding scale of concentration. Although EDB reduced significantly the germination of the Cordyceps clavae from infected cadavers, its effect on fungal growth and the branching of germinated clavac were not significant. Although estimated mortality of white grubs caused by Cordyceps in stress rearing experiment was low (0.27-27%), from field surveys the contribution of the fungus as a natural control agent of white grubs was very high (54-94%). Studies on the effect of EDB on non target organisms used soil fumigant, was assessed in controlling the white grubs and its impact on in sugarcane fields, and development of alternative white grubs control strategies which are sustainable and less harmful to the environment have been recommended.
The effect of times of contact and rates of minjingu phosphate rock (mpr) on its dissolution in an oxic (kanhaplic) haplustults
(Sokoine University of Agriculture, 2001) Nsenga, Justus Vincent
An incubation glasshouse pot experiment was conducted at the Sokoine University of Agriculture Morogoro, Tanzania to study the effect of time of contact and rates of Minjingu phosphate rock (MPR) applied to an Oxic (Kanhaplic) Haplustults on its dissolution and the release of P and Ca for plant uptake. The soil was mixed with MPR at rates equivalent to 0, 50, 75, 100 and 150 kg P/ha. The incubation periods were 120, 90, 60, 30 and zero days prior to sowing the maize (Zea mays. L. var. Staha). The moisture content in the soil was maintained at about field capacity during the incubation period and throughout the maize growing period with distilled water. Results from this study showed that MPR dissolution increased significantly with increase in MPR rates and incubation period. However, the increase in the amounts of P released tended to increase with time of incubation up to about 75 days and decreased thereafter. Presumably the P released was largely sorbed by Al and Fe oxides in the soil. The amounts of MPR dissolved ranged from 1.17 to 13.11 mg P/kg and 10.74 to 15.91% as regards to extractable P and AP% values, respectively. The interaction between equilibration periods and MPR rates explained about 86.8% of the variation in MPR dissolution, MPR rates predicted about 76.6% of the dissolution of MPR, and 10.3% of the dissolution predicted by equilibration period. The soil pH and extractable Ca were found to increase slightly with increase in MPR rates but decreased with increase in incubation period. The exchangeable acidity and exchangeable Al decreased with increase in MPR rates, and slightly increased with increase in incubation periods. Maize dry matter yields, P and Ca uptakes were found to increase significantly with increase in MPR levels. Elemental P and Ca contents in the plant materials were found to decrease significantly with the increase in MPR rates probably indicating the effect of dry matter yield on nutrient dilution or depletion of phosphate and Ca2+ in the soil. Application of MPR at sowing time led into higher dry matter yields than when applied prior to sowing and increase in incubation period decreased the uptakes of P and Ca though inconsistent with %P and %Ca in the plant shoots. Application of MPR at sowing time was recommended for Oxic Haplustults which are strongly acid, with low amounts of P and exchangeable Ca in order to increase the agronomic effectiveness of MPR.
Effects of Land Degradation in the uplands on Land use Changes in the Plains: The case study of Chimala River Catchment in the Usangu plains
(Sokoine University of Agriculture, 2002) Mwalukasa, Emmanuel Hudson
A study was carried out in Chimala River catchment in Makete-Iringa (uplands) and Mbarali-Mbeya (plains), Tanzania to relate land use changes occurring in the plains to upland degradation. The objectives of this study were: (a) to establish land use/cover inventory for the catchment; (b) to assess upland vegetation degradation; (c) to assess upland soil erosion by gully expansion; (d) to assess catchment soil fertility status; (e) to assess the Chimala River water flow trend; and (f) to assess the socio-economic activities related to land degradation. Aerial photographs and satellite images were used, interpreted and analysed using GIS ArcView/ArcINFO and ERDAS Imagine softwares. Mean monthly water levels were compared using a student t-Test. Soil samples were collected from four different forest-covers for organic carbon (OC) content analyses. Total nitrogen (N) contents were estimated using C:N ratios. A structured questionnaire and SPSS programme were used to collect and analyse socio-economic survey data. Results showed that upland grassland decreased by 3.6% and 45.8% for 1963-77 and 1977-2001 periods respectively due to extending cultivation activities. On the scarp, dense and open woodlands decreased by 56.2% and 4.6% respectively for 1963-77 while for 1977- 2001 dense woodland decreased by 100% due to firewood collection; open woodland increased by 21.2% through regeneration. Gully erosion expanded by 206% between 1963 and 1977 because of poor land management but decreased by 69% for 1977-2001 through natural recovery and afforestation. Consequently upland vegetation degradation and gully erosion caused soil transfer from the mountains and deposition in the plains. About 0.4% (1977) and 0.6% (2001) of the catchment area under irrigation were abandoned to bushland due to siltation problems. River valleyiii soils in the plains indicated adequate OC (3.4%) due to alluvial deposition thus attracting more agricultural activities. Low OC (0.61-1.09%) indicated low N (0.06- 0.11%) as a limiting factor for paddy rice production in upper areas of the plains. No significant variations (P<0.05) in the stream flows of Chimala River were observed between 1960 and 1993 as a result of upland degradation. It is therefore concluded that upland degradation has contributed significantly to land use changes/degradation occurring in the plains that calls for more efforts to safeguard land resources in the uplands by concerned stakeholders
Effects of limestone, Minjingu phosphate rock and green manure application on improvement of acid soils in Tonga Butare, Rwanda
(Sokoine University of Agriculture, 2003) Nabahungu, Leon Nsharwasi
A study was conducted under pot and field conditions to assess the effects of limestone, Minjingu Phosphate Rock (MPR) and green manures (GMs) on maize yield, soil properties and nutrient uptake. The treatments tested in the greenhouse experiment were four rates of limestone applied either alone or in combination with MPR and/or green manures. In the field experiment, 13 treatments were tested namely an absolute control, recommended rate of NPK and burned lime, NP and limestone, combinations of any two of the following materials: limestone, MPR, Tithonia GM, Tephrosia GM, and combinations of three of these amendments. Soil analysis at the beginning of the experiment revealed that the soil was deficient in N, P, and K, had low levels of Ca and Mg and toxic levels of exchangeable AI. Application of GMs improved the supply of N and K appreciably while limestone played a great role in reducing exchangeable AI. A significant contribution of P was from MPR. A combination of MPR, GMs and limestone supplied ample amounts of N, P, K, Ca, Mg and reduced exchangeable AI and hence resulted into high yield. However, high rates of limestone decreased DM yield and nutrient uptake in the treatment with three amendments. A significant increase in DM yield was obtained in pots, which received a combination of low rate of limestone (1/4 of the lime requirement), MPR and GMs. In general Tithonia application gave higher yields than Tephrosia. These results were consistent with the higher quality of Tithonia biomass relative to Tephrosia biomass. The green manures in combination with MPR increased P uptake significantly. Nutrient concentration data from both field and pot experiments indicated serious deficiencies of P, K and N consistent with soil analysis data but Ca, Mg, Zn and Cu were in the sufficiency range. Furthermore, the results indicated that using a combination of moderate rates of limestone, MPR and GMs is the best strategy in improving acid soils in Tonga, Rwanda.
Assessment of the fertility status of soils of rice growing areas of Same District, Kilimanjaro Region, Tanzania.
(Sokoine University of Agriculture, 2003) Amur, Nyambilila
This study was conducted to assess the fertility status of the soils of rice growing areas of Same district. Thirty soil samples were collected from ten different sites where rice is grown. Following laboratory analysis, three bulk soil samples were collected from Kisiwani, Ndungu and Kihurio for pot experiments. The laboratory analysis included determination of total N, organic carbon, P by Bray 1 and Olsen methods, and exchangeable bases by ammonium acetate saturation. The micronutrients were determined by extracting with 0.005M DTPA at pH 7.3. The response of rice (Oryza saliva L) variety super SSD5 to N, P and K, as well as to different levels of Zn were assessed in a glasshouse experiment where plants were grown for 56 days. The harvested plant samples were analysed for N, P, K, Ca, Mg, Zn and Fe using the HNO3-H2O2 wet digestion procedure. The results showed that all the soils in this study were deficient in N. About 53% of the soils had low available P. All the soils had adequate levels of K, Ca, Mg and Na, with the exception of soils from Ndungu, which had a low K, supply. Also, most of the soils had low Zn levels, and only two sites had adequate Zn levels. Soils from Mbugani had low Fe while the rest had adequate Fe and Cu. The glasshouse experiments showed that application of N, P and K increased rice dry matter yields in all the soils used. It was further revealed that Zn supplementation in addition to NPK also increased rice dry matter yields further. The results also indicated that the uptake of each nutrient applied was consistent with the dry matter yields increases. It was concluded that most of the soils under rice cropping in the district were deficient in N, P and Zn and required fertilisation using these nutrients. Iron was also required in Mbugani soils, whichiii were deficient of this element. Field experiments are recommended to confirm these initial findings.
Influence of seed storage practices on germination, growth, and yield of Bambara groundnut [Vigna subterranea (L.) Verde].
(Sokoine University of Agriculture, 2003) Mkwachu,Seif Omari
Two experiments were conducted at Sokoine University of Agriculture to assess the influence of storage containers, seed shells and priming treatment on germination, growth and final seed yield of bambara groundnut [Vigna subterranea (L.) Verde.]. Good quality seeds with germination of 95% were stored unshelled and shelled using germination test was conducted as per ISTA methods after priming seeds stored in different containers by soaking for 24 hours, wetting prior to germination with dry germination as the control. The results indicated that germination percentage was decreased in seeds stored in various containers and primed by different treatments. Storing seeds unshelled gave the higher germination of 10.07% compared to those stored after shelling which gave germination of 6.34%. Significant differences (P < 0.05) between storing in different containers were observed. Shelled seeds stored in deep freezer were the best in germination (27%) followed by unshelled seeds stored in basket and hanged over the fireplace (21.94%). Seeds stored in plastic bucket were the least with only 1.45% germination. Also container differences in maintaining 100 seed weight, seed moisture content and proportion of carbohydrate in food reserve was observed. Germination percentage was positively correlated to 100 seed weight (r = 0.88**) and to proportion of carbohydrate in seed food reserve (r = 0.51”3) but correlated negatively to seed moisture content after storage (r = -0.47ns). Strong negative correlation was recorded between seed moisture content and proportion of carbohydrate in seed food reserve (r = -0.93**). This study has shown that differences seven different storage containers for a period of six months. After sixth months, in seed quality induced by different storage containers have major effects only on germination and mean relative growth rate at early growth stages. No significant differences in mean relative growth rate at later growth stages and partitioning coefficients of plants from surviving seeds were observed. Soaking bambara groundnut seeds for in water 24 hours significantly accelerated germination and early seedling growth. No significant differences in yield were observed between priming treatments tested. Based on the results in this study, storing of unshelled bambara groundnut seeds in jute bags or woven basket and hanged over the fireplace is recommended. However, further study is recommended to assess the role of pod drying methods in seed deterioration during storage
Effects of some industrial organic wastes on maize grain yield and some soil properties
(Sokoine University of Agriculture, 2003) Timbula,Kastory Matembele
A study was conducted to evaluate paper sludge and pyrethrum marc as alternative sources of plant nutrients using maize as a test crop. The study was carried out at Magadu Morogoro, Tanzania. Kaaya (1989) classified the soil of Magadu as Oxic Haplustult. Laboratory analyses revealed the soil to be clay, compacted and acidic with low CEC (11.2 Cmol(+) kg'1) Total nitrogen, (0.09 %) exchangeable Ca (1.77 Cmol (+)kg‘‘ ) and Na (0.67 Cmol (-j-)kg'1 were low, exchangeable K (0.69 Cmol (-i-)kg'1) and Mg (1.51 Cmol (-r)kg'1 were high, extractable Fe (46.48 mg kg'1) and Mn (70.06 mg kg'1) were very high while Cu (1.14 mg kg'1) and Zn (0.51 mg kg'1) were adequate for plant growth. Four rates of paper sludge and pyrethrum marc (0, 10, 20, and 30 tons ha'1) on air-dry basis were applied to soil in a randomized block design. The wastes were characterized before incorporation into the soil. Paper sludge and pyrethrum marc were alkaline and acidic in reaction respectively. Paper sludge had high C/N (37.7) C/P (245) and Ca/Mg (105.22) ratios .The high C/N and C/P ratios mean that biological immobilization of nitrogen and phosphorus would be the major limiting factors for this waste to be used as a source of plant nutrients. High Ca/Mg ratio indicates that paper sludge can be used as a liming material. Paper sludge had lower sodium adsorption ratio (SAR) (0.22) as compared to pyrethrum marc (0.62). This suggested that sufficient Ca and Mg are present to counteract the negative effects of sodium. Levels of Fe (333.4) Mn (543.71) Cu (21.00) and Zn (42.9) for paper sludge and 107.55; 901.85; 14.4 and 51.00 respectively for pyrethrum marc, were well within the limits for environmental pollution. Maize grain yield in plots amended with pyrethrum marc increased from 0.64 to 3.33 tons ha’1 with increasing iii rate of pyrethrum marc while in plots treated with paper sludge grain yield decreased from 1.43 to 0.52 tons ha"‘as the rate of application of paper sludge increased. The Increasing the rates of the wastes ameliorated the bulk density from 1.50 tol.38 mg cmrivas associated with decrease in soil bulk density. For pyrethrum marc treated plots, soil pH, OC, total N, extractable P and exchangeable Ca, Mg, and Na and CEC increased with increasing rates of the waste. Cu and Fe were significantly lowrelative to the control, and Zn was higher than the control. Soil pH, exchangeable Ca and CEC of the plots amended with paper sludge increased with increasing rates of the material from 5.28; 2.61; 10.57 to 7.7914.74; 14.20 respectively. Increasing the rates of paper sludge had a negative effect on exchangeable Mg, K, Na, and extractable P. Total nitrogen and organic carbon were not statistically different from for the lowest rate and 0.81 mgkg'1 for the highest rate of paper sludge). Zn was not statistically different compared to the control, and Fe was significantly lower than the control. Both wastes alleviated Al and Mn concentrations remarkably

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