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Jones, Mark W. "Soil compaction caused by timber harvesting in central Appalachian hardwood forests". Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2926.
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Thesis (M.S.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains viii, 52 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 47-52).
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Kachamba, Daud Jones. "Impact of harvesting machinery on soil physical parameters : evaluation of ProFor model in three main forestry regions of South Africa /". Link to the online version, 2007. http://hdl.handle.net/10019/648.
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Siegel-Issem, Cristina Marie. "Forest Productivity as a Function of Root Growth Opportunity". Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/36323.
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Compaction caused by certain intensive forest management practices can reduce tree growth, but the causes of growth reduction are usually complex interactions between soil properties and tree species. We used a 7 by 7 factorial greenhouse experiment to create a matrix of bulk density ((Ï b)) and volumetric water content (θv) to determine soil compaction effects on seedling growth of: (i) ponderosa pine (Pinus ponderosa Dougl. ex Laws) grown on Dome and Cohasset soils from California; (ii) shortleaf pine (Pinus echinata) on a Clarksville soil from Missouri; and (iii) loblolly pine (Pinus taeda) on an Argent soil from South Carolina. We also characterized soil physical properties and determined compaction effects on soil strength, air/water balance and least limiting water range (LLWR) for each of the soils. Optimum water content for compaction varied from 19%(Argent) to 34%(Cohasset). Compactive effort curves varied for the four soils;maximum Ï b were 1.33, 1.52, 1.58 and 1.65 Mg m-3 for the Cohasset, Dome, Clarksville, and Argent soils, respectively. Compression indices ranged from 0.33 to 0.38. In general, soil strength increased linearly with a θv decrease at the higher Ï b levels, but the effect varied with each soil type. Cohasset, with the lowest BD, had the highest soil strength (3.5 MPa), while strengths exceeding 2.0 MPa were not found for the Argent soil. Compaction affected the soil water retention curves and associated air/water balance parameters for all soils, particularly the Cohasset and Dome soils. Aeration porosity became limiting at Ï b of 1.3, 1.42, 1.44 and 1.55 Mg m-3 for the Cohasset, Dome, Clarksville and Argent soils respectively. The LLWR was lowest for the Dome and Argent soils (0.3 cm 3 cm-3 ) and in some cases increased with compaction. Models of root growth opportunity were developed using multiple regression. The general model of root length density (RLD) = b0 + b1 θv + b2 Ï b + b3 θv2 described rooting response for the Clarksville-shortleaf and Argent-loblolly soil-species combinations (p = 0.005). However, the root response of ponderosa pine on Cohasset was linear and pine roots in the Dome soil responded to an interaction between θv and Ï b. No model adequately described oak seedling growth as a function of BD and VW. High soil strength at low water contents and low aeration porosity at high water contents limited root growth. Shoot mass of seedlings growing within the least limiting water range (LLWR) was greater than those growing outside the range for all soil-species combinations except the Argent-loblolly pine (p = 0.05). The loblolly pines had greater shoot mass at volumetric water contents above the upper LLWR limits (aeration limiting). The LLWR is a promising method for integrating compaction's influence on soil properties and thus root growth potential since single factors did not appear to adequately explain each soil's compressibility. Furthermore, response surface models of RLD as a function of VW and BD in conjunction with the LLWR and seasonal site water data have potential for determining compaction- induced soil limitations for tree growth, but need to be calibrated for both soil and species.Master of Science
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Zhao, Yihai (Simon). "Relative bulk density as an index of soil compaction and forest productivity in British Columbia". Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/10318.
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Soil compaction often limits conifer regeneration on sites degraded by construction of landings and roads, but inadequate understanding of compaction characteristics has sometimes led to inappropriate rehabilitation efforts. This warrants development of new methods to assess compaction and its relation to tree growth. The objective of this study was to develop a high-level integration indicator that will characterize compaction of forest soils and that could be correlated to tree height growth. Mineral particle density of soils from interior British Columbia (BC) forests varied significantly among the geographic locations. Oxalate-extractable Fe- and Al-oxides and particle size distribution (PSD) were related to soil and mineral particle densities, while soil organic matter (SOM) and Al- and Fe-oxides were important soil properties in relation to soil particle density. The significance of levels of single soil properties in predicting maximum bulk density (MBD) were in the order: plastic and liquid limits, organic matter content, oxalate-extractable oxide, and PSD. Stratification of the sample according to Atterberg limits improved the predictability of MBD, and variation in particle density was included in the prediction by other soil properties used in the models. Height growth of interior Douglas-fir (Pseudotsuga menziesii var. glauca [Bessin] Franco) was restricted when relative bulk density (RBD) was > 0.72. For lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and hybrid white spruce (Picea glauca [Moench] Voss × engelmannii Parry ex Engelm.), an RBD of 0.60 - 0.63 corresponded to maximum height growth, while that of 0.78 - 0.84 appeared to limit height growth. The presence of surface organic material mitigated compaction and was often associated with lower RBD. Interior Douglas-fir and lodgepole pine planted in low elevation sites in north-central BC did not grow well and their height growth was weakly related to RBD. The results suggest that soil rehabilitation should be considered on disturbed sites where soil RBD is > 0.80.
Findings in this study have implications in assessing forest soil compaction and its effect on site productivity. The results will help predict soil behaviour and associated tree growth in response to timber harvesting and site rehabilitation.
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Day, Susan D. "Growth and Physiology of Several Urban Tree Species in Soils Disturbed by Construction Fill or Compaction". Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/28639.
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Experiments were conducted to determine the effects of applying fill soil around existing trees and mechanisms for species tolerance to soil compaction, both common site disturbances in urban forestry. Groups of 22-year-old white oak (Quercus alba) and 13-year-old sweetgum (Liquidambar styraciflua) were subjected to one of three treatments: a control, fill (20 cm of subsoil spread over the root zones), and compacted fill (same as fill soil, but compacted). Additionally, individual trees had tree wells (fill soil pulled away from trunks), or not. After three years, treatments had no consistent effect on tree growth, chlorophyll fluorescence, or soil respiration. However, soil treatments disrupted normal soil moisture patterns at both sites. Roots of white oak grew into fill layers, although overall root growth was not significantly affected by treatment. Sweetgum roots grew very little into fill soils. However, root distribution shifted upward in the original soil under uncompacted fill. Other factors associated with raising the soil grade, such as soil trafficking and root severance, may be largely responsible for the tree decline often attributed to construction fill.
Another experiment investigated the relationship between tolerance of wet soils and the ability to grow in compacted soils. It was hypothesized that tree species tolerant of wet soils would have opportunities for root growth in compacted soil when high soil moisture reduced soil strength. Seedlings of flowering dogwood (Cornus florida), a species intolerant of inundation, and silver maple (Acer saccharinum), a bottomland species, were grown in a loam soil maintained at various combinations of soil strength and soil matric potential. In moderately compacted soil (1.5 g cm-3 bulk density), maple seedlings, but not dogwoods, had greater root growth rate, root length per plant, and ratio of root length to root dry weight in the wet soil (0.006 MPa soil matric potential) than in the moist and dry soils (0.026 and 0.06 MPa, respectively). No such effect was detected in highly compacted soil (1.7 g cm-3). It can be concluded that silver maple roots can grow in moderately compacted soil when high soil water content decreases soil strength, whereas dogwood is unable to take advantage of this opportunity.Ph. D.
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Silva, Jair Rosas da [UNESP]. "Compactação do solo causada pelo tráfego de máquinas na colheita de madeira de Eucalyptus grandis Hill ex Maiden". Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/101742.
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silva_jr_dr_botfca.pdf: 1243112 bytes, checksum: a6ff73d1d32431a4754520748d549e85 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Foram avaliados os efeitos causados ao solo pelo tráfego de máquinas florestais de corte e baldeio de madeira, com ênfase à compactação, em floresta de Eucalyptus grandis Hill ex Maiden, de 91 meses de idade, através do comportamento de parâmetros físicos e mecânicos de um Latossolo Vermelho Amarelo, com 480 g.kg-1 de areia total e 430 g.kg-1 de argila. Os tratamentos avaliados foram o trânsito anterior ao experimento, a fase de corte e processamento de madeira, efetuada por colhedora (harvester) sobre esteiras e a fase de extração, por trator transportador autocarregável (forwarder) com rodado de pneus, considerando-se as condições de presença ou ausência de cobertura de galhada. Os parâmetros físicos empregados na avaliação foram: densidade do solo, porosidade total, macroporosidade, microporosidade, água disponível no solo, taxa de infiltração de água, temperatura do solo e estabilidade de agregados a seco. Os parâmetros mecânicos avaliados foram resistência do solo à penetração e ao cisalhamento, densidade máxima do solo, teor de água crítico para compactação e grau de compactação. Também foram avaliadas a área de contato rodado-solo e a pressão de rodados sobre o solo. Adotou-se o delineamento inteiramente casualizado, sendo os resultados obtidos submetidos à análise de variância pelo Statistical Analysis System (SAS), com aplicação do teste Tukey a 5% e 10% de significância. Comparativamente, a densidade do solo, a resistência mecânica ao cisalhamento e a pressão de rodados sobre o solo foram maiores após o tráfego do trator transportador em relação ao conferido pela colhedora de madeira. Os parâmetros porosidade total, macroporosidade, microporosidade, água disponível e estabilidade de agregados a seco foram maiores na fase de corte de madeira do que na fase de baldeio...
A study of soil compaction was carried out on a Red-Yellow Latosol with 43% of clay and 48% of sand, according to some soil physical and mechanical parameters in a harvester of a 91-month-old Eucalyptus grandis Hill ex-Maiden forest. The aim was to evaluate the influence caused by the traffic of a 100 kWa-tracked harvester followed by a 190 kWa-wheeled-forwarder, over and without slash, in comparison to the soil conditions before the harvesting operations. The physical parameters used were soil dry bulk density, total porosity, air-filled porosity, micro porosity, soil water availability and infiltration rate, temperature and soil mean aggregate sizes. The mechanical parameters were soil penetrometer resistance, shear strength, Proctor test and machine ground pressure. A randomized-block trial with 15 replicates was used, applying Statistical Analysis System (SAS) and Tukey test at 5% and 10% significance levels. Results showed that wheeled-forwarder increased soil dry bulk density, soil shear strength and soil machine pressure in relation to the tracked-harvester. Thus, the parameters total porosity, air-filled porosity, micro porosity, soil water availability and soil mean aggregate sizes were higher on harvesting than on wood hauling. The wheeled-forwarder operating without slash produced a higher soil dry bulk density, temperature and soil compaction degree. Also, this work condition decreased total porosity and air-filled porosity in relation to the same operation accomplished over slash. Micro porosity, water availability, soil infiltration rate, soil penetrometer resistance and the maximum soil dry bulk density were not affected by both machines working on both slash conditions. All the soil mechanized operations evaluated were rated higher than 2 MPa on soil penetrometer resistance parameter, looked like a soil limit to allow the root growing... (Complete abstract, click eletronic address below)
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Morales, Cedinara Arruda Santana. "PREPAROS E ATRIBUTOS FÍSICOS DE SOLOS PARA PLANTIO DE EUCALIPTO". Universidade Federal de Santa Maria, 2014. http://repositorio.ufsm.br/handle/1/3773.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorWith the expansion of cultivated forest in Rio Grande do Sul, there was an increase of the forest plantations, now occupying areas previously used for livestock and agricultural crops. The objective was to generate reccomendations for soil tillage, based on soil quality indicators. The study was conducted in three areas for the cultivation of clonal seedlings of Eucalyptus saligna Smith belonging to Celulose Riograndense in the state of Rio Grande do Sul. The soils are classified as Planossolo Háplico Eutrófico gleissólico (SXe), Nitossolo Vermelho Distrófico típico (NVd) and Neossolo Regolítico Eutroúmbrico típico (RReh). Initially a pilot survey was done to quantify the spatial variability of texture and soil resistance to penetration (RP); subsequently, soil samples were taken at depths of 0-10, 10-20, 20-40 and 40-60 cm. After the characterization and analysis of soil areas different soil tillages (subsoiling to 50 cm depth plus rotary hoe (S50), subsoiling to 50 cm depth with ridge (S50C), and subsoiling to 70 cm depth plusr rotary hoe (S70). Planting of Eucalyptus saligna Smith clones (3.5 x 2.6 m) was carried out. At 6, 12, 18 and 24 months after planting, the dendrometric evaluation of total height and diameter at breast height (dbh 1.30 m). The joint use of factor analysis and spatial variability of RP enabled us to identify locations with different compaction states. The least limiting water range (LLWR) was strongly affected by the penetration resistance and soil aeration in clayey soils. The bulk density values of Argissolos, in the larger states of soil compaction, were above the critical density based on the LLWR. The soil tillage with greater volume of soil disturbed (S50C), in SXe (1267.1 m3 ha- 1) and RReh (836.8 m3 ha-1), favored the initial development of Eucalyptus saligna Smith. In SXe at 24 months-old forest, the height was 10.38 cm and dbh of 9.90, whereas for the RReh the height was 10.15 m and dbh of 10.60 cm. In NVd, the highest growth was observed in the treatment S70, with an average height at 24 months of 9.77 m and dbh of 9.68 cm. The results of this study indicate that the choice of the best tillage depends on the texture, degree of compaction, critical density and penetration resistance of the soil. Thus, for Planossolo Háplico Eutrófico gleissólico and the Neossolo Regolítico Eutroúmbrico típico the best tillage was S50C, while for the Nitossolo Vermelho Distrófico típico was S70.
Com a expansão da produção florestal no Rio Grande do Sul, houve aumento na área dos plantios florestais anteriormente dominadas pela pecuária e pelos cultivos agrícolas. O objetivo foi gerar recomendações adequadas de preparo, com base nos indicadores de qualidade. O estudo foi realizado em três áreas destinadas ao cultivo de mudas clonais de Eucalyptus saligna Smith, pertencentes à empresa Celulose Riograndense, nos municípios de São Gabriel e Vila Nova do Sul, no RS. Os solos das áreas estudadas são classificados como Planossolo Háplico Eutrófico gleissólico (SXe), Nitossolo Vermelho Distrófico típico (NVd) e Neossolo Regolítico Eutroúmbrico típico (RReh). Na área de estudo foi feito, inicialmente, um levantamento piloto para observar a variabilidade espacial da textura e da resistência mecânica do solo à penetração (RP); posteriormente, foram realizadas amostragens do solo, nas camadas de 0-10, 10-20, 20-40 e 40-60 cm. Após a caracterização e análise do solo das áreas, foram aplicados diferentes preparos de solo (subsolagem a 50 cm de profundidade mais enxada rotativa (S50), subsolagem a 50 cm de profundidade mais camalhão (S50C) e subsolagem a 70 cm de profundidade mais enxada rotativa (S70)) e, posteriormente, foi realizado o plantio de clones de Eucalyptus saligna Smith (3,5 x 2,6 m). Aos 6, 12, 18 e 24 meses após o plantio, foram feitas as avaliações dendrométricas de altura total e diâmetro à altura do peito (dap 1,30 m). O uso conjunto da análise fatorial e da variabilidade espacial da RP permitiu identificar, locais com diferentes estados de compactação. O intervalo hídrico ótimo (IHO) foi fortemente limitado pela resistência à penetração e pela aeração do solo, nos solos mais argilosos. Os valores de densidade do solo mais Argissolo, nos maiores estados de compactação, foram superiores à densidade crítica com base no IHO. O preparo do solo com maior volume de solo mobilizado (S50C), no SXe (1267,1 m3 ha-1) e no RReh (836,8 m3 ha-1), favoreceu o melhor desenvolvimento inicial do Eucalyptus saligna Smith. No SXe a altura média aos 24 meses de idade foi de 10,38 m e dap de 9,90 cm e, no RReh, a altura foi de 10,15 m e dap de 10,60 cm. No NVd, o maior crescimento foi observado no tratamento S70, com altura média aos 24 meses de idade de 9,77 m e dap de 9,68 cm. Os resultados deste trabalho indicam que a escolha do melhor preparo de solo depende da textura, grau de compactação, densidade crítica e da resistência à penetração do solo. Assim, para o Planossolo Háplico Eutrófico gleissólico e para o Neossolo Regolítico Eutroúmbrico típico o melhor preparo de solo foi o tratamento S50C e, no Nitossolo Vermelho Distrófico típico, foi o tratamento S70.
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Goutal, Noémie. "Modifications et restauration de propriétés physiques et chimiques de deux sols forestiers soumis au passage d'un engin d'exploitation". Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00737884.
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Les risques de dégradation physique des sols forestiers sous l'effet de contraintes mécaniques externes liées à la mécanisation des opérations forestières, augmentent considérablement. Les mécanismes et le temps nécessaires à la restauration non assistée de la qualité des sols forestiers tassés restent encore peu étudiés, et leur identification nécessite de coupler les approches physiques, chimiques et biologiques. L'objectif de ce travail était d'étudier l'impact de la circulation d'un porteur forestier sur les conditions de l'enracinement (aération, régime hydrique et pénétrabilité) ainsi que son évolution à court terme. Ce travail s'appuie sur l'observation de deux sites expérimentaux mis en place dans le Nord Est de la France, concernant des sols de morphologie similaire (couche limono-argileuse de 50 cm d'épaisseur reposant sur un substrat argileux) et ayant subi des contraintes identiques. Des paramètres physiques (température et humidité du sol, densité apparente et résistance à la pénétration) et chimiques (composition de l'atmosphère du sol) ont été suivis pendant trois à quatre ans, à des fréquences allant d'un pas de temps quotidien à annuel. Le suivi du climat du sol et de la composition de son atmosphère a mis en évidence une diminution forte des conditions aérobies pendant un à un an et demi après le passage du porteur. Cet effet initial sur l'aération du sol a diminué subitement dès l'apparition de la première période de sécheresse édaphique, probablement grâce à la formation de fissures dans l'horizon de surface du sol tassé. Cependant un effet significatif du traitement sur la composition de l'atmosphère du sol pouvait toujours être observé trois à quatre ans après tassement. Pour suivre l'évolution des propriétés physiques du sol après circulation du porteur, il a été nécessaire d'opérer une normalisation par rapport à l'humidité au moment du prélèvement. Trois ou quatre ans après la circulation du porteur, une différence toujours significative existe entre les propriétés physiques des sols témoins et celles des sols tassés. Cependant une évolution de l'impact du porteur peut être mise en évidence dans la couche de surface (0-10 cm) des deux sites. Ce début de restauration se traduit, sur un des deux sites, par une différence entre traitement qui n'est plus significative quand les sols sont humides mais qui l'est encore quand les sols sont secs. Sur le deuxième site, cette différence a diminué quelle que ce soit l'humidité du sol. Ainsi, le début de régénération de la structure du sol perturbé ne s'accompagne pas d'une disparition de son comportement de prise en masse lors de son desséchement sur un des deux sites. Ce travail a permis de mettre en évidence une évolution des conséquences du porteur en surface du sol tassé qui serait liée à des processus physiques (gonflement -retrait, gel - dégel). Cependant, l'impact sur les conditions de l'enracinement (forte résistance à la pénétration quand les sols sont secs, faible aération quand ils sont humides) reste élevé de même que sur la résilience à long terme du peuplement.
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Silva, Jair Rosas da 1943. "Compactação do solo causada pelo tráfego de máquinas na colheita de madeira de Eucalyptus grandis Hill ex Maiden /". Botucatu, [s.n.], 2003. http://hdl.handle.net/11449/101742.
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Orientador: Paulo Torres FennerBanca: Cláudio Angeli Sansígolo
Banca: Sérgio Hugo Benez
Banca: Jorge Roberto Malinovski
Banca: Fernando Seixas
Resumo: Foram avaliados os efeitos causados ao solo pelo tráfego de máquinas florestais de corte e baldeio de madeira, com ênfase à compactação, em floresta de Eucalyptus grandis Hill ex Maiden, de 91 meses de idade, através do comportamento de parâmetros físicos e mecânicos de um Latossolo Vermelho Amarelo, com 480 g.kg-1 de areia total e 430 g.kg-1 de argila. Os tratamentos avaliados foram o trânsito anterior ao experimento, a fase de corte e processamento de madeira, efetuada por colhedora (harvester) sobre esteiras e a fase de extração, por trator transportador autocarregável (forwarder) com rodado de pneus, considerando-se as condições de presença ou ausência de cobertura de galhada. Os parâmetros físicos empregados na avaliação foram: densidade do solo, porosidade total, macroporosidade, microporosidade, água disponível no solo, taxa de infiltração de água, temperatura do solo e estabilidade de agregados a seco. Os parâmetros mecânicos avaliados foram resistência do solo à penetração e ao cisalhamento, densidade máxima do solo, teor de água crítico para compactação e grau de compactação. Também foram avaliadas a área de contato rodado-solo e a pressão de rodados sobre o solo. Adotou-se o delineamento inteiramente casualizado, sendo os resultados obtidos submetidos à análise de variância pelo Statistical Analysis System (SAS), com aplicação do teste Tukey a 5% e 10% de significância. Comparativamente, a densidade do solo, a resistência mecânica ao cisalhamento e a pressão de rodados sobre o solo foram maiores após o tráfego do trator transportador em relação ao conferido pela colhedora de madeira. Os parâmetros porosidade total, macroporosidade, microporosidade, água disponível e estabilidade de agregados a seco foram maiores na fase de corte de madeira do que na fase de baldeio... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: A study of soil compaction was carried out on a Red-Yellow Latosol with 43% of clay and 48% of sand, according to some soil physical and mechanical parameters in a harvester of a 91-month-old Eucalyptus grandis Hill ex-Maiden forest. The aim was to evaluate the influence caused by the traffic of a 100 kWa-tracked harvester followed by a 190 kWa-wheeled-forwarder, over and without slash, in comparison to the soil conditions before the harvesting operations. The physical parameters used were soil dry bulk density, total porosity, air-filled porosity, micro porosity, soil water availability and infiltration rate, temperature and soil mean aggregate sizes. The mechanical parameters were soil penetrometer resistance, shear strength, Proctor test and machine ground pressure. A randomized-block trial with 15 replicates was used, applying Statistical Analysis System (SAS) and Tukey test at 5% and 10% significance levels. Results showed that wheeled-forwarder increased soil dry bulk density, soil shear strength and soil machine pressure in relation to the tracked-harvester. Thus, the parameters total porosity, air-filled porosity, micro porosity, soil water availability and soil mean aggregate sizes were higher on harvesting than on wood hauling. The wheeled-forwarder operating without slash produced a higher soil dry bulk density, temperature and soil compaction degree. Also, this work condition decreased total porosity and air-filled porosity in relation to the same operation accomplished over slash. Micro porosity, water availability, soil infiltration rate, soil penetrometer resistance and the maximum soil dry bulk density were not affected by both machines working on both slash conditions. All the soil mechanized operations evaluated were rated higher than 2 MPa on soil penetrometer resistance parameter, looked like a soil limit to allow the root growing... (Complete abstract, click eletronic address below)
Doutor
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Hausman, Constance Elizabeth. "The Ecological Impacts of the Emerald Ash Borer (Agrilus Planipennis): Identification of Conservation and Forest Management Strategies". Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1291002276.
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Suzuki, Luis Eduardo Akiyoshi Sanches. "QUALIDADE FÍSICO-HÍDRICA DE UM ARGISSOLO SOB FLORESTA E PASTAGEM NO SUL DO BRASIL". Universidade Federal de Santa Maria, 2008. http://repositorio.ufsm.br/handle/1/3716.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorSoil compaction is a problem in different production systems: agriculture, pasture and forest. In the agriculture soil compaction is well documented, while in the pasture and forest its study is scarce. The objective of this study was to evaluate the physical-hydric quality of an Alfisol under forest and pasture in South Brazil, and stabilish parameters and values indicatives of soil quality. The study was carried out in Butiá county, located in the physiographic region of Serra do Sudeste (Escudo Rio- Grandense) in the Rio Grande do Sul state. Four areas were studied: native forest; five-years old pasture, installed under conventional tillage and constituted of Brachiaria brizantha associated with Paspalum lourai and Trifolium sp.; 20-years old Eucalyptus saligna, installed under conventional tillage in 1986; 4.5-years old Eucalyptus saligna in second cycle, where the first cycle was cut 8.5 years after installed. manually and carried out with forwarder. Soil physical properties (bulk density, soil porosity, soil aggregation, air permeability and parameter S), hydrical properties (hydraulic conductivity and soil water retention curve) and mechanical properties (soil penetrations resistance, degree of compactness and compressibility) of soil were evaluated. The depth of soil compaction in the pasture is around 0.10 m, while in the mechanized harvest of eucalyptus may reach 0,40 m, which indicates the need for permanent controlled traffic to minimize soil compaction in forest areas. The critical values of soil physical properties to the growth and yield of annual crops looks effective for perennial and pasture crops. With the increment of soil compaction there is compression of soil aggregates, increase of bulk density and decrease of soil porosity, affecting negatively the fluxes of air and water of soil. Intermediate levels of soil compaction are favorable to the environment, and probably to the plant growth, due to the better soil structure (porosity and bulk density) and greater water availability, along with more efficient to the deformations and susceptibility to compaction. Using bulk density, soil penetration resistance and soil moisture, it is possible to estimate the soil load support ability and its susceptibility to compaction. Biological pores, formed by the action of soil organisms and root decomposition, are effective to increment air flux, fundamental to water infiltration and air flux under conditions of high bulk density. To obtain the reference bulk density to calculate the degree of compactness in forest and pasture, the soil with preserved structure must be sampled in the layer of 0.10 0.125 m, equilibrated under tension of 33 kPa and the reference bulk density must be that obtained from pressure of 1600 kPa.
A compactação é um problema que tem sido verificado nos diferentes sistemas de manejo do solo: agrícola, pecuária e florestal. Na área agrícola a compactação tem sido documentada, enquanto na pecuária e florestal os estudos ainda são incipientes. Com o objetivo de avaliar a qualidade físicohídrica de um Argissolo sob floresta e pastagem no Sul do Brasil, e estabelecer parâmetros e valores indicadores de qualidade do solo, realizou-se um estudo no município de Butiá, situado na região fisiográfica Serra do Sudeste (Escudo Rio-Grandense) do Estado do Rio Grande do Sul, sob um Argissolo Vermelho distrófico. Foram utilizadas quatro áreas: floresta antropizada constituída por espécies arbóreas e arbustivas; pastagem implantada há 5 anos sob preparo convencional e constituída do consórcio de braquiária brizanta (Brachiaria brizantha) com pensacola (Paspalum lourai) e trevo (Trifolium sp.); povoamento de Eucalyptus saligna com vinte anos de idade, sendo realizado o preparo convencional do solo para implantação do povoamento no ano de 1986; e plantio clonal de Eucalyptus saligna conduzido em 2ª rotação com 4,5 anos de idade, sendo a colheita do eucalipto no primeiro corte, aos 8,5 anos de idade, feita manualmente com motosserra e a extração da madeira realizada com Forwarder. Foram avaliadas propriedades físicas (densidade, porosidade, agregação do solo, permeabilidade ao ar e parâmetro S), hídricas (condutividade hidráulica do solo saturado e curva de retenção de água) e mecânicas (resistência à penetração, grau de compactação e compressibilidade) do solo. A profundidade de compactação em área de pastagem é até 0,10 m, enquanto em área de colheita mecanizada de eucalipto pode alcançar 0,40 m, sendo necessários canais permanentes de tráfego para minimizar a compactação em áreas florestais. Os valores críticos de propriedades físicas do solo para o crescimento e rendimento de culturas anuais também parece ser efetivo para culturas perenes e pastagem. Com aumento da compactação há compressão dos agregados do solo, incrementando a densidade e reduzindo a porosidade, afetando negativamente os fluxos de ar e água do solo. Níveis intermediários de compactação são favoráveis ao meio ambiente e, possivelmente, ao crescimento de plantas, devido à melhor estrutura do solo (porosidade e densidade) e ao maior armazenamento e disponibilidade de água, além de ser mais eficiente quanto à deformação e suscetibilidade do solo à compactação. Através de propriedades como a densidade do solo, resistência do solo à penetração e umidade é possível estimar a capacidade de suporte de carga do solo e sua suscetibilidade à compactação. Os poros biológicos, formados pela ação de organismos do solo e decomposição de raízes, são efetivos no incremento do fluxo de ar, sendo fundamentais na infiltração de água e fluxo de ar em condições de elevada densidade do solo. Para obtenção de uma densidade referência do solo para cálculo do grau de compactação em áreas de floresta e pastagem, a coleta de amostras com estrutura preservada deve ser feita na camada de 0,10 0,125 m, equilíbriadas na tensão de 33 kPa, e o valor de densidade referência deve ser aquele obtido na pressão de 1600 kPa.
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Martin, Manon. "Développement d'un modèle de transfert hydrique des sols forestiers partiellement tassés dans un contexte de données parcimonieuses". Thesis, Avignon, 2019. http://www.theses.fr/2019AVIG0713.
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L'augmentation de la mécanisation lors de l'exploitation forestière combinée aux changements climatiques augmente le risque de circuler dans les mauvaises conditions et donc de dégrader les sols. C'est pourquoi il est nécessaire de développer des outils d'aide à la décision capables de prédire la praticabilité des sols forestiers. Cependant, évaluer la praticabilité avec des outils simples et des données facilement accessibles est complexe. En effet, elle dépend de multiple facteurs : la susceptibilité du sol à se déformer, la charge appliquée, le seuil de déformation toléré et l'état hydrique du sol. Ce travail vise à mieux comprendre et prévoir la dynamique hydrique des sols forestiers et des cloisonnements (i.e. chemins dédiés à la circulation des engins forestiers). Les objectifs sont les suivants : (i) améliorer notre compréhension de l'effet du tassement sur la teneur en eau des sols forestiers, (ii) paramétrer un modèle de fonctionnement hydrique en contexte forestier et (iii) être capable de prédire l'humidité des sols dans un contexte opérationnel. Nous avons mis en place un observatoire des cloisonnements qui a permis de fournir une base de données sur les propriétés hydrodynamiques des sols forestiers et sur l'évolution de la teneur en eau. Nous avons estimé les paramètres hydrodynamiques (PH) avec la méthode BEST sur des binômes de sols circulés-non circulés. Nous avons développé une loi de passage prédisant les valeurs de la teneur en eau à saturation et de la conductivité hydraulique à saturation des sols circulés à partir de ceux non circulés. Ensuite, nous avons paramétré un modèle de fonctionnement hydrique mécaniste basé sur l'équation de Richards en contexte forestier. Nous avons évalué la capacité du modèle à prédire la teneur en eau selon différents jeux de PH estimés par : la méthode BEST, une fonction de pédotransfert FPT ou calage. Le modèle combiné aux PH estimé par la méthode BEST mène à des problèmes de dessèchement de la couche intermédiaire en période estivale. L'utilisation d'une FPT conduit à un plus faible pouvoir prédictif mais ne simule la phase de dessèchement. La stratégie choisie consiste à utiliser la méthode BEST comme première estimation des PH et ensuite d'en caler certains par inversion. Enfin, nous avons développé un modèle empirique utilisable en conditions opérationnelles. Nous avons utilisé le modèle mécaniste pour générer une base de données virtuelle permettant (i) d'identifier les principaux mécanismes impliqués dans la dynamique de dessèchement des sol à prendre en compte et (ii) de caler et valider le modèle empirique. Il est capable de prédire le "jour de praticabilité" avec une résolution de 1.5 à 2.5 jours en période estivale. En période hivernale, sa précision n’est pas satisfaisante (rmse = 8.4 j), elle s'explique par la sensibilité du modèle aux évènements pluvieux fréquents et rapprochés. Le modèle empirique s'applique pour une seule configuration "sol x peuplement x climat x seuil" et mérite d'être calé dans d'autres contextesThe increase of the mechanization during logging combined with climate changes increases the risk of driving in not suitable conditions and thus degrading soils. This is why it is necessary to develop decision support tools capable of predicting the practicability of forest soils. However, assessing practicability with simple tools and easily accessible data is complex. It depends on the susceptibility of the soil to deformation, the load applied, the accepted threshold of soil deformation and the water state of the soil. This work aims to better understand and predict the water dynamics of forest soils and of the skid trails (i.e. roads dedicated to the circulation of forest machines). The objectives are: (i) to improve our knowledge of the compaction effect on forest soil water dynamic, (ii) to parametrize a model predicting the soil water flow under forest context and (iii) to be able to predict the soil water content of forest soils in an operational context. This work was carried out in three stages. First, we established an observatory of skid trails that has provided a data base on forest soil hydraulic properties and water dynamic. We estimated the hydraulic properties with the BEST method on circulated and non-circulated soils. We have developed a law predicting the values of the saturation water conten and the saturation hydraulic conductivity of circulated soils from those not circulated. Then, we have parametrized in forest context a mechanistic model based on Richards equation. We evaluated the ability of the model to predict the soil water content according to different hydraulic parameters: BEST method, pedotransfert function PTF and optimization. With the hydraulic parameters estimated from BEST method, the model leads to problem of middle layer drying during the summer period. With pedotransfer function, the model leads to a poorer prediction but does not simulate the drying phase. The strategy chosen is to use the BEST method as the first estimate of the hydraulic parameters and then to calibrate some of them by inversion. Finally, we have developed an empirical model that can be used in operational conditions. We used the mechanistic model to generate a virtual data set to (i) identify the main mechanisms involved in soil drying dynamics that need to be taking into account and (ii) calibrate and validate the empirical model. It is able to predict the "day of traffic" with accuracy of 1.5 to 2.5 days in summer. In winter, its accuracy is not satisfactory (rmse = 8.4 days) and is explained by the model sensitivity to weather sequences composed of frequent and nearby rainfall events. The empirical model is applicable to a single configuration "soil x stand x climate x threshold" and should be calibrated in other contexts
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Stinghen, Geovanne Silva. "Assessment of nitrogen efficiency in maize due to soil compaction and changes in soil physical properties /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422967.
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Mobley, Thomas Jackson Melville Joel G. "Erodibility testing of cohesive soils". Auburn, Ala, 2009. http://hdl.handle.net/10415/1776.
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Chen, Cheng-Wei. "A constitutive model for fiber-reinforced soils". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4768.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Typescript. Vita. Title from title screen of research.pdf file (viewed on March 6, 2009) Includes bibliographical references.
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Duval, Jean. "Assessing porosity characteristics as indicators of compaction in a clay soil". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59275.
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Persistent soil compaction by heavy-axle-load vehicles is a growing concern for the long-term productivity of clay soils. For optimum soil management, however, we must be able to evaluate adequately soil structural damages. This study compares different methods of assessing soil structure as affected by compaction and subsoiling treatments in a clay soil under corn production.The tests used were: total porosity as calculated from densimeter readings and from soil cores; structural porosity; water desorption characteristics; and soil profile examination. These tests were performed in three layers of 20 cm and evaluation was based on their practicality and their ability to differentiate between treatments and to correlate with corn yield.
The results confirm that total porosity is a poor indicator of compaction in the subsoil. In soil profile assessments, ped descriptions were preferable to examination of pores. Water content and saturation deficit at $-$4.0 and $-$100 kPa were the best indicators of treatments and plant response.
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Ishihara, Katsuji. "At-rest and compaction-induced lateral earth pressures of moist soils". Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07122007-103943/.
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Romero, Ricardo J. "Development of a constitutive model for fiber-reinforced soils /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115585.
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Troost, Jan J. "Factors influencing laboratory vibratory compaction". Master's thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/17651.
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Includes bibliography.The thesis consists of a literature review and a limited experimental investigation in a soils laboratory. The objective of the literature review is to determine what standard laboratory test methods based on vibration exist for the control of compaction, to what soil types these tests are applicable and what the factors are which affect laboratory vibratory compaction. The study revealed that extensive research has been carried out in the USA and Europe, where standard laboratory compaction tests exist for the determination of the maximum dry density of cohesionless, free-draining soil. The US methods are based on the use of a vibratory table, while the European practice is based on the use of a vibratory tamper. No standard tests appear to exist for soil exhibiting cohesion, though limited research has been carried out in the USA into the behaviour of such soils under laboratory vibratory compaction. The factors; frequency, amplitude, mould size and shape surcharge intensity and manner of application, soil type, time of vibration, number of layers and moisture content are all reported to have an effect on the maximum dry density achievable. It has been recognised that significant interaction occurs between the factors affecting vibratory compaction, but the extent of the interaction appears to be only partly understood. The objective of the limited experimental program was to determine whether a specific graded crushed stone could be compacted to Modified AASHTO maximum dry density with a laboratory vibratory compaction technique using a vibratory table, and how this could best be achieved. The effects on dry density of changing the frequency, the time of vibration, mould size, surcharge pressure, grading and moisture content were investigated. It is concluded that the graded crushed stone in question can be compacted to Mod. AASHTO maximum dry density but that before reliable reproducible results can be achieved with this type of test further work is necessary. Such research should be aimed at investigating the interaction effect between the amplitude of vibration, the soil type and the type and intensity of the applied surcharge pressure.
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Pengthamkeerati, Patthra. "Soil physical and microbiological properties affected by soil compaction, organic amendments and cropping in a claypan soil /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3164537.
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Gameda, S. "Quantification, predictability and alleviation of high axle load compaction in Quebec soils". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39818.
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Soil structure and crop response under annual compactive loads of 10 and 18 t/axle and compaction alleviation treatments were assessed in a continuous corn production system. The alleviation treatments consisted of chemical conditioning with a non-ionic surfactant, and subsoiling with narrow-tined and winged implements. Parameters utilized for determining effects on soil structure were bulk density, water retention characteristics and soil profile characteristics. Significant topsoil and subsoil compaction resulted from both loading levels. Crop yield reductions due to compactive loading ranged from 18 to 27% under optimal weather conditions and were as high as 55 to 86% under adverse weather conditions. Soil amendments by chemical conditioning had no beneficial effect on soil structure or crop yields. Inter-row subsoiling with narrow-tined and winged subsoilers was effective in reducing soil compaction and increasing crop yields.Soil bulk density measurements gave good indication of overall compaction to a depth of 0.4 m and correlated well with crop yields, but were unable to locate differences between compactive treatments. Water retention characteristics indicated significant differences between compactive treatments to a depth of 0.6 m. Soil profile characteristics were useful for determining ped type and size as well as rooting depth and gave the best overall assessment of compaction alleviation effects.
Studies were also conducted to develop a method for predicting soil compactibility that would serve to manage soil compaction at the farm level. Preliminary studies focused on the determination of soil material properties for predicting bulk density changes under applied loads. Further investigations were conducted on the variations in constrained modulus, cone index and soil bulk density values under uniaxial loading. A model relating constrained modulus as a function of cone index, bulk density and soil moisture content was developed. Subsequent studies conducted yielded significant relationships between penetration resistance and soil compactibility as indicated by constrained modulus and coefficient of compressibility. Relationships obtained between penetration resistance and parameters of compactive work and bulk density change indicated the feasibility of assessing soil compactibility at the farm level.
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Ekrami-Nasab, Nader. "An advanced numerical model for the dynamic compaction of unsaturated granular soils". Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/608.
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Fair, Barbara A. "Growth response and adaptability of acer rubrum and acer XFREEMANII cultivars to soil compaction". The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1117571227.
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Jenkins, Anthony Blaine. "Organic carbon and fertility of forest soils on the Allegheny Plateau of West Virginia". Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2486.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains x, 282 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
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Taillon, Kate. "Modeling surface complexation relationships in forest and agricultural soil". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82435.
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The adsorption behaviour of trace metals in soil may provide us with a way to more accurately predict and assess the toxicity of metals in the environment. This thesis reports efforts to apply surface complexation modeling to agricultural and forest soil and to relate model parameters to common soil properties. This study considered Ca, Cd, Cu, Pb and Zn but the methods here could be applied to other metals. In Chapter 2, the surface charge and adsorption behaviour of a set of Ap horizons was characterised using back-titration and batch adsorption techniques. With the objective of simplifying the application of the NICCA model to surface charge and cation adsorption in whole soils the parameters of the NICCA model were related to soil properties (Chapter 3). Four of the six surface charge parameters could be predicted from soil properties and this enabled me to reasonably predict the surface charge of a second group of soils from soil properties. These results suggest that it is possible to make reasonable predictions about the surface charge and adsorption behaviour of a given type of soil using some easily measurable soil properties and a set of generic NICCA adsorption parameters for that soil type. In Chapter 4 this idea is applied to the determination of lime requirement for the agricultural soils.
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Green, Russell A. "Energy-Based Evaluation and Remediation of Liquefiable Soils". Diss., Virginia Tech, 2001. http://scholar.lib.vt.edu/theses/available/etd-08132001-170900.
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Sampietro, Jean Alberto. "PROPRIEDADES MECÂNICAS E TRAFEGABILIDADE DE SOLOS EM PLANTIOS FLORESTAIS". Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/3759.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorMechanization significantly increased the productivity, quality and cost reduction for forests cultivation. However, it may be responsible for environmenral impacts, such as soil compaction, which is a result of traffic, mostly during wood harvesting operations. The objectives of this research were to evaluate the physical quality, trafficability and soil compaction due to traffic of wood harvesting machines of Eucalyptus sp. and developing functions to estimate physical and mechanical properties. The research was conducted in soils coming from implantation areas of Eucalyptus sp., and from an operational area of harvesting of Eucalyptus saligna Sm, belonging to CMPC Celulose Riograndense. To answer the hypotheses and meet the objectives, this work was divided into two studies. In Study I, five forest soils with different textural compositions were evaluated, determining physical quality indicators, trafficability indicators coming from the Proctor Normal test and uniaxial compression, and Atterberg consistency limits. The main results showed that both indicators of physical and trafficability were related to textural composition of soil, being estimated from these, as well as being influenced by different states of compaction. Furthermore, it was found that changing the bearing capacity has resulted in alteration of least limiting water range, which are related and, in this way, allowed to estimate the critical pressure for the plants growth. In Study II, we assessed the effect of different traffic intensities of a Harvester and a Forwarder on a Haplic Cambissol with sandy loam texture in Eucalyptus saligna Sm. stands, by determining the machines contact area and ground pressure exerted on soil, bulk density, pore size distribution, water retention curve, available water content, saturated hydraulic conductivity, air permeability, penetration resistance, compressibility, degree of compaction and shear strength. Were also evaluated the relationship of these properties and parameters. The main results indicated that few machines passes (one pass of Harvester and the four more of Forwarder) resulted in great part in soil deformation and changing in all evaluated properties and parameters. Mostly effects occurred until the depth of 20 cm. However, increasing the number of passes also caused changes in the deeper layers of soil. In general, the effects were higher in the area below within tracks, but, even so, effects occurred in areas between the wheels tracks and outside the areas of machines tracks. It was concluded that actions to minimize the compaction of forest soils should be associated with moisture conditions, traffic intensity and soil type.
A mecanização possibilitou aumento da produtividade, qualidade e redução de custos das atividades para o cultivo de florestas. Entretanto, tem sido responsável por impactos ambientais, destacando-se a compactação do solo, a qual é resultado do tráfego intenso de máquinas, principalmente nas operações de colheita. Os objetivos desta pesquisa foram avaliar a qualidade física, trafegabilidade e a compactação de solos, em função do tráfego de máquinas de colheita da madeira de Eucalyptus sp. e desenvolver funções para a estimativa de propriedades físicas e mecânicas. A pesquisa foi desenvolvida em solos advindos de áreas de implantação de povoamentos de Eucalyptus sp., e de uma área operacional de colheita de Eucalyptus saligna Sm., pertencentes à empresa CMPC Celulose Riograndense. Para responder as hipóteses e atender aos objetivos, o trabalho foi dividido em dois estudos. No Estudo I, foram avaliados cinco solos de uso florestal de diferentes composições texturais, determinando-se os indicadores de qualidade física, indicadores de trafegabilidade advindos do ensaio de Proctor Normal e compressão uniaxial, e limites de consistência. Os principais resultados mostraram que os indicadores de qualidade física e de trafegabilidade foram relacionados aos atributos texturais, podendo ser estimados a partir destes, além de serem influenciados por diferentes estados de compactação. Além disso, constatou-se que a alteração da capacidade de suporte resultou na alteração do intervalo hídrico ótimo, sendo estes relacionados, permitindo, assim, ser estimada a pressão crítica para o crescimento de plantas. No Estudo II, foi avaliado o efeito de diferentes intensidades de tráfego de um Harvester e um Forwarder sobre um Cambissolo Háplico de textura franco-arenosa em povoamentos de Eucalyptus saligna Smith, por meio da determinação da área de contato, pressão exercida pelas máquinas sobre o solo, densidade, distribuição de tamanho de poros, curva de retenção de água, conteúdo de água disponível, condutividade hidráulica do solo saturado, permeabilidade ao ar, resistência do solo à penetração, compressibilidade, grau de compactação e resistência ao cisalhamento. Foram avaliadas, também, as relações dessas propriedades e parâmetros. Os principais resultados indicaram que poucas passadas das máquinas (uma do Harvester e quatro do Forwarder) foram responsáveis em grande parte pela deformação e alteração de todas as propriedades e parâmetros. Os efeitos foram maiores até os 20 cm de profundidade. Entretanto, o aumento do número de passadas também causou alterações nas camadas mais profundas do solo. Em geral, os efeitos foram maiores na zona abaixo da trilha dos rodados, porém, ainda ocorreram efeitos nas zonas entre os rodados e fora da trilha dos rodados das máquinas. Conclui-se que as ações para minimização da compactação de solos florestais devem estar associadas às condições de umidade, intensidade de tráfego e tipo de solo.
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Ring, Eva. "Nitrogen in soil water at five nitrogen-enriched forest sites in Sweden /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5795-5.pdf.
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Ficklin, Robert L. "An empirical approach for better estimating soil organic carbon and bulk density using a fixed-volume sampling method /". free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3074401.
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Ohu, John Olutunde. "Peatmoss influence on strength, hydraulic characteristics and crop production of compacted soils". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71960.
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The quantitative effects of increasing the organic matter contents of three soils upon their susceptibility to compaction, the recovery of tilth after compaction and the fertility of the soils were investigated. These effects were further studied on the production of bush bean (Phaseolus vulgaris).Soil consistency limits, soil water status, applied pressure and organic matter contents were used to predict shear strength, penetration resistance and water retention characteristics of compacted soils, with the aim of meeting the widespread demand for possible techniques of soil compaction prediction.
Soil compaction increased the ability of the soils to retain moisture, increased penetration resistance, shear strength and decreased the available water capacity of soils. On the other hand, organic matter increased the ability of the soils to retain moisture, expanded the available water capacity and decreased the penetration resistance and shear strength of compacted soils.
Although soil compaction increased the stem diameter of bush bean; the height, yields and root dry matter of the crop decreased with higher compaction levels. On the contrary, higher organic matter levels increased the plant and yield parameters of the crop.
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Montagu, Kelvin D. "Whole plant response to soil compaction : from field practices to mechanisms /". View thesis View thesis, 1995. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030522.092251/index.html.
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Chandler, Douglas Scott. "An area approach to forest slope stability /". Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/10181.
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Gibson, Richard W. "The characterisation of soluble organic matter from forest soils". Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295565.
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The characteristics of water-soluble organic material in soil solutions has been studied extensively 'in situ'. Relatively little attention has focused on isolation of such material, particularly when comparison of a number of samples has been attempted. In this study the water-soluble organic acids leached from the soil horizons beneath eight different tree species were isolated by adsorption onto macroporous resins. Amberlite XAD-8 and XAD-4 resins were used in series therefore two samples, labelled as 'hydrophobic' and 'hydrophilic' acids were obtained. Practical amounts of free organic acids for characterisation purposes were isolated from each resin. Elemental analysis (carbon, nitrogen and sulphur) and acidity (measured by potentiometric titration) reflected the probable state of oxidation of the material. Lower molecular weight material was more abundant with depth. Copper binding ability correlated well with the acidity generally but a group of samples isolated from similar horizons and resin showed high acidity and poor metal binding ability. This was probably due to the inability of the acidic sites to be involved in chelation reactions. Metal binding was measured using gel filtration, dialysis and an ion-exchange method. Chromatography in gel filtration was monitored by direct feed of column effluent into an atomic absorption spectrophotometer, a technique attempted but not used successfully before. The method measured directly metal bound and required only 0.2 mg of sample per determination. For these reasons this method was used for routine analysis whereas dialysis and ion-exchange were only used for comparison purposes. As expected the samples isolated on each resin were very different. Comparison of samples from the horizons showed clearly the increased state of oxidation with depth. It was possible to establish differences in the organic material in the soil horizons on the basis of whether the stands were coniferous or deciduous trees but the similarities between the samples were perhaps equally striking.
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Ilstedt, Ulrik. "Soil degradation and rehabilitation in humid tropical forests (Sabah, Malaysia) /". Umeå : Swedish University of Agricultural Sciences, 2002. http://diss-epsilon.slu.se/archive/00000233/.
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Thesis (doctoral)--Swedish University of Agricultural Sciences, 2002.Abstract inserted. Appendix reprints four papers and manuscripts co-authored with others. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix.
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Dennis, Wilson Dennis. "Estimation of Carbon Dioxide emissions from forest soils based on CO2 concentrations". Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-33240.
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Forest soil is an important source of atmospheric CO2. Emission of CO2 from soil is the result of respiration of plant roots and soil organisms (Autotrophic and Heterotrophic respiration). This soil CO2 emission has a variation throughout the year with maximum emissions being in the summer. However, the seasonal variation affected by the external factors is not fully known. The aim of this thesis is to analyze a relationship between concentration of CO2 in the soil-atmosphere and CO2 emissions to the aboveground atmosphere. When knowing the relationship between CO2 concentration in the soil-atmosphere and the emission of CO2 from the soil atmosphere, a function (equation) can be established. Usually, the best fit is considered to establish the relationship. With the equations obtained, it is possible to calculate CO2 emissions using data different projects, where only soil-atmosphere CO2 concentrations were determined. Using the relationships, emissions rates in different soil types and in forest transect have been analyzed for a large number of samples. The effect of nitrogen deposition on CO2 emissions and seasonal variation of CO2 emission has also been studied. The sampled sites chosen for this study were located in different parts of Southern Scandinavia and Germany. A closed chamber was used to measure CO2 emission from soil. Soil CO2 concentrations were measured at every station and the equations were established. Finally, these relationships were used for analyses and comparison of the sites. An equation (best fit) obtained was used to calculate the emission values of CO2. The soil texture had a great influence on the CO2 from the soil besides the atmospheric pressure and temperature variations during the seasons. It is concluded that, therefore the soil texture and had a great influence on the CO2 emission from the soil besides the atmospheric pressure and temperature variations during the season. When knowing the equation between CO2 concentration and emission for a special type of soil, it is possible to estimate emissions based on CO2 concentrations. Therefore large scale sampling of CO2 concentrations could be done and this will facilitate the inventories carried out in e.g. global change studies.
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Kraus, Tamara Esther Caroline. "Tannins and nutrient dynamics in forest soils : plant-litter-soil interactions /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Sjödin, Sophia. "The Forest Fire in Västmanland, South Central Sweden, and its Effects on Soils and Forest Recovery". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303526.
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Forest fires can have a great impact on the relationship between soil organic matter (SOM) and soilbulk density (SBD). SOM will reduce with increased fire intensity, which ultimately leads to more compaction of the soil. The compaction rate might increase to the limit of where root growth will be absent thus leading to actions to restore the soil. This study investigates changes in the relationship between SOM and SBD in spodosol and histosol in Seglingsberg, located in South-central Sweden, where a forest fire occurred summer 2014. In addition, changes of pH values in the two types of soilwere examined in order to receive information about the chemical states of the different soil types.A total of 29 samples at depths of 0-17 cm were received from one day of fieldwork and these were later analysed concerning the pH, the SBD and the SOM content. The results showed an increase of pH-values in the fire-exposed area compared to pH values measured at the reference site (pH ~5). More importantly, the results from the SBD and SOM analyses indicated that there was in fact an inversely proportional relationship between the two soil parameters. In addition, high pH values were measured at the same subareas of which the highest SBD- and the lowest SOM values were obtained.Statistical analyses were applied on the results in order to conclude if the soil property changes caused by the fire were significantly different from normal conditions or not. The results from the statistical analyses revealed that 25% of the fire-exposed sites had changed significantly. However, more samples should have been taken while in field, since lack of data is thought to have had a great impact on the final results.Although there were no strong statistical evidence for the hypothesis, it is clear that the forest firein Västmanland year 2014 affected both the SOM, SBD and pH values in the soils.Under sommaren år 2014 utbröt en omfattande skogsbrand i Västmanlands län, vilket medföljdedramatiska konsekvenser för framförallt ett flertal skogsbolag, men även för boende i området. Med skogsbränder följer negativa såväl som positiva konsekvenser, där de positiva framförallt gäller med avseende på arter som har evolverat i samband med bränder. Förutom ovannämnda konsekvenser så finns det risk för att markförhållandena ändras till följd av en skogsbrand. I denna studie undersöktes hur markegenskaper i torv- samt podsoljordar hade förändrats med avseende på pH, halten avorganiskt material samt packningsgrad. Fältstudien genomfördes i ett drabbat brandområde strax norrom Seglingsberg, Surahammars kommun. Totalt togs 29 stycken jordprover inom fem stycken transekter i området. Av dessa kunde 25 stycken användas till alla tre analyserna. Resultaten från jordprovsanalyserna användes därefter till att genomföra statistiska undersökningar. Detta för att se hur stor spridningen var mellan och inom de fem transekterna samt för att kunna avgöra om jordproverna visade sig vara signifikant förändrade från ursprungsförhållanden.Resultaten från jordprovsanalyserna visade att det fanns mest organiskt material kvar i de östra delarna av området, medan det var kraftigt reducerat ju längre nordväst jordproverna hade hämtats. I samband med att markens organiska material hade reducerats kunde man även bevittna att jordtäcket hade blivit mer kompakterat. Resultaten från pH-analysen pekar också på att förändringarna varit som störst i de nordvästliga delarna. pH-analysen bevisade att markkemin ser annorlunda ut än innanbranden, då värdena ibland låg 2 enheter för högt än vad man vanligen brukar observera i podsol- ochtorvjordar. Då pH-skalan är logaritmisk innebär detta en minskad försurning med 100 gånger. Resultaten från alla jordprovsanalyser tyder att branden varit som mest intensiv i den nordvästra delen av undersökningsområdet, i området bestående av ungskog.Även om resultaten från jordprovsanalyserna pekade på att branden orsakat tydliga mark- förändringar, visade majoriteten av de statistiska undersökningarna inte på signifikanta förändringar. Det är därför inte möjligt att generalisera resultaten och således applicera dessa på hela brandområdet i Västmanland.Eftersom att naturligt förekommande skogsbränder är relativt få till antalet i Sverige, finns därmed få studier tillgängliga inom ämnesområdet. Det finns en upplaga av studier inom kontrollerade och anlagda brandfält, men i och med att dessa förhållanden är fixerade, så påverkas markegenskaperna sällan avsevärt. Forskningsrapporter indikerar på ett mer extremt klimat i framtiden, som förmodas leda till en ökad omfattning samt ett ökat antal naturligt förekommande skogsbränder. Om denna prognos stämmer är det viktigt att undersöka markförhållandena, då en skogsbrand kan ha direktavgörande effekt på återväxten.
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Dumont, Marc. "Molecular ecology of methanotrophs in a forest soil". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33396.
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Upland soils are a significant sink of atmospheric methane, but the organisms responsible for methane consumption have yet to be identified. The ecology of methanotrophs was investigated in a beech forest soil which exhibited atmospheric-methane-uptake. Maximal methane-oxidation was observed in the upper mineral layer between the organic and inorganic horizons at a rate of 3.1 +/- 0.3 nmoles CH 4 g [fresh wt soil]-1 d-1. A clone bank of the methanotroph pmoA gene was constructed by PCR amplification from soil DNA extracts. The PCR primers used coamplify the related amoA gene of ammonia-oxidizers. The clones recovered grouped into three clusters: Nitrosospira-like sequences, a group somewhat related to alpha-Proteobacteria methanotrophs and previously referred to as the RA14 group, and a cluster which could not be characterized as either amoA or pmoA sequences. No pmoA genes closely related to genera of cultured methanotrophs were obtained. The 16S rDNA was also targeted using eubacterial and methanotroph-specific primers. 16S rDNA sequence analysis revealed the presence of organisms distantly related to known methanotrophs. Methanotroph enrichment cultures were established by inoculating mineral salts medium with soil and incubating under an atmosphere of 10% methane in air. Gene sequencing from the enrichments indicated the presence of organisms belonging to the genera Methylosinus and Methylocystis. The results suggest that the dominant methanotrophs in the forest soil are not related to known organisms and do not grow under conditions typically used to isolate methanotrophs.
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Gärdenäs, Annemieke. "Soil organic matter in forest soils : effects of climate and water balance /". Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5530-8.gif.
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Kabzems, Richard Darwin. "Quantitative classification of soil nutrient regimes of some mesothermal Douglas-fir ecosystems". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24691.
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Previous attempts to classify nutrient regimes of forest soil have been qualitative evaluations utilizing vegetation and/or physiographic site characteristics, morphological soil properties, and parent material. The major objective of this study was to describe and classify the soil nutrient regimes (SNR) of some Pseudotsuga menziesii ecosystems on southern Vancouver Island, British Columbia. The order of increasing variability for forest floor properties was pH(H₂0) Graduate
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Daniels, W. Lee. "Virgin hardwood forest soils of western North Carolina". Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/52288.
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Little is known about the original properties of soils in the East. Eight virgin soils and associated southern Appalachian hardwood vegetation were studied in western North Carolina. The study sites ranged in elevation from 720 to 1200 m on steep slopes. Overall these soils are quite deep and highly weathered due to high rainfall (>200 cm) and soluble feldspathic parent material. Organic matter contents of the surface·horizons were quite high (4.5 - 16 %), and they contained moderate to strong crumb structure. All but one soil contained cambic subsurface horizons and were either Typic Haplumbrepts or Umbric Dystrochrepts. The majority of soils in the watershed are formed in colluvium, but significant amounts of residual soils occur on sideslopes, and appear to be quite stable. The present day landforms appear to be the result of periglacial activity.
North-facing soils were higher in whole soil clay, organic matter, and A horizon exchangeable cations than south-facing soils. Cation exchange capacity in these soils is almost totally dependent on organic matter content, and the mineral fraction is relatively inert. All soils were in the oxidic mineralogy class. Bibbsite was common throughout all soils and hydroxy-interlayered vermiculite (HIV) is the dominant clay-sized phyllosilicate in surface horizons. Kaolinite was low in all soils, but was more abundant on south-facing slopes. The silt fractions and sand fractions contained significant quantities of weathered 2:1-type minerals
The vegetation varied from mixed-mesophytic cove hardwoods on north-facing slopes to mixed oak-hickory and oak-pine on south-facing slopes. Many trees in coves exceed 1.3 m in diameter and 50 m in height. Total litter production averaged 3494 kg/ha, and the litter layers were typified by thin leaf (L), and well developed fermentation (F) and humus (H) layers. Cations and P are concentrated in the litter layers and immediate surface soil, while N is mixed deep into the profile. Due to their oxidic mineralogy, low CEC, decreasing clay content with depth, and concentration of cations and P in litter and standing biomass these soils highly resemble tropical Oxisols.Ph. D.
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Pelletier, Bernard 1964. "A multivariate analysis of tree species influence on forest floor fertility /". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68239.
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The objective of this study was to assess tree species influence on forest floor fertility in a mixed forest stand using Redundancy Analysis (RDA). Eighty microsites were located in a beech-hemlock-red maple forest. Forest floor was analyzed for thirteen variables; total N, P, K, Ca and Mg, extractable Ca, Mg and K, mineralizable N (NH$ sb{4+}$), basal microbial respiration (CO$ sb2$), pH, thickness and bulk density. The influence of seven tree species was calculated as a function of tree diameter and distance from each microsite. Spatial patterns were detected by using correlograms and incorporated in a variation-partitioning model with trend surface analysis. Tree species, microtopography, and spatial structure explained 53% of the total variation in forest floor data. The fraction explained by tree species alone (16%) was studied with a RDA ordination biplot. The main source of variation in the soil data was related mainly to the opposite effects of American beech and eastern hemlock on calcium while most of the other species had a beneficial effect on soil fertility. This study showed the potential of RDA as a tool for studying the role of tree species in mixed forests.
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Regmi, Sanjeev. "EFFECT OF PLASTICITY AND INITIAL COMPACTION CONDITIONS ON SOIL WATER CHARACTERISTICS CURVE OF FINE-GRAINED SOILS". OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2625.
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The soil water characteristics curve (SWCC) of a soil plays an important role in study of unsaturated soil mechanics. The behavior of unsaturated soil is a complex phenomenon to understand and the direct measurement of unsaturated soil properties in laboratory or in field is costly and time consuming. Knowing the SWCC of a soil is useful in estimating the unsaturated property of a soil, which is close to the natural soil conditions and can be used in effective design procedure. The present study deals with the effect of plasticity and initial compaction conditions of a soil in the SWCC by using SWC-150 (Fredlund SWCC device) and WP4C dewpoint potentiometer. The test data obtained from both the device were best fitted using Fredlund and Xing (1994) equation (FX), Van Genutchen (1980) equation (VG), Burdine (1958) equation, and Mualem (1976) equation.
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Wang, ShuHong. "Soil substrate selection for urban trees under deicing salt and compaction conditions". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82446.
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The effects of high sodium chloride (NaCl) levels on Na and nutrient retention of three soil substrates and on littleleaf linden growth in different soil substrates were studied in the laboratory and the greenhouse, within the framework of a substrate selection program for trees planted in downtown Montreal. In addition, the effects of the structural soil (SS) compaction were studied in the first greenhouse experiment. The first greenhouse experiment was established in a factorial arrangement of four soils x four salt levels in a completely randomized design with five replicates. The four soil types were (1) L with a bulk density (BD) of 1.53 g/cm3, (2) LP with a BD of 1.26 g/cm3, (3) SS with a BD of 1.8 g/cm 3 (SS1.8), and (4) SS with a BD of 2.0 g/cm3 (SS2.0). The second greenhouse experiment had a split plot design. Two fertilization levels (with fertilizer and without fertilizer) were randomly arranged as the main plots on ten benches. Within each main plot, the combinations of three NaCl levels (0, 0.5 and 1.0 g NaCl/kg soil) and three soil substrates (L with a BD of 1.40 g/cm3, LP with a BD of 1.13 g/cm 3 and SS2.0) were randomized in the sub-plots. Results from the laboratory leaching experiment indicated that SS had the fastest Na leaching rate and highest Na loss, while LP retained more Na than SS or L. (Abstract shortened by UMI.)
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Carr, William Wade. "Restoring productivity on severely degraded forest soil in British Columbia". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25572.
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Forest road building and timber harvesting operations have been recognized as principal causes of forest soil degradation. These activities can result in accelerated soil erosion, excessive scarification, and/or increased soil density, which may adversely affect site productivity.
A study of landing areas emphasize the deficiencies in current rehabilitation guidelines Increased soil density on both summer and winter landings was still evident at 30 cm and the soil nutrient quality was poor. Two field tests of a green fallow system on subsoil materials exposed by erosion and landing construction proved successful in building site nutrient capital to acceptable levels. Seedling growth response to green fallow crop establishment in the coastal study verified these findings.
A benefit-cost analysis of several forest soil rehabilitation scenarios demonstrated the importance of including secondary and intangible factors. From a pecuniary standpoint, based on primary benefits and costs, rehabilitation was economically feasible only when a low social discount rate (2%) and an optimistic stumpage increase projection (3% per year), were used. A discussion of some secondary and intangible benefits (i.e., harvesting rates, employment, government revenues, erosion control, and industry image) stresses the need for effective forest soil rehabilitation.Forestry, Faculty of
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Almond, Peter C. "Soils and geomorphology of a lowland rimu forest managed for sustainable timber production". Lincoln University, 1997. http://hdl.handle.net/10182/1782.
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Saltwater Forest is a Dacrydium cupressinum-dominated lowland forest covering 9000 ha in south Westland, South Island, New Zealand. Four thousand hectares is managed for sustainable production of indigenous timber. The aim of this study was to provide an integrated analysis of soils, soil-landform relationships, and soil-vegetation relationships at broad and detailed scales. The broad scale understandings provide a framework in which existing or future studies can be placed and the detailed studies elucidate sources of soil and forest variability. Glacial landforms dominate. They include late Pleistocene lateral, terminal and ablation moraines, and outwash aggradation and degradation terraces. Deposits and landforms from six glacial advances have been recognised ranging from latest Last (Otira) Glaciation to Penultimate (Waimea) Glaciation. The absolute ages of landforms were established by analysis of the thickness and soil stratigraphy of loess coverbeds, augmented with radiocarbon dating and phytolith and pollen analysis. In the prevailing high rainfall of Westland soil formation is rapid. The rate of loess accretion in Saltwater Forest (ca. 30 mm ka⁻¹) has been low enough that soil formation and loess accretion took place contemporaneously. Soils formed in this manner are known as upbuilding soils. The significant difference between upbuilding pedogenesis and pedogenesis in a topdown sense into an existing sediment body is that each subsoil increment of an upbuilding soil has experienced processes of all horizons above. In Saltwater Forest subsoils of upbuilding soils are strongly altered because they have experienced the extremely acid environment of the soil surface at some earlier time. Some soil chronosequence studies in Westland have included upbuilding soils formed in loess as the older members of the sequence. Rates and types of processes inferred from these soils should be reviewed because upbuilding is a different pedogenic pathway to topdown pedogenesis. Landform age and morphology were used as a primary stratification for a study of the soil pattern and nature of soil variability in the 4000 ha production area of Saltwater Forest. The age of landforms (> 14 ka) and rapid soil formation mean that soils are uniformly strongly weathered and leached. Soils include Humic Organic Soils, Perch-gley Podzols, Acid Gley Soils, Allophanic Brown Soils, and Orthic or Pan Podzols. The major influence on the nature of soils is site hydrology which is determined by macroscale features of landforms (slope, relief, drainage density), mesoscale effects related to position on landforms, and microscale influences determined by microtopography and individual tree effects. Much of the soil variability arises at microscales so that it is not possible to map areas of uniform soils at practical map scales. The distribution of soil variability across spatial scales, in relation to the intensity of forest management, dictates that it is most appropriate to map soil complexes with boundaries coinciding with landforms. Disturbance of canopy trees is an important agent in forest dynamics. The frequency of forest disturbance in the production area of Saltwater Forest varies in a systematic way among landforms in accord with changes in abundance of different soils. The frequency of forest turnover is highest on landforms with the greatest abundance of extremely poorly-drained Organic Soils. As the abundance of better-drained soils increases the frequency of forest turnover declines. Changes in turnover frequency are reflected in the mean size and density of canopy trees (Dacrydium cupressinum) among landforms. Terrace and ablation moraine landforms with the greatest abundance of extremely poorly-drained soils have on average the smallest trees growing most densely. The steep lateral moraines, characterised by well drained soils, have fewer, larger trees. The changes manifested at the landform scale are an integration of processes operating over much shorter range as a result of short-range soil variability. The systematic changes in forest structure and turnover frequency among landforms and soils have important implications for sustainable forest management.
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Kranabetter, John Marty. "Pulp fibre waste as a soil amendment : rates of net carbon mineralization". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29193.
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The potential for using RMP (refiner mechanical process) pulp mill fibre waste as a soil amendment was investigated by determining levels of net carbon mineralization. Under optimum conditions (laboratory incubation study), the pulp fibre waste, being a relatively homogeneous substrate, was found to mineralize at one rate of -0.0078 d⁻¹. In field applications the rate of net mineralization was slower, with rates of -0.0034 d⁻¹ and -0.0037 d⁻¹, as determined by soil respiration and litter bag trials, respectively. A loading effect was noted for this amendment, where increasing the levels of application was found to cause decreases in the mineralization rate.
Using pulp fibre waste in forest landing rehabilitation appears to increase the levels of microbial activity in the surface horizon. The higher levels of productivity should lead to improvements in soil structure, and would be a better alternative to only tilling and fertilizing the soil.Land and Food Systems, Faculty of
Graduate
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Boström, Björn. "Achieving carbon isotope mass balance in Northern forest soils, soil respiration and fungi /". Örebro : Department of Natural Sciences, Örebro University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-2101.
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Meyer, Natalie Jo. "Soil and plant response to slash pile burning in a ponderosa pine forest". Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2008/meyer/MeyerN1208.pdf.
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Slash pile burning is the most common method of forest residue disposal following ponderosa pine restoration harvests, which are intended to reduce the risk of catastrophic fire and restore the historical structure and function of forests in western Montana. The impact of high-intensity, long-duration fire (pile burning) on soil processes and plant community dynamics is not well understood. The objectives of this study were: (1) to characterize the influence of slash pile burning on soil nutrient availability, soil microbial activity, and arbuscular mycorrhizal (AM) infection; (2) to compare seeding and soil amendment effects on burn scars. In May 2006, slash piles were burned in a ponderosa pine stand near Florence, Montana and 45 scars were sampled. Soil samples were collected from three locations in each slash pile to a depth of 10 cm and characterized for available soil NH4 +-N, NO3 - -N, potentially mineralizable nitrogen (PMN), and total C and N, water-soluble PO4 3- -P, microbial biomass, and mycorrhizal inoculum potential (MIP). In the burned center, soil NH4 +-N was greatest one month post-burn and remained elevated one year later. There was no observable increase in NO3 - -N until one year post-burn. Soluble PO4 3- -P was not impacted by burning. Microbial biomass was reduced by burning and did not recover one year later. Pile burning greatly reduced MIP. In October 2006, fire scars were either seeded with native graminoids or left non-seeded, divided into subplots, and assigned to one of five treatments: control, addition of local organic matter, scarification, scarification and organic matter addition, or scarification and commercial compost addition. Soils were monitored for the previously measured soil parameters and resin-sorbed inorganic N. Scarification with organic matter amendment and scarification with compost amendment both ameliorated soil properties. Seeding most effectively increased plant cover and suppressed non-native invasive species, while scarification or scarification with organic matter amendment further improved early plant establishment. Collectively, these data help characterize the impacts of slash pile burning as a management technique in ponderosa pine forests and illustrate potential treatments for restoring burn pile scars.
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Mwalukomo, A. C. W. "Plant-soil relations in forest, scrub and grassland on chalk in Southern England". Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234020.
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The chief objective of the research was to establish the relative fertility of forest, scrub and grassland soils on chalk in SE England and to test hypotheses on the origin of fertility differences between the soils. A subsidiary objective was to relate the beech forests of the chalk in England to continental beech forests on calcareous parent materials and thus to utilize the results of continental studies on discussion of the nutrient status of the different forest types of Europe. Previous research by B.A. Key had concentrated on scrub and grassland, and my research concerned chiefly scrub and forest. The fertility of soils was assessed by bioassays with commonly occuring test species, i.e. Galium aparine, Deschampsia caespitosa and Arctium minus, by foliar analysis of component woody species and by soil incubation tests. The results of bioassays show that the scrub soils of the chalk in SE England are more fertile than either grassland or forest soils. Bioassay plants grown on forest soils showed considerable variation in yield and nutrient content indicating that there is much variation in the fertility of forest soils. Mercury beech forest soils as a class were more consistent and produced better growth of test species than grassland soils while beech forests without mercury, traditionally classed as sanicle beechwoods, were found to have soils of very wide ranging fertility. Beech foliar analysis did not distinguish between mercury and sanicle beech forests, although the trend was for higher N status in the beech leaves of mercury sites. No trend was observed in the P status of beech leaves. The potential for nitrogen mineralization was favourable in both scrub and forest soils but much lower in grassland soils. Soils underneath mercury beech forests were consistent in nitrification and yielded similar concentrations of nitrate during one-month incubation to soils beneath relict ash-hazel forests. No such consistency was found for the soils of beech forests without mercury, and contrary to expectation, their potential to supply nitrogen appeared to be higher than that of mercury beech forest soils. The fertility differences shown by bioassays were most probably due to phosphorus supply. Experiments with several species have shown that the primary limiting nutrient in chalk soils is phosphorus; especially when plants are grown in pots at low rooting density. Nitrogen limitation has been found but only after adding a phosphorus fertilizer solution or when plants are grown at high rooting density. In these experiments, except where the objective was to separate the effects of nitrogen from phosphorus, test plants were grown one per pot for a relatively short time. It was hypothesized that the differences in fertility level of soils supporting forest, scrub and grassland on chalk in SE England were chiefly the result of differences in the amounts of nutrients added each year in litter. Freshly fallen litter of several woody species of chalk beech forests was collected from nylon nets set out on the forest floor in autumn 1984 and 1985. In order to investigate the role of nutrient withdrawal, in autumn 1985 mesh bags were used to collect freshly fallen litter within the canopy of scrub and forest. In both types of experiments N and P content was analysed on a species-specific basis. In addition, fine litterfall in a typical mercury beech forest was estimated in 1984 and rates of litter decomposition of five key species were measured over a period of 1 1/2 yr. Beech litter has relatively low phosphorus concentrations and is slow to decompose. Phosphorus is retranslocated from falling leaves in greater amounts in beech than in Crataegus, and Cornus, the main constituents of scrub which would seem to explain the lower phosphorus status of beech forest soils than scrub soils.