Academic literature on the topic 'Plant available water-holding capacity'
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Journal articles on the topic "Plant available water-holding capacity"
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Silva, Bruno Montoani, Érika Andressa da Silva, Geraldo César de Oliveira, Mozart Martins Ferreira, and Milson Evaldo Serafim. "Plant-available soil water capacity: estimation methods and implications." Revista Brasileira de Ciência do Solo 38, no. 2 (April 2014): 464–75. http://dx.doi.org/10.1590/s0100-06832014000200011.
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The plant-available water capacity of the soil is defined as the water content between field capacity and wilting point, and has wide practical application in planning the land use. In a representative profile of the Cerrado Oxisol, methods for estimating the wilting point were studied and compared, using a WP4-T psychrometer and Richards chamber for undisturbed and disturbed samples. In addition, the field capacity was estimated by the water content at 6, 10, 33 kPa and by the inflection point of the water retention curve, calculated by the van Genuchten and cubic polynomial models. We found that the field capacity moisture determined at the inflection point was higher than by the other methods, and that even at the inflection point the estimates differed, according to the model used. By the WP4-T psychrometer, the water content was significantly lower found the estimate of the permanent wilting point. We concluded that the estimation of the available water holding capacity is markedly influenced by the estimation methods, which has to be taken into consideration because of the practical importance of this parameter.
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Bordoloi, Reetashree, Biswajit Das, Gyati Yam, Pankaj K. Pandey, and Om Prakash Tripathi. "Modeling of Water Holding Capacity Using Readily Available Soil Characteristics." Agricultural Research 8, no. 3 (September 11, 2018): 347–55. http://dx.doi.org/10.1007/s40003-018-0376-9.
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Ghassemi-Golezani, Kazem, and Salar Farhangi-Abriz. "Improving plant available water holding capacity of soil by solid and chemically modified biochars." Rhizosphere 21 (March 2022): 100469. http://dx.doi.org/10.1016/j.rhisph.2021.100469.
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Araya, Sofanit, Greg Lyle, Megan Lewis, and Bertram Ostendorf. "Phenologic metrics derived from MODIS NDVI as indicators for Plant Available Water-holding Capacity." Ecological Indicators 60 (January 2016): 1263–72. http://dx.doi.org/10.1016/j.ecolind.2015.09.012.
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Lawes, R. A., Y. M. Oliver, and M. J. Robertson. "Integrating the effects of climate and plant available soil water holding capacity on wheat yield." Field Crops Research 113, no. 3 (September 2009): 297–305. http://dx.doi.org/10.1016/j.fcr.2009.06.008.
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Basiri Jahromi, Nastaran, Amy Fulcher, Forbes Walker, and James Altland. "Optimizing Substrate Available Water and Coir Amendment Rate in Pine Bark Substrates." Water 12, no. 2 (January 29, 2020): 362. http://dx.doi.org/10.3390/w12020362.
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Water resources can be used more efficiently by including sustainable substrate components like coir that increase water-holding capacity. The first objective of this study was to evaluate the impact of coir amendment rate on plant available water and plant gas exchange, with the goal of optimizing substrate available water and determining the optimum coir amendment rate in a greenhouse environment. The second objective was to establish the optimum method of determining plant available water using either plant gas exchange parameters or substrate physical properties. Greenhouse experiments were conducted with Hydrangea paniculata ‘Jane’ (Little Lime® hardy hydrangea) potted with one of five different coir rates (0%, 10%, 25%, 40% and 65%) mixed with pine bark on a volume basis. Plant gas exchange parameters and substrate water content were measured daily over a range of increasingly drier substrate moisture contents. Actual photosynthetic rates increased with increasing coir amendment rate and were highest with 65% coir amendment. Amending pine bark with coir increased the water storage capacity, plant available water, and plant gas exchange parameters. Results suggest that 65% coir amendment rate was the optimum amendment rate among those tested in a greenhouse environment and plant photosynthetic rate was the better method of determining plant available water.
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Nel, P. C., and J. G. Annandale. "Plant available water." Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 6, no. 3 (March 17, 1987): 109–14. http://dx.doi.org/10.4102/satnt.v6i3.953.
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The amount of water in the soil available for plant use, as well as water use efficiency, can be largely influenced by managerial practices. Field capacity is a useful arbitrary upper limit of plant available water (PAW), but factors such as redistribution of soil water, evaporative demand and root distribution may influence it. The lower limit of PAW is often referred to as the wilting coefficient, below which soil water is unavailable to plants. Yield losses occur long before the lower limit of available water is reached. Leaf water potential, transpiration, photosynthesis and various other plant processes are drastically reduced after soil water content has reached a certain threshold level. The presence of this threshold soil water content is being questioned by some researchers. Various soil, plant and climatic factors influence PAW. Laboratory measurements of PAW have a few serious shortcomings. In situ measurements are time consuming and for this reason work is still being done on streamlining laboratory methods.
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Kusvuran, Alpaslan, and Sebnem Kusvuran. "Using of Microbial Fertilizer as Biostimulant Alleviates Damage from Drought Stress in Guar (Cyamopsis Tetragonoloba (L.) Taub.) Seedlings." International Letters of Natural Sciences 76 (August 2019): 147–57. http://dx.doi.org/10.18052/www.scipress.com/ilns.76.147.
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Drought is a significant environmental stress that limits plant growth and yield. In this study, an investigation of guar, grown under different drought level conditions [(S0: 100% of field capacity), S1 (depletion of 75% the available water holding capacity), S2 (depletion of 50% the available water holding capacity), S3 (depletion of 25% the available water holding capacity), S4 (no applied irrigation water)] with regards to the impact of Chlorella vulgaris based microbial fertilizer on physiological, morphological, and enzymatic activity was performed. Microbial fertilizer applications significantly increased shoot length, fresh and dry weight of the shoot and root, and leaf number and area of guar plants compared to the only drought stress treatments. In addition, following the above-mentioned procedures, there were significant increases in the relative water content, total phenolic and flavonoid contents, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR) activity. However, the malondialdehyde (MDA) content were significantly decreased. Hence, the results support the administration of a foliar application to the microbial fertilizer containing microalgae in order to increase the guar plant’s defense system, enabling it to tolerate the negative effects resulting from drought stress.
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Kusvuran, Alpaslan, and Sebnem Kusvuran. "Using of Microbial Fertilizer as Biostimulant Alleviates Damage from Drought Stress in Guar (<i>Cyamopsis Tetragonoloba</i> (L.) Taub.) Seedlings." International Letters of Natural Sciences 76 (August 6, 2019): 147–57. http://dx.doi.org/10.56431/p-x0z5sx.
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Drought is a significant environmental stress that limits plant growth and yield. In this study, an investigation of guar, grown under different drought level conditions [(S0: 100% of field capacity), S1 (depletion of 75% the available water holding capacity), S2 (depletion of 50% the available water holding capacity), S3 (depletion of 25% the available water holding capacity), S4 (no applied irrigation water)] with regards to the impact of Chlorella vulgaris based microbial fertilizer on physiological, morphological, and enzymatic activity was performed. Microbial fertilizer applications significantly increased shoot length, fresh and dry weight of the shoot and root, and leaf number and area of guar plants compared to the only drought stress treatments. In addition, following the above-mentioned procedures, there were significant increases in the relative water content, total phenolic and flavonoid contents, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutation reductase (GR) activity. However, the malondialdehyde (MDA) content were significantly decreased. Hence, the results support the administration of a foliar application to the microbial fertilizer containing microalgae in order to increase the guar plant’s defense system, enabling it to tolerate the negative effects resulting from drought stress.
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Grabosky, Jason, Edward Haffner, and Nina Bassuk. "Plant Available Moisture in Stone-soil Media for Use Under Pavement While Allowing Urban Tree Root Growth." Arboriculture & Urban Forestry 35, no. 5 (September 1, 2009): 271–78. http://dx.doi.org/10.48044/jauf.2009.041.
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Three avenues of experimental observation detail aspects of plant available water holding capacity in compacted stone-soil media designed for urban tree establishment in paved situations. The various compacted media provided an estimated plant available moisture content of 7%–11% by volume, comparable to a loamy sand. Changes in aggregate and of soil influenced initial field capacity moisture content, but high matric potential moisture content was consistent, presumably as a reflection of the aggregate content of the designed system. A large portion of plant available moisture was weakly held in large voids, consistent with related infiltration and permeability data, and could be an influence in water storage and irrigation planning to use layers of designed soils in a layered pavement section for urban vegetation.
Dissertations / Theses on the topic "Plant available water-holding capacity"
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Costa, André da. "Retenção e disponibilidade de água em solos de Santa Catarina: avaliação e geração de funções de pedotransferência." Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/592.
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Studies on the retention and availability of water are scarce for humid subtropical and temperate regions in the Southern Hemisphere. The objectives of this study were to evaluate, generate and validate some pedotransfer functions (PTFs) to estimate the retention and the availability of water in soils of Santa Catarina. Were sampled 44 profiles, in areas under different vegetal coverings, to determine the water retention at suctions from zero to 1.500 kPa, the particles size distribution (7 classes), the organic matter content, the bulck density and particle density of soil, the conductivity hydraulic, and the aggregate stability. Regarding the attributes, soils with finer texture and / or more organic matter retain higher water content, where the organic matter is the main attribute that governs the availability of water, mainly in the surface horizons. Some classes of sand, mainly very fine sand, fine and coarse fractions, have greater effects on water availability than the silt fraction. The soils with contrasting textural classes, with high contents of clay or sand, have the same content of water available, although the sand soils have very low field capacity. Increased water availability occurs in soils with textural class loam, with higher content of organic matter and the lower availability occurs in sand class soils. In relation to lithology, there is a higher retention in soils derived from igneous extrusive rocks of the Serra Geral Formation, metamorphic, intrusive igneous, and sedimentary with fine texture, and a lower retention in those derived from rocks or sedimentary deposits rich in quartz. Increased availability of water occurs in soils derived from siltstone and less in soils derived from granite and recent alluvial deposits. Regarding soil classes (suborders), the water retention is higher in Cambisols, Ferralsols and Nitosols, and lower in Quartzarenic Neosols. In relation the regions, the soils of the Midwest and West, Serrano Highlands and Valley of Itajaí have high water retention, the intermediary are the Eastern Sierra, and lower in the coast. Humic Cambisols and Entisols, located in the Serrano Highlands has increased availability of water, mainly because of high contents of organic matter. In relation to soil types in the normative instruction n. 2/2008 of the MAPA (BRAZIL, 2008), which classifies the soils as a function of clay and sand, it is observed that is not adequate to classify the soils of Santa Catarina in terms of availability of water, although, the hydraulic conductivity of the unsaturated soil is lower in Type 1 soils. In relation the pedotransfer functions of literature, they better estimate the retention than water availability and with greater precision by the functions originated from climate regions subtropical and for the subsurface horizons of the soil. Most functions evaluated underestimates the water retention, with greater deviations in soils with 20-60 % clay. About the functions generated for the soils of Santa Catarina, the estimation of retention and availability of water was better in those adjusted separately for surface and subsurface horizons. To estimate the water retention, the point PTFs must be used including data of the texture, organic matter and their interactions. To estimate the availability, the point PTFs should include the five classes of sand, silt, clay, organic matter, soil bulk density, soil particles density, total porosity and their interactions. The parametrics PTFs estimate properly the water retention curve for most of the textural classes of the soil, when data of texture, organic matter, soil bulk density, soil particles density, total porosity and their interactions are included as predictors. The class PTFs estimate properly the water retention curve for most of the soil textural classes of Santa Catarina
Estudos sobre a retenção e disponibilidade de água são escassos para as regiões de clima subtropical ou temperado úmido do hemisfério sul. Os objetivos deste estudo foram avaliar, gerar e validar funções de pedotransferência (FPTs) para estimar a retenção e a disponibilidade de água em solos de Santa Catarina. Foram amostrados 44 perfis, em áreas sob diferentes coberturas vegetais, para determinar a retenção de água nas sucções de zero até 1.500 kPa, a distribuição do tamanho de partículas (7 classes), o teor de matéria orgânica, a densidade do solo e de partículas, a condutividade hidráulica e a estabilidade de agregados. Em relação aos atributos, solos com textura mais fina e/ou com maior teor de MO retêm maior conteúdo de água, sendo a MO é o principal atributo que governa a disponibilidade de água, principalmente nos horizontes superficiais. Algumas classes de areia, principalmente as areias muito fina, fina e grossa, possuem maiores efeitos sobre disponibilidade de água do que a fração silte. Os solos com classes texturais contrastantes, com elevados teores de argila ou de areia, disponibilizam o mesmo conteúdo de água disponível, embora os arenosos tenham baixa capacidade de campo. Maior conteúdo de água disponível ocorre em solos das classes com textura franca e com maior teor de MO, enquanto que a menor disponibilidade ocorre em solos da classe areia. Em relação à litologia, ocorre uma maior retenção em solos derivados de rochas ígneas extrusivas da Formação Serra Geral, e de rochas metamórficas, ígneas intrusivas e sedimentares de textura fina, e menor nos derivados de rochas ou depósitos sedimentares ricos em quartzo. Maior disponibilidade de água ocorre em solos derivados de siltitos e o menor em solos derivados de granito e de depósitos aluvionares recentes. Em relação às classes de solos (subordens), a retenção de água é maior nos Cambissolos, Nitossolos e Latossolos e menor nos Neossolos Quartzarênicos. Em relação às regiões, os solos do Meio Oeste e Oeste, Planalto Serrano e Vale do Itajaí possuem elevada retenção de água, euquanto que, nos da Serra Leste é intermediária e os do Litoral é baixa. Os Cambissolos Húmicos e os Neossolos Litólicos, localizados no Planalto Serrano, têm maior disponibilidade de água, principalmente devido aos elevados teores de matéria orgânica. Em relação aos tipos de solos da instrução normativa n. 2/2008 do MAPA (BRASIL, 2008), que classifica os solos em função do teor de argila e areia, observa-se que a mesma não é adequada para classificar os solos catarinenses quanto a disponibilidade de água. Entretanto, a condutividade hidráulica não saturada é menor nos solos do Tipo 1. Em relação às funções de pedotransferência (FPTs) publicadas na literatura, elas estimam melhor a retenção do que a disponibilidade de água, com maior precisão pelas funções originadas de regiões de clima subtropical e para os horizontes subsuperficiais do solo. A maioria das funções avaliadas subestima a retenção de água, com erros maiores nos solos com 20 a 60% de argila. Quanto às funções geradas para os solos de Santa Catarina, as que melhor estimam a retenção e disponibilidade de água são aquelas ajustadas separadamente para os horizontes superficiais e subsuperficiais. Para estimar a retenção de água devem ser utilizadas as FPTs pontuais que incluem dados de textura, matéria orgânica do solo e suas interações. Para estimar a disponibilidade de água devem ser utilizadas as FPTs pontuais que utilizam as cinco classes de areia, silte, argila, matéria orgânica, densidade do solo e de partículas, porosidade total e suas interações. As FPTs paramétricas estimam adequadamente a curva de retenção de umidade do solo para a maioria das classes texturais, quando são incluídos dados de textura, matéria orgânica, densidade do solo e de partículas, porosidade total e suas interações como variáveis preditoras. As FPTs de classe estimam adequadamente a curva de retenção de água do solo para a maioria das classes texturais dos solos de Santa Catarina
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Radimy, Raymond Tojo. "Cinétique d'évolution structurale des sols argileux : relation stress hydrique-stress salin ; Application à la biodiversité et rendement de culture." Thesis, Poitiers, 2015. http://www.theses.fr/2015POIT2310/document.
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Les marais de l'Ouest ont été gagnés sur les sédiments fluvio-marins par poldérisation débutée dès le moyen âge. Les aménagements hydrauliques avaient, initialement, des objectifs sanitaires et d'élevage. A partir des endiguements, ils ont divisé les territoires en marais mouillés et marais desséchés. Depuis les années 1970 le développement des cultures intensives de céréales a nécessité un rabaissement complémentaire de la nappe par drainage en partie pour augmenter la désalinisation de surface et limiter l’engorgement des sols. Néanmoins, ces territoires restent caractérisés par des nappes proches de la surface. En conséquence les profils hydriques vont être gouvernés par les conditions météorologiques y compris l'évapotranspiration, la pluviométrie, mais également par les remontées capillaires issues d'une nappe salée. D'autre par la nature argileuse des sols et ses propriétés de retrait conditionnent énormément le fonctionnement hydrodynamique et les évolutions de structure.La première partie du travail a été de suivre les évolutions des profils hydriques et de salinité en parcelles non drainées (prairies) et en parcelles drainées (Maïs, Blé, Tournesol). Ces suivis ont été complétés par les mesures des niveaux de nappes et par des mesures tensiométriques via des bougies poreuses implantées à différentes profondeurs. L'objectif final a été de calculer et modéliser les profils de réserve utile (RU) et de RU "résiduelle" utilisable par les plantes. Dans ces systèmes alimentés par les remontées capillaires, le réseau racinaire puise l'eau dans la zone non saturée de surface (vadose) puis dans la zone saturée sous-jacente. La teneur en eau caractéristique de l'interface zone non saturée - zone saturée a été déterminée par analogie entre les chemins d'état de la matrice argileuse le long de sa courbe de retrait et du sol le long de sa courbe de compaction. Les profils de RU résiduelle utilisable par les plantes ont été calculés à partir des profils de teneurs en eau puis comparés aux profils de RU obtenus via les données de station météorologique. Ces profils de RU résiduelle ont pu être écrits sous forme d'équation polynomiale du second degré puis modélisés. Dans cet environnement alimenté par les remontées capillaires, ces profils de RU résiduelles peuvent être modélisés à partir d'un paramètre facilement mesurable en surface qui prend en compte la structure du sol et les conditions météorologique : soit la teneur en eau à 10 cm de profondeur. Cette modélisation reste suffisamment réaliste pour être utilisée comme un outil prédictif face à la pédodiversité et/ou les rendements de culture.A ce travail s'ajoute deux études préliminaires : - les mesures des conductivités thermiques effectives de ces sols par la méthode du fil chaud et leurs modélisations dans les systèmes biphasés : eau - argile et air - argile, mais également pour les systèmes triphasés non saturés : eau - air - argile. Les perspectives sont la modélisation des transferts thermiques et hydriques dans le sol à partir de la surface, - et l'élaboration d'un protocole d'imprégnation-polymérisation des sols argileux humides par des résines de type HEMA. Cette imprégnation permet d'envisager la confection de lames minces dans le matériau argileux induré avec conservation de sa structure initiale humide. Les perspectives sont la pétrographie quantitative à l'interface racine - sol le long de profils verticaux dans les environnements argileux à degrés de saturation et structure évolutivesThe coastal marshlands are territories generally reclaimed on primary fluvio-marine sediments. They result from hydraulic managements and/or polderization which may date from the Middle Ages. Historically these hydraulic managements were built for goals of wholesomeness, breeding and farming. They isolate two territories: the dried marshes and the wet marshes. For the intensive cereal crops the slow drying caused by land reclamation was recently improved by the drainage, in part for increase the depth of desalinization and decrease waterlogging. Nevertheless, these territories remain characterized by shallow ground water of initial salt water. Consequently, the hydric profiles are governed by the meteoric conditions including the Evapotranspiration, the rainfall, but also the capillarity rises from the salt groundwater. Moreover, the clay dominated nature of the soils and their drastic shrinkage properties govern the hydrodynamic functioning and the soil structure behavior.The first part of the work was the monitoring of the water content and salinity profiles in drained cereal crops and in undrained grasslands. These measurements have been completed by the ground water level and tensiometric monitoring. The final goal was the calculation and modeling of the available water capacity (AWC) and plant available water (PAW) profiles. In these systems mainly supplied by the capillarity rises, the root network gets water in the subsurface vadose zone and then in the deeper saturated groundwater zone. The water content characteristic of the interface between the vadose and saturated zone was determined by comparison between the clay material state paths along its shrinkage curve and along its compaction curve. The PAW profiles were calculated from the water content profiles and then compared to the AWC profiles. The PAW profiles have been equated as polynomial second degree equations. In these shallow groundwater environments the PAW profiles have been modeled taking into account an easy measurable surface parameter which includes the soil structure behavior and the meteoric conditions: i.e. the water content measured at 10 cm depth. The PAW modelling remains sufficiently realistic to be used as a tool for farming management. Two preliminary studies were added to this work: - the measurement of effective thermal conductivity of the clayey soils by the transient hot wire method, and the modeling of the effective thermal conductivity of biphasic air-clay and water-clay media, but also triphasic unsaturated air-water-clay media. The prospect is the modeling of thermal and hydric transfer from the surface to the depth. - and the elaboration of a protocol of impregnation - hardening for wet clay dominated soils by HEMA resins. This impregnation allows the making of thin sections in these clay materials with conservation of their initial wet structures. The prospective is the quantitative petrography at the root - clay matrix interface along vertical profiles in clayey soils at different degrees of saturation and different structures
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Svedin, Jeffrey David. "Characterizing the Spatial Variation of Crop Water Productivity for Variable-Rate Irrigation Management." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6878.
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Irrigated agriculture is the primary consumer of limited worldwide freshwater resources. Drought, growing world populations, and environmental demands compete with irrigation for freshwater resources"”threatening sustainable global food, fuel, and fiber production. This escalating global crisis demands that agriculture produce more food using less water. Traditional irrigation management has used technology to apply uniform irrigation rates across landscapes"”ignoring natural environmental variation. This provides inherent inefficiencies of over- or under- irrigation within individual fields. Variable-rate irrigation (VRI) is modern technology that employs global positioning systems and geographic information systems to match irrigation to spatially variable crop water demands within a field. Although commercially available, VRI lacks scientifically validated decision support systems to determine spatially and temporally variable crop water demand. The purpose of this research is to explore spatial and temporal variations in crop water demand to inform growers utilizing VRI. This research consists of four seasons of winter wheat (Triticum aestivum L.) production on a commercial farm in Idaho that employs a VRI system. In Chapter 1, the spatial variation of crop water productivity (CWP, the grain produced per unit of water consumed), is characterized for two seasons (2016-2017) and we propose a unique conceptual strategy for VRI management targeted at CWP. Observed CWP ranged from 4.1-21 kg ha-1 mm-1 with distinct spatial variation that, when considered together with grain yield, were shown to be useful for VRI management. During the 2017 growing season, VRI zones conserved 25% of irrigation compared to traditional uniform irrigation management. In the second chapter the spatial variation of soil water holding capacity (SWHC) was measured at 90 sampling points throughout the field. Then, during the 2016-2017 growing seasons, the spatial and temporal variation of soil moisture were modelled to characterize crop stress and its influence on grain yield. Soil within the field showed large spatial variation of SWHC, ranging from 147-369 mm. Under uniform irrigation in 2016, the natural variation of TAW created 21 day variation in the onset of crop stress throughout the field and under VRI in 2017 the onset of crop stress spanned 56 d. Surprisingly the variations in TAW did not statistically influence yield in 2016, and in 2017 the rate of irrigation predicted yield and TAW again did not statistically predict yield. This suggests that other environmental variables should be included when delineating irrigation zones and rates for VRI.
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Araya, Sofanit Girma. "Multi-temporal remote sensing for estimation of plant available water-holding capacity of soil." Thesis, 2017. http://hdl.handle.net/2440/114500.
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Soil maps are fundamental for agricultural management. However, mapping soils is a difficult task because of their high spatial variability and the challenge of choosing representative field sites for soil analysis. Globally, soil information is becoming a prioritized agenda, due to the increasing demand for soil information for quantitative ecological, environmental and agronomic modelling. Hence, improved digital soil mapping techniques are required to fulfill this demand. The Plant Available Water-holding Capacity (PAWC) is a key soil property in most agricultural management activities as it determines the maximum water that can be readily extracted by plants. Globally, there is an increasing demand for spatially explicit soil PAWC data for understanding the potential consequences of climate change and development of adaptation strategies. The coarse resolution of current PAWC information limits the spatial detail of future predictions and decision support. Plant growth in water-limited Mediterranean climates is predominantly controlled by soil water availability. In rain-fed cropping systems, differences in PAWC can explain a large proportion of the spatial and temporal crop yield variability. The overall aim of this research was to develop a methodology to estimate spatial pattern of PAWC at a high spatial resolution using satellite-based remote sensing techniques. The underlying hypothesis is that the spatio-temporal plant growth patterns contain integrated information about soil properties and plant-soil-water interaction in the profile. The objective was to evaluate if phenological metrics derived from MODIS-NDVI (Moderate Resolution Imaging Spectroradiometer Normalized Difference Vegetation Index) can be used to infer about PAWC. The study was conducted in the South Australian agricultural region, which is one of the major grain producing regions of the country. Central to facilitating the research was the design and development of a flexible software package (CropPhenology) to extract phenological metrics that are indicators of crop condition at different growth stages. The CropPhenology package was developed in R to be used for analyzing data for all later stages of the project. It is available in the public domain repository GitHub. Initially, the sensitivity of remote sensing phenological metrics for differences in soil PAWC was assessed in a controlled situation. Phenological metrics for crop grown in soils of contrasting PAWC values under identical agricultural management were compared. The results identified potential phenological metrics to be used as indicators for soil PAWC. The findings support that the soil signal can be extracted from time-series vegetation growth dynamics. The research further evaluated the efficacy of the phenological metrics for assessment of spatio-temporal crop growth variability for management practices. The association between phenological metrics and management zones were analyzed in a South Australian cropping field. The result shows that phenological metrics have potential to inform about both spatial variability and temporal variability, highlighting a pathway towards alternative approaches for assessing the spatio-temporal variability in cropping fields. Finally, an approach was developed for spatial PAWC estimation. Multiple linear regression models were developed that analytically associate of the measured soil PAWC values with MODIS-NDVI phenological metrics. The PAWC map shows significant agreement with the landscape-scale soil map of the region with realistic detail of PAWC variability within the soil map units across management units. The evidence from this result indicates the potential of phenological metrics from satellite remote sensing for soil PAWC mapping at unprecedented detail over a broad regional extent. Advances in PAWC mapping as demonstrated in this thesis will improve models assessing future climate change development of adaptation strategies and will narrow the gap in spatial detail between regional decision making and farm-based precision agriculture.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2017.
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Ruilova-Duval, María Esther. "Factors affecting water holding capacity and texture in cooked Albacore tuna (Thunnus alalunga)." 2008. http://www.lib.ncsu.edu/theses/available/etd-08012008-201026/unrestricted/etd.pdf.
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Sukati, Bonokwakhe Hezekiel. "The potential of biological sludge amended combustion coal ash residues as artificial plant growth media : a laboratory column study to assess the influence of weathering on elemental release." Diss., 2012. http://hdl.handle.net/2263/29622.
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Sasol biological sludge, coal fine and gasification ash were the three waste streams involved in this study. The main concern is that on their own they are not suitable as growth mediums, the ash is alkaline (pH>12) with high salinity (total dissolved solids of 8000 mg ℓ-1). Fine ash is microporous (particle size diameter <250 μm) and forms cemented layers that can restrict root growth while, gasification ash in macroporous (most particle size diameter ranged between 1 and 75 mm) and has a low water holding capacity. Sludge is unstable and can inhibit gaseous exchange. However, these wastes potentially, have physical, biological and chemical attributes that make them suitable as hospitable growth medium. Sludge can promote micro-fauna activity and, provide plant available nitrogen (N) as well as phosphorus (P) the ash is poor in. On a short term bases and in the long term it can also contribute to cation exchange capacity (CEC). Fine ash can increase water holding capacity and gasification ash can improve gaseous exchange. It was hypothesized that if the ash was treated with sludge, pH will be reduced to between 5.5 and 8, and weathering will reduce salinity to less than 400 mSm-1, increase CEC and increase plant available N and P. Therefore, the main purpose of this laboratory column study was to establish combinations of these waste streams that hold promise as plant growth media, based on various chemical and physical criteria link to hospitable plant growth media, as well as the influence of weathering on the release of essential plant nutrients. A total of 51 mixtures (each weighing 2.6 kg) were formulated based on wet mass basis and divided into 6 groups based on sludge content (0, 10, 20, 30, 40 and 50%) and packed into columns, subjected to wetting and drying for 1 year (10 wetting and drying cycles) by passing through deionized water equivalent to the pore volume and allowing the mixtures to dry in between. The leachates were analysed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Kjeldahl procedures (for N release). Total elemental analysis was done using X-ray Fluorescence Spectroscopy (XRF) and acid digestion method. Particle size distribution was done using the sieve method. Cation exchange properties were assessed using ammonium acetate (NH4OAc), lithium chloride (LiCl) and potassium chloride (KCl) methods. Results indicated that sludge was critical for these mixtures,at a minimal content of 10% it increased the water holding capacity of the mixtures. In the mineralization of inorganic N at a lower limit of 20% sludgeenabled the production of plant available NH4+ and NO3- and less NO2-. Increasing sludge to 50% further reduced the production of NO2- in the mixtures. In terms of elemental release, mixtures without sludge were dominated by Na and the order of abundance was as follows; Na>K>Ca>Mg>P on mmol kg-1 but the introduction of sludge at a lower content limit of 10% changed the abundance of the elements as follows; P>Mg>Ca>Na>K on mmol kg-1. Sludge content as low as 10% reduced the pH of the mixtures to between 7.6 and 8 and EC to less than 400 mSm-1. However, increasing sludge to 50% increased the leachate EC dramatically and kept the EC high (415 mSm-1) till the end. Introduction of sludge at a low limit of 10 % content increased the CEC above 8 cmolc kg-1. The effects of fine ash on the water holding capacity of the mixtures were seen at the 10 % level, for example, mixture 13 with 10% fine ash had 0.3 mg kg-1, while mixture 12 with 0% fine ash had 0.27 mg kg-1. Increasing fine ash content above 40% increased pozzalanic properties, pH (>8), EC (>400 mSm-1), Na release and reduced CEC.Gasification ash is the biggest waste stream and utilizing these wastes as growth media will mean that it realistically will always dominate these mixtures. This study showed that on its own it will be a challenging environment. However, the amendent with sludge and fine ash resulted in some chemically and physically favourable changes in these media. It can be concluded that the main objective has been achieved and bio assay evalution of theses mixtures is recommended CopyrightDissertation (MSc(Agric))--University of Pretoria, 2012.
Plant Production and Soil Science
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"Infiltration and Drainage through Coarse Layered Soil: A Study of Natural and Reclaimed Soil Profiles in the Oil Sands Region, Alberta, Canada." Thesis, 2014. http://hdl.handle.net/10388/ETD-2014-04-1487.
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Natural coarse textured soils comprise a significant portion (approximately 20%) of the area to be mined at Suncor, Syncrude (aurora mine), Albian/Shell, and CNRL mines in the Alberta’s oil sands (Macyk, 2006). Although similar in soil textural classifications, the undisturbed areas support a range of ecosite types which exhibit different moisture regimes, suggesting that there are natural mechanisms controlling the plant available water sufficient for forest development.
The global objective of this study was to evaluate the potential for textural variability to enhance water storage in coarse textured soil. The observations of the infiltration and drainage behaviour of natural and reclaimed coarse-texture soils in this study have demonstrated that this potential exists and can be applied in reclamation design to achieve the ranges of soil water storage needed to establish different ecosites.
Field based infiltration and drainage testing, pit excavation and sampling have been completed on 14 sites (7 natural and 7 reclaimed). Bulk saturated hydraulic conductivity and field capacity were estimated for each of the 14 sites based on the field test results. The observed transient water dynamics give an indication of the effect of layering on these material properties.
Laboratory analysis of water content (650 samples), particle size (650 samples), water retention (35 samples), organic carbon (100 samples) as well as calibration of field instrumentation were completed on a large number of samples (approximate values shown in brackets above) across all sites. The laboratory analysis was used to characterize textural variability (mean and standard deviation of the particle diameter) for the layered sites and estimate the soil water retention curve (SWRC) relationships for the range of soil textures encountered at the study sites. Pedotransfer functions (PTFs) were used to investigate if there were significant differences in the residual sum of squares between estimated and measured SWRCs. The measured organic carbon was used to aid in estimating permanent wilting point (WP) used in the calculation of the available water holding capacity (AWHC) of all profiles. An investigation into the calibration of the moisture capacitance probe (MCP) was undertaken as part of a comparison of the measured and simulated volumetric water content (VWC) profiles.
Water storage at the cessation of drainage was related to the soil texture and textural variability as measured in the laboratory. Sites with more textural variability generally stored more water for plant use. There appeared to be a limit to what can be considered ‘useful’ textural variability. If adjacent soil layers had too extreme a contrast in texture and therefore hydraulic conductivity, unstable/preferential flow (i.e. bypassing of some of the water and nutrients from plant roots) occurred. The total porosity calculated from field samples was often higher than the maximum measured VWC in each layer which may be indicative of one or more factors that resulted in less than full saturation being attained within the targeted 1 m depth of saturation during the test. Some of these factors include: errors in sampling leading to an overestimate of total porosity; lateral flow along textural interfaces; air entrapment within the rapidly advancing wetting front; unstable/preferential flow as a result of the high contrast in hydraulic conductivity (fine over coarse) between adjacent layers (i.e. Ks Ratio >20) or where tests were conducted on slopes (i.e. funnel flow). This latter case was common at the reclaimed sites.
A modelling study of one uniform (SV10) and one layered (NLFH1) natural site was conducted. The models were built by incorporating soil properties of the layers in the various soil profiles as estimated from field and/or laboratory testing. This study offers a comparison between various PTFs and their ability to capture the soil-water storage/dynamics during infiltration and drainage testing. The Arya PTF gave a better estimation of the laboratory measured SWRCs. However, when modeling the measured infiltration and drainage testing for the relatively uniform site SV10, the Arya PTF and Modified Kovacs (MK) PTF performed similarly. The Arya PTF performing slightly better for the infiltration phase and the MK PTF performing slightly better for the drainage phase. Both PTFs gave a reasonable estimation of water storage but the MK PTF gave a better estimation of the water storage with time as compared to the Arya PTF. For the highly layered site NLFH1, neither model performed well. The Arya PTF gave a substantially better estimation of the infiltration phase and gave the better estimation of the magnitude of water storage with time, the MK PTF performed marginally better for the drainage phase and gave a better estimation of the shape of the water storage with time.
Generally, the study showed that the replication of the profile water storage requirements for the layered natural ecosites (‘b’ and ‘d’ ecosites) has been achieved and can be achieved by layering (or even mixing) available coarse textured reclamation materials. This study has indicated that replicating the highly uniform ecosites (‘a’ ecosites) is where the bigger challenge lies in reclamation. Reclaiming with a diversity of target ecosites is essential to achieving the pre-disturbance land capability standard that the mine operators are bound by. The temptation may exist to simply condone reclamation that has met or exceeded the pre-exisiting land capability. However, problems with ground water recharge and regional water distribution are likely to arise if large areas of lower functioning ecosites are replaced with higher functioning ecosites.
Book chapters on the topic "Plant available water-holding capacity"
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Reetsch, Anika, Didas Kimaro, Karl-Heinz Feger, and Kai Schwärzel. "Traditional and Adapted Composting Practices Applied in Smallholder Banana-Coffee-Based Farming Systems: Case Studies from Kagera and Morogoro Regions, Tanzania." In Organic Waste Composting through Nexus Thinking, 165–84. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-36283-6_8.
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AbstractIn Tanzania, about 90% of the banana-coffee-based farming systems lie in the hands of smallholder farmer families. In these systems, smallholder farmers traditionally add farm waste to crop fields, making soils rich in organic matter (humus) and plant-available nutrients. Correspondingly, soils remained fertile during cultivation for over a century. Since the 1960s, the increasing demand for food and biofuels of a growing population has resulted in an overuse of these farming systems, which has occurred in tandem with deforestation, omitted fallows, declined farm size, and soil erosion. Hence, humus and nutrient contents in soils have decreased and soils gradually degraded. Inadequate use of farm waste has led to a further reduction in soil fertility, as less organic material is added to the soils for nutrient supply than is removed during harvesting. Acknowledging that the traditional use of farm waste successfully built up soil fertility over a century and has been reduced in only a few decades, we argue that traditional composting practices can play a key role in rebuilding soil fertility, if such practices are adapted to face the modern challenges. In this chapter, we discuss two cases in Tanzania: one on the traditional use of compost in the Kagera region (Great African Rift Valley) and another about adapted practices to produce compost manure in the Morogoro region (Uluguru Mountains). Both cases refer to rainfed, smallholder banana-coffee-based farming systems. To conclude, optimised composting practices enable the replenishment of soil nutrients, increase the capacity of soils to store plant-available nutrients and water and thus, enhance soil fertility and food production in degraded banana-coffee-based farming systems. We further conclude that future research is needed on a) nutrient cycling in farms implementing different composting practices and on b) socio-economic analyses of farm households that do not successfully restore soil fertility through composting.
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Morgan, Lynette. "Substrate-based Hydroponic Systems." In Hydroponics and protected cultivation: a practical guide, 77–99. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789244830.0006.
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Abstract This chapter focuses on substrate-based hydroponic systems. The main purpose of the substrate in hydroponic systems is to provide plant support, allowing roots to grow throughout the medium absorbing water and nutrients from the nutrient solution. Topics discussed are properties of hydroponic substrates, open and closed soilless systems, common hydroponic substrates, substrates and water-holding capacity, substrates and oversaturation, matching substrates to crop species, physical properties of soilless substrates, chemical properties of hydroponic substrates, nutrient delivery in substrate systems, irrigation and moisture control in substrates, and microbial populations in substrates.
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Morgan, Lynette. "Substrate-based Hydroponic Systems." In Hydroponics and protected cultivation: a practical guide, 77–99. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789244830.0077.
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Abstract This chapter focuses on substrate-based hydroponic systems. The main purpose of the substrate in hydroponic systems is to provide plant support, allowing roots to grow throughout the medium absorbing water and nutrients from the nutrient solution. Topics discussed are properties of hydroponic substrates, open and closed soilless systems, common hydroponic substrates, substrates and water-holding capacity, substrates and oversaturation, matching substrates to crop species, physical properties of soilless substrates, chemical properties of hydroponic substrates, nutrient delivery in substrate systems, irrigation and moisture control in substrates, and microbial populations in substrates.
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Keefer, Robert F. "Effective Water Use—Irrigation." In Handbook of Soils for Landscape Architects. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195121025.003.0010.
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Soils that are suitable for irrigation are deep soils that are permeable and have a high available water-holding capacity (usually containing much organic matter). Limitations for irrigation include presence of restrictive layers (pans), erodible soils, sloping land, susceptibility to stream overflow, salinity or alkalinity, stoniness, and hazard of soil blowing. The amount of plant-available water in a soil depends on rooting depth and soil texture. Coarse textured sands hold much less available water than finer textured clayey soils. Available water increases as the texture becomes finer up to a silt loam. Any soil texture finer than that results in no additional increase in available water. In shallow soils, the rooting depth is limited by the soil depth. In deep soils, root depth is determined by the kind of plants present: . . . Trees and large shrubs 48 inches depth Medium shrubs and vines 40 inches depth Small shrubs and ground cover 24 inches depth . . . A number of techniques can be used to determine when water should be applied to soil in which plants are growing. These techniques include observing the plants, especially for wilting; feeling the soil; using tensiometers or electrical resistance meters installed in the soil; and measuring temperatures of plant leaves. Wilting—When plants begin to lose water they droop and wilting results. If plants remain in this condition very long, they soon die. It is better to water plants before they become wilted. Any plant that is wilted will require some time to reestablish its water equilibrium, thereby slowing the growth of that plant. The amount of moisture in a soil can be roughly estimated by the “feel method”. The degree of moisture can be determined by rolling or squeezing the soil into a ball. The soil moisture condition can be divided into six categories from dry to very wet: . . . a. If a ball will not form → soil is too dry for plants. b. If the ball formed will not crumble when rubbed → soil is too wet for plants. . . .
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Kirkham, M. B. "Field Capacity, Wilting Point, Available Water, and the Nonlimiting Water Range." In Principles of Soil and Plant Water Relations, 153–70. Elsevier, 2014. http://dx.doi.org/10.1016/b978-0-12-420022-7.00010-0.
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Kirkham, M. B. "Field Capacity, Wilting Point, Available Water, and the Non-Limiting Water Range." In Principles of Soil and Plant Water Relations, 101–15. Elsevier, 2005. http://dx.doi.org/10.1016/b978-012409751-3/50008-6.
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Keefer, Robert F. "Macronutrients—Calcium, Magnesium, and Sulfur." In Handbook of Soils for Landscape Architects. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195121025.003.0015.
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Application of limestone to a soil changes the (a) soil physical properties by encouraging granulation and improving tilth; (b) soil chemical properties by decreasing soil acidity, increasing availability of a number of essential plant nutrients, and decreasing levels of aluminum, iron, and manganese that potentially may be toxic; and (c) soil biological properties by improving conditions for micriobial organic matter decomposition with release of nitrogen, phosphorus, and sulfur for plant use, and by stimulating root development. Granulation Encouraged. Applying lime to soils improves soil physical conditions by encouraging granulation and crumb formation and aggregation. Tilth Improved. Tilth is the ability to work or cultivate a soil. By improving physical conditions with more granulation and crumb formation, soil tilth is improved. Lowering H+ Concentration (Acidity). When lime is applied to a soil, acidity is reduced and pH is raised. This is especially important in the humid regions where rainfall and other factors constantly make a soil more acid (explained in Chapter 9). Plant Nutrient Availability Increased. Liming a soil will increase availability of plant nutrients by (a) increasing Ca and Mg in the soil from added liming material; (b) adjusting soil to a higher pH so that N, P, K, S, and Mo are solubilized; and (c) reducing solubility of potentially toxic levels of Fe, Al, or Mn. Lowering of Potentially Toxic Levels of Al, Fe, and Mn. At very low soil pH, Al, Fe, and Mn are soluble and may be present in a high enough concentration to be toxic to plant growth. When lime is applied, the pH increases and these three elements become less soluble and less available for plants. Microbial Decomposition Enhanced. Soils that are limed provide conditions for active microbial decomposition of organic materials in soils, resulting in mineralization and release of N, P, and S in forms that plants can use. Liming also increases the amount of humus formed, thereby improving water infiltration and water-holding capacity. Furthermore, liming soils stimulates other types of biological transformations, such as nitrification, N-fixation, and S-oxidation, that improve plant growth. Deep Rooting Stimulated.
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Juo, Anthony S. R., and Kathrin Franzluebbers. "Soil Fertility." In Tropical Soils. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195115987.003.0009.
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In the natural world, plant species evolve and adapt to specific soil and climatic conditions. The productivity and stability of a natural soil-plant continuum or ecosystem are maintained through diversity, succession, and internal nutrient cycling. Hence, there are no rich soils or poor soils but different soils supporting different ecosystems. From an agricultural viewpoint, however, the term soil fertility may be defined as the capacity of a soil, under a given rainfall or water management regime, to support the growth of common food and fiber crops with minimum or no external inputs for a long period of time without adversely degrading the chemical, physical, and biological properties of the soil. Thus, a naturally fertile or productive soil usually possesses the following features: • good soil tilth or workability • adequate organic matter content in the surface layer • adequate permeability • adequate available water-holding capacity • slightly acidic to neutral pH • loamy-textured topsoil • moderate amounts of smectite and weatherable minerals Worldwide, the most fertile soils are prairie soils derived from glacial till, young alluvial soils in river valleys and deltas and high-base-status volcanic ash soils. These soils are also known as Mollisols, high-base-status Entisols and high-base- status Andisols, respectively, according to the Soil Taxonomy classification. At the other end of the scale are the so-called infertile soils. These are the highly weathered and strongly leached soils or “lateritic soils” of the tropics. Ultisols and Oxisols rich in kaolinite and Fe and Al oxides fall into this category. The soil fertility status of other types of soils falls in between these two groups. In general, parent material and stage of weathering are good indicators of soil fertility. Moderately weathered soils derived from basic parent rocks such as basalts and limestone and recent alluvial deposits are invariably more fertile than those derived from acidic parent rocks such as sandstone, quartzite, and coarse-grained granite. Strongly weathered soils generally have a low fertility because primary minerals containing plant nutrients such as Ca, Mg, and K have long disappeared through dissolution, acidification, and leaching. The dominant clay-size minerals in strongly weathered soils, kaolinite and Fe and Al oxides, possess little capacity to retain these cations.
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Juo, Anthony S. R., and Kathrin Franzluebbers. "Properties and Management of Allophanic Soils." In Tropical Soils. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195115987.003.0017.
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Allophanic soils are dark-colored young soils derived mainly from volcanic ash. These soils typically have a low bulk density (< 0.9 Mg/m3), a high water retention capacity (100% by weight at field capacity), and contain predominantly allophanes, imogolite, halloysite, and amorphous Al silicates in the clay fraction. These soils are found in small, restricted areas with volcanic activity. Worldwide, there are about 120 million ha of allophanic soils, which is about 1% of the Earth's ice-free land surface. In tropical regions, allophanic soils are among the most productive and intensively used agricultural soils. They occur in the Philippines, Indonesia, Papua New Guinea, the Caribbean and South Pacific islands, East Africa, Central America, and the Andean rim of South America. Allophanic soils are primarily Andisols and andic Inceptisols, Entisols, Mollisols, and Alfisols according to the Soil Taxonomy classification. Allophanic soils generally have a dark-colored surface soil, slippery or greasy consistency, a predominantly crumb and granular structure, and a low bulk density ranging from 0.3 to 0.8 Mg/m3. Although allophanic soils are apparently well-drained, they still have a very high water content many days after rain. When the soil is pressed between fingers, it gives a plastic, greasy, but non-sticky sensation of a silty or loamy texture. When dry, the soil loses its greasiness and becomes friable and powdery. The low bulk density of allophanic soils is closely related to the high soil porosity. For example, moderately weathered allophanic soils typically have a total porosity of 78%, with macro-, meso-, and micropores occupying 13%, 33%, and 32%, respectively. Water retained in the mesopores is readily available for plant uptake. Water retained in the micropores is held strongly by soil particles and is not readily available for plant use. The macropores provide soil aeration and facilitate water infiltration. The high water retention capacity is also associated with the high soil porosity. In allophanic soils formed under a humid climate, especially those containing large amounts of allophane, the moisture content at field capacity can be as high as 300%, calculated on a weight basis. Such extremely high values of water content seem misleading.
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Perkins, John H. "Science and the Green Revolution 1945-1975." In Geopolitics and the Green Revolution. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195110135.003.0013.
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In the years after the end of World War II, farmers, agricultural scientists, and policy makers in many countries all knew, or learned, that higher yields of wheat were what they wanted, and they were successful in achieving them. Their specific motivations were different, but their objectives were not. Not only were the objectives clear, but a central method by which the higher yields were to be achieved was plant breeding. Plant breeding itself was an applied science that had to be nested within organizations that supported it and its allies in the agricultural, biological, and engineering sciences. By 1950 wheat breeders believed that the number of factors governing yield was small, which meant that the research avenues likely to be fruitful were also few in number. The amount of water available and the responsiveness to soil fertility, especially nitrogen, were in most cases the key ingredients for higher yields. For wheat, the ability of the plant to resist invasion by fungal pathogens was almost as important as water and soil fertility. Water and fertility were needed in every crop year, but damage from fungal pathogens varied with weather. Thus plant disease was not necessarily a destructive factor every year. Control of water, soil fertility, and plant disease was therefore at the center of research programs in wheat breeding. A wheat breeder would find success if his or her program produced new varieties that gave higher yields within the context of water, soil fertility, and plant disease existing in the area. Ancillary questions also existed and in some cases matched the major factors in importance. Weed control was always a problem, so high-yielding wheat had to have some capacity to resist competition from weeds. Similarly, in some areas and some years, insects could cause damage. Wheat varieties therefore had to be able to withstand them somehow. Other factors of importance to wheat breeders were habit of growth and the color and quality of the grain. Winter wheats were useful in climates that had winters mild enough to allow planting in the fall and thus higher yields the next summer.
Conference papers on the topic "Plant available water-holding capacity"
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"Sensitivity of simulated yield of dryland wheat to uncertainty in estimated plant-available water capacity." In 22nd International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand (MSSANZ), Inc., 2017. http://dx.doi.org/10.36334/modsim.2017.b3.chen.
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"The Applicability of VRI for Managing Variability in Infiltration Capacity and Plant-Available Water: A Preliminary Discussion and GIS Study." In 2014 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers, 2014. http://dx.doi.org/10.13031/aim.20141897710.
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Cohen, Stuart M., Kristen Averyt, Jordan Macknick, and James Meldrum. "Modeling Climate-Water Impacts on Electricity Sector Capacity Expansion." In ASME 2014 Power Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/power2014-32188.
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Climate change has the potential to exacerbate water availability concerns for thermal power plant cooling, which is responsible for 41% of U.S. water withdrawals. This analysis describes an initial link between climate, water, and electricity systems using the National Renewable Energy Laboratory (NREL) Regional Energy Deployment System (ReEDS) electricity system capacity expansion model. Average surface water projections from Coupled Model Intercomparison Project 3 (CMIP3) data are applied to surface water rights available to new generating capacity in ReEDS, and electric sector growth is compared with and without climate-influenced water rights. The mean climate projection has only a small impact on national or regional capacity growth and water use because most regions have sufficient unappropriated or previously retired water rights to offset climate impacts. Climate impacts are notable in southwestern states, which experience reduced water rights purchases and a greater share of rights acquired from wastewater and other higher-cost water resources. The electric sector climate impacts demonstrated herein establish a methodology to be later exercised with more extreme climate scenarios and a more rigorous representation of legal and physical water availability.
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Seyedan, Babak, Rory Hynes, and Satish K. Bhan. "Case Study Heat Capacity for an Industrial Plant Facility in a Complex." In International Joint Power Generation Conference collocated with TurboExpo 2003. ASMEDC, 2003. http://dx.doi.org/10.1115/ijpgc2003-40008.
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Cogeneration systems are typically used for supplying heat and electricity generation. The main advantages of such systems are energy savings and reduced operational costs. Plants that use cogeneration systems are often equipped with parallel components feeding various internal energy vector networks. The energy consumption of the plant can be improved by selecting suitable operating levels of the various parallel machines and components connected to the cogeneration system. Recently, cogeneration systems have been equipped with comprehensive monitoring systems. With the availability of these monitoring systems, the concept of a computerized procedure capable of recognizing the status of the equipment from the monitoring data to optimize the plant operation has been established. This can lead to significant economic and energy consumption improvements. In this paper, heat capacity of a typical installation is presented and a procedure to optimize energy utilization is developed. The procedure is presented for a cogeneration system based on natural gas engines, hot water boilers and other heat sources. Plant existing condition is taken as a reference condition. To improve system heat capacity, two alternate methods have been proposed and compared with plant existing condition. First option is the use of system available heat sources as a prime heat source and the second option is adding new gas boilers to improve complex heat production and also as a back up heat source to meet peak complex heat demand requirements. General block diagram of the system is presented and discussed. Installation heat load allocation is analyzed.
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Iijima, Toru, Hiroshi Abe, and Takafumi Fujita. "Program Outline of Seismic Fragility Capacity Tests on Nuclear Power Plant Equipment." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49524.
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A seismic probabilistic safety assessment (PSA) is an available method to evaluate residual risk of nuclear plant that is designed with definitive seismic design condition. Seismic fragility capacity data are necessary for seismic PSA, but we don’t have sufficient data of active components of nuclear plants in Japan. This paper describes a plan of seismic fragility capacity tests on nuclear power plant equipment. The purpose of those tests is to obtain seismic fragility capacity of important equipment from a safety design point of view. And the equipment for the fragility capacity tests were selected considering effect on core damage frequency (CDF) that was evaluated by our preliminary seismic PSA. Consequently horizontal shaft pump, electric cabinets, Control Rod Drive system (CRD system) of BWR and PWR plant and vertical shaft pump were selected. The seismic fragility capacity tests are conducted from phase-1 to phase-3, and horizontal shaft pump and electric cabinets are tested on phase-1. The fragility capacity test consists of two types of tests. One is actual equipment test and another is element test. On actual equipment test, a real size model is tested with high-level seismic motion, and critical acceleration and failure mode are investigated. Regarding fragility test phase-1, we selected typical type horizontal shaft pump and electric cabinets for the actual equipment test. Those were Reactor Building Closed Cooling Water (RCW) Pump and eight kinds of electric cabinets such as relay cabinet, motor control center. On the test phase-1, maximum input acceleration for the actual equipment test is intended to be 6G-force. Since the shaking table of TADOTSU facility didn’t have capability for high acceleration, we made vibration amplifying system. In this system, amplifying device is mounted on original shaking table and it moves in synchronization with original table. The element test is conducted with many samples and critical acceleration, median and deviation are evaluated. For the element test we selected bearings and liner rings of horizontal shaft pump and about thirty kinds of electric parts. The actual equipment test of phase-1 started from September 2003, and it will finish March 2004. The test phase-2 for CRD system and phase-3 for vertical shaft pump will start following test phase-1.
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Maulbetsch, John S. "Hybrid Cooling for Thermal-Electric Power Generation." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17812.
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Water use by power plant cooling systems has become a critical siting issue for new plants and the object of increasing pressure for modification or retrofit at existing plants. Wet cooling typically costs less and results in more efficient plant performance. Dry cooling, while costing more and imposing heat rate and capacity penalties on the plant, conserves significant amounts of water and eliminates any concerns regarding thermal discharge to or intake losses on local water bodies. Hybrid cooling systems have the potential of combining the advantages of both systems by reducing, although not eliminating, water requirements while incurring performance penalties that are less than those from all-dry systems. The costs, while greater than those for wet cooling, can be less than those for dry. This paper addresses parallel wet/dry systems combining direct dry cooling using a forced-draft air-cooled condenser (ACC) with closed-cycle wet cooling using a surface (shell-and-tube) steam condenser and a mechanical-draft, counterflow wet cooling tower as applied to coal-fired steam plants, gas-fired combined-cycle plants and nuclear plants. A brief summary of criteria used to identify situations where hybrid systems should be considered is given. A methodology for specifying and selecting a hybrid system is described along with the information and data requirements for sizing and estimating the capital costs and water requirements a specified plant at a specified site. The methodology incorporates critical plant and operating parameters into the analysis, such as plant monthly load profile, plant equipment design parameters for equipment related to the cooling system, e.g. steam turbine, condenser, wet or dry cooling system, wastewater treatment system. Site characteristics include a water budget or constraints, e.g. acre feet of water available for cooling on an annual basis as well as any monthly or seasonal “draw rate” constraints and meteorological data. The effect of economic parameters including cost of capital, power, water and chemicals for wastewater treating are reviewed. Finally some examples of selected systems at sites of varying meteorological characteristics are presented.
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Carmona, Jose. "Gas Turbine Evaporative Cooling: A Novel Method for Combined Cycle Plant Part Load Optimization." In ASME 2020 Power Conference collocated with the 2020 International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/power2020-16026.
Full textAbstract:
Abstract In power plant engineering, gas turbine (GT) evaporative cooling is traditionally thought as one of the few power augmentation alternatives for existing plants. For most combined cycle plants operating at part load, the GT Inlet Guide Vanes (IGV) will throttle the air flow to the combustor to maintain the turbine exhaust temperature (TET) as high as possible, thus maximizing the overall combined cycle efficiency. The IGV air throttling results in a reduction of the turbine inlet air temperature (TIT) due to a reduction on the mass of fuel burned in the combustors as the available combustion air decreases due to IGV throttling to maintain an optimum air to fuel ratio, resulting on a lower TET compared with the same GT at base load. The compounded result of these effects limits the maximum steam production capacity on the heat recovery steam generator, particularly for the high-pressure section, hampering the efficiency of the steam turbine. The methodology developed in the subject study aims at counteracting the afore-mentioned effects by optimizing the evaporative cooler air/water ratio which results in the lower possible heat rate for full load and part load operation. By dynamically controlling the air/water ratio, a preheating effect can be achieved in the compressor inlet air, which results on higher exhaust gas temperature, thus augmenting the high-pressure steam production on the heat recovery steam generator and accordingly the steam turbine efficiency. For a newly built 907 MWe Combined Cycle Gas Turbine (CCGT) plant, application of the evaporative cooling part load optimization methodology presented in this study could lead to a potential reduction of up to 158kJ/kWh on heat rate and 9.318 g/kWh of CO2 emissions if compared with the same plant without dynamic control of the evaporative cooler air/water ratio.
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Carmona, Jose. "Gas Turbine Evaporative Cooling, A Novel Method for Combined Cycle Plant Part Load Optimization." In ASME 2021 Power Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/power2021-65289.
Full textAbstract:
Abstract In power plant engineering, gas turbine (GT) evaporative cooling is traditionally thought as one of the few power augmentation alternatives for existing plants. For most combined cycle plants operating at part load, the GT Inlet Guide Vanes (IGV) will throttle the air flow to the combustor to maintain the turbine exhaust temperature (TET) as high as possible, thus maximizing the overall combined cycle efficiency. The IGV air throttling results in a reduction of the turbine inlet air temperature (TIT) due to a reduction on the mass of fuel burned in the combustors as the available combustion air decreases due to IGV throttling to maintain an optimum air to fuel ratio, resulting on a lower TET compared with the same GT at base load. The compounded result of these effects limits the maximum steam production capacity on the heat recovery steam generator, particularly for the high-pressure section, hampering the efficiency of the steam turbine. The methodology developed in the subject study aims at counteracting the afore-mentioned effects by optimizing the evaporative cooler air/water ratio which results in the lower possible heat rate for full load and part load operation. By dynamically controlling the air/water ratio, a preheating effect can be achieved in the compressor inlet air, which results on higher exhaust gas temperature, thus augmenting the high-pressure steam production on the heat recovery steam generator and accordingly the steam turbine efficiency. For a newly built 907 MWe Combined Cycle Gas Turbine (CCGT) plant, application of the evaporative cooling part load optimization methodology presented in this study could lead to a potential reduction of up to 158kJ/kWh on heat rate and 9.318 g/kWh of CO2 emissions if compared with the same plant without dynamic control of the evaporative cooler air/water ratio.
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Samanta, S., and S. Ghosh. "Energetic and Environmental Analysis of Partial Repowering of a Coal Fired Power Plant Through Upstream GT Integration and Employing Waste Heated Feed Water Heaters." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-27027.
Full textAbstract:
This paper presents a theoretical study of partial repowering scheme for an existing 210MW coal fired power plant and reports predicted performance improvement obtainable from the repowering by using Cycle Tempo software. In this method old boiler is used as it is, only modifying its air heater and forced flow sections. Out of four operating coal mills, one mill is considered to be taken out. A new natural gas fired gas turbine (GT) block is considered to be integrated with the existing plant whose exhaust is fed to the existing boiler. The GT size is selected such that its exhaust provide heat input equivalent to the replaced coal mill. The burners associated with that coal mill are assumed to be modified to handle hot exhaust gas from the GT block. It is noticed that a substantial amount of energy is available in the flue gas, coming out from the boiler, after the air preheater which can partially meet the heat loads of feed water heaters. This helps in saving of intermediate pressure (IP) and low pressure (LP) bleed steam and consequent increase in the output of the steam cycle. The partial repowering results in nearly 40% increase in capacity of the plant (from 210MW to 284MW). It also results in substantial increase in overall efficiency of the repowered plant by 28%, and consequent decrease in plant heat rate by 22%. The specific CO2 emission of the plant decreases about 31% after repowering.
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Othman, S., H. M. Mahmoud, and S. A. Kotb. "Interaction of a Nuclear Power Plant With the Egyptian Electrical Grid Based on PSS/E." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29051.
Full textAbstract:
The capacity of the electrical power system in Egypt will increase rapidly in the coming twenty years. In year 2018, nuclear power generation will be connecting to the Egyptian electrical grid. Consequently, the interaction of nuclear power plants and other systems becomes a very important issue, and a detailed nuclear power model for the medium-term and long-term power system stability should be developed. However, there is no nuclear unit model that can describe the detailed characteristics of the nuclear unit in the available commercial power system simulation software. In this paper, a detailed pressurized water reactor (PWR) nuclear unit model for medium-term and long-term power system transient stability is proposed. The model is implemented by a user defined program in PSS/E through PSS/E Matlab Simulink Interface. This model can be used to analyze the interaction of nuclear power plants and other power systems. The simulation results show that the proposed model is valid.