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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Phosphorous dynamics in soils under contrasting long-term agricultural management practices in the KwaZulu-Natal midlands.

Majaule, Ugele. January 2006 (has links)
Little is known regarding the effects of land use on soil organic matter and P status of South African soils. For that reason, the effects of the main agricultural land uses in the midlands region of KwaZulu-Natal [maize (Zea mays), sugarcane (Saccharum spp), annual ryegrass pasture (Lolium multiflorum), permanent kikuyu pasture (Pennisetum clandestnum), gum (Eucalyptus grandis) and pine (Pinus patula)] on soil organic matter content, microbial biomass C and P and inorganic and organic P pools derived from a modified Hedley P fractionation was investigated on two sites where the longterm history of land management was known. In comparison with undisturbed native grassland, permanent kikuyu pasture resulted in an increase in organic C, organic P and microbial biomass C and P. Maize and sugarcane production resulted in a decrease in organic C, organic P and microbial C and P. Under annual pasture, gum and pine forests, organic matter and microbial biomass concentrations remained similar to those under native grassland. Under native grassland, extractable organic P accounted for 50% or more of the total P content of soils but under agricultural management with regular applications of fertilizer P, there was an increase in the percentage of total P present as inorganic P. Agricultural management greatly affected the distribution of P among the various inorganic and organic P fractions. Resin-Pi and NaHC03-Pi (the potentially-available forms of Pi) showed similar trends with land use being greatly elevated under kikuyu pasture at both sites and sugarcane and maize at one site. This accumulated Pi was thought to have originated from recent fertilizer applications and possibly recently mineralized organic P. Trends for NaOH-Pi with land use differed greatly from those of the Resin- and NaHC03Pi fractions. Concentrations were notably high under maize and sugarcane production. Of the pools of soil organic P, the NaHC03-Po fraction was most greatly affected by land use, being elevated under kikuyu and decreased under maize and sugarcane. This supports the assertion that it is the NaHC03-Po fraction that is the most labile soil organic P pool. It was concluded that land use greatly affects soil organic C and P status, soil microbial biomass C and P contents, soil inorganic P concentrations and the distribution of P among the various P fractions. A short-term (8 weeks) laboratory incubation experiment was carried out to compare the effects of inorganic (KH2P04) and organic (cattle manure, poultry manure and maize crop residues) sources of P, applied at a rate equivalent to 30 kg P ha-1 , on soil inorganic and organic P fractions and the potential availability of soil P. Additional treatments consisted of lime [Ca(OHhl at 5 ton ha-1 and lime plus inorganic P. Applications of lime raised soil pH to a similar extent after 1, 4 and 8 weeks incubation. After 8 weeks, a small increase in soil pH was also noted for the cattle and poultry manure and maize residue treatments. For the inorganic P fractions, substantial treatment effects were observed only for the Resin-Pi fraction. The inorganic P source was more effective than the organic ones at increasing Resin-Pi after 1 and 4 weeks incubation and of the organic sources, cattle and poultry manure were more effective than maize residues. Resin-Pi concentrations generally increased between 1 and 4 weeks incubation but then declined rapidly between 4 and 8 weeks incubation. After 8 weeks incubation, treatment effects on Resin-Pi were small. Concentrations of NaHC03-Pi, dilute HCI-Pi and concentrated HCI-Pi all declined over the incubation period. There was no clear trend with incubation for NaOH-Pi although for the poultry manure and maize treatments, concentrations declined between 4 and 8 weeks incubation. In general, concentrations of NaHC03-Po were greater for organic than inorganic P sources after 8 weeks incubation suggesting microbial immobilization of P in these treatments. There were increases in NaHC03-Po and concentrated HCI-Po over the incubation period suggesting progressive immobilization of P from the Pi fractions that declined in concentration during the incubation. Concentrations of NaOH-Po were not greatly affected by incubation period. The lime treatments, however, had lower NaOH-Po concentrations than the others suggesting that liming may have stimulated microbial mineralization of Po. Residual-P concentrations increased over the incubation period. This was attributed to conversion of extractable Pi fractions into recalcitrant, non-extractable Pi forms and/or immobilization of Pinto intransigent organic forms. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
112

The effect of trees and grass on soil aggregate stability in Potshini catchment, KwaZulu-Natal, South Africa.

Mthimkhulu, Sandile Siphesihle. January 2011 (has links)
Long-term environmental quality is closely linked to maintaining soil quality. Therefore, assessment of the effect of land use on soil chemical, physical and biological properties provides fundamental information about soil sustainability. The role of vegetation on soil structural and aggregate stability has received much attention over the last few decades. The loss of soil due to erosion and reduction in organic matter due to change in vegetation is usually caused by invasion of grassland by trees. The response of soils to land use depends on the inherent soil properties and environmental conditions thus the effect of land use on soil stability is site specific. The objectives of this study were to assess and compare soil aggregate stability under trees and in open grassland from open-savannah woodland and nearby deeply eroded dongas (gullies). Within the dongas, tree encroachment was expected to improve soil structural stability by increasing the organic matter content. Results that were obtained from this study are aimed at improving management of soil for smallholder and pastoral farming systems. The study site was located at Potshini, KwaZulu-Natal Province, South Africa, about 18 km south-east of Bergville. The vegetation of the area is classified as grassland biome. Acacia sieberiana var. Woodii has encroached into the valley especially onto the eroded areas. Within the study area itself the dominant parent materials are sandstone and dolerite, with colluvium covering the lower slopes. The dominant soil was classified as Hutton form. Effects of different vegetation types (grass and trees) on the soil structural stability was evaluated for their effects on soil organic carbon (SOC), mean weight diameter, bulk density, root density, clay mineralogy and some other chemical properties. For this study the site was divided into two areas i.e., the donga (D) and the grassland (G). These were then each subdivided into two parts namely, donga under a tree (DUT) with a corresponding open area (DOA), and grassland under a tree (GUT) with its corresponding open area (GOA). Three bulk samples were collected from each sampling area from 0 to 20 cm (topsoil only) using a spade. Samples for bulk density were collected from 0 - 10 cm. For soil aggregate stability determinations, samples were dried and sieved to collect soil aggregates between 2.8 and 5 mm. Some of the bulk sample was analysed for SOC, pH, exchangeable bases, nitrogen and clay mineralogy. For root biomass, soil samples were collected from 0 - 10 cm using a stainless steel cylinder of 1766 cm3 volume. The type of vegetation affected the soil physical and chemical properties of the soil in the investigated horizon (A horizon). Although the results were not significantly (p > 0.05) different, the open area showed a positive effect on soil structural stability where higher soil aggregate stability and root density were observed, as opposed to under trees in both donga and grassland. Due to the non-significant differences observed in both donga and grassland, the effect of trees and grass on the aggregate stability was considered as the positive effect. The bulk density showed an unusual trend. Bulk density was higher in the open areas where high aggregate stability was observed. From these results it was concluded that because trees have larger roots than grass these are more effective in loosening the soil particles but less effective in stabilizing the soil aggregates. In other words, the high amount of fine roots increased the soil stability while large roots improved the loosening of the soil particles. The amount of vegetation considerably affected all the physical and chemical soil properties investigated. The SOC and root density was considerably higher under grassland compared to the donga. The clay mineralogy differed between the donga and grassland. The donga soils had a higher kaolinite content and amount of interstratified smectite/mica compared to grassland. The presence of interstratified smectite/mica in the donga could cause lower aggregate stability due to shrinking-swelling cycles during wetting-drying conditions. The effects of mineralogy have been overridden by organic carbon in the grassland. From this study it was revealed that soil aggregate stability is the product of interactions between soil clay minerals, and organic fractions which are influenced by soil environment, land use and soil properties. This means that all the factors involved in aggregate formation and their stabilization are interdependent. It is suggested that factors that were driving the soil aggregate stability in the donga were different to the ones in grassland. It is suggested that the aggregate stability was driven by inorganic factors i.e., clay, clay mineralogy, bases and CEC in the donga while organic carbon and plants roots were dominating in the grassland / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
113

An assessment of synthetic landfill leachate attenuation in soil and the spatial and temporal implications of the leachate on bacterial community diversity.

Govender, Kamenthren. January 2008 (has links)
The temporal fate of selected parameters, including redox potential; pH; phenol; nitrates; sulphates; copper and zinc, of a young synthetic acetogenic phase landfill leachate was assessed by perfusing a series of sequential soil (Hutton) microcosms (arrays) at two hydraulic loading rates (HLR). We chose HLRs that were representative of areas in South Africa with typically elevated rainfall (Pietermaritzburg – HLRh) and one with relatively low rainfall (Kimberley – HLRl). Preliminary phenol, copper, and zinc adsorption investigations on gamma radiation sterilized soil and unsterilized soil revealed superior adsorption rates for each compound in the unsterilized soil. This revealed the importance of the biological component of soil in phenol, copper, and zinc attenuation in soil. The results presented in this thesis suggest that the HLR of leachate into soil arrays contributes to significant differences in the fate of the landfill leachate parameters mentioned earlier. In addition, we assessed the temporal and spatial succession of bacterial community diversity in each of the soil arrays by polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE). Prior to this, we compared two soil DNA isolation techniques, the modified method of Duarte et al. (1998) (Bead Beat) and the commercial Mo-Bio UltraClean™ Soil DNA isolation kit (Kit). The DNA isolated by the Kit method was significantly superior regarding purity and absence of DNA fragmentation. However, the Bead Beat method produced a significantly higher yield per reaction before further purification with Wizard™ Clean-Up columns produced DNA extracts of similar purity at the cost of a significant reduction in DNA yield. The Kit method was chosen for future DNA isolation and PCR-DGGE based on the quality of the PCR amplicons generated from the Kit isolated DNA. PCR-DGGE was further optimized by comparing the efficiency and sensitivity of a silver stain against ethidium bromide. Silver stain generated DGGE gels with greater number of bands (species richness – S) and stronger band signal intensities. Captured DGGE fingerprints generated data that were subjected to the Shannon-Weaver Index (H’) and the associated Shannon-Weaver Evenness Index (EH) to measure the change in spatial and temporal bacterial diversity. There was a significant shift in S and H’ for both HLRs but a significant change in EH was only observed for HLRh. Furthermore, a temporal comparison of S and H’ between both HLRs revealed significant differences throughout the investigation. Canonical Correspondence Analysis (CCA) revealed spatial distribution of bacterial community diversity with depth. Effects of phenol concentration, redox potential, and pH of the effluent leachate on bacterial community diversity was tentatively assessed by three-dimensional graphical representation on PlotIT 3.2 software. Bacterial community diversity showed a decrease with elevated pH and phenol concentration along with decreasing redox potentials for both HLRs. While this study reveals the spatial and temporal dynamics of bacterial community diversity in situ, it provides important evidence with respect to: (i) the effects of rainfall / leaching rates (HLR) on spatial and temporal bacterial community succession; (ii) the importance of the biological component in natural attenuation; (iii) the ability of soil, previously unexposed to landfill leachate, to initiate natural attenuation of phenol and other leachate constituents; (iv) the capacity of PCRDGGE to fingerprint successional changes in bacterial community diversity, (v) and the potential to clone and sequence selected members of bacterial associations for future reference in environmental remediation strategies. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
114

Desenvolvimento urbano no município de Chapecó, Santa Catarina: uma abordagem sobre critérios geomorfológicos / Urban development in the municipality of Chapecó, Santa Catarina: an approach on geological and geomorphological criteria

Zenaro, Fábio Alex 10 November 2017 (has links)
O ambiente natural sofre alterações climáticas, ambientais e humanas ao longo dos anos. Na sociedade moderna, a implantação dos espaços urbanos nem sempre levam em conta os elementos naturais da paisagem no momento de intervenção para a edificação das cidades, gerando muitas vezes, consequências desastrosas para o ambiente e as pessoas que nela vivem. Este trabalho tem a finalidade de apresentar as áreas de suscetibilidade ao movimento de massa no perímetro urbano do município de Chapecó-SC, a partir de estudos do solo realizados com critérios geológicos e geomorfológicos. Os procedimentos metodológicos foram: coleta e ensaios de solos realizados em 10 pontos da área de estudo identificando as propriedades físicas e geológicas do mesmo, elaboração de tabelas com as precipitações anuais de chuva verificando o volume médio de chuva no município, teste de permeabilidade realizado com os anéis de infiltrômetro apresentando a velocidade básica de infiltração no solo, cálculos do ângulo de atrito e coesão do solo a partir de dados de 20 pontos de sondagem SPT e elaboração de mapas temáticos referente à altimetria, direção de encostas e declividade que forneceram informações importantes para a elaboração dos mapas de fator de segurança do solo natural e saturado, com e sem vegetação. Os resultados demonstram três tipos de solos presente no perímetro urbano do município de Chapecó-SC sendo, 71% de Latossolos com declividade máxima de 20 %, 23 % de Nitossolos com declividade de 20 à 45% e 6% de Cambissolos com declividade de 20 à 75%. Os testes de infiltração de solo mostraram que, a velocidade básica de infiltração variou de 64 mm/h a 466 mm/h e auxilia nos projetos de drenagem, uma vez que o município vem apresentando nos últimos anos irregularidades nas precipitações e um aumento do volume de chuva com média anual de 1900 mm. Os cálculos e elaboração de mapas apresentaram que, as áreas de maior suscetibilidade ao movimento de massa na área de estudo encontram-se em faixas estreitas de solo na região sudoeste conhecido como Contorno Viário e bairro Efapi, além de pequenos pontos em áreas da região leste e norte. A maioria dessas áreas situa-se em solo do tipo Cambissolo com elevada declividade. Estes solos quando saturados e sem vegetação apresentam-se como áreas instáveis e necessitam de maior atenção devido ao fator de segurança ser inferior a 1. Esses resultados subsidiam as ações de gestão e planejamento urbano identificando as possíveis áreas de riscos, uma vez que, a maioria delas ainda não foi ocupada e estão dentro do perímetro urbano do município. / The natural environment has undergone climate, environmental and human changes over the years. In modern society, the implantation of urban spaces does not always take into account the natural elements of the landscape at the moment of intervention for the construction of cities, often generating disastrous consequences for the environment and the people who live in it. This work has the purpose of presenting the areas of susceptibility to mass movement in the urban perimeter of the municipality of Chapecó-SC, based on soil studies conducted with geological and geomorphological criteria. The methodological procedures were: soil sampling and tests carried out at 10 points of the study area, identifying the physical and geological properties of the same, elaboration of tables with the annual rainfall, verifying the average rainfall volume in the municipality, the infiltrator rings presenting the basic velocity of infiltration in the soil, calculations of the angle of friction and soil cohesion from data of 20 points of SPT probing and elaboration of thematic maps referring to the altimetry, direction of slopes and slope that provided important information for the preparation of the maps of factor of safety of the natural and saturated soil, with and without vegetation. The results show three types of soils present in the urban perimeter of the municipality of Chapecó-SC, 71% of Latosols with a maximum slope of 20%, 23% of Nitosols with a slope of 20 to 45% and 6% of Cambisols with a slope of 20 to 75%. The soil infiltration tests showed that the basic infiltration velocity of all the evaluated points ranged from 64 mm ha to 466 mm and aids in drainage projects, since the municipality has presented in recent years irregularities in rainfall and an increase in rainfall with an annual average of 1900 mm. The calculations and mapping showed that the areas of greatest susceptibility to mass movement in the study area are in narrow bands of soil in the southwest known as Road Contour and district Efapi, as well as small points in areas of the eastern region and north. Most of these areas are located on Cambisol soil with high slope. These soils when saturated and without vegetation present as unstable areas and need more attention due to the safety factor being less than 1. These results subsidize the management and urban planning actions identifying the possible risk areas, since the most of them have not yet been occupied and are within the urban perimeter of the municipality.
115

Diagnóstico da fertilidade dos solos em áreas para produção de silagem de milho / Diagnosis of soil fertility under silage of corn

Rupp, Jorge Henrique 07 June 2016 (has links)
No estado do Paraná a atividade leiteira assume papel fundamental na manutenção e na viabilização econômica das propriedades, especialmente aquelas voltadas a agricultura familiar. Esta atividade tem na silagem de milho seu principal volumoso, nas épocas de carência alimentar, e para a maioria dos produtores é usada na alimentação do gado de leite o ano todo. O diagnóstico foi realizado na safra 2014/2015, em 14 áreas tradicionalmente utilizadas para produzir milho para silagem, coletando-se informações sobre o histórico de produção, além da observação sobre o espaçamento entre linhas das plantas de milho. Foram amostradas plantas inteiras de milho silagem para quantificação da produção de matéria verde (MV) e seca (MS) e teor e exportação de nutrientes. Também foram coletadas amostras de solo nas camadas de 0-10, 10-20 e 20-40 cm, coletando-se oito amostras simples de cada talhão estudado; nessas amostras foram determinados a matéria orgânica (MO), pH em CaCl2, alumínio trocável, fósforo, potássio, cálcio, magnésio, saturação por alumínio e saturação por bases. Os resultados obtidos mostraram que o espaçamento entrelinhas de milho de 0,45 m apresenta maior produtividade média de MV e MS atingindo 58% e 50% a mais quando comparado ao espaçamento de 0,80 ou 0,90 m, respectivamente. Os baixos teores de MO, P e K nas análises de solo, nas camadas entre 10 e 40 cm do solo, apresentam correlação positiva, com os baixos índices de NPK na MS apurados na análise química da silagem. A acidez das áreas é maior na camada superficial (0-10 cm) e reduziu com a profundidade. Todas as áreas avaliadas apresentam teores de fósforo acima do nível de suficiência na camada superficial, porém com valores muito baixos, especialmente abaixo de 20 cm. Para potássio, 64% das amostras têm teores acima do nível de suficiência na camada superficial, porém em apenas duas áreas os valores podem ser considerados muito altos. A exceção de uma área, todas as demais apresentaram valores de matéria orgânica variando de médio a baixo, em todas as profundidades, evidenciando um certo esgotamento dos solos sob cultivos sucessivos de silagem. / In the state of Paraná the milk production activity for the family farmer takes fundamental role in the maintenance and economic viability of the sector in Paraná Southwest. This activity has in the corn silage its main bulky, in times of food shortage, and for most producers is used in feeding of milk cattle all year.The diagnosis was made in the 2014/2015 crop, in 14 areas traditionally used to produce corn for silage.Whole plant corn silage was sampled to quantify the green matter production (MV) and dried (MS) and nutrient content. Also soil samples were collected in the layers soil of 0-10, 10-20 and 20-40 cm, by collecting 08 simple samples in each block it studied ; In this sample was determined the MO, pH CaCl2, SMP index, phosphorus, potassium, calcium, magnesium, aluminum saturation and calculated the sum of bases. The results show that the spacing corn lines of 0.45 m presents a higher average productivity M.V. and M.S. reaching 58% and 50% more than compared to the spacing of 0.80 or 0.90 m; Low rates of NPK soil test, in layers between 10 and 40 cm from the ground, are positively correlated, hows low NPK rates in MS calculates on the chimecal analysis of whole plant silage. The acidity of the areas is greater in the surface layer (0-10-cm) and reduced with depth. All areas have evaluated phosphorus above the fill level in the surface layer, but with very low values, especially bellow 20 cm. For potassium, 64% of samples have levels above the fill level in the surface layer, but only in two areas values can be considered very high. The exception of one area, all other present values of organic material ranging from medium to low, at all depths, showing a certain exhaustion of soil under successive silage crops.
116

Características químicas do solo e desempenho de culturas após quatro anos de aplicações de cama de aviário em diferentes épocas e níveis / Soil chemical characteristics, and crop performance after four years of poultry litter application at different times and levels

Tabolka, Cleiton Luiz 31 March 2016 (has links)
Em função de alta oferta a custo atrativo, a cama de aviário vem sendo utilizada na região sudoeste do Paraná para a melhoria da fertilidade do solo visando maior produção de grãos e pastagens. No entanto, o seu uso sem conhecimento técnico pode minimizar os benefícios da cama ou até provocar efeitos indesejáveis no solo, poluição ambiental e perdas de produtividade nas culturas utilizadas. O objetivo deste trabalho foi avaliar a influência de diferentes épocas de aplicação de cama de aviário, antecedendo a cultura de inverno, associada a níveis crescentes, sobre características químicas do solo, liberação de nutrientes e desempenho de culturas em quatro anos consecutivos (2011 a 2014). Nos três primeiros anos o delineamento experimental foi de blocos ao acaso com parcela subdividida e quatro repetições. Nas parcelas principais foram testadas quatro épocas de aplicação de cama de aviário antecedendo a cultura do trigo: 0, 15, 30 e 45 dias antes da semeadura (DAS); nas subparcelas aplicaram-se quatro níveis de cama de aviário (base úmida): 0, 4, 8 e 12 Mg ha-1. No último ano fez-se mais uma subdivisão das parcelas, avaliando-se o uso ou não de nitrogênio em cobertura no trigo, na dose de 100 kg de N ha-1. A cultivar de trigo usada nos quatro anos foi a BRS 220. Em três anos se avaliou o efeito residual sobre a cultura da soja (cultivar BMX Turbo RR) e em um ano sobre o feijão. Foram avaliados os atributos químicos do solo em quatro profundidades (0-2,5cm, 2,5-5cm, 5-10cm e 10-20cm), a taxa de decomposição e de liberação dos nutrientes da cama de aviário (usando litter bags e somente no último ano do estudo) e a produtividade das culturas. As diferentes épocas de aplicação da cama de aviário tiveram pouca influência sobre as variáveis estudadas, demonstrando que o produtor não necessita se deter a uma época (antes do plantio) para fazer a aplicação da cama de aviário. O potássio foi totalmente liberado 60 dias após a alocação dos litter bags a campo; para o nitrogênio e fósforo a liberação foi mais lenta. O uso de níveis crescentes de cama de aviário aumentou os teores de vários elementos do solo, com destaque para o potássio que atingiu os 20 cm de profundidade já no segundo ano de avaliação. O aumento de pH e saturação por bases se deu apenas nas camadas mais superficiais, enquanto o fósforo chegou aos 10 cm de profundidade no terceiro ano do estudo. O uso de doses crescentes de cama de aviário contribuiu na nutrição das plantas de trigo aumentando significativamente o peso de mil grãos e o rendimento de grãos de trigo em todos os anos avaliados; a adubação nitrogenada em cobertura também teve efeito significativo para o quarto ano avaliado. Também ocorreu resposta significativa do efeito residual da cama de aviário para as culturas implantadas no verão, tanto para a soja quanto para o feijão. / Due to the high supply and its attractive cost, the poultry litter has been used in the southwestern region of Parana to the improvement of soil fertility seeking greater production of grains and pastures. However, the use without technical knowledge can minimize the benefits of poultry litter or even cause undesirable effects on soil, environmental pollution and also productivity losses in the used crops. The objective of this study was to evaluate the influence of different times of poultry litter application, predating the winter crop, associated with increasing levels, about soil chemical properties, release of nutrients and crop performances in four consecutive years (2011-2014). In the first three years the experimental design was randomized blocks with a split plot system and four replications. In the main plots were tested four poultry litter application times preceding the wheat production: 0, 15, 30 and 45 days before sowing (DAS); in the subplots were applied four poultry litter levels (wet basis): 0, 4, 8 and 12 Mg ha-1. Last year one more subdivision of plots was done, evaluating the use or not of nitrogen in coverage in wheat, at a dose of 100 kg N ha-1. The wheat cultivar used in the four years was the BRS 220. In three years it was evaluated the residual effect on soybean production (cultivar - BMX Turbo RR) and in one year on the beans. The chemical soil attributes were evaluated at four depths 0-2,5cm, 2,5-5cm, 5-10cm and 10-20cm, and also the rate of decomposition and nutrient release of poultry litter and the crop productivity. The different times of application concerning the poultry litter had little influence on the studied variables, demonstrating that the producer does not need to have a specific date (before planting) to the application of poultry litter. Potassium was fully released 60 days after the allocation of litter bags into the field; for nitrogen and phosphorus the release was slower. The use of increasing levels of poultry litter increased the levels of various soil elements, highlighting the potassium which reached 20 cm deep in the second year of evaluation. The increase in pH and in the base saturation occurred only in the upper layers, while the phosphorus reached 10 cm deep in the third year of the study. It was observed increased pH and base saturation. The use of increasing doses of poultry litter contributed to the wheat plant nutrition, significantly increasing the weight of a thousand grains, and the grain yield of wheat in all the evaluated years; the nitrogen fertilization in coverage also had significant effect for the fourth evaluated year. Also there was a significant response from the residual effect of poultry litter for crops planted in summer for both soybeans and beans.
117

Diagnóstico da fertilidade dos solos em áreas para produção de silagem de milho / Diagnosis of soil fertility under silage of corn

Rupp, Jorge Henrique 07 June 2016 (has links)
No estado do Paraná a atividade leiteira assume papel fundamental na manutenção e na viabilização econômica das propriedades, especialmente aquelas voltadas a agricultura familiar. Esta atividade tem na silagem de milho seu principal volumoso, nas épocas de carência alimentar, e para a maioria dos produtores é usada na alimentação do gado de leite o ano todo. O diagnóstico foi realizado na safra 2014/2015, em 14 áreas tradicionalmente utilizadas para produzir milho para silagem, coletando-se informações sobre o histórico de produção, além da observação sobre o espaçamento entre linhas das plantas de milho. Foram amostradas plantas inteiras de milho silagem para quantificação da produção de matéria verde (MV) e seca (MS) e teor e exportação de nutrientes. Também foram coletadas amostras de solo nas camadas de 0-10, 10-20 e 20-40 cm, coletando-se oito amostras simples de cada talhão estudado; nessas amostras foram determinados a matéria orgânica (MO), pH em CaCl2, alumínio trocável, fósforo, potássio, cálcio, magnésio, saturação por alumínio e saturação por bases. Os resultados obtidos mostraram que o espaçamento entrelinhas de milho de 0,45 m apresenta maior produtividade média de MV e MS atingindo 58% e 50% a mais quando comparado ao espaçamento de 0,80 ou 0,90 m, respectivamente. Os baixos teores de MO, P e K nas análises de solo, nas camadas entre 10 e 40 cm do solo, apresentam correlação positiva, com os baixos índices de NPK na MS apurados na análise química da silagem. A acidez das áreas é maior na camada superficial (0-10 cm) e reduziu com a profundidade. Todas as áreas avaliadas apresentam teores de fósforo acima do nível de suficiência na camada superficial, porém com valores muito baixos, especialmente abaixo de 20 cm. Para potássio, 64% das amostras têm teores acima do nível de suficiência na camada superficial, porém em apenas duas áreas os valores podem ser considerados muito altos. A exceção de uma área, todas as demais apresentaram valores de matéria orgânica variando de médio a baixo, em todas as profundidades, evidenciando um certo esgotamento dos solos sob cultivos sucessivos de silagem. / In the state of Paraná the milk production activity for the family farmer takes fundamental role in the maintenance and economic viability of the sector in Paraná Southwest. This activity has in the corn silage its main bulky, in times of food shortage, and for most producers is used in feeding of milk cattle all year.The diagnosis was made in the 2014/2015 crop, in 14 areas traditionally used to produce corn for silage.Whole plant corn silage was sampled to quantify the green matter production (MV) and dried (MS) and nutrient content. Also soil samples were collected in the layers soil of 0-10, 10-20 and 20-40 cm, by collecting 08 simple samples in each block it studied ; In this sample was determined the MO, pH CaCl2, SMP index, phosphorus, potassium, calcium, magnesium, aluminum saturation and calculated the sum of bases. The results show that the spacing corn lines of 0.45 m presents a higher average productivity M.V. and M.S. reaching 58% and 50% more than compared to the spacing of 0.80 or 0.90 m; Low rates of NPK soil test, in layers between 10 and 40 cm from the ground, are positively correlated, hows low NPK rates in MS calculates on the chimecal analysis of whole plant silage. The acidity of the areas is greater in the surface layer (0-10-cm) and reduced with depth. All areas have evaluated phosphorus above the fill level in the surface layer, but with very low values, especially bellow 20 cm. For potassium, 64% of samples have levels above the fill level in the surface layer, but only in two areas values can be considered very high. The exception of one area, all other present values of organic material ranging from medium to low, at all depths, showing a certain exhaustion of soil under successive silage crops.
118

Evaluation and mapping of the spatial variability of soil fertility at Zanyokwe Irrigation Scheme in the Eastern Cape, South Africa

Manyevere, Alen January 2010 (has links)
No description available.
119

Analyses of the impacts of bacteriological seepage emanating from pig farming on the natural environment

Mofokeng, Dikonketso Shirley-may 03 1900 (has links)
Modern pig farming production may over burden the environment with organic substances, exposure of bacterial pathogens and introduction of resistance gene. This may be caused by the pig’s droppings, lack of seepage management or accidental spillage of seepage which may impact on the environment and its physicochemical parameters. The objective of this study is to determine and assess the level of bacteriological pollution emanating from the pig farm and their impact on the physicochemical parameters of soil and water as well as to identify the presence of antibiotic resistance gene of these prevailing bacteria. Soil and water samples were collected monthly for a period of six months (March- August 2013). Samples were collected at pig enclosures, soil 20 m and 100 m away from pig enclosures, constructed wetland used for treating pig farm wastewater, soil 20m and 100 m away from constructed wetland. Procedure followed for analysing soil and water samples includes physicochemical analyses, viable cell counts of 10-1 to 10-8 dilutions, identification of bacteria using API 20E test kit, antibiotic susceptibility analyses, and identification of resistance gene using molecular procedures. The media that were used for viable cell counts were, Nutrient agar, MacConkey Agar, Xylose Lysine Deoxycholate agar (XLD agar), and Eosin Methylene Blue (EMB). Physicochemical parameters of water showed unacceptable high levels of analysed parameters for BOD (163 mg/L to 3350 mg/L), TDS (0.77 g/L to 6.48 mg/L), COD (210 mg/L to 9400 mg/L), NO3 (55 mg/L to 1680 mg/L), NO2 (37.5 mg/L to 2730 mg/L), and PO43− (50 mg/L to 1427 mg/L) were higher than the maximum permissible limits set by Department of Water Affairs and Forestry (DWAF). For soil samples TDS (0.01g/L to 0.88 g/L), COD (40 mg/L to 304 mg/L), NO3 (32.5 mg/L to 475 mg/L), and NO2 (7.35 mg/L to 255 mg/L) and PO43- (32.5 mg/L to 475 mg/L ) were observed to be higher than recommended limits set by Federal Ministry for the Environmental (FME). The viable cells in soil samples 30cm depth ranged from 0 cfu/mL to 2.44 x 1010cfu/mL, in soil 5cm depth ranged from 1.00 x 101 cfu/mL to 1.91 x 1010 cfu/mL, and in water samples viable cells ranged from 5.00 x 101 to 5.05 x 109. Pseudomonas luteola (Ps. luteola), Escherichia vulneris (E. vulneris), Salmonella choleraesuis spp arizonae, Escherichia coli 1(E. coli 1), Enterobacter cloacae, Pseudomonas flourescens/putida (Ps. flourescens/putida), Enterobacter aerogenes, Serratia ordoriferal, Pasteurella pneumotropica, Ochrobactrum antropi, Proteus vulgaris group, Proteus vulgaris, Salmonella spp, Aeromonas Hydrophila/caviae/sobria1, Proteus Mirabillis, Vibrio fluvials, Rahnella aquatillis, Pseudomonas aeruginosa (Ps. aeruginosa), Burkholderia Cepacia, Stenotrophomonas maltophilia (St. maltophilia), Shwenella putrefaciens, Klebsiela pneumonia, Cedecea davisa, Serratia liquefaciens, Serratia plymuthica, Enterobacter sakaziki, Citrobacter braakii, Enterobacter amnigenus 2, Yersinia pestis, Serratia ficaria, Enterobacter gergoriae, Enterobacter amnigenus 1, Serratia marcescens, Raoutella terrigena, Hafnia alvei 1, Providencia rettgeri, and Pantoa were isolated from soil and water samples from the pig farm. Isolates were highly resistant to Penicillin G, Sulphamethaxazole, Vancomycin, Tilmocozin, Oxytetracycline, Spectinomycin, Lincomycin, and Trimethoprim. The most resistance genes detected in most isolates were aa (6’)-le-aph (2”)-la, aph (2”)-lb, aph (3”)-llla, Van A, Van B, Otr A and Otr B. Pig farm seepage is causing bacterial pollution which is impacting negatively on the natural environment in the vicinity of pig farm by introducing bacterial pathogens that have an antibiotic resistance gene and is increasing the physicochemical parameters for soil and water in the natural environment at the pig farm. It is therefore recommended that pig farms should consider the need to implement appropriate regulatory agencies that may include the regular monitoring of the qualities of final effluents from waste water treatment facilities. In addition there is a need to limit soil pollution in order to safe guard the natural environment in the vicinity of pig farm from bacteriological pollution and introduction of antibiotic resistance gene. It is also recommended that more advanced technologies should be introduced that will assist pig farms to manages the seepage properly. / Environmental Sciences / M. Sc. (Environmental Sciences)
120

Effects of acacias on the physical and chemical properties of granitic soils in Hong Kong.

January 1995 (has links)
by Fung, Chun-hong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 111-123). / Abstract --- p.i / Acknowledgments --- p.iii / List of Tables --- p.v / List of Figures --- p.vii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Reforestation in Hong Kong --- p.1 / Chapter 1.2 --- Conceptual framework of the study --- p.2 / Chapter 1.3 --- Objectives of the study --- p.5 / Chapter 1.4 --- Significance of the study --- p.6 / Chapter 1.5 --- Organization of the thesis --- p.6 / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Vegetation and soils --- p.8 / Chapter 2.2 --- Trees and soil physical properties --- p.9 / Chapter 2.2.1 --- Aggregate stability --- p.9 / Chapter 2.2.2 --- Organic matter and aggregate stability --- p.10 / Chapter 2.2.3 --- Other factors affecting aggregate stability --- p.12 / Chapter 2.2.4 --- Reforestation and bulk density --- p.12 / Chapter 2.2.5 --- Reforestation and soil moisture --- p.13 / Chapter 2.3 --- Trees and soil chemical properties --- p.14 / Chapter 2.3.1 --- Exchangeable acidity --- p.14 / Chapter 2.3.2 --- Exchangeable acidity and cation exchange capacity --- p.15 / Chapter 2.3.3 --- Organic matter and cation exchange capacity --- p.15 / Chapter 2.3.4 --- Clay and cation exchange capacity --- p.16 / Chapter 2.3.5 --- Organic matter and nitrogen --- p.17 / Chapter 2.3.6 --- Organic matter and phosphorus --- p.18 / Chapter 2.4 --- Litter decomposition --- p.18 / Chapter 2.4.1 --- Factor affecting litter decomposition --- p.19 / Chapter 2.4.2 --- Effects of litter on soil nutrient reserve --- p.21 / Chapter Chapter 3 --- The Study Area / Chapter 3.1 --- Location --- p.23 / Chapter 3.2 --- Geology --- p.23 / Chapter 3.3 --- Soils --- p.25 / Chapter 3.4 --- Vegetation --- p.27 / Chapter 3.4.1 --- Reforestation since the mid-1980s --- p.27 / Chapter 3.4.2 --- Growth performance of the acacias --- p.28 / Chapter 3.4.3 --- Undergrowth of the acacia woodlands --- p.29 / Chapter Chapter 4 --- Effects on Soil Physical Properties / Chapter 4.1 --- Introduction --- p.31 / Chapter 4.2 --- Methodology --- p.33 / Chapter 4.2.1 --- Soil texture --- p.33 / Chapter 4.2.2 --- Bulk density and porosity --- p.33 / Chapter 4.2.3 --- Penetration resistance --- p.34 / Chapter 4.2.4 --- Aggregate stability --- p.34 / Chapter 4.2.5 --- Water characteristic curve --- p.35 / Chapter 4.2.6 --- Infiltration rate --- p.35 / Chapter 4.3 --- Statistical analysis --- p.35 / Chapter 4.4 --- Results --- p.36 / Chapter 4.4.1 --- Soil texture --- p.36 / Chapter 4.4.2 --- "Bulk density, porosity and penetration resistance" --- p.36 / Chapter 4.4.3 --- Aggregate stability --- p.38 / Chapter 4.4.4 --- Infiltration --- p.39 / Chapter 4.4.5 --- Water characteristic curve --- p.40 / Chapter 4.5 --- Discussion --- p.42 / Chapter 4.5.1 --- Inherent physical properties of granitic soil --- p.42 / Chapter 4.5.2 --- Effects of acacias on the aeration of granite soil --- p.44 / Chapter 4.5.3 --- Effects of acacias on the penetration resistance and aggregate stability of granitic soil --- p.46 / Chapter 4.5.4 --- Effects of acacias on the water transmission property of granitic soil --- p.47 / Chapter 4.5.5 --- Effects of acacias on the water retention property of granitic soil --- p.50 / Chapter 4.6 --- Conclusion --- p.52 / Chapter Chapter 5 --- Effects on Soil Chemical Properties / Chapter 5.1 --- Introduction --- p.54 / Chapter 5.2 --- Methodology --- p.55 / Chapter 5.2.1 --- Sampling --- p.55 / Chapter 5.2.2 --- Soil reaction and conductivity --- p.55 / Chapter 5.2.3 --- Organic carbon --- p.55 / Chapter 5.2.4 --- Total Kjeldahl nitrogen --- p.56 / Chapter 5.2.5 --- Total phosphorus --- p.56 / Chapter 5.2.6 --- "Exchangeable K, Ca, Mg and Na" --- p.56 / Chapter 5.2.7 --- Exchangeable A1 and H --- p.57 / Chapter 5.2.8 --- Carbon : nitrogen ratio --- p.57 / Chapter 5.3 --- Statistical analysis --- p.57 / Chapter 5.4 --- Results --- p.58 / Chapter 5.4.1 --- Conductivity --- p.58 / Chapter 5.4.2 --- Soil pH and exchangeable acidity --- p.58 / Chapter 5.4.3 --- Soil organic matter --- p.61 / Chapter 5.4.4 --- Total Kjeldahl nitrogen --- p.62 / Chapter 5.4.5 --- Total phosphorus --- p.63 / Chapter 5.4.6 --- "Exchangeable K, Ca, Mg and Na" --- p.64 / Chapter 5.5 --- Discussion --- p.67 / Chapter 5.5.1 --- Inherent chemical properties of granitic soil --- p.67 / Chapter 5.5.2 --- Effects of acacias on the acidity of granitic soil --- p.69 / Chapter 5.5.3 --- "Effects of acacias on the organic matter, total nitrogen and phosphorus of granitic soil" --- p.71 / Chapter 5.5.4 --- Effects of acacias on the exchangeable cations of granitic soil --- p.74 / Chapter 5.6 --- Conclusion --- p.76 / Chapter Chapter 6 --- Litter Decomposition / Chapter 6.1 --- Introduction --- p.78 / Chapter 6.2 --- Methodology --- p.79 / Chapter 6.2.1 --- Standing litter --- p.79 / Chapter 6.2.2 --- Litter decomposition --- p.80 / Chapter 6.2.3 --- Chemical analysis --- p.80 / Chapter 6.3 --- Statistical analysis --- p.81 / Chapter 6.4 --- Results --- p.81 / Chapter 6.4.1 --- Standing litter --- p.81 / Chapter 6.4.2 --- Chemical composition of fresh litters --- p.82 / Chapter 6.4.3 --- Cumulative dry weight loss of litters --- p.82 / Chapter 6.4.4 --- Cumulative weight loss of nutrients --- p.84 / Chapter 6.4.5 --- C : element ratios --- p.88 / Chapter 6.5 --- Discussion --- p.88 / Chapter 6.5.1 --- Litter decomposition --- p.88 / Chapter 6.5.2 --- Litter decomposition and soil organic matter --- p.93 / Chapter 6.5.3 --- Nutrient release patterns --- p.94 / Chapter 6 5 --- 4 Litter decomposition and soil nutrient reserves --- p.96 / Chapter 6.6 --- Conclusion --- p.98 / Chapter Chapter 7 --- Conclusion / Chapter 7.1 --- Summary of findings --- p.100 / Chapter 7.2 --- Implication of the study --- p.103 / Chapter 7.3 --- Limitations of the study --- p.106 / Chapter 7.4 --- Suggestion for future study --- p.108 / References --- p.111 / Appendice --- p.124

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