No description available.

Leung Hoi-gok. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 188-205). / Abstracts in English and Chinese. / Abstract --- p.i / 槪論 --- p.iv / Acknowledgements --- p.vi / List of Tables --- p.vii / List of Figures --- p.viii / List of Plates --- p.ix / List of Appendices --- p.x / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- The Problems --- p.6 / Chapter 1.3 --- Conceptual Framework --- p.10 / Chapter 1.4 --- Significance of the Study --- p.15 / Chapter 1.5 --- Scope of Study --- p.17 / Chapter 1.6 --- Organization of the Thesis --- p.19 / Chapter CHAPTER 2 --- STUDY AREA / Chapter 2.1 --- Physical Setting of Hong Kong --- p.22 / Chapter 2.2 --- "Towngas Pipeline Project, the Land Section" --- p.25 / Chapter 2.3 --- Study Plots --- p.30 / Chapter 2.4 --- Observation on the Site --- p.39 / Chapter 2.5 --- Post-planting Care --- p.40 / Chapter CHAPTER 3 --- SOIL PROPERTIES AND IMPACTS BY PIPELINE CONSTRUCTION / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Methodology --- p.47 / Chapter 3.2.1 --- Sampling --- p.47 / Chapter 3.2.2 --- Bulk density --- p.48 / Chapter 3.2.3 --- Soil texture --- p.43 / Chapter 3.2.4 --- Soil reaction --- p.49 / Chapter 3.2.5 --- Organic carbon --- p.49 / Chapter 3.2.6 --- Total Kjedahl nitrogen (TKN) --- p.50 / Chapter 3.2.7 --- Available phosphate --- p.50 / Chapter 3.2.8 --- "Exchangeable K, Ca and Mg" --- p.50 / Chapter 3.3 --- Statistical Analysis --- p.51 / Chapter 3.4 --- Results --- p.51 / Chapter 3.4.1 --- Soil texture --- p.51 / Chapter 3.4.2 --- Bulk density --- p.53 / Chapter 3.4.3 --- Soil pH --- p.53 / Chapter 3.4.4 --- Soil organic matter --- p.55 / Chapter 3.4.5 --- Total Kjeldahl nitrogen --- p.55 / Chapter 3.4.6 --- Available phosphorus --- p.59 / Chapter 3.4.7 --- "Exchangeable potassium, calcium and magnesium ions" --- p.59 / Chapter 3.5 --- Discussion --- p.64 / Chapter 3.5.1 --- Nutrient content of shoulder and proper soils --- p.64 / Chapter 3.5.2 --- Causes for the change of soil properties --- p.72 / Chapter 3.5.2.1 --- Construction of the pipeline --- p.72 / Chapter 3.5.2.2 --- Influence of localized factors --- p.74 / Chapter 3.5.3 --- Recommendations on soil management --- p.75 / Chapter 3.6 --- Conclusion --- p.77 / Chapter CHAPTER 4 --- SPECIES SELECTION IN RESTORATION PLANTING / Chapter 4.1 --- Introduction --- p.79 / Chapter 4.2 --- Methodology --- p.83 / Chapter 4.2.1 --- Vegetation sampling --- p.83 / Chapter 4.3 --- Results --- p.85 / Chapter 4.3.1 --- Species composition of the undisturbed habitats --- p.85 / Chapter 4.3.2 --- Species composition of the restored vegetation --- p.88 / Chapter 4.4 --- Discussion --- p.95 / Chapter 4.4.1 --- Inadequate baseline and impact prediction in project EIA --- p.95 / Chapter 4.4.2 --- Restoration strategy --- p.98 / Chapter 4.4.3 --- Species selection in restoration planting --- p.101 / Chapter 4.4.4 --- Compatibility of species in restoration planting --- p.105 / Chapter 4.5 --- Conclusion --- p.110 / Chapter CHAPTER 5 --- GROWTH PERFORMANCE OF VEGETATION AND NATURAL INVASION IN THE SITES / Chapter 5.1 --- Introduction --- p.112 / Chapter 5.2 --- Methodology --- p.117 / Chapter 5.3 --- Results --- p.119 / Chapter 5.3.1 --- Growth performance of shrubs and trees --- p.119 / Chapter 5.3.2 --- Ground cover --- p.131 / Chapter 5.3.3 --- Species invading the pipeline corridor --- p.132 / Chapter 5.4 --- Discussion --- p.133 / Chapter 5.4.1 --- Growth performance of the restored saplings --- p.133 / Chapter 5.4.2 --- Site constraints --- p.135 / Chapter 5.4.3 --- Natural invasion on the pipeline corridor --- p.140 / Chapter 5.5 --- Conclusion --- p.141 / Chapter CHAPTER 6 --- RESTORATION TECHNIQUES AND MANAGEMENT / Chapter 6.1 --- Introduction --- p.144 / Chapter 6.2 --- Overview of the Project EIA --- p.146 / Chapter 6.2.1 --- Guidelines for site preparation --- p.146 / Chapter 6.2.2 --- Planting techniques of the restored vegetation --- p.148 / Chapter 6.2.3 --- Maintenance and aftercare --- p.149 / Chapter 6.3 --- Evaluation on Restoration Techniques and Aftercare --- p.149 / Chapter 6.3.1 --- Site preparation --- p.149 / Chapter 6.3.2 --- Restoration techniques of the vegetation --- p.151 / Chapter 6.4 --- Conclusion --- p.153 / Chapter CHAPTER 7 --- IMPROVEMENT ON ECOLOGICAL IMPACT ASSESSMENT / Chapter 7.1 --- Introduction --- p.154 / Chapter 7.2 --- Integrative Discussion --- p.156 / Chapter 7.2.1 --- Scoping and focusing procedures --- p.156 / Chapter 7.2.2 --- Impact assessment --- p.160 / Chapter 7.2.3 --- Impact mitigation --- p.161 / Chapter 7.2.4 --- Monitoring and auditing --- p.165 / Chapter 7.2.5 --- Guidelines of restoration in the technical memorandum of EIAO --- p.167 / Chapter 7.3 --- Conclusion --- p.169 / Chapter CHAPTER 8 --- CONCLUSION / Chapter 8.1 --- Summary of Findings --- p.171 / Chapter 8.2 --- Implications of the Study --- p.179 / Chapter 8.2.1 --- Criteria for the selection of species in restoration --- p.179 / Chapter 8.2.2 --- Silvicultural knowledge of native species --- p.180 / Chapter 8.2.3 --- Soil impact assessment for project involving soil alternation --- p.182 / Chapter 8.2.4 --- Improvement on environmental monitoring and auditing --- p.182 / Chapter 8.3 --- Limitation of the Study --- p.183 / Chapter 8.4 --- Suggestion for Further Studies --- p.185 / REFERENCES --- p.188 / APPENDICES --- p.206

Made available in DSpace on 2017-07-25T19:29:43Z (GMT). No. of bitstreams: 1 Ademir Oliveira Ferreira.pdf: 1294842 bytes, checksum: 8d7036f6aefa0cf3c549b0c63029e109 (MD5) Previous issue date: 2009-07-13 / Decrease in soil organic carbon (SOC) content of the surface layer into deeper layers indicates the occurrence of the stratification in the profile due to continuous C addition of crop residues enriching the soil surface layer. The objective of this study was: in Chapter 3 the relationship of stratification (RE) of C of the soil organic matter (SOM) pools can be an indicator of C sequestration in no-tillage soils? In the chapter 4 the tensile strength of aggregates is affected by the C content of Pedosequence of Latosol with medium and clay texture? in Chapter 5 which is the C balance and the amount of crop residue needed to maintain a stable C balance in a Latosol with a medium and clay texture? The experimental design was a completely randomized 2x2x2 factorial with 12 treatments. Treatments consisted of: a) an Oxisol (Red Latosol) with medium and clayey texture, b) two soil sampling periods (T1 and T2) with one year interval between them, and c) two soil sampling depths (0-5 and 5-20 cm). The soil attributes assessed were: the separation of water stable aggregates classes (19-8, 8-4, 4-2, 2-1, 1-0,5 and 05-0,25 mm), particulate organic carbon (POC), total particulate nitrogen (TPN) in the aggregate classes. Also was determined total organic carbon (TOC) and total nitrogen (NT) in the whole sample and in the aggregates sizes classes and tensile strength of aggregates. The relationship of stratification was calculated by dividing the TOC and TN values of 0-5 cm layer by the values of the same attributes of 5-20 cm layer. The C sequestration rate and the stratification ratio changes were calculated by the difference between the T2 values minus T1. The tensile strength was measured in soil aggregates and assessed in 1920 aggregates for each sampling time. Also TOC and NT content were measured in aggregates. The aggregates greater than 8 mm represented more than 70 of the total mass in both the clay and in sandy soil. The relationship of stratification ratio (0-5:5-20 cm) of SOC, TN, POC and TPN soil indicated the improvement of the surface layer. A significant linear relationship between the SR and C sequestration rate in both textural classes showed an increase in C sequestration and was more evident in LV with medium texture. The increase in TOC content resulted in decreased tensile strength (TS) of the aggregates and was more evident in the 0-5 cm layer. The TS showed inverse relationship with the soil density and was higher in the LV medium texture. The rate of sequestration of C was 0.86 for the LV with medium texture and 0.76 Mg ha-1 for the clay texture and to maintain the stable balance of C is required an input of 8.6 Mg ha-1 of crop residues. The results presented confirm the hypothesis of SR to be a sensitive indicator for the rate of carbon sequestration in no-tillage soil. Key-words: Carbon stock, Carbon balance, Carbon sequestration, Soil management systems, particulate organic carbon, particulate nitrogen. / A redução no conteúdo de carbono (C) da camada superficial em direção as camadas mais profundas do solo indica a formação da estratificação no perfil devido à adição contínua de C pelos resíduos orgânicos resultando no enriquecendo a camada superficial do solo. O objetivo deste trabalho foi avaliar os seguintes assuntos: a) a relação de estratificação (RE) de C dos compartimentos da matéria orgânica do solo (MOS) pode ser um indicador do seqüestro de C no sistema plantio direto. b) a resistência tênsil dos gregados pode ser afetada pelo conteúdo de C em Pedossequencia de Latossolo com textura média e argilosa. c) o balanço de C e a quantidade de resíduos culturais necessária para manter o equilíbrio estável de C em um Latossolo com textura média e argilosa. O delineamento experimental foi um fatorial 2x2x2 inteiramente casualizado com 12 tratamentos. Os tratamentos constituíram-se de: a) um Latossolo Vermelho com textura média e argilosa, duas épocas de amostragem do solo (E1 e E2) com um ano de intervalo entre si e duas profundidades de amostragem (0-5 e 5-20 cm). Os atributos avaliados foram: a separação das classes de agregados do tamisamento úmido (19-8, 8-4, 4-2, 2-1, 1-0,5 e 05-0,25 mm), o carbono orgânico particulado (COP), o nitrogênio total particulado (NTP) nas classes de agregado, o C orgânico total (COT) e o nitrogênio total (NT) na amostra integral e nas classes de agregados e a resistência tênsil dos agregados. A relação de estratificação (RE) foi calculada dividindo-se o valor de COT e NT da camada de 0-5 cm pelo valor na camada 5-20 cm. A taxa de seqüestro de C e a variação da relação de estratificação foram calculadas através da diferença (D) entre os valores da E2 menos o da E1. A resistência tênsil (RT) do solo foi avaliada em 1920 agregados de cada época de coleta, determinando-se, também o conteúdo de COT e NT. A classe de agregado > 8 mm representou mais de 70% da massa dos agregados tanto na textura argilosa como na arenosa. Da mesma forma, o conteúdo de COT e NT foram maiores na classe de agregado > do que 4 mm comparado as demais classes nas duas classes texturais. A relação de estratificação 5:5-20 cm) de COT, NT, COP e NTP do solo indicou a melhoria da qualidade do solo da camada superficial. A relação linear e significativa entre o DRE com a taxa de seqüestro de carbono nas duas classes texturais mostrou o aumento no seqüestro de C e foi mais evidente no LV com textura média. O incremento do conteúdo de COT resultou na diminuição da resistência tênsil (RT) dos agregados e foi mais evidente na camada de 0-5 cm. A RT apresentou relação inversa com a densidade do solo e foi superior no LV textura média. A taxa de seqüestro de C foi de 0,86 para o LV textura média e 0,76 Mg ha-1 para o textura argilosa e para manter o equilíbrio estável de C é necessário o aporte de 8,6 Mg ha-1 de resíduos culturais. Os resultados apresentados confirmaram a hipótese da RE ser um indicador sensível para a taxa de seqüestro de carbono no solo em um sistema sob plantio direto consolidado.

Orientador: Morel de Passos e Carvalho / Banca: Marcelo Andreotti / Banca: Célia Regina Lopes Zimback / Resumo: O arroz é uma das fontes básicas de alimentação da humanidade. No processo de modernização e racionalização da agricultura brasileira, o uso de adubação adequada constitui um fator importante para o aumento da produtividade das culturas, redução dos custos de produção, maior retorno econômico para os produtores e redução do risco de degradação do meio ambiente. Assim, durante o ano agrícola 2009/2010, no município de Selvíria (MS), no Cerrado Brasileiro, foram estudados os atributos do arroz de terras e os atributos químicos de um LATOSSOLO VERMELHO Distroférrico sob sistema plantio direto, irrigado por pivô central. O objetivo foi selecionar entre os atributos pesquisados, aquele com a melhor correlação, linear e espacial, para explicar a variabilidade da produtividade do arroz de terras altas. Foi instalada a malha geoestatística, para a coleta de dados do solo e da planta, com 120 pontos amostrais, numa área de 3,0 ha e declive homogêneo de 0,055 m m-1. Do ponto de vista linear, o número de espiguetas viáveis por panícula apresentou correlação potencial direta com a produtividade de grãos de arroz. Entretanto, do ponto de vista espacial, o teor da matéria orgânica do solo, quando avaliada na camada 0,10 - 0,20 m, apresentou-se como indicador da produtividade de grãos de arroz. Dessa forma, visando-se auxiliar futuros trabalhos voltados à agricultura de precisão, os quais venham a utilizar os mesmos atributos que os do presente, os valores dos alcances da dependência espacial a serem empregados deverão estar compreendidos entre 40,2 e 181,2 metros / Abstract: The rice is one of the basic sources of the humanity's feeding. In the modernization process and rationalization of the Brazilian agriculture, the use of appropriate fertilization constitutes an important factor for the increase of the yield crop, reduction of the production costs, larger economical return for the producers and reduction of the risk of degradation of the environment. Like this, during the agricultural year 2009/2010, in Selvíria County, Mato Grosso do Sul State, in the Brazilian Savannah, they were studied the attributes of the rice uplands and the chemical attributes in a Dystropherric Red Latosol (Typic Acrustox) under no-tillage, irrigated by central pivot. The objective was to select among the researched attributes, that with the best correlation, spatial and linear, to explain upland rice yield variability. The geostatistical grid was installed, to collect the soil and plant data, with 120 sampling points, in an area of 3.0 ha and and homogeneous slope of 0.055 m m-1. Of the linear point of view, the number of viable spikelets per panicle showed direct potential correlation with the yield of grains of rice. However, of the spatial point of view, the organic matter soil, when appraised in the layer 0.10-0.20 m, showed up came as indicator of the yield of grains of rice. Thus, in order to support future researches concern precision agriculture, which uses the same attributes of this research, the values of the range of the spatial dependence to be utilized should be among 40.2 and 181.2 meters / Mestre

A cama de semeadura é uma das principais condições físicas do solo para crescimento das plantas. A avaliação da qualidade física desse ambiente do solo, onde ocorre a germinação e emergência das culturas, é de fundamental importância para compreender os fatores que afetam o seu desenvolvimento. A presente pesquisa foi realizada, inicialmente, no Brasil, com o objetivo de avaliar a qualidade física da cama de semeadura do solo, pela determinação de propriedades estruturais e físico-hídricas do solo, e parâmetros de emergência das culturas milho e soja em sistema plantio direto de longa duração submetido à escarificação mecânica e biológica do solo. O trabalho foi desenvolvido em área pertencente à Universidade Estadual de Ponta Grossa, Paraná. Os tratamentos avaliados foram: sistema plantio direto por 16 anos, sistema plantio direto submetido à escarificação mecânica até 0,25 m de profundidade e sistema plantio direto submetido à escarificação biológica por meio do nabo forrageiro. As amostragens de solos foram realizadas aos seis e 18 meses após a implantação dos tratamentos, correspondentes às semeaduras das culturas do milho (Outubro de 2009) e da soja (Novembro de 2010) nas camadas 0-5 e 5-10 cm de profundidade. Para o experimento desenvolvido nos Estados Unidos, o objetivo foi avaliar a qualidade física da cama de semeadura do solo, pela determinação do intervalo hídrico ótimo, e parâmetros de emergência da cultura do trigo, em dois experimentos de longa duração que envolveu sistemas de cultivo e sistemas de preparo do solo. Esses experimentos foram conduzidos em área da Kansas State University, em Hays, Kansas, EUA. Os sistemas de preparo do solo envolveram a rotação trigo/sorgo/pousio sob o preparo convencional, reduzido e plantio direto implantados há 46 anos. Os sistemas de cultivo consistiram das sucessões trigo/pousio, trigo/sorgo/pousio e trigo/trigo manejadas sob preparo reduzido e plantio direto, implantados há 35 anos. A amostragem do solo foi realizada na cama de semeadura do trigo (Outubro/Novembro de 2011) nas camadas 0-5 e 5-10 cm de profundidade. Os dados foram submetidos à análise de variância e, quando significativos, as médias dos tratamentos foram comparadas pelo teste Tukey. Os resultados do estudo feito no Brasil demonstraram que a escarificação mecânica apresentou um baixo efeito residual sobre as propriedades físicas do solo, indicando ser desnecessária sua aplicação com vistas a melhorar a qualidade física do solo. A cultura do nabo forrageiro, como alternativa de escarificação biológica, pode ser incluída no sistema de rotação de culturas, uma vez que se mostrou eficiente em melhorar algumas propriedades físicas do solo. No estudo realizado nos EUA, no experimento sobre sistemas de preparo, o preparo reduzido resultou em melhor condição física da cama de semeadura do solo. O preparo convencional foi o tratamento que apresentou uma condição física do solo menos favorável ao crescimento inicial das plantas. O sistema de cultivo trigo/trigo sob preparo reduzido apresentou o melhor IHO da cama de semeadura. O procedimento boundary line demonstrou que os parâmetros de emergência das culturas foram dependentes das propriedades físicas da cama de semeadura do solo. / The seedbed is one of the most important soil physical conditions for plant growth. The evaluation of the soil physical quality in such soil environment is essential to understand the factors that affect crop development, as it is where seed germination and plant emergence and establishment take place. The objective of the experiment carried out in Brazil was to evaluate: the physical quality of the soil seedbed by the determination of its structural and physical-hydric properties; and the emergence parameters of the corn and soybean crops under long-term no tillage submitted to mechanical and biological chiseling. This experiment was carried out in Ponta Grossa, Paraná State, Brazil, at the farm-school belonging to Ponta Grossa State University. The treatments were no-tillage for 16 years, no-tillage submitted to mechanical chiseling at 0.25 m soil depth and no-tillage submitted to biological chiseling by a forage radish crop. Soil samples were collected at six and 18 months after the treatments were implemented, corresponding to a maize seedbed (October 2009) and a soybean seedbed (November 2010), for the 0 to 5 and 5 to 10 cm soil depths. For the experiments developed in the United States, the objective was to evaluate: the physical quality of the soil seedbed by the least limiting water range determination; and the wheat emergence parameters from two longterm experiments involving different cropping systems (35 years) and soil tillage systems (46 years). These experiments were conducted in an area belonging to Kansas State University located in Hays, Kansas, USA. The tillage systems experiment consisted of a wheat/sorghum/fallow rotation under conventional, reduced and no tillage. The cropping systems experiment consisted of wheat/fallow, wheat/sorghum/fallow and wheat/wheat rotations cultivated under reduced and no tillage. Soil samples were collected from the wheat seedbed (October/November 2011) at the 0 to 5 and 5 to 10 cm soil depths. The data were submitted to the variance analysis and, when significant, the means were compared by the Tukey test. The results from the experiment performed in Brazil showed that the mechanical chiseling had a lower residual effect on the soil physical properties, indicating that it is unnecessary when the aim is to improve the soil physical quality. The forage radish cultivation, as an alternative of biological chiseling, can be included in the crop rotation system once it was efficient at improving some soil physical properties. For the tillage systems experiment, which was conducted in the United States, the reduced tillage treatment resulted in a better physical condition of the soil seedbed. The conventional tillage was the treatment that presented the least favorable soil physical condition for the initial plant growth. The wheat/wheat cropping system under reduced tillage showed the best least limiting water range of the soil seedbed. The boundary line approach demonstrated that the crop emergence parameters were dependent on the physical properties of the soil seedbed.

Orientador: Marco Eustaquio de Sá / Banca: Orivaldo Arf / Banca: Salatiér Buzetti / Banca: Rogério Peres Soratto / Banca: Charline Zaratin Alves / Resumo: A maioria dos trabalhos com diferentes sistemas de manejo do solo e com uso de regulador vegetal (citocinina, giberelina e auxina) busca obter resultados quanto a aumentos na produtividade. Já, quanto ao seu efeito nos teores de nutrientes nas folhas e sementes e na qualidade fisiológica das sementes produzidas nessas condições há carência de informações. Desta forma, o objetivo deste trabalho foi avaliar o desenvolvimento, produtividade, nutrientes nas folhas e sementes e qualidade fisiológica das sementes de feijão, cultivares Carioca Precoce, IAC Apuã e IAC Alvorada, em função do uso de regulador vegetal, via foliar, em sistema convencional e plantio direto em implantação, no inverno com uso de irrigação. A pesquisa foi conduzida em 2009 e 2010, no Município de Selvíria/MS. Realizaram-se três experimentos com os cultivares Carioca Precoce, IAC Apuã e IAC Alvorada, em blocos casualizados, em faixas, com quatro repetições. Os fatores foram: sistemas de semeadura convencional com incorporação da palhada do milheto ao solo e direta sobre a palhada do milheto e cinco doses do regulador vegetal (0; 1,0; 2,0; 3,0 e 4,0 L p.c ha-1) composto por três hormônios vegetais: cinetina, ácido giberélico e ácido indolbutírico, aplicadas em R5. Avaliou-se: clorofila e nutrientes foliares, características agronômicas e produtivas, teor de proteína e nutrientes nas sementes e a qualidade fisiológica das sementes através dos testes de: germinação, primeira contagem, emergência de plântulas em campo, índice de velocidade de emergência, altura de plântula, massa da matéria seca de plântula, envelhecimento acelerado, teste de frio sem solo e condutividade elétrica. O plantio direto mesmo em fase de implantação propiciou: aumento na clorofila e nos teores foliar de N, P e Mg variando em função do cultivar e do ano; e de maneira geral, considerando os três cultivares... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The most studies with different systems of soil management and use of plant growth regulator (cytokinin, auxin and gibberellin) search results as increases in productivity. Already, in its effect on nutrient concentrations in leaves and seeds and physiological quality of seed produced under these conditions there is a lack of information. Thus, the objective was to evaluate the development, productivity, nutrients in the leaf and seeds and physiological seed quality of common bean cultivars, Carioca Precoce, IAC Apuã and IAC Alvorada, depending on the use of growth regulators on leaf, in the conventional or no-tillage system in the implantation, in the winter with irrigation use. The research was conducted in 2009 and 2010, in Selvíria - MS State. They were conducted three experiments with varieties Carioca Precoce, IAC Apuã and IAC Alvorada, in a randomized blocks design in strips with four replicates. The treatments were: conventional tillage system with millet straw incorporation to the soil or directly over the millet straw, and five doses of the plant growth regulators (0, 1.0, 2.0, 3.0 and 4.0 L cp ha -1) which consists of three plant hormones, kinetin, gibberellic acid and IBA, applied at R5. It was evaluated: chlorophyll and foliar nutrients, agronomic and productive characteristics, protein and nutrients in the seeds and physiological quality of seeds through the tests of germination, first count, seedling emergence in the field, speed of emergence index, seedling height, mass of dry matter of seedlings, accelerated aging, cold test without soil and electric conductivity. The no-tillage even in implantation phase resulted in: increased leaf chlorophyll and on N, P and Mg, depending on the cultivar and year, and in general, considering the three cultivars used, it was the better development of plants and seed yield. The growth regulator did not affect the levels... (Complete abstract click electronic access below) / Doutor

Soils in the urban environment are distinctive in that they are modified through waste amendments. Consideration has been given to how urban soil properties reflect current human influence; however, recent studies highlight their potential as historical archives. The impact of waste disposal on the nature, properties and formation of urban soils is significant, especially in historic small towns where the extent and complexity of refuse management practices is only just emerging. This study uses a multi-method approach to characterise and understand modes of urban anthrosol formation in three Scottish burghs; Lauder, Pittenweem and Wigtown. The objectives of this study are threefold; to establish the nature and diversity of urban anthrosols in and near to historic small towns, to characterise and account for the multiplicity of urban anthrosols in and near to historic small towns, and to elucidate the processes associated with waste management and disposal in historic small towns. Physical, chemical and micromorphological analysis of topsoil deposits indicate sustained addition of past waste materials to soils within and near to historic small towns. Soil characteristics were heterogeneous across burghs; however, distinct patterns according to past functional zones were identified. The burgh core and burgh acres are important areas of interest at all three burghs. Soil modification was most pronounced within burgh cores resulting in the formation of hortic horizons. Soils within burgh cores are characterised by neutral pH, increased organic matter content, enhanced magnetic susceptibility and elevated elemental concentrations such as calcium, phosphorus and potassium. In comparison the nature and extent of soil modification within burgh acres is more varied. At Lauder hortic soils were identified in the burgh acres suggesting pronounced soil modification through cultivation. Deepened topsoil in the burgh acres at Pittenweem provided evidence for application of mineral rich waste materials in the past. Moreover, magnetic and elemental enhancement (barium, phosphorus, lead, zinc) within the burgh acres south of Wigtown revealed historic soils based anthropogenic signal. It is argued that changes in soil characteristics at Lauder, Pittenweem and Wigtown can be explained through processes of waste management and disposal in the past. Evidence from micromorphological analyses suggests that waste in burgh cores typically comprised domestic waste, animal waste, building materials and fuel residues. These materials were also identified within burgh acres, although it is noted that their abundances were significantly lower. Variation in urban anthrosol characteristics between burghs is attributed to differing industries and patterns of resource exploitation, for example marine waste associated with fishing was only identified in coastal burghs. The sustained addition of waste materials to soils within and near to historic small towns was an effective waste management strategy. Waste disposal in burgh cores was likely to be a combination of direct application and midden spreading in back gardens. This led to enhanced soil fertility which was important in the development of urban horticulture; particularly for poorer inhabitants who did not have access to arable farm land adjacent to the burgh. Dunghills acted as temporary stores of waste in the main thoroughfares of Lauder, Pittenweem and Wigtown. These dunghills were systematically transported to the burgh acres for further use as a fertiliser; hence, an early form of urban composting. Processes of waste disposal could not be deduced from soil characteristics alone; however, likely methods include direct waste deposition, storage and redistribution of midden waste, and storage and redistribution of dunghills. The limitations of soil classification systems and mapping are highlighted, for example urban soils are either omitted from soil maps or are misclassified. It is recommended that urban soils in historic towns should be incorporated into future regional soil maps. Urban soils represent a complex archive of past human behaviour not necessarily reflected in archaeological excavation or documentary analysis. It is argued that soil and artefacts are equally important, hence soil should be a consideration in urban heritage and conservation strategies.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / Mulches have been used for evaporation suppression in facilitating vegetable production under arid lands conditions. A study was undertaken in order to evaluate the effectiveness of plastic aprons, supplied by the FAO, as compared to gravel mulches. The vinyl aprons were 6 mils thick and about 1 meter square. Squash plants (Cucurbita pepo) were planted with gravel or plastic aprons or in bare areas and under different watering schedules. The yields under plastic aprons were considerably greater than under gravel and required slightly less water. Bare soil yields lagged far behind. Soil temperatures under the plastic aprons were consistently higher over 24 hours than bare soil, which within limits, would facilitate faster crop growth. Additionally, the apron collects and diverts rainfall to the plant. The vinyl used lasts only 2 seasons, and gravel would probably be a more suitable mulch for developing countries where capital is scarce.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Space-age technology has produced tools which when turned to earthly pursuits can provide information on food and fiber production. Soil moisture has the potential for being remotely assessed, and three techniques for accomplishing this are under study. Two of the methods, reflectance and thermal, are sensitive to the conditions of the bare soil surface. The third technique, microwave emission, appears to have a good potential for assessing soil moisture with depth, because of its greater wavelength.

From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / This study was undertaken to compare the water harvesting potential of several residual waxes with that of refined paraffin. These residual waxes could possibly have advantages over refined paraffin as a soil treatment for water-harvesting catchments in that they are byproducts rather than an end product (constituting an energy savings), are slightly cheaper, and are more adhesive and less brittle. However, these residual waxes have high physical - chemical property variability which complicates testing for utility in water-harvesting. The lack of an easily obtainable ' characterization index ' is a particular deficiency. Upon laboratory testing, several of the residual waxes were found to be superior to refined paraffin in water-repellancy, structural stability, erosion and freeze-thaw resistance and ozone and ultraviolet radiation effects. The need for further laboratory and field testing was noted.