Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Little scientific information regarding the effect of different geological parent materials on grapevine performance is currently available in South Africa. This aspect is of special significance for the Helderberg area, where parent material may change from granite to shale over a short distance. This results in shale- as well as granite-derived soils often occurring within the same vineyard. The objectives of this study were to (i) quantify the nutritional status and other soil properties of different parent materials (shale and granite) and overlying soils (ii) investigate the impact of geological differences in the soil on the vine nutritional status and certain vine parameters. This study was done over two seasons (2006/2007 and 2007/2008). Two Sauvignon blanc and two Cabernet Sauvignon vineyard blocks were selected at two different localities for each cultivar in the Helderberg area, South Africa. Shale- and granitederived soils were identified within each block. Kaolinite was the dominant mineral, whereas quartz and feldspar were sub-dominant. Traces of mica were also present in some shale- and granite-derived soils. Granite- contained significantly higher contents of coarse sand than shale-derived soils, whilst the opposite occurred in terms of fine sand. These differences affected the water holding capacity, in general making it higher in shale- than granite-derived soils. Shale-derived soils had higher concentrations of total K but granite-derived soils had a higher ability to release K as they contained higher concentrations of soluble K. The Q/I parameters, potential buffering capacity of K (PBCK) and equilibrium activity ratio of K (ARK) showed no consistent responses to geological differences. Potassium concentrations were higher in the leaf blades (obtained before harvest in 2007) from Sauvignon blanc grapevines on granite- than on shale-derived soils. Potassium concentrations in the Cabernet Sauvignon juice (obtained in 2007) tended higher in juice from granite- than from shale-derived soils. In 2008, K concentrations tended higher in juice from shale- than from granite-derived soils for both cultivars. The pH of the Sauvignon blanc juice (obtained in 2008) tended higher in juice from shale-than from granite-derived soils, thus corresponding with the K concentrations in the juice in this season. Nitrogen concentrations were higher in Cabernet Sauvignon juice (obtained in 2007) and Sauvignon blanc juice (obtained in 2008) from shalethan from granite-derived soils. In terms of vine water status, vines on granite-derived soils appeared more stressed than those on shale-derived soils in both seasons at one of the vineyards. In these Sauvignon blanc and Cabernet Sauvignon vineyards, the K nutritional status was not affected by geology in a consistent manner but there were some noticeable tendencies for a specific cultivar during certain seasons. On account of vines being planted on shale- and granite-derived soils within the same block, soil preparation was done similarly for both soils, and they were exposed to similar irrigation schedules, canopy management strategies and climatic conditions. Therefore, there is a high probability that all these practices may have negated the effect of geology on the K status of soils and especially on juice K concentration at the time of harvest. It was clear that seasonal differences and fertilisation affected the nutritional status of the vines more than geology. / AFRIKAANSE OPSOMMING: In Suid-Afrika is daar tans min wetenskaplike inligting oor die effek van verskillende geologiese moedermateriale op die prestasie van wingerd beskikbaar. Hierdie aspek is veral van belang in die Helderberg-area, waar moedermateriaal oor ‘n baie kort afstand van graniet na skalie kan wissel. Dit lei daartoe dat skalie-, sowel as granietgronde, dikwels binne dieselfde wingerd voorkom. Die doelwitte van die studie was om: (i) die voedingstatus en ander grondkundige eienskappe van die verskillende moedermateriale (skalie en graniet) en oorliggende gronde te kwantifiseer (ii) die impak van geologiese verskille in die grond op wingerd se voedingstatus en sekere wingerdkundige parameters, te ondersoek. Hierdie studie is oor twee seisoene (2006/2007 en 2007/2008) gedoen. Twee Sauvignon blanc en twee Cabernet Sauvignon wingerdblokke is geselekteer by twee verskillende lokaliteite vir elke kultivar in die Helderbergarea, Suid-Afrika. Beide skalie- en granietgrond is binne elke blok geïdentifiseer. Kaoliniet was die dominante mineraal, met kwarts en veldspaat sub-dominant, terwyl spore van mika ook in beide skalie- en granietgronde gevind is. Granietgronde het betekenisvol hoër hoeveelhede growwe sand bevat, terwyl skaliegronde meer fyn sand bevat het. Hierdie verskille het ‘n effek op waterhouvermoë gehad en daartoe gelei dat waterinhoude oor die algemeen hoër was vir skaliegronde. Skaliegronde het groter hoeveelhede totale K bevat, maar granietgronde se vermoë om K vry te stel was hoër, omdat hulle ‘n hoër konsentrasie oplosbare K bevat het. Die Q/I parameters, potensiële buffervermoë vir K (PBCK) en ewewig aktiwiteitsverhouding vir K (ARK), is nie op ‘n konsekwente wyse deur geologiese verskille beïnvloed nie. Vir die Sauvignon blanc wingerde was kalium konsentrasies in blaarskywe (gemonster voor oes in 2007) hoër vir graniet- as vir skaliegronde. Kalium konsentrasies in die sap vanaf Cabernet Sauvignon (gemonster in 2007) het hoër geneig vir granietgronde. In 2008 het die kalium konsentrasies, vir beide kultivars, hoër geneig in sap vanaf skaliegronde. Gedurende dié seisoen het die pH van sap ook hoër geneig vir Sauvignon blanc vanaf skaliegronde, wat dus ooreenstem met die K inhoud van die sap. Stikstof konsentrasies was hoër in sap vanaf skaliegronde vir Cabernet Sauvignon (2007) en vir Sauvignon blanc (2008). In terme van die wingerde se waterstatus, het stokke op die granietgrond, by een van die lokaliteite, geneig om gedurende beide seisoene onder groter stremming te wees op graniet as op skaliegrond. In hierdie Sauvignon blanc en Cabernet Sauvignon wingerde, is K voedingstatus nie op ‘n konsekwente wyse deur geologie geaffekteer nie, maar gedurende sommige seisoene was daar wel duidelike tendense vir ‘n spesifieke kultivar. Omdat die stokke binne dieselfde blok op skalie- en graniet gronde geplant is, was grondvoorbereiding eenders vir die twee grondtipes terwyl besproeiingskedule, lowerbestuur en klimaatstoestande ook identies was. Daar is dus ‘n hoë waarskynlikheid dat al hierdie faktore daartoe kon bygedra het dat die effek van geologie op die K status van van gronde versluier is, veral die effek op die K inhoud van sap teen oestyd. Dit was duidelik dat seisoenale klimaatsverskile en bemestingspraktyke ’n groter effek as geologie op die voedingstatus van die wingerd gehad het.

Thesis (MScAgric)--Stellenbosch University, 1932. / No Abstract Available

MESHWR / Department of Hydrology and Water Resources / Communities in South Africa have been noted to consume earthy materials such a soil among others. Geophagy is largely practised in the rural areas as opposed to urban places, and in these places the level of sanitation is low and people usual practice open defecation. The practice of Geophagia has been associated with cultural, medicinal, psychological, religious and nutritional deficiency among others. The aim of the study was to investigate the effects of open defecation on geophagic soils and water resources in Siloam village. The study also aimed to understand the reasons why people practice geophagia in Siloam village and the health effect associated with consumption of geophagic soils. To carry out the aim of the study, a questionnaire survey was conducted among women who practice geophagia between the ages of 18 and above in Siloam village. Two hundred and eighty-three (283) women were selected using snowball sampling method to take part in the study. From the (283) women, (200) women represent the geophagic group and (83) women represent the control group. The existing standard questionnaire adopted to generate data on human geophagia included aspects on demography, socio-economic, cultural, ecological, physicochemical aspects, indigenous knowledge and health effects of geophagic consumers. Participants were asked basic questions on why they practice geophagy, their geophagic material preferences, where they collect the geophagic material and other related questions. A total of twelve soil samples were collected from Siloam village, from the twelve soil samples collected eight were collected from sites known for geophagic practice and another four soil samples were collected from sites where geophagia is not practiced and the samples were used as control soil samples. All the twelve soil samples were analysed for the presence of geohelminths ova using Ammonium Bicarbonate Protocol (AMBIC protocol). The AMBIC protocol consists of four analytical procedures, namely, sample preparation, sample washing with AMBIC solution, geohelminths ova recovery through a modified zinc flotation method and microscopic analysis. vi Furthermore, a total of twelve water samples were collected from Nzhelele River and ponds water in Siloam village. From the twelve water samples, eight samples were collected close to where geophagic materials were collected and where open defecation is reported to be taking place and the remaining four water samples were collected randomly from Nzhelele river and water ponds in Siloam village and was recorded as a control group. A total of 12 water samples were analysed for total coliform and faecal coliform Escherichia Coli (E.coli) indicator using the membrane filter technique. The results from the administration of the questionnaire revealed there was prevalence in the practice of geophagia in the area. The study found that most of the villagers in Siloam consumed soil nearly on daily basis. According to the results, only women were involved in the geophagic practices in the area. Additionally, the study revealed that geophagic consumers were mainly in the age of child bearing age group and reddish and yellowish soils were the most preferred. Furthermore, the results showed that geophagic consumers in the area generally consumed soil commonly because of cravings and pregnancy, however, those who were not pregnant also consumed soil. The respondents reported that they mostly consumed clay and this material was consumed in its dry state and mostly unprocessed, if processed, it would be baked. This geophagic material was mainly found in the wild (riverbed, valley etc.); it was also found that most of the soil consumers did not know that the substances they consumed could be harmful to them. Among those who knew the consequences of consuming the material stated that soil consumption causes constipation, tooth decay, body poisoning, and abdominal pains. The results from the control group, 83 women who do not practice geophagia, aged between 18 and above, analysed using chi-square revealed a significant association of age with consuming soils (p<0.05), while there was no association of income source (p>0.05) and educational level (p>0.05) with consuming soils. Chi-square (χ2) analyses further revealed that there was no association of knowledge on the harmful nature of the substance (p>0.05), frequency of getting infections (p>0.05) and experiencing chronic illnesses (p>0.05) with frequency of consuming soils. vii The results of geophagic soils revealed the absence of geohelminths ova in the entire geophagic sample. Meaning geophagic consumers in Siloam village are not at risk of acquiring geohelminths infection which may be of potential risk to human health. However, geophagic consumers may be exposed to various other potentially hazardous biological and non-biological soil contents. The results of the water samples revealed that most of the water samples in the areas where open defection is reported to be practised had higher composition of faecal and total coliform bacteria. The composition was above the South African recommended standard for negligible risk of microbial infection. This has caused a great threat to those who consume soil collected near water resources, especially from riverbed and those who also use these water sources on their daily basis. The study recommends that geophagic consumers should continue to bake their materials before consumption as it might reduce the bacteria and toxic substances found in soils. The study also recommends that the residents of Siloam be made aware of the potential health hazards that might be posed to soil consumers and the effects of practicing open defecation near community water resources as high level of faecal coliform (E. coli) were found in the water. / NRF

MESMEG / Department of Mining and Environmental Geology / Vhembe District has several clay deposits which are traditionally use for clay products such as burnt bricks without taking into account the chemical and mineralogical characteristics of clay being used. The ever-increasing market demand for these clay products cannot be met with the traditional method of clay utilization due to the paucity of scientific information on properties of the clay in the area. Consequently, there is a need to gain better understanding of the characteristics of the clay in Vhembe District and to establish the suitability of the variety of clay for different purposes. The current study was undertaken to better understand the compositional relationship between the clay deposits and surrounding rocks present in the study area. It further aimed at characterizing the clay deposits on the basis of chemical, mineralogy, physical, mechanical, thermal and micro structural properties with a view of evaluating the clays for possible industrial use. A total of thirty-nine clay and rock samples were collected from thirteen different locations across the Vhembe District. Thirteen representative samples from each location were obtained after thorough mixing until homogenization was attained and then quartered for subsequent analyses. The mineralogical and chemical characteristics of the clay and rock samples were determined using XRD and XRF respectively. Thin-sections of the rock samples were prepared and examined under petrographic microscope to better understand the mineral assemblages present in the rocks. The thermal and micro structural properties of the clays were determined using DTA-TGA and SEM analyses and the physical properties which include colour, cation exchange capacity (CEC) and soil pH were assessed. The particle distribution and Atterberg limits tests of the clay samples were also conducted in order to establish their mechanical properties. The petrographic results showed that the clay deposits exhibited an intense weathering and sedimentation processes which incorporated detrital minerals from the surrounding rock units. The rock units which include basalt, granodiorite, gneiss and quartzofeldspathic gneiss were found to be differentiated from subalkaline and/or tholeiitic magmatic composition. Although the value of SiO2 content in rock samples was higher when compared with clay samples, it indicated an ongoing desilicication and allitization processes. The high values of chemical index of alteration (CIA), low values of K/Cs (<6200), Ce* normalized value and higher values of LILE enrichment in the clay deposits indicated oxidizing environments during period of deposition. v The mineralogical composition of the studied clayey deposits showed that smectite (8.25 - 29.32%), kaolinite (14.91 - 59.26%) and chlorite (5.94 -16.54%) were present as clay minerals although associated with other non-clay minerals such quartz, plagioclase, talc and geothite. The chemical composition results revealed high silica and alumina content in most studied clay samples. Their fluxing oxides which include K2O, Na2O, CaO, and MgO, varied slightly from 0.06% to 1.78% in abundance while the Fe2O3 and TiO2 contents in most samples averages at 9.2% and 1.3% respectively. The plasticity index of the studied deposits ranged from 9.50 to 62.00% while liquid limit ranged from 31.34 to 73.62%. The microanalysis using SEM indicated that the microstructure framework of most studied clay exhibited a porous skeleton structure owing to numerous tiny voids. The composite results of SEM and CEC analyses suggested their possible application in water filter and chemical fertilizer industries since they provided passage for water and soil cations transmission. The particle size distribution demonstrated that the studied soils have clayey silt texture with wide range coverage of the well graded and sorted particle sizes. Compressibility and plasticity properties were found to be high in Mukondeni, Mashamba-1, Mashamba-2 and Mashamba-3 clay samples. The thermal behavior of Mukondeni, Mashamba-1, Mashamba-2 and Mashamba-3 samples showed relatively high shrinkage (>9%). The high shrinkage percentage suggests the preponderance of smectite minerals. Other samples which are rich in kaolinite and chlorite minerals exhibited low shrinkage (<2%). The drying trends of the studied clay suggest their suitability for fast drying processes like soft and hard refractoriness, sanitary wares and ceramics. Empirical assessment of most studied clay showed their suitability for pottery-making and manufacturing of roofing tiles and masonry bricks. / NRF

MSCAGR (Soil Science) / Department of Soil Science / The effects of tillage on soil structure and associated soil properties such as soil respiration may differ in different soils. The study determined the effects of tillage, soil texture and mineralogy in selected soil properties on different soil types. Soil samples were collected from four different sites in the Limpopo province, South Africa. The soils were classified as Glenrosa with sandy loam texture, Dundee with loamy sand, Hutton with clay, and Shortlands with clay. Glenrosa and Dundee were dominated by quartz, while Hutton and Shortlands with kaolinite. Soil samples were taken from the surface 0 – 20 cm under conventional tillage and no-till land. Soil organic matter, texture, and mineralogy were determined. The soils were wetted to activate the microorganisms and incubated for 70 days at 30℃ and soil respiration was determined using alkali trap method on a weekly basis. The study was conducted in triplicates and arranged in a completely randomized design. Data was subjected to analysis of variance using general linear model procedure of Minitab version 19. Means were compared using paired t-test at (p ≤ 0.05). The Pearson correlation coefficient (r) was used to measure the strength of linear dependence between variables. There was a significant difference in soil organic matter (p≤0.000) among all studied soils. The mean values of soil organic matter were 2.19% in Hutton, 2.0% in Shortlands, 0.54% in Glenrosa, and 0.43% in Dundee. Quartz had a strong negative linear relationship (r = -0.66) with soil organic matter while kaolinite had a strong positive linear relationship (r = 0.96). Soil respiration increased in soils dominated with quartz and decreased in soils dominated with kaolinite. The soil respiration increased by 18.95 g CO2 m-2 d-1 in conventional tillage and decreased by 13.88 g CO2 m-2 d-1 in no-tillage due to increased exposure of soil organic matter under conventional. It was concluded that less intensive tillage such as no-tillage reduces soil respiration. / NRF

Thesis (MSc(For))--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Recognizing the biological significance of gaps, the South African Department of Water Affairs and Forestry (DWAF) in 1989 initiated a Gap Dynamics Project in the indigenous forests of Tsitsikamma (Eastern Cape, South Africa). This consists of three sub-projects: Koomansbos (9300 m2), created by a ground fire in 1989; Plaatbos (1600 m2), made by a Podocarpus falcatus (Thunb.) R. Br. ex Mirb. (Podocarpaceae) windfall in 1994; and nine gaps of different sizes, artificially created by selective tree felling in 1995: three small (100-150 m2), three medium (300-500 m2) and three large (800-1000 m2). All the gaps were surveyed after creation and permanent plots were established for subsequent monitoring. The current timber harvesting system practiced in South African indigenous forests attempts to minimize gap size. It has been proposed by Euston-Brown et al. (1996) that this practice is likely to benefit the more shade tolerant species, but may inhibit the regeneration of less shade tolerant plants in the forest. Therefore, the present study aimed to verify two hypotheses: gaps may close in a process that is determined by their size, their origin and the plant species characteristics; soil quality might change inside those gaps. For the purpose of the study, the gaps cited above were re-surveyed between 2002 and 2003. It was found that: 1) there was little clear difference in the community structure of plant species between gaps of different sizes and origins; as expected from the species-area relationship, large gaps had higher species richness, plant diversity and herbaceous percentage cover than medium and small gaps; diversity indices were higher in the large windfall gap than in the large fire and artificial gaps; generally, context and stochastic events were largely more important in determining gap diversity and regeneration than gap sizes and origins; 2) diversity indices in the gaps were higher than recorded previously; 3) soil pH and Electrical Conductivity were respectively lower and higher inside the gaps than adjacent to them; these variations were statistically significant. Present data on the vegetation in the gaps were compared to past measurements, and future vegetation structure has been predicted, as a function of current gap vegetation. Recommendations have been made for sustainable management of the indigenous forest of Tsitsikamma. / AFRIKAANSE OPSOMMING: Voortspruitend uit die erkenning van die biologiese belang van gapings, het die Suid-Afrikaanse Departement van Waterwese en Bosbou (DWB) in 1989 'n projek oor gapingsdinamika in die inheemse woude van Tsitsikamma (Oos-Kaap, Suid-Afrika) geïnisieer. Dit bestaan uit drie subprojekte: die gaping in Koomansbos (9300 m2) wat in 1989 deur 'n grondvuur geskep is; die gaping in Plaatbos (1600 m2) wat veroorsaak is toe bome van die spesie Podocarpus falcatus (Thunb.) R. Br. ex Mirb. (Podocarpaceae) in 1994 omgewaai is; en nege gapings van verskillende groottes wat in 1995 kunsmatig deur geselekteerde boomkappery geskep is: drie is klein (100-150 m2), drie mediumgrootte (300-500 m2) en drie groot (800-1000 m2). Alle gapings is ná hulle ontstaan opgemeet en ondersoek en permanente terreine is vir daaropvolgende monitering gevestig. Die stelsel wat tans vir die oes van hout in Suid-Afrikaanse inheemse woude gebruik word, poog om die grootte van gapings te minimaliseer. Euston Brown et al. (1996) doen aan die hand dat hierdie praktyk spesies wat meer skaduweeverdraagsaam is waarskynlik sal bevoordeel, maar die regenerasie van plante in die woud wat minder skaduweeverdraagsaam is, kan inhibeer. Hierdie studie het dus ten doel gehad om twee hipoteses te verifieer: Gapings kan toegroei in 'n proses wat deur hul grootte, oorsprong en die eienskappe van die plantspesies bepaal word; en die gehalte van die grond binne daardie gapings kan verander. Die gapings waarna hierbo verwys is, is vir die doel van hierdie studie tussen 2002 en 2003 weer gemonitor. Daar is bevind dat: 1) daar min duidelike verskille was tussen die gemeenskapstruktuur van plantspesies tussen gapings van verskillende groottes en oorsprong; soos van die verhouding tussen spesies en area verwag kan word, het groter gapings 'n hoër spesierykheid, plantdiversiteit en persentasie niehoutagtige dekking as medium- en klein gapings gehad; diversiteitsindekse was hoër in die groot Plaatbosgaping as in die groot Koomansbosgaping of die kunsmatige gapings; in die algemeen was konteks en stochastiese gebeure grootliks belangriker in die bepaling van gapingsdiversiteit en -regenerasie as gapingsgrootte of -oorsprong; 2) diversiteitsindekse in die gapings was hoër as wat voorheen aangeteken is; en 3) grond-pH en elektriese geleidingsvermoë was onderskeidelik laer en hoër binne die gapings as neffens hulle; hierdie variasies was statisties beduidend. Huidige data oor die plantegroei in die gapings is met vorige metings vergelyk, en 'n toekomstige plantegroeistruktuur is as 'n funksie van huidige gapingsplantegroei voorspel. Aanbevelings is gemaak rakende die volhoubare bestuur van Tsitsikamma se inheemse woud.

Degree of Master of Forestry (Conservation Ecology) / Thesis (MSc)--Stellenbosch University, 2003. / Full text to be digitised and attached to bibliographic record. / ENGLISH ABSTRACT: This study investigates the use of top-soiling, irrigation and translocating indigenous plants to facilitate the cost-effective return of a mined landscape to its former land-use (small stock farming) in an arid winter rainfall Succulent Karoo shrub land biome on the West Coast of South Africa. Effects of topsoil stockpiling and subsoil mineral concentration on soil fertility and chemistry were investigated, as soils are likely to determine rates of vegetation recovery on post-mined areas. Results of a radish bioassay show that stockpiling topsoil and mineral concentration subsoil decreased soil fertility. Mineral concentration decreased phosphorus, potassium, calcium, magnesium, carbon and nitrogen levels significantly relative to other soil treatments. Sodium in freshly deposited tailings was at potentially toxic levels and significantly higher than for all other soil treatments. Spreading of stockpiled topsoil over tailings may ameliorate harsh conditions created by mineral separation. Translocation of plants from pre-mined to post-mined areas was carried out on a trial basis in an effort to facilitate the return of natural vegetation and processes to strip-mined landscapes. Five local indigenous plant species: Asparagus spp., Ruschia versicolor, Othonna cylindrica, Lampranthus suavissimus and Zygophyllum morgsana were planted into multi-species clumps in a replicated experiment. Variables examined in the translocation trial included the effects of plant origin, soil treatment and/or irrigation on plant survival and establishment. The proportion of O. cylindrica transplants surviving for 15 months was greater than for other species. Whole plants survived better than salvaged plants, and Asparagus spp., R. versicolor, L. suavissimus and Z. morgsana survived better on stockpiled topsoil spread over tailings than on tailings alone. Irrigation had no consistent effect across species and treatment replicates. Salvaged-plant clumps were significantly larger than whole-plant clumps at planting, however, this effect was not observed after 12 months, indicating that whole-plant clumps grew faster than salvaged-plant clumps. The evergreen, leaf succulent shrubs O. cylindrica, L. suavissimus and R. versicolor appeared to be most suitable for large-scale translocation at Namakwa Sands. The return of biodiversity and changes in soil quality 15 months after translocation trials began were compared for combinations of top-soiling, irrigation, plant translocation and unmodified tailings. Irrigation may reduce biodiversity and seedling densities. Over a 15-month period following back filling and topsoil spreading, sodium, potassium and calcium appeared to return to levels observed for undisturbed soils. Magnesium remains at levels lower than in pre-mined soil conditions. Soil conditions may be more conducive to plant establishment and rehabilitation after back-filling of tailings and topsoil spreading. Electrical resistance increased over time indicating a reduction of free salts and salinity on rehabilitation sites. Phosphorus did not return to pre-disturbance levels, and carbon remained below pre-mining levels for at least 15 months after rehabilitation began, remaining a potential limiting factor in rehabilitation. Each rehabilitation technique that a mine employs has costs and benefits, and it is increasingly important that insights from ecology and economics are coupled if restoration efforts are going to succeed. A review of valuation systems indicates that Discounted Cash Flow Techniques (DCF) are suitable for valuation of rehabilitation operations. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die gebruik van bogrond, besproeiing en die oorplanting van inheemse plante om die koste-effektiewe rehabilitasie van 'n stroopmynlandskap in die droë, winter reënval streek, Vetplant Karoo aan die Weskus van Suid-Afrika, wat vroeër gebruik is vir kleinvee boerdery, te bespoedig Die uitwerking van bogrondopberging en minerale konsentrasie op vrugbaarheid en chemise komposisie van grond is ondersoek, aangesien dié gronde gewoonlik die herstelspoed van plantegroei op 'n ou myn terein bepaal. Uitslae van radys proewe toon dat berging van bogrond en minerale konsentrasie van die onderliggende grond vrugbaarheid van grond laat afneem. Mynaktiwiteite en die minerale konsentrasie lei tot 'n betekenisvolle verlies aan fosfaat, kalium, kalsium, magnesium, koolstof en stikstof as die geval met ander bedrywighede. Die vlak van natrium in oorgeblywende sand na die minerale ekstraksie is hoogs giftig en is veel hoër as na ander bedrywighede. Die toediening van bogrond oor die oorblywende sand verbeter die toestand wat deur die skeiding van minerale veroorsaak is. Oorplasing van plante vanaf ongemynde na rehabilitasie gebiede is op proefbasis uitgevoer in 'n poging om die terugkeer van natuurlike plantegroei by die strookmyn te bespoedig. Vyf plaaslike inheemse plantspesies: Asparagus spp., Ruschia versicolor, Othonna cylindrical, Lampranthus suavissimus en Zygophyllum morgsana is in multi-spesie groepe geplant. Veranderlikes getoets tydens hierdie proef sluit in plantoorsprong, grond behandeling, en/of besproeiing, op die oorlewing en vestiging van plante. 'n Groter proporsie O. cylindrical as enige ander spesie het na 15 maande oorleef. Heel plante het beter oorleef as beskadigde plante. Asparagus spp., R. versicolor, L. suavissimus en Z. morgsana het beter oorleef op gebergde bogrond oor oorblywende sand as op oorblywende sand self. Besproeiing het nie 'n volgehoue uitwerking gehad op spesies of op herhaalde replisering nie. Beskadigde plantgroepe was groter as heelplant groepe toe hulle geplant is maar na 12 maande is opgemerk dat die heel-plante vinniger gegroei het. Die immergroen vetplante, 0. cylindrical, L. suavissimus en R. versicolor blyk die mees geskik vir grootskaalse oorplanting by Namakwa Sands. Herstel van biodiversiteit en veranderings in grondeienskappe 15 maande na proewe begin het, is vergelyk m.b.t. die toediening van bogrond, besproeiing, oorplanting en onbehandelde oorblywende sand. Besproeiing kan biodiversiteit en digtheid van saailinge verminder. Vyvtien maande na opvulling en die toediening van bogrond, het kalium, natrium en kalsium teruggekeer na vlakke in onversteurde grond. Magnesium vlakke was nog altyd laer as dié voordat mynaktiwiteite aangevang is. Terugplasing van sand en toediening van bogrond mag die vestiging en rehabilitasie van plante bespoedig. Weerstand vermeerder met tyd wat 'n verlaaging in vry soute en soutagtigheid in die grond wat gebruik is vir rehabilitasie aantoon. Fosfor het nie teruggekeer tot vlakke van voorheen nie en vlakke van koolstofhet na 15 maande verlaag gebly, en kan die potential tot rehabilitasie belemmer. Elke rehabilitasie tegniek wat die myn gebruik bring kostes sowel as voordele mee. Om restorasie pogings te laat slaag moet insigte vanaf ekologie en ekonomie saam ingespan word. 'n Oorsig van waardasie sisteme toon dat Afslag Kontant Vloei Tegnieke geskik is vir die evaluasie van rehabilitasie programme.

Thesis (MScFor)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: A field trial of six replications was established to test the effect of various wood ash and fertilisers application rates on soil chemistry, tree nutrition and early growth rate of a clonal Eucalyptus grandis x urophylla stand. Wood ash from pulpmills is currently disposed of in landfills. Increasing costs and potential environmental risks have driven companies to investigate alternative disposal methods. Ash consists of a combination of carbonates, hydroxides and other calcium containing minerals that induce the liming effect if ash is applied to a soil. The trial was established near Richards Bay in October 2013 on a sandy soil with a low buffer capacity and a pH of approximately 5.5. The trial consists of four wood ash application rates in combination with three levels of fertiliser, viz. no fertiliser, 150 g conventional NPK fertiliser mixture, or 320g NPK controlled release mixture. Fertiliser mixtures and application levels were based on previous fertiliser trials in the region. Ash application rates for the field trial were based on a lab incubation study done with soil samples from Richards Bay, to which increasing amounts of lime were added. The study tested wood ash application rates of 0, 300, 600 and 1200 kg/ha. Field measurements were taken at 4 and 8 months after trial establishment. The primary objective was to investigate which application levels in combination with the type of fertiliser could be applied to soils without negatively affecting the stand nutrition or increase the levels of potentially harmful elements in the soil; thus investigating the feasibility of safely disposing wood ash on plantation soils as an alternative disposal method. Soil nutrient concentrations were not affected by individual wood ash treatments, but more a product of the time interval after the ash additions were made. Soil C, P, K+ and Mg2+ showed decreased concentrations from 4-8 months after establishment. Ca2+ concentrations increased in the same time interval. In addition, Na+ and B concentrations decreased from 4-8 months. Soil heavy metal concentrations for Cd, Hg, Cr and Pb, analysed for 0-1200 kg/ha ash rates, were well below toxic levels at both time intervals. Wood ash induced a temporary liming effect. Mean soil pH increased with 0.6 units for the period 0 - 4 months and decreased with 0.4 units at 4 - 8 months after trial establishment. Foliar nutrient analyses and assessment techniques revealed sub-optimal nutrient concentrations for P, K and Zn at 4 and 8 months of age. Concentrations were defined as sub-optimal, as none of the nutrients were below critical levels. Foliar heavy metal concentrations for Cd, Hg, Cr and Pb, measured at both time intervals, were less than 1mg/kg. The small concentrations found in this project were attributed to the low bioavailability of all four elements and were likely a product of the edaphic factors at Richards Bay, which was representative of a large greater portion of the Zululand coastal plain sites. The response in biomass index ranged between 13 % and 683 % relative to the control treatment (A0F0). Results showed that application of purely wood ash, or in combination with a supplementary N and P source increased growth up to 8 months after trial establishment for wood ash applications up to 1200 kg/ha. This project demonstrated that 1200 kg/ha wood ash can safely be disposed of on a typical Zululand coastal sand with little environmental risk and no supressed growth, provided that it is balanced with an appropriate NP fertiliser. / AFRIKAANSE OPSOMMING: ‘n Veldproef met ses herhalings is in Oktober 2013 uitgelê met die doel om die uitwerking van verskillende vlakke hout as en kunsmis toedienings op die grond-voedingstof status, boom-voedingstof status en die groei-tempo van ‘n Eucalyptus grandis x urophylla hibried plantasie te bestudeer. Hout as by pulpmeulens word tans weggegooi op stortingsterreine. Toenemende onkostes vir storting en die omgewingsrisiko’s gebonde aan stortingsterreine, dryf maatskappye om verbeterde en meer omgewingsvriendelike metodes te ondersoek om van die as ontslae te raak. Hout as bestaan uit ‘n reeks karbonate, hidroksiede en kalsium bevattende minerale en is verantwoordelik vir die bekalkingseffek op die grond na toediening. Die veldproef is geleë naby Richardsbaai op ‘n sanderige grond met n lae bufferkapasiteit en pH van ongeveer 5.5. Die proef het vier hout as vlakke getoets, gekombineer met drie vlakke van bemesting: geen, 150g konvensionele landbou kunsmis (CV) óf 320g beheerd-vrystellende kunmis (CRF). Die kunsmismengsels en vlakke van bemesting is gebaseer op bestaande of voltooide bemestingseksperimente in die streek. Hout as vlakke was bereken in gekontroleerde laboratorium toestande en gebaseer op ‘n inkubasie studie met grond monsters verkry vanaf Richardsbaai, waarby toenemende vlakke suiwer landboukalk gevoeg is. Die veldproef het hout as vlakke van 0, 300, 600 en 1200 kg/ha getoets. Veld metings is op 4 en 8 maande na behandeling geneem. Die primêre doelwit van die studie was om te bepaal watter vlak hout as en kunmis kombinasie toegedien kan word, sonder om die grond-voedingstof status negatief te beïnvloed of ‘n potensiële skadelike uitwerking op die plantasie groei te veroorsaak. Die uiteinde van die studie was om die haalbaarheid van hout as toedienings op plantasie gronde te bestudeer relatief tot die huidige praktyk van storting, insluitend die risiko van moontlike skadelike newe-effekte. Grondvoedingstatus was nie beduidend beïnvloed deur individuele hout as toevoegings nie, maar was eerder ‘n funksie van die tydsduur sedert behandeling. Grond koolstof, P anione, K+ en Mg2+ konsentrasies het beduidend afgeneem in die periode van 4 - 8 maande na behandling. Die Ca2+ konsentrasies het toegeneem tussen 4 en 8 maande en terselfdertyd het Na+ en B konsentrasies afgeneem. Die swaarmetaal status, spesifiek vir Cd, Hg, Cr en Pb, vir toevoegings van 0-1200 kg/ha hout as was beduidend laer as toelaatbare vlakke in gronde op albei tydsintervalle. Die hout as het ‘n tydelike toename in grond pH veroorsaak. Die gemiddelde pH het tussen 0 - 4 maande toegeneem met 0.6 eenhede en gedurende 4 - 8 maande afgeem met 0.4 eenhede. Blaarontledings en voedingstof assesseringsmetodes het sub-optimale konsentrasies vir P, K en Zn getoon op die ouderdom van 4 en 8 maande. Voedingstof konsentrasies is as sub-optimaal geklassifiseer, omdat konsentrasies nooit laer as kritieke waardes vir gebreksimptome was nie. Die inhoud van Cd, Hg, Cr en Pb in blare was aansienlik kleiner as 1 mg/kg op albei tydsintervalle. Die merkwaardige lae konsentrasies wat in die projek aangeteken is, word toegekryf aan die lae bio-beskikbaarheid van al vier elemente as gevolg van die edafiese faktore eie aan die Richardsbaai omgewing (en ook aan groot dele van die Zoeloelandse kusvlakte). Die groeireaksie (bepaal as biomassa indeks op ouderdom 8 maande) het gewissel van 13 % - 683 % groter as die kontrole behandeling (A0F0). Resultate het bewys dat toedienings van suiwer hout as, of hout as gekombineer met ‘n addisionele N en P kunsmisbron die groei postief beïnvloed tot op die ouderdom van 8 maande. Die studie het bewys dat 1200 kg/ha hout as veilig toegedien kan word op die sandgronde van die kusgebiede in Zululand, met minimale omgewingsrisiko en geen tekens onderdrukte groei nie, mits dit gebalanseer word met ‘n geskikte NP kunsmisbron.

MENVSC / Department of Environmental Sciences

Department of Ecology and Resource Management / MENVSC