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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Preparo profundo e calagem em solos arenoso e argiloso na física e carbono do solo e na produtividade de cana-de-açúcar /

Guimarães, Tiara Moraes, 1985. January 2019 (has links)
Orientador: Juliano Carlos Calonego / Banca: Alexandrius de Moraes Barbosa / Banca: Gustavo Pavan Mateus / Banca: Kleber Pereira Lanças / Banca: João Paulo Gonsiorkiewicz Rigon / Resumo: Com o advento de sistemas de direcionamento via satélite, onde é possível controlar tanto o tráfego das máquinas, quanto planejar e realizar o preparo e a sulcação apenas em locais pré-definidos, onde não haverá tráfego de máquinas, novos sistemas de preparo do solo têm surgido. O preparo profundo cateirizado consiste em preparar, corrigir e adubar o terreno somente na área onde serão confeccionados os sulcos de plantio, ou seja, somente na zona de crescimento das plantas, limitando a compactação em área específica de trânsito de maquinários. Porém, ainda é pouco conhecido os efeitos desse sistema de preparo na estrutura do solo e produtividade da cana-de-açúcar. Objetivou-se com esse trabalho avaliar, em área de cultivo de cana-de-açúcar, o efeito da calagem e do preparo do solo, na produtividade de colmos, nos atributos físicos do solo e na qualidade da matéria orgânica. Para isso, foram realizados dois experimentos, sendo um em solo de textura argilosa (Nitossolo Vermelho) e outro em solo de textura franco-arenosa (Latossolo Vermelho-Amarelo), utilizando-se o delineamento experimental de blocos casualizados, com quatro repetições. Os tratamentos foram constituídos por: Preparo Convencional (PC) sem aplicação de calcário, PC com aplicação de calcário, Preparo Profundo (PP) sem aplicação de calcário, e PP com aplicação de calcário. Foram avaliados os atributos físicos, carbono orgânico total (COT), fracionamento físico da MOS, biomassa microbiana do solo e produtividade de c... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The advent of satellite guidance systems promoted the emergence of the new tillage systems due to the possibility to control machine traffic, as well as to plan and prepare and furrow only in pre-defined locations where there will be no machine traffic. The deep soil tillage in the plant growth zone consists in the descompactation, liming and fertilization only in the area where the planting furrows will be made, ie only in the plant growth zone, limiting soil compaction in a specific machine traffic zone. However, the effects of this tillage system on soil structure and sugarcane yield are still poorly known.The aim of this experiment was to assess the effect of liming and soil tillage (deep tillage banded and conventional tillage), in the area of sugarcane production, on stalks yield, soil physical attributes and soil organic matter quality. For this, two experiments were carried out, one in clayey soil and the other in sandy soil, using a randomized blocks experimental design with four replications. The treatments were constituted by: conventional preparation (PC) without application of limestone, PC with limestone application, deep preparation (PP) without application of limestone, and PP with application of limestone. The physical attributes, total organic carbono, physical fractionation of organic matter, soil microbial biomass and stalk yield were evaluated. In both experiments, the soil tillage reduced the soil organic carbon in the plant growth zone, up to 20 cm depth, independent of the limestone application, and when PC with liming was carried out with higher carbon impact associated with minerals. The ability of C immobilization by soil microbial biomass was inversely proportional to soil management intensity, with higher levels of microbial biomass carbon and microbial quotient in the conventional tillage system, independent of the limestone application to the clayey soil, and with ... / Doutor
72

Armazenamento e disponibilidade de água no solo para as plantas em sistema de manejo de longa duração /

Silva, Gustavo Ferreira da. January 2019 (has links)
Orientador: Juliano Calonego Calonego / Banca: Marcelo de Almeida Silva / Banca: Fernando Ferrari Putti / Resumo: Os sistemas de manejo do solo podem influenciar o armazenamento e a disponibilidade de água no solo. Todavia, ainda há divergência na literatura quanto aos efeitos deste manejo nas propriedades físicas do solo e nas respostas das plantas, devido aos diferentes tempos de adoção em cada trabalho. Pesquisas em áreas já consolidadas podem gerar dados mais precisos em relação a estas modificações, considerando que na fazenda experimental da Faculdade de Ciências Agronômicas (FCA/UNESP), Botucatu (SP), há experimentos de longa duração com sistemas de manejo, o objetivo deste trabalho foi avaliar o efeito de manejos do solo de longa duração na capacidade de armazenamento de água no solo e sua disponibilidade às plantas, bem como na resposta das plantas de soja. Para isso foram conduzidos dois experimentos. O primeiro comparou o efeito do sistema de semeadura direta com o preparo convencional do solo, ambos conduzidos por 32 anos. O segundo experimento comparou o efeito do sistema de semeadura direta com diferentes rotações de culturas durante a safra de primavera, sendo testado o efeito do milheto, crotalária e um tratamento com ausência de cultivo de plantas, porém com escarificação do solo a cada três anos. Os sistemas de manejo alteraram as propriedades físico-hídricas do solo, sendo que os sistemas sem revolvimento do solo garantiram menor vulnerabilidade ao déficit hídrico às plantas de soja. E apesar dos sistemas conduzidos sob semeadura direta apresentarem maior resistência d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Soil management systems can influence the storage and availability of water in the soil. However, there is still divergence in the literature regarding the effects of this management on soil physical properties and plant responses, due to the different implementation times used. Research in already consolidated areas can generate more precise data in relation to these modifications, considering that in the experimental farm of the School of Agricultural Sciences (FCA/UNESP), Botucatu (SP), there are long - term experiments with management systems, the aim of this study was to evaluate the effect of long - duration of soil water storage capacity and their availability to plants, as well as the response of soybean plants. For this, two experiments were conducted. The first one compared the effect of the no-tillage system with conventional tillage, both conducted for 32 years. The second experiment compared the effect of the no - tillage system with different crop rotations during the spring harvest, being the effect of millet, sunn hemp and a treatment with no plant cultivation was tested, but with chiseling soil each three years. Management systems altered the physical and hydraulic properties of the soil, being that the no-tillage systems ensured less vulnerability to the drought stress to the soybean plants. And although the no-tillage systems presented greater soil resistance to root penetration in the superficial depth, there was no root system compromise and did not affect the soybean yield. / Mestre
73

Processes and effects of root-induced changes to soil hydraulic properties

Scanlan, Craig Anthony January 2009 (has links)
[Truncated abstract] Root-induced changes to soil hydraulic properties (SHP) are an essential component in understanding the hydrology of an ecosystem, and the resilience of these to climate change. However, at present our capacity to predict how roots will modify SHP and the consequences of this is limited because our knowledge of the processes and effects are highly fragmented. Also, current models used to investigate the relationship between plants and root-induced changes to SHP are based on empirical relationships which have limited applicability to the various and often contrasting ecosystems that occur. This thesis focuses specifically on the quantifying the processes by which roots modify SHP and developing models that can predict changes to these and the water balance. Both increase and decreases in saturated hydraulic conductivity have been attributed to the presence of roots. In general, decreases occur when the root system is relatively young, and increases occur when the roots senesce and begin to decay, creating voids for water flow. The evidence available suggests that the change in pore geometry created by roots is the dominant process by which roots modify SHP because they are more permanent and of a greater magnitude than changes to fluid properties or soil structure. We first quantified the effects of wheat roots on SHP of a coarse sand with a laboratory experiment where we measured changes in both SHP and the root system at 3, 5, 7 and 9 weeks after sowing (weeks). ... The main message that can be drawn from this thesis is that root-induced changes to SHP are dynamic, and dependent upon the combination of soil texture, connectivity of root-modified pores and the ratio of root radius to pore radius. Consequently, root-induced changes to the water balance have the same dependencies. The work in this thesis provides a significant first step towards improving our capacity to predict how roots modify soil hydraulic properties. By defining the range for the parameters used to predict how the soil is modified by roots, we are able to make quantitative assessments of how a property such as hydraulic conductivity will change for a realistic circumstance. Also , for the first time we have measured changes in soil hydraulic properties and roots and have been able to establish why a rapid change from a root-induced decrease to increase in Ks occurred. The link between physiological stage of the root system, and the changes that are likely to occur has implications for understanding how roots modify SHP: it may provide an effective tool for predicting when the switch from a decrease to increase occurs. Further work is required to test the validity of the assumptions we have made in our models that predict changes to SHP. While we have endeavoured to define the parameter space for those parameters that we have introduced, there is still some uncertainty about the connectivity of root-modified pores. Also, the parameterisation of the soil domain with roots is based upon work that measures 'fine' roots only which may not provide a true representation of the effect trees and perennial shrubs have on SHP. It is inevitable that root-induced changes to SHP will affect the fate of solutes in the soil, and temporal dynamics of root-induced changes to these may be particularly important for the timing of nutrient and pesticide leaching.
74

INFRARED THERMOMETER TECHNIQUE TO EVALUATE DAILY SOIL HEAT FLUX IN SITU.

Hares, Mohammed Abu. January 1982 (has links)
No description available.
75

Characterisation of heavy mineral sands and soils by radiometry and its use in mineral benefication and agriculture

De Villiers, Dawid 03 1900 (has links)
Thesis (PhD (Physics))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Radioactivity is well known and well understood, but its usefulness in industrial applications to optimise processes or increase economic viability is not yet fully utilised by many industries. This study focuses on the measurement of natural radioactivity and its application in heavy mineral separation and vineyard soil classification. The gamma radiometry set-up consisted of a high purity germanium detector, a Marinelli beaker as sample container and associated electronics. It was calibrated for laboratorybased measurements by minimising the background radiation with the use of lead castle and energy and resolution calibrations. Furthermore, detection parameters were optimised; these included the counting time, the selection of gamma rays used for analysis of a sample, the peak area calculation for the detector dead time and the detector efficiency. Given that the samples had different densities and volumes, the detector efficiency had to be corrected for volume and density effects. After implementation of the corrections and optimisations the detection system was tested and found able to accurately measure radioactivity concentrations. The systematic measurement errors for 238U were 5.1 % in the case of the heavy mineral sands and 34.3 % for the vineyard soils, 4.5 % for the 232Th concentrations and 4.7 % for 40K concentrations. Statistical errors were kept below 2 %. The application of radiometry has not been done before at any South African heavy mineral separation plant. For this reason radiometry is suggested as an easier, faster and cheaper alternative to X-ray fluorescence (XRF) for effective implementation of grade control for zircon to improve the cost benefit of the heavy mineral separation process. Zircon is an example of a heavy mineral that is worldwide in demand with a consumption of more than a million tonnes per year. It is used in a wide range of industrial applications and products that include tiles, sanitary ware and plasma displays. South Africa is the second largest producer of zircon in the world and also has the second largest reserve of available zircon, making this mineral a viable source of income for several years to come. Radioactivity, in the form of uranium and thorium, and other impurities such as iron oxide and titanium oxide are found in the crystal lattice of zircon. For it to be a sellable product, the sum of the uranium and thorium concentrations must be less than 500 parts per million for prime or first grade zircon and less than 1000 parts per million for second grade zircon. At present the concentrations of uranium and thorium in zircon concentrates are measured on a whole rock basis by XRF during and at the end of the processing cycle before the final products are ready to be shipped. This is not an ideal situation as the grab samples are taken periodically and are not necessarily representative of the stream or final assignment and has resulted in significant losses by the producer. The solution is to accurately measure the uranium and thorium concentrations fast or immediately, preferably the measurements must be made online and in real time so that processing decisions can be implemented quickly to optimise the final product. Heavy mineral sand samples were obtained from the various separation processes in a Mineral Separation Plant and their 238U and 232Th concentrations determined. The results indicated that the samples’ uranium to thorium ratios together with their total concentrations can be used to differentiate between the samples (i.e. separation processes). The measurement results were compared with those obtained with XRF. The correlations with radiometry were excellent for the uranium (r2 = 0.992), thorium (r2 = 0.998) and total concentrations (r2 = 0.998). Radiometric measurements were also conducted by decreasing the counting time from 3600 s to 1 s to investigate its effect on the accuracy of the results. Correlations between the different times and 3600 s ranged from excellent to good. The obtained results are then used to recommend that radiometry is used in a Mineral Separation Plant to verify that the zircon and zirkwa meet the specifications, to optimise the entrance feed and the other separation processes and to monitor the tailings streams. Finally the practical aspects of the implementation of radiometry are discussed. As a second application was radiometry applied in an agricultural pilot study to demonstrate the applicability of radiometry as a possible useful tool in soil classification. The creation of a vineyard is a long term and expensive investment and its yield and quality will be influenced by many factors such as the type of soil, viticultural preparations and climate. Information on the different soil types in a vineyard is therefore indispensable for the optimisation of land use with respect to vine cultivar, wine quality and production. Soil samples were obtained from Kanonkop, Simonsig and Spier vineyards and their 238U, 232Th and 40K concentrations determined, assuming that fertilisers would have no effect on the results. The difference in 40K concentrations were related to the clay fraction of the soil and demonstrated that the Kanonkop and Simonsig soils are fine-grained and clay-rich compared to the sandy coarse-grained soils of Spier. The uranium and thorium concentrations were indicators of whether the mineralogy of the soil is the same as the underlying bedrock as well as soil maturity. The measurement results were compared with those obtained with XRF. The correlation with radiometry were poor for the uranium concentrations (r2 = 0.314), as many of the samples concentrations were below the XRF detection limit. The correlations were excellent for both thorium (r2 = 0.985) and potassium (r2 = 0.999). As a positive result from the findings of the study was an in-situ measurement performed by Newman et al. for the radiometric mapping of a Simonsig vineyard for soil classification. / AFRIKAANSE OPSOMMING: Radioaktiwiteit is wel bekend en word goed verstaan, tog is die gebruik daarvan in industriele toepassings om prosesses te optimiseer of winsgrense te verhoog nog nie deur baie industrië ten volle benut nie. Hierdie studie fokus op die meting van natuurlike radioaktiwiteit en die toepassing daarvan in swaar mineraal skeiding en wingerd grond klassifikasie. Die gamma radiometrie opstelling het bestaan uit ‘n hoë suiwerheid germanium detektor, 'n Marinelli beker as monster houer en verwante elektronika. Dit was gekalibreer vir laboratorium gebaseerde metings deur die vermindering van die agtergrondstraling met die gebruik van lood kasteel en energie en resolusie kalibrasies. Verder was deteksie parameters geoptimaliseer, dit sluit in die teltyd, die keuse van gammastrale wat gebruik word vir die ontleding van 'n monster, die piek area berekening, die korreksie vir die detektor se dooie tyd en die detektor doeltreffendheid. Gegee dat die monsters van mekaar verskil het in terme van dighteid en volume was dit nodig om die detektor doeltreffendheid te korrigeer vir volume en digtheid effekte. Na die implementering van die korreksies en optimalisasie was die detektor stelsel getoets en was gevind dat radioaktiwiteit konsentrasies akkuraat gelewer kan lewer. Die sistematiese meet foute vir 238U was 5.1 % vir die mineraal sand en 34.3 % vir wingerd grond, 4.5 % vir 232Th konsentrasies en 4.7 % vir 40K konsentrasies. Statistiese foute was onder 2 % gehou. Die toepassing van radiometrie was nog nie voorheen by enige Suid-Afrikaanse swaar mineraal skeidings aanleg gedoen nie. Vir die rede is radiometrie voorgestel as ‘n makliker, vinniger en goedkoper alternatief teenoor XSF vir effektiewe implementering van graad beheer vir zirkon om die koste voordeel van die swaar mineral skeiding proses te verbeter. Zirkon is ‘n voorbeeld van ‘n swaar mineraal wat wêreldwyd in aanvraag is met ‘n verbruik van meer as ‘n miljoen ton per jaar. Dit word in ‘n wye reeks van industriele toepassings en produkte gebruik onder andere teëls, sanitêre ware en plasma skerms. Suid Afrika is die tweede grootste vervaardiger van zirkon in die wêreld en het ook die tweede grootste reserwe van besikbare zirkon. Dit veroorsaak dat die mineraal ‘n lewensvatbare brom van inkomste is vir nog etlike jare. Radioaktiwiteit, in die vorm van uraan en thorium, word tesame met ander onsuiwerhede soos ysteroksied en titaanoksied in zirkon se kristal rooster gevind. Om ‘n verkoopbare produk te wees moet die som van die uraan en thorium konsentrasies minder wees as 500 dele per miljoen vir prima en eerste graad zirkon en minder wees as 1000 dele per miljoen vir tweede graadse zirkon. Huidiglik word die uraan en thorium konsentrasies in die zirkon konsentraat gemeet op ‘n heel gesteente basis met X-straal fluoroskopie (XSF) gedurende en op die einde van die prosesering siklus net voor die finale produk reg is om versend te word. Dit is nie die ideale situasie nie, want die monsters word periodies geneem en is nie noodwendig verteenwoordigend van die stroom of die finale produk nie en het al tot beduidende verliese deur die vervaardiger gelei. Die oplossing is om die uraan en thorium konsentrasies vinnig of onmiddelik te meet, verkieslik moet die metings inlyn en intyds gedoen word om verwerkings besluite vinnig geimplementeer kan word om die finale produk te optimaliseer. Swaar mineraal sand monsters was verkry van die verskeie skeidingsprosesse in ‘n Mineraal Skeidings Aanleg en hul 238U en 232Th konsentrasies bepaal. Die resultate het aangetoon dat die monsters se uraan en thorium verhoudings saam met hul totale konsentrasies gebruik kan word om te onderskei tussen die monsters (oftewel die skeiding prosesse). Die meting resultate was vergelyk met dié verkry met XSF. Die korrelasies met radiometrie was uitstekend vir die uraan (r2 = 0.992), thorium (r2 = 0.998) en totale konsentrasies (r2 = 0.998). Radiometriese metings was ook uigevoer deur die teltyd te verminder van 3600 s tot 1 s om die uitwerking daarvan op die akkuraatheid van die resultate te ondersoek. Korrelasies tussen die verskillende tye en 3600 s het gewissel van uitstekend tot goed. Die bevindinge was dan gebruik om aan te beveel dat radiometrie in a Mineraal Skeidings Aanleg gebruik kan word om te verifeer dat daar aan die zirkon en zirkwa spesifikasies voldoen word, om die begin voer en ander skeidings prosesse te optimaliseer en ook die uitskot strome te monitor. Laastens is die praktiese aspekte van die implementering van radiometrie bespreek. Vir die tweede toepassing was radiometrie toepgepas in ‘n loods studie in die landbou om die toepaslikheid van radiometrie as ‘n moontlike nuttige instrument in grond klassifikasie te demonstreer. Die skepping van ‘n wingerd is ‘n lang termyn en duur belegging waarvan die opbrengs en kwaliteit beinvloed sal word deur vele faktore, onder andere die tipe grond, wynbou voorbereidings en die klimaat. Inligiting oor die verskillende grond tipes in ‘n wingerd is daarom onmisbaar vir die optimalisering van land gebruik in betrekking tot die wingerdstok kultivar, wyn kwaliteit en produksie. Radiometrie is toegepas om te demonstreer die toepaslikheid daaran as ‘n moontlike nuttige instrument in grond klassifikasie. Grondmonsters was verkry vanaf Kanonkop, Simonsig en Spier wingerde en hul 238U, 232Th en 40K konsentrasies bepaal met die aanname dat kunsmis nie ‘n uitwerking op die resultate sou hê nie. Die verskil in 40K konsentrasies was verwant aan die kleifraksie van die grond en het getoon dat die Kanonkop en Simonsig gronde is fyn korrelrig en kleiryk is in vergelyking met die sanderige growwe korrel grond van Spier. Die uraan en thorium konsentrasies het gedui op die samestelling van die grond en ook aangedui watter grond dieselfde is as die onderliggende rots. Die meting resultate was vergelyk met dié verkry met XSF. Die korrelasie met die radiometrie was sleg vir die uraan konsentrasies (r2 = 0.314) aangesien baie van die monster konsentrasies laer was as die XSF deteksie limiet. Die korrelasies was uitstekend vir beide thorium (r2 = 0.985) en kalium (r2 = 0.999). As ‘n positiewe resultaat van die studie se bevindinge was ‘n in-situ meting gedoen deur Newman et al. om ‘n Simonsig wingerd radiomeries te karteer vir grond klassifasie.
76

The nature and magnitude of soil compaction in different human-modified habitats in Hong Kong

彭美兒, Pang, Mei-yee. January 2001 (has links)
published_or_final_version / Geography and Geology / Master / Master of Philosophy
77

Spatial variability of water related soil physical properties.

Coelho, Mardonio Aguiar. January 1974 (has links)
A study of soil variability was performed on an 87 hectare area within a uniform mapping unit--Pima Clay loam-- at The University of Arizona Branch Experiment Station at Marana. The primary interest was with respect to soilwater parameters. From 36 sites selected by an unbalanced three-stage nested design, 180 core samples were collected at 30 cm depth intervals to 150 cm. In addition, 500 bulk samples were taken at the 60 cm depth on an equally spaced grid over a secondary sampling area of 96 by 76 meters. The measured parameters showed different patterns of spatial variation. For example, to estimate means within 10% for the 30 cm depth 5, 51, and 1,011 samples would be needed for bulk density, the porosity index, and the saturated hydraulic conductivity, respectively (using the 0.05 level of significance). Most of the other estimates for number of samples required were in a range of 50 to 100. Most coefficients of variation were between 10 and 50% with bulk density lower and saturated hydraulic conductivity higher. Variance components for the three stages obtained from the analysis of variance revealed that the variation among fields was smaller than within fields and sections for the majority of the measured parameters, their average relative contribution to the total variance being 25, 44, and 31%, respectively. Values of 15-bar moisture retention corresponding to the 500 bulk samples showed a frequency distribution close to the normal with a slight tendency toward skewness. Values of bulk density were normally distributed at each depth and on the combined 180 samples. The highly skewed distributed values of the saturated hydraulic conductivity proved to be normally distributed after a logarithmic transformation. The porosity index showed a nonconsistent distribution pattern at the different depths and a moderately skewed frequency distribution for the composite 180 samples. Close relationships were found between bulk density and per cent sand and silt. A highly significant correlation (significant at th 0.01 level) between 15-bar water retention and clay content existed. Values of the logarithm of the hydraulic conductivity showed a high degree of correlation with values of per cent pores drained at 50 millibars (correlation coefficients of high absolute values and significant at the 0.01 level). Particle size distribution exhibited a decrease of silt and clay and a corresponding increase of sand with depth. The average percentages of sand, silt, and clay at 30 cm depth were 23.3, 41.2, and 35.3, and at the 150 cm depth were 39.7, 35.6, and 24.7, respectively. A similar trend was revealed for bulk density which ranged from 1.42 at 30 cm depth to 1.57 g/cm³ at the 150 cm depth. Soil moisture release curves for each depth showed similar general shapes. The "porosity index" describing the moisture release curve in the low pressure range varied from 3.58 at 30 cm depth to 5.79 at the 150 cm depth. Mean values of the saturated hydraulic conductivity also tended to increase with depth--1.71 and 7.03 cm/hr at 30 and 150 cm depth, respectively. Comparison between the sampling scheme used and three-stage balanced designs revealed that at least two alternatives would be more effective in decreasing the variance of the mean, but they do not provide any degrees of freedom for the third stage. An apparent compromise was found to exist between the scheme used and the optimum unbalanced designs selected for efficient estimation of variance components for the majority of the measured parameters.
78

Classificação taxonômica e atributos físico-químicos de solos com usos em vitivinicultura na serra do sudeste do Rio Grande do Sul / Morphological classification and soil quality of a property intended for the production of sparkling commercial grapes in the serra do sudeste in the Rio Grande do Sul

Santos, Caroline Valverde dos January 2017 (has links)
O Estado do Rio Grande do Sul é responsável por 90% da produção nacional de uvas, sobretudo para a elaboração de vinhos finos. O município de Encruzilhada do Sul apresenta potencial edafoclimático ideal para a produção de uvas que abastecem grandes vinícolas da Serra Gaúcha. Entretanto o uso indiscriminado do solo pode resultar em uma degradação do solo. Este trabalho foi dividido em três estudos, que tiveram como objetivo Identificar as classes de solos ocorrentes no vinhedo, de acordo com a descrição morfológica e análise dos atributos químicos e físicos dos horizontes superficiais e subsuperficiais; Avaliar o efeito do manejo na qualidade química do solo de um vinhedo comercial, em áreas com 4, 9 e 16 anos de manejo após o plantio de videira da variedade Vitis vinifera L. cv. Pinot Noir para a elaboração de espumantes; Avaliar o efeito do tráfego de máquinas agrícolas na qualidade física do solo de um vinhedo comercial com diferentes anos de condução após o plantio das mudas. Foram realizados análises de perfis de 8 trincheiras em campo e com análises laboratoriais. Foi realizado o estudo dos atributos químicos e físicos do solo utilizados como indicadores de qualidade do solo, para avaliar o efeito do manejo do vinhedo com 4, 9 e 16 anos de condução após o plantio das mudas. Para análise da qualidade química do solo foram coletadas amostras indeformadas do solo nas profundidades de 0-10, 10-20, 20-30, 30-40, 40-50 e 50-60 cm, em três repetições. Os atributos físicos do solo foram analisados nas mesmas áreas e profundidades, que foram coletadas no local de trafego do rodado (R), entre rodados (ER) e linha de plantio (LP). 80% da propriedade é constituída por Argissolos diversificados, além de Cambissolos, estes ideais para a cultura da videira. Além desses solos, foi identificado na propriedade a presença de Gleissolo, que não são recomendados para o cultivo devido ao seu caráter hidromórfico. Pode-se observar uma redução na acidez do solo e incremento da fertilidade devido ao histórico de cultivo do vinhedo. Para a análise dos indicadores de qualidade física do solo, foram coletadas amostras do solo nas mesmas profundidades, em três locais na entrelinha: entre rodados, rodados e linha de plantio. A área com 16 anos de condução após o plantio apresentou maior efeito do uso de máquinas no vinhedo, sobretudo na posição de tráfego dos rodados do trator, afetando seriamente a qualidade física devido à compactação e baixa infiltração de água no solo. / The State of Rio Grande do Sul is responsible for 90% of the national production of grapes, mainly for the elaboration of fine wines. The municipality of Encruzilhada do Sul presents ideal edafoclimatic potential for the production of grapes that supply large wineries in the Serra Gaúcha. However the indiscriminate use of the soil can result in a degradation of the soil. This work was divided into three studies, which aimed to identify the soil classes occurring in the vineyard, according to the morphological description and analysis of the chemical and physical attributes of the superficial and subsurface horizons; To evaluate the effect of the management on the chemical quality of the soil of a commercial vineyard in areas with 4, 9 and 16 years of management after planting Vitis vinifera L. cv. Pinot Noir for the preparation of sparkling wines; To evaluate the effect of the traffic of agricultural machines on the physical quality of the soil of a commercial vineyard with different years of driving after planting the seedlings. Analyzes of profiles of 8 trenches were carried out in the field and with laboratory analyzes. The study of soil chemical and physical attributes used as soil quality indicators was carried out to evaluate the effect of vineyard management at 4, 9 and 16 years of age after planting the seedlings. For the analysis of soil chemical quality, undisturbed soil samples were collected at depths of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm in three replicates. The physical attributes of the soil were analyzed in the same areas and depths, which were collected in the traffic site of the wheel tracks of the tractor (WT), between the wheel tracks (BWT), and in the area under the line projection of the canopy (CLP). 80% of the property consists of diversified Argissolos, in addition to Cambisols, these are ideal for vine growing. In addition to these soils, the presence of Gleissolo was identified in the property, which are not recommended for cultivation due to its hydromorphic character. A reduction in soil acidity and an increase in fertility can be observed due to the vineyard's cultivation history. For the analysis of soil physical quality indicators, soil samples were collected at the same depths, at three sites in the interline: between rounds, rounds and planting line. The area with 16 years of driving after planting showed a greater effect of the use of machines in the vineyard, especially in the traffic position of tractor wheels, seriously affecting the physical quality due to compaction and low infiltration of water in the soil.
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Avaliação do regime estacionário em experimentos de fluxo de água em colunas de solo saturado / Evaluation of the stationary condition in experiments of water flow in saturated soil columns

Cunha, Luciana de Pinho 02 March 2006 (has links)
O presente trabalho teve por objetivo estudar o tempo necessário para que o fluxo da água no solo sob condições de saturação atinja o equilíbrio dinâmico, medindose a condutividade hidráulica saturada (K0) do solo. A condição de equilíbrio dinâmico é a etapa que antecede a aplicação do íon no solo em estudos de eluição de solutos. Utilizaram-se amostras deformadas de três solos com diferentes granulometrias: muito argilosa, média e arenosa, coletadas em área experimental da ESALQ/USP. As amostras foram acondicionadas em colunas de PVC, e utilizou-se água destilada e deaerada para saturação e posterior escoamento nas colunas, conforme a montagem experimental do permeâmetro de carga constante. Os resultados demonstraram que para as amostras dos solos muito argiloso e médio, o equilíbrio foi atingido após 15 dias de drenagem e para o arenoso essa condição só foi verificada após 27 dias, sendo a variabilidade de K0 maior nos primeiros seis dias de ensaio. Concluindo-se, portanto pela inadequação da utilização de um tempo fixo para a adição dos solutos. / The purpose of this work is to study the time for the water flow in soil under saturation to reach the steady-state, by measuring the saturated hydraulic conductivity (K0) of soil. The steady-state is the stage that precedes the application of the ion solution in the soil sample in solute elution studies. Disturbed soil samples with different granulometries were used: very clayey, clay-sandy and sandy soil, collected in experimental area of the ESALQ/USP. The samples were conditioned in PVC columns, and distilled and deaerated water were used for saturation and subsequent drainage in the columns, the test is in accordance with the experimental assembly of constant head permeameter. The data demonstrated that for very clayey and clay-sandy samples, the steady-state was reached after 15 days and for sandy soil this condition was verified after 27 days, being the variability of K0 bigger in the first six days of the test. Therefore it was concluded that is inadequate to use a fixed time for the addition of solutes in soil.
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Avaliação do solo em duas épocas cultivado com milho sob manejo ecológico e convencional / Soil assessment at the two different stages of a maize crop under ecological and conventional system

Longaresi, Rodrigo Henriques 24 June 2014 (has links)
A intensificação da agricultura está causando a degradação do ambiente agrícola, dos recursos hídricos e do solo. O manejo ecológico de solo e planta do Centro de Pesquisa Mokiti Okada (CPMO) tem como objetivo proporcionar ao agricultor, alternativas viáveis para atividade agrícola sustentável. Este sistema de manejo deve compensar a ausência dos insumos agrícolas - tradicionalmente utilizados na agricultura convencional - através da manutenção da qualidade física, química e microbiológica do solo. Esta pesquisa foi realizada no CPMO e no Sítio Camaquã, propriedade vizinha com solo de características similares. Os objetivos foram: i) caracterizar os atributos físico-hídricos do solo nos sistemas de manejo adotados; ii) verificar o efeito dos manejos nos atributos físico-hídricos do solo; iii) quantificar o rendimento do milho em cada sistema de manejo. Os tratamentos foram: manejo ecológico irrigado (MEI); manejo ecológico não irrigado (MENI) e manejo usual do Sítio Camaquã (MSQ). Cada tratamento foi composto por 8 parcelas com 54 m2 cada, para determinação da produtividade. Para determinação dos parâmetros físico-hídricos realizou-se amostragem do solo em duas épocas do ciclo do milho: 50 dias após a semeadura (50 DAS) e 140 DAS, ambas nas parcelas. Dentre os tratamentos com sistema de manejo ecológico, o MEI apresentou os melhores resultados: a densidade do solo diminuiu significativamente de 1,37 para 1,32 g.cm-3 e 1,26 para 1,22 g.cm-3 a 10 e 30 cm respectivamente da amostragem 50 para 140 DAS; a porosidade total aumentou significativamente de 51 para 55% e 54 para 57% a 10 e 30 cm respectivamente da amostragem 50 para 140 DAS. O tratamento MSQ se mostrou susceptível a processos de degradação devido ao manejo adotado, de elevada mobilização do solo: as médias de densidade, diâmetro médio geométrico, porosidade total e macroporosidade da amostragem 50 DAS para 140 DAS a 10 cm de profundidade variaram significativamente de 1,23 para 1,41 g.cm-3; 1,58 para 1,29 mm; 55 para 49% e 24 para 13% respectivamente. O rendimento do milho foi 5,0; 4,1 e 4,8 t.ha-1 nos tratamentos MEI, MENI e MSQ respectivamente. / The intensification of agriculture is causing the degradation of agricultural environment, water resources and soil. The soil and plant ecological management of Mokiti Okada Research Center (CPMO) has as a goal to provide viable alternatives of techniques for sustainable agriculture. This proposed management must compensate the no use of agricultural input, traditionally applied in a conventional model, through the maintenance of the soil physical, chemical and microbiological quality. This assay was performed in the CPMO experimental field and in an adjacent area, belonging to the neighbor Camaquã farm, whose soil characteristic is similar. The aims of this work were: i) to characterize soil physic-hydric attributes; ii) to survey the effect from crop system on the soil physic-hydric attributes; iii) to quantify the maize yield of the treatments. The treatments were: ecological crop system with irrigation (ECSI); ecological crop system without irrigation (ECSNI); conventional crop system (CCS) as usual in the Camaquã farm. Each treatment was comprised of 8 plots with 54 m2, where the grain yield was measured. Soil cores were sampled from the plots, at the two different growth stages, in order to survey the soil physics parameters: at 50 days after sowing (DAS) and 140 DAS. Among ecological crop system the ECSI treatment showed the best results. The soil bulk density decreased significantly from 50 to 140 DAS at 10 and 30 cm depth (1.37 to 1.32 g.cm-3 and 1.26 to 1.22 g.cm-3). The soil total porosity increased significantly at the same time and depth (51 to 55% and 54 to 57%). The soil of the CCS treatment showed it was susceptible to degradation pressures from usual high soil tillage management. At the 10 cm depth there were significantly differences between 50 to 140 DAS to bulk density (1.23 to 1.41 g.cm-3), mean geometric diameter (1.58 to 1.29 mm), total porosity (55 to 49%) and macro porosity (24 to 13%). The grain yields were: 5.0, 4.1 and 4.8 t.ha-1 to ECSI, CSNI and CCS treatments, respectively.

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