Academic literature on the topic 'Zone of improved soil'
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Journal articles on the topic "Zone of improved soil"
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FARID, H. U., A. BAKHSH, N. AHMAD, A. AHMAD, and Z. MAHMOOD-KHAN. "Delineating site-specific management zones for precision agriculture." Journal of Agricultural Science 154, no. 2 (May 8, 2015): 273–86. http://dx.doi.org/10.1017/s0021859615000143.
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SUMMARYDelineating site-specific management zones within fields can be helpful in addressing spatial variability effects for adopting precision farming practices. A 3-year (2008/09 to 2010/11) field study was conducted at the Postgraduate Agricultural Research Station, University of Agriculture, Faisalabad, Pakistan, to identify the most important soil and landscape attributes influencing wheat grain yield, which can be used for delineating management zones. A total of 48 soil samples were collected from the top 300 mm of soil in 8-ha experimental field divided into regular grids of 24 × 67 m prior to sowing wheat. Soil and landscape attributes such as elevation, % of sand, silt and clay by volume, soil electrical conductivity (EC), pH, soil nitrogen (N) and soil phosphorus (P) were included in the analysis. Artificial neural network (ANN) analysis showed that % sand, % clay, elevation, soil N and soil EC were important variables for delineating management zones. Different management zone schemes ranging from three to six were developed and evaluated based on performance indicators using Management Zone Analyst (MZA V0·1) software. The fuzziness performance index (FPI) and normalized classification entropy NCE indices showed minimum values for a four management zone scheme, indicating its appropriateness for the experimental field. The coefficient of variation values of soil and landscape attributes decreased for each management zone within the four management zone scheme compared to the entire field, which showed improved homogeneity. The evaluation of the four management zone scheme using normalized wheat grain yield data showed distinct means for each management zone, verifying spatial variability effects and the need for its management. The results indicated that the approach based on ANN and MZA software analysis can be helpful in delineating management zones within the field, to promote precision farming practices effectively.
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Alafeena, Mustafa A., and Ala Nasir Aljorany. "Experimental Study on the Modulus of Subgrade Reaction for Sandy Soil Improved by Grouting Materials." Key Engineering Materials 857 (August 2020): 358–66. http://dx.doi.org/10.4028/www.scientific.net/kem.857.358.
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Many methods have been used for soil improvement at site, one of these methods is grouting. Cement grouted soils consist of particulate soil media and cementation agents. Such soils have been widely used to improve the shear strength and stiffness of weak soils and for preventing of water seepage through soils. The modulus of subgrade reaction may give a good indication about the soil bearing capacity and stiffness. This geotechnical parameter can be measured by using the plate load test. In this study, an experimental work is done to assess the improvement in the stiffness of sandy soils by injection two different cementing agents (cement and colloidal silica). The work includes plate loading tests with two different plate diameters (B= 150 and B= 250 mm). The effects of plate size, depth of the grouted zone (0-B and B-2B) as well as the effect of grouting material type on the performance of the grouted soil are investigated. The results show that the colloidal silica grout is more effective in increasing the modulus of sub grade reaction (ks) than the cement grout. Also, the use of plate with 150 mm diameter gives higher value of (ks) than that of 250 mm diameter. Furthermore, grout injection at depth (from 0 to B) gives a higher value of (ks) than that for deeper grouted zone.
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Wiseman, P. Eric, Susan Day, and J. Roger Harris. "Organic Amendment Effects on Soil Carbon and Microbial Biomass in the Root Zone of Three Landscape Tree Species." Arboriculture & Urban Forestry 38, no. 6 (November 1, 2012): 262–76. http://dx.doi.org/10.48044/jauf.2012.036.
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There is increasing interest in amending degraded soils with organic matter to improve soil quality, especially in urban areas where rehabilitation of damaged soils may enhance tree growth and provision of ecosystem services. To assess the potential of such organic amendments for producing a sustained alteration in soil biological characteristics, researchers studied the effects of three organic amendments incorporated into the root zone of three tree species on root development, soil carbon dynamics, and soil microbial biomass over one year beginning 20 months after amendment application. Soil amendment with leaf-based, and to a lesser extent, biosolids-based composts increased root length within the amended root zone of red maple (Acer rubrum), but not of pin oak (Quercus palustris) or chestnut oak (Q. montana). There was a concomitant increase in microbial biomass carbon for red maple. Across all species, sphagnum peat moss amendment reduced microbial biomass carbon by 47% compared to unamended root zones and suppressed maximum seasonal soil respiration relative to composts. In contrast, leaf-based compost increased microbial biomass carbon by 12% (P = 0.0989) compared to unamended root zones. Carbon/nitrogen ratios remained stable throughout most of the year except in the root zones of chestnut oak and pin oak amended with peat, where it declined 44%–85%. Total soil carbon was stable in all treatments, although unamended soils averaged about 40% lower than amended soils. Across all species and treatments, cumulative fine root length explained 19% of the variation in microbial biomass carbon. The study authors conclude that soil microbial activity can be increased by compost amendment of the root zone and that this increase is mediated to some degree by tree roots. In addition, stable C/N ratios suggest this alteration in the root zone may be sustainable. Further research may clarify whether compost amendment combined with tree planting can accelerate soil restoration.
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Tian, Siyuan, Luigi J. Renzullo, Albert I. J. M. van Dijk, Paul Tregoning, and Jeffrey P. Walker. "Global joint assimilation of GRACE and SMOS for improved estimation of root-zone soil moisture and vegetation response." Hydrology and Earth System Sciences 23, no. 2 (February 21, 2019): 1067–81. http://dx.doi.org/10.5194/hess-23-1067-2019.
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Abstract. The lack of direct measurement of root-zone soil moisture poses a challenge to the large-scale prediction of ecosystem response to variation in soil water. Microwave remote sensing capability is limited to measuring moisture content in the uppermost few centimetres of soil. The GRACE (Gravity Recovery and Climate Experiment) mission detected the variability in storage within the total water column. However, root-zone soil moisture cannot be separated from GRACE-observed total water storage anomalies without ancillary information on surface water and groundwater changes. In this study, GRACE total water storage anomalies and SMOS near-surface soil moisture observations were jointly assimilated into a hydrological model globally to better estimate the impact of changes in root-zone soil moisture on vegetation vigour. Overall, the accuracy of root-zone soil moisture estimates through the joint assimilation of surface soil moisture and total water storage retrievals showed improved consistency with ground-based soil moisture measurements and satellite-observed greenness when compared to open-loop estimates (i.e. without assimilation). For example, the correlation between modelled and in situ measurements of root-zone moisture increased by 0.1 (from 0.48 to 0.58) and 0.12 (from 0.53 to 0.65) on average for grasslands and croplands, respectively. Improved correlations were found between vegetation greenness and soil water storage on both seasonal variability and anomalies over water-limited regions. Joint assimilation results show a more severe deficit in soil water anomalies in eastern Australia, southern India and eastern Brazil over the period of 2010 to 2016 than the open-loop, consistent with the satellite-observed vegetation greenness anomalies. The assimilation of satellite-observed water content contributes to more accurate knowledge of soil water availability, providing new insights for monitoring hidden water stress and vegetation conditions.
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Kirkby, M. J. "Water in the critical zone: soil, water and life from profile to planet." SOIL 2, no. 4 (December 12, 2016): 631–45. http://dx.doi.org/10.5194/soil-2-631-2016.
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Abstract. Earth is unique in the combination of abundant liquid water, plate tectonics and life, providing the broad context within which the critical zone exists, as the surface skin of the land. Global differences in the availability of water provide a major control on the balance of processes operating in the soil, allowing the development of environments as diverse as those dominated by organic soils, by salty deserts or by deeply weathered lateritic profiles. Within the critical zone, despite the importance of water, the complexity of its relationships with the soil material continue to provide many fundamental barriers to our improved understanding, at the scales of pore, hillslope and landscape. Water is also a vital resource for the survival of increasing human populations. Intensive agriculture first developed in semi-arid areas where the availability of solar energy could be combined with irrigation water from more humid areas, minimising the problems of weed control with primitive tillage techniques. Today the challenge to feed the world requires improved, and perhaps novel, ways to optimise the combination of solar energy and water at a sustainable economic and environmental cost.
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Li, Chang Yu, Han Bing Liu, and Hai Bin Wei. "An Experimental Study on Engineering Properties of Rubber Particles-Improved Fly Ash Soil." Applied Mechanics and Materials 71-78 (July 2011): 3401–6. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.3401.
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In this paper, by studying the engineering properties of rubber particles-improved fly ash soil, the authors provide technical parameters for setting up cold-resistance layer in the seasonal frozen zone. In the experiment, rubber particles are mixed into the fly ash soil by mass of 0%, 1%, 2%, 3%, 5% and 7% and unconfined compressive strength testing, frost heave test, insulation test and thermal conductivity test. By analyzing the test results, the authors drew the conclusion that fly ash soil improved by rubber particles has a high compressive strength, a small amount of frost heave, good insulation performance, small thermal conductivity coefficient.Therefore, improved fly ash soil with rubber particles is one of the preferred materials to set up the cold resistance layer in seasonal frost zone.
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Li, Dayang, Zhongmin Liang, Binquan Li, Xiaohui Lei, and Yan Zhou. "Multi-objective calibration of MIKE SHE with SMAP soil moisture datasets." Hydrology Research 50, no. 2 (November 1, 2018): 644–54. http://dx.doi.org/10.2166/nh.2018.110.
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Abstract Root zone soil moisture plays an important role in water storage in hydrological processes. The recently launched Soil Moisture Active Passive (SMAP) mission has produced a high-resolution assimilation product of global root zone soil moisture that can be applied to improve the performance of hydrological models. In this study, we compare three calibration approaches in the Beimiaoji watershed. The first approach is single-objective calibration, in which only observed streamflow is used as a benchmark for comparison with the other approaches. The second and third approaches use multi-objective calibration based on SMAP root zone soil moisture and observed streamflow. The difference between the second and third approaches is the metric used to characterize the root zone soil moisture. The second approach applies the mean, which was commonly used in previous studies, whereas the third approach applies the hydrologic complexity μ, a dimensionless metric based on information entropy theory. These approaches are implemented to calibrate the distributed hydrological model MIKE SHE. Results show that the root zone soil moisture simulation is clearly improved, whereas streamflow simulation suffers from a slightly negative impact with multi-objective calibration. The hydrologic complexity μ performs better than the mean in capturing the features of root zone soil moisture.
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Nian, Ting Kai, Zhong Kai Feng, Peng Cheng Yu, and Hui Jun Wu. "Shear Test on Mixed Slide-Zone Soils of Landslide under Different Water Content." Advanced Materials Research 301-303 (July 2011): 1208–13. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.1208.
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This study is based on a typical residual soil landslide adjacent to Daxishan Reservior in Dalian city of China. By drilling the original samples in the field and remodeling the copy samples in the laboratory, a series of geotechnical experiments are carried out by the improved direct shear apparatus to obtain the changing law between the shear strength and water content of the mixed slide-zone soils. Emphasis is given on the shear stress-strain behavior and the corresponding constitutive model under different water content for the soils. Especially, the typical fitting equation is achieved to reflect the state of shear stress-normal stress-water content, some strain softening and hardening behavior on the mixed slide-zone soils of landslide is also discussed in detail. The results indicate that the shear strength is significantly related to water content of mixed slide-zone soils of landslide. The bigger water content of slide-zone soil is, the smaller the shear strength of soils is. When water content of mixed slide-zone soils approaches to certain value (i.e., 15%), the curve of shear stress and displacement shows a remarkable softening behavior, and the shear strength has marked a peak value.
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Rebel, K. T., R. A. M. de Jeu, P. Ciais, N. Viovy, S. L. Piao, G. Kiely, and A. J. Dolman. "A global analysis of soil moisture derived from satellite observations and a land surface model." Hydrology and Earth System Sciences 16, no. 3 (March 16, 2012): 833–47. http://dx.doi.org/10.5194/hess-16-833-2012.
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Abstract. Soil moisture availability is important in regulating photosynthesis and controlling land surface-climate feedbacks at both the local and global scale. Recently, global remote-sensing datasets for soil moisture have become available. In this paper we assess the possibility of using remotely sensed soil moisture – AMSR-E (LPRM) – to similate soil moisture dynamics of the process-based vegetation model ORCHIDEE by evaluating the correspondence between these two products using both correlation and autocorrelation analyses. We find that the soil moisture product of AMSR-E (LPRM) and the simulated soil moisture in ORCHIDEE correlate well in space and time, in particular when considering the root zone soil moisture of ORCHIDEE. However, the root zone soil moisture in ORCHIDEE has on average a higher temporal autocorrelation relative to AMSR-E (LPRM) and in situ measurements. This may be due to the different vertical depth of the two products – AMSR-E (LPRM) at the 2–5 cm surface depth and ORCHIDEE at the root zone (max. 2 m) depth – to uncertainty in precipitation forcing in ORCHIDEE, and to the fact that the structure of ORCHIDEE consists of a single-layer deep soil, which does not allow simulation of the proper cascade of time scales that characterize soil drying after each rain event. We conclude that assimilating soil moisture, using AMSR-E (LPRM) in a land surface model like ORCHIDEE with an improved hydrological model of more than one soil layer, may significantly improve the soil moisture dynamics, which could lead to improved CO2 and energy flux predictions.
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Tian, Siyuan, Luigi J. Renzullo, Robert C. Pipunic, Julien Lerat, Wendy Sharples, and Chantal Donnelly. "Satellite soil moisture data assimilation for improved operational continental water balance prediction." Hydrology and Earth System Sciences 25, no. 8 (August 24, 2021): 4567–84. http://dx.doi.org/10.5194/hess-25-4567-2021.
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Abstract. A simple and effective two-step data assimilation framework was developed to improve soil moisture representation in an operational large-scale water balance model. The first step is a Kalman-filter-type sequential state updating process that exploits temporal covariance statistics between modelled and satellite-derived soil moisture to produce analysed estimates. The second step is to use analysed surface moisture estimates to impart mass conservation constraints (mass redistribution) on related states and fluxes of the model using tangent linear modelling theory in a post-analysis adjustment after the state updating at each time step. In this study, we assimilate satellite soil moisture retrievals from both Soil Moisture Active Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) missions simultaneously into the Australian Water Resources Assessment Landscape model (AWRA-L) using the proposed framework and evaluate its impact on the model's accuracy against in situ observations across water balance components. We show that the correlation between simulated surface soil moisture and in situ observation increases from 0.54 (open loop) to 0.77 (data assimilation). Furthermore, indirect verification of root-zone soil moisture using remotely sensed Enhanced Vegetation Index (EVI) time series across cropland areas results in significant improvements from 0.52 to 0.64 in correlation. The improvements gained from data assimilation can persist for more than 1 week in surface soil moisture estimates and 1 month in root-zone soil moisture estimates, thus demonstrating the efficacy of this data assimilation framework.
Dissertations / Theses on the topic "Zone of improved soil"
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Zhang, Hongjuan [Verfasser]. "Improved characterization of root zone soil moisture by assimilating groundwater level and surface soil moisture data in an integrated terrestrial system model / Hongjuan Zhang." Jülich : Forschungszentrum Jülich GmbH, Zentralbibliothek, 2018. http://d-nb.info/1163839310/34.
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Erindi-Kati, Anila. "Remote sensing and root zone soil moisture." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84027.
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This study investigated the possibility of three approaches in determination of soil moisture in the root zone. The aim of the study was to contribute to the development of soil moisture monitoring methods to better help crop best management practices.Two fields were examined, one at the Macdonald Campus of McGill University and the other near St. Jean-sur-Richelieau. Three approaches were used; (1) a hand-held hyper-spectral sensor (350-2500 nm), (2) a Geonics RTM EM-38 conductivity meter and, (3) gravimetric soil moisture sampling.
The first experiment (at St. Jean-sur-Richelieu) investigated the possibility of monitoring soil moisture with the EM_38, in the presence of field elevation and soil texture. The second experiment (at Macdonald Campus) investigated the possibility of using hyper-spectral sensor data for determination of soil characteristics in the root zone, in the presence of such factors as (a) irrigation (main treatment), (b) nitrogen (sub-treatment), and (c) weed control (sub-sub-treatment). Statistical regression analyses and Artificial Neural Network models were used to select the best waveband region for determination of soil root zone moisture.
The coefficients of determination obtained by the statistical analyses ranged from 0.75 to 0.94. The wavebands most frequently identified by these analyses ranged from 1100 nm-1900 nm.
The performances of the ANN training models were considered acceptable (R2 from 0.6 to 0.8). The lack of sufficient data greatly impacts this approach.
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Joshi, Gyawali Ayush. "A fresh soil health perspective: Soil health dynamics and improved measurement techniques." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89949.
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Encouraging greater implementation of conservation agriculture practices such as reduced tillage and cover crops may require better understanding of the effect of these practices on soil health. The overall objective of this study was to quantify soil health dynamics due to conservation agriculture practices and address methodological gaps in terms of measuring soil health parameters. We developed five sites across the state of Virginia; each site had replicated plots with combinations of reduced tillage versus disk tillage and wintertime cover crops versus no cover crops as experimental treatments. Soil and plant samples were collected 1-2 times per year for 3 years, and were analyzed for 30 soil health parameters. The parameters were first evaluated to determine if any consistently detected treatment differences. We then quantified the temporal dynamics of the eight most responsive soil health parameters, while considering influences of soil water content at time of tillage, cover crop biomass, and previous land management history.
Of the analyzed parameters, only 2-4 mm aggregate stability and magnesium showed high responsiveness and consistency in identifying tillage and cover crop effects. None of the parameters detected treatment differences in all sites or at all times, yet samples collected after high biomass cover crops or after tillage in wet conditions tended to show significant treatment differences for multiple indicators. The previous history of management in each site may have affected trends in aggregate stability, but did not appear to influence other indicators.
As soil aggregate stability was found to be the most important soil health parameter, our third study developed an improved method for measuring soil aggregate stability. This new method, Integrated Aggregate Stability (IAS), interprets aggregate stability using a laser diffraction machine. Overall, IAS showed higher correlation with the wet sieving method (R2 = 0.49 to 0.59) than widely used median aggregate size (d50) (R2 = 0.09 to 0.27). IAS can also quantify stability of macro- and micro-sized aggregates, which d50 cannot. When comparing between IAS and wet sieving, IAS requires considerably less time and sample amounts.
Our fourth study focused on creating an inexpensive yet accurate tool for measuring soil respiration, as microbial assessments based on respiration rates have great potential for detecting rapid changes in soil health. Using an Arduino-based infrared gas analyzer (IRGA) sensor, we developed the Soil Microbial Activity Assessment Contraption (SMAAC) for less than $150. Our results show that SMAAC provided consistent readings with a commercial IRGA unit when tested using three different configurations.
Altogether, the research presented in this dissertation identifies important soil health parameters and quantifies their temporal and between-site dynamics. Using this narrower set of indicators can help producers and practitioners save resources when conducting measurements to assess soil health effects of agricultural practices. Further, this work also provides improved measurement techniques for useful soil health parameters like aggregate stability and soil respiration. These findings and innovations should help to encourage greater adoption of agricultural management practices that build and preserve soil health.Doctor of Philosophy
If we want to make sure that ample and safe food is available to future generations, then it is time that we produce food without damaging the soil. Many widely used soil management techniques like tillage and leaving the field bare can harm the soil and decrease productivity in the long run. One potential technique to produce food while protecting the soil and environment is conservation agriculture, which can include reduced tillage and cover cropping. Reduced tillage is a technique in which we grow food without majorly disturbing the soil, while cover crops are planted when cash crops are not in the field in order to improve or sustain the soil. Understanding the soil-related benefits of conservation agriculture practices is important to encourage farmers to adopt these practices. In this study we tested the effects on soils of reduced tillage and cover crop practices versus conventional tillage and bare soil practices, using five locations across Virginia. We also developed improved methods for measuring two informative soil parameters. We found that, when looking at all of our five sites, the stability of soil aggregates, the rate at which water enters soil, and the nutrients in surface soils were all affected by the type of management that the soils were subjected to. Reduced tillage increased stability of soil aggregates when compared with conventional till. This increased stability of aggregates indicators lower potential for surface water runoff, erosion, and flooding when we practice reduced tillage. Cover cropping also increased stability of soil aggregates, especially when the cover crops attained substantial above-ground mass. Soil nutrients (which are essential for plants to grow) were also overall higher in the surface soil layers under no-till. Since the stability of soil aggregates was found to be an important benefit of CA practices, we also perceived a need for a better method for measuring stability of these aggregates. In response, we developed a new index called Integrated Aggregate Stability (IAS). IAS was found to give similar results as established methods, but the time required to get IAS result is about 10 minutes, whereas the time required for established methods like wet sieving is around 2 days. IAS measurements are therefore both accurate and quick to perform. We also focused on developing an inexpensive tool for measuring soil respiration. Soil respiration-based measurements help us to understand the activity of microbes in the soil. These microbes are very important for soils to function. Our tool, Soil Microbial Activity Assessment Contraption (SMAAC), was very consistent with a currently used tool and shows high potential for future use. Altogether, we found that no-tillage and cover cropping can increase stability of soil aggregates even within 1-3 years of starting those practices. No-till can also increase nutrient concentrations in the top soil layer. The tools and innovations developed in this study have the potential to increase the ability of farmers to assess soil health and also encourage greater adoption of conservation agriculture practices.
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Zhang, Jing. "Modeling considerations for vadose zone soil moisture dynamics." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001982.
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Omotere, Olumide Olubunmi. "Improvement of the Soil Moisture Diagnostic Equation for Estimating Root-Zone Soil Moisture." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157607/.
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Soil moisture information can be used accurately in determining the timing and amount of irrigation applied to plants. Pan and Pan et al. proposed a robust and simple daily diagnostic equation for estimating daily soil moisture. The diagnostic equation evaluates the relationship between the soil moisture loss function and the summation weighted average of precipitation. The loss function uses the sinusoidal wave function which employs day of the year (DOY) to evaluate the seasonal variation in soil moisture loss for a given year. This was incorporated into the daily diagnostic equation to estimate the daily soil moisture for a location. Solar radiation is an energy source that drives the energy and water exchanges between vegetation and the atmosphere (i.e., evapotranspiration), and thus impacts the soil moisture dry-down. In this paper, two parameters (the actual solar radiation and the clear sky solar radiation) are introduced into loss function coefficient to improve the estimation of soil moisture. After the Introduction of the solar radiation data into soil moisture loss function, a slight improvement was observed in the estimated daily soil moisture. Pan observed that generally the correlation coefficient between the estimated and the observed soil moisture is above 0.75 and the root mean square error is below 5.0 (%v/v). The introduction solar radiation data (i.e. clear sky solar radiation and actual solar) improve the correlation coefficient average for all the sites evaluated by 0.03 when the root mean square error is generally below 4.5(%v/v) for the entire root zone.
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Wetterlind, Johanna. "Improved farm soil mapping using near infrared reflection spectroscopy." Uppsala : Dept. of Soil and Environment, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200968.pdf.
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Губашова, Валентина Євгенівна. "Обґрунтування раціональних технологічних параметрів струменевої цементації в складних геотехнічних умовах." Doctoral thesis, Київ, 2021. https://ela.kpi.ua/handle/123456789/40256.
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Дисертація присвячена обґрунтуванню раціональних технологічних параметрів струменевої цементації в складних геотехнічних умовах. В роботі досліджено та встановлено взаємозв’язки технологічних параметрів струменевої цементації з діаметром ґрунтоцементної колони в різних типах ґрунтів. На основі отриманих експоненціальних залежностей діаметра ґрунтоцементного елементу круглого перерізу від енергії високонапірного струменя цементного розчину розроблено методику розрахунку діаметра струменево-цементаційної колони. В процесі дослідження експериментальним шляхом доведено змінення фізико-механічних властивостей ґрунту, що оточує ґрунтоцементний елемент під час його виконання за струменевою технологією. На підставі математичного моделювання визначено закономірності формування в ґрунтових масивах зон з поліпшеними фізико-механічними параметрами в міжколонному просторі в різних типах ґрунтів. Удосконалено методику комп’ютерного моделювання управління напружено-деформованим станом основи будівлі під час її підсилення струменево-цементаційними елементами з урахуванням складних геотехнічних умов.
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Fall, Thioro. "Soil Management for Improved Rice Production in Casamance, Senegal." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/81457.
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Rice is a staple crop for many countries around the world, and is one of the top three food sources globally. Many environments where rice is grown contain stressors likely to limit its growth and yield. In southern Senegal (Casamance region), rice is mainly cultivated in lowlands near estuaries where drought, salinity, acidity, poor soil fertility, and iron toxicity are the main limiting factors. In Casamance, average rice yield for local farmers is 1 to 2 tons per hectare (809 to 1618 pounds per acre), compared to worldwide average yield of more than 4 tons per hectare. The soil where our 2-year experiment (2014 and 2015) was conducted is highly saline-sodic and acidic, and the salt tolerant cultivar we grew yielded 3.4 tons per hectare in 2013. Our main objective was to increase rice yield. The water table height, salinity, and pH were measured weekly during the rice growing season, and the soil was described, sampled, and analyzed to better understand the water and soil resources. Two planting methods were tested: flat planting and planting on beds. Two soil amendments were compared with each planting method: biochar and crushed oyster shells, alone and in combination. An untreated control was included in the experiment. All plots were fertilized. Treatment effects on soil properties and yield were compared in a split-plot design. Plant tissue was sampled for elemental content. The water table was above the surface and was saline during half of the growing season in 2014, and decreased after rice grain head emerged. Planting methods and amendments did not have an effect on yield in 2014, but biochar amendment increased yield in 2015. In 2014, soil salinity and sodium decreased to below toxic levels late in the growing season in the flat plots but not in the bedded plots. Therefore, flat planting is more appropriate in these lowland rice production systems. Soil pH increased from 4.4 to 7.7 in flat planting where biochar+shell was applied. Soil available nutrients such as P, Mn, and Zn were significantly higher in flat planting compared to beds. Toxic levels of Na (> 2000 milligrams per kilogram) were measured in leaves sampled just before flowering. We recommend flat planting and amending soil with biochar in saline-sodic acid-sulfate paddy soils in Casamance to improve rice yield.Master of Science
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Inoue, Keisuke. "ESTIMATION OF DAMAGED ZONE IN SOIL USING RESISTIVITY MONITORING." Kyoto University, 2017. http://hdl.handle.net/2433/225322.
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Mahmood-Ul-Hassan, Muhammad. "Water movement through the unsaturated zone." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244907.
Full textBooks on the topic "Zone of improved soil"
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Kanmegne, Jacques. Slash and burn agriculture in the humid forest zone of southern Cameroon: Soil quality dynamics, improved fallow management, and farmers' perceptions. Wageningen: Wageningen University, 2004.
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Robert, Michel. Soil carbon sequestration for improved land management. Rome: Food and Agricultural Organization of the United Nations, 2001.
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R, Calvet, and Prost R. 1938-, eds. Soil pollution: Processes and dynamics. Berlin: Springer, 1996.
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Luckner, Ludwig. Migration processes in the soil and groundwater zone. Chelsea, Mich: Lewis Publishers, 1991.
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Miller, Perry Ray. Introducing alternative crops to the brown soil zone. Ottawa, Ont: Agriculture and Agri-Food Canada, Research Branch, 1995.
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Tindall, James A. Unsaturated zone hydrology for scientists and engineers. Upper Saddle River, N.J: Prentice Hall, 1999.
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Samt͡sov, A. S. Ėkologii͡a khvoĭnykh porod i formirovanie fitot͡senozov v zone vodokhranilishch. Minsk: Navuka i tėkhnika, 1991.
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Murray, E. J. Unsaturated soils: A fundamental interpretation of soil behaviour. Chichester, West Sussex, U.K: Wiley-Blackwell, 2010.
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Ng, C. W. W. Unsaturated soil mechanics and engineering. London: Taylor & Francis, 2007.
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Gooding, Dominic Edward Maxwell. Improved processes for the production of soil-cement building blocks. [s.l.]: typescript, 1994.
Find full textBook chapters on the topic "Zone of improved soil"
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Patle, Kamlesh S., Salman siddiqui, Hemen K. Kalita, and Vinay S. Palaparthy. "Reduced Graphene Oxide Soil Moisture Sensor with Improved Stability and Testing on Vadose Zone Soils." In Lecture Notes in Electrical Engineering, 115–23. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6940-8_10.
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Bell, Michael J., Antonio P. Mallarino, Jeff Volenec, Sylvie Brouder, and David W. Franzen. "Considerations for Selecting Potassium Placement Methods in Soil." In Improving Potassium Recommendations for Agricultural Crops, 341–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59197-7_12.
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AbstractPlacement strategies can be a key determinant of efficient use of applied fertilizer potassium (K), given the relative immobility of K in all except the lightest textured soils or high rainfall environments. Limitations to K accessibility by plants caused by immobility in the soil are further compounded by the general lack of K-stimulated root proliferation in localized soil zones enriched with K alone, compared with root proliferation due to concentrated N and P. Further, effects of K fixation reactions in soils with certain clay mineralogies and the declining concentration and activity of soil solution K with increasing clay content can also limit plant K acquisition. Variation in root system characteristics among crops in a rotation sequence and fluctuating soil moisture conditions in fertilized soil horizons in rain-fed systems increase the complexity of fertilizer placement decisions to ensure efficient K recovery and use. This complexity has resulted in extensive exploration of fertilizer K application strategies, with this chapter focusing on K applications to the soil. Issues discussed include comparisons of broadcast versus banded applications, depth of fertilizer placement, and the impacts of co-location of K with other nutrients. While research findings are often specific to the crop, soil, and seasonal conditions under which they are conducted, we attempt to identify strategies that most consistently deliver improved crop recovery and utilization of fertilizer K.
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Rosolem, Ciro A., Antonio P. Mallarino, and Thiago A. R. Nogueira. "Considerations for Unharvested Plant Potassium." In Improving Potassium Recommendations for Agricultural Crops, 147–62. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-59197-7_6.
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AbstractPotassium (K) is found in plants as a free ion or in weak complexes. It is easily released from living or decomposing tissues, and it should be considered in fertilization programs. Several factors affect K cycling in agroecosystems, including soil and fertilizer K contributions, plant K content and exports, mineralization rates from residues, soil chemical reactions, rainfall, and time. Soil K+ ions can be leached, remain as exchangeable K, or migrate to non-exchangeable forms. Crop rotations that include vigorous, deep-rooted cover crops capable of exploring non-exchangeable K in soil are an effective strategy for recycling K and can prevent leaching below the rooting zone in light-textured soils. The amount of K released by cover crops depends on biomass production. Potassium recycled with non-harvested components of crops also varies greatly. Research with maize, soybean, and wheat has shown that 50–60% of K accumulated in vegetative tissues is released within 40–45 days. A better understanding of K cycling would greatly improve the efficacy of K management for crop production. When studying K cycling in agricultural systems, it is important to consider: (1) K addition from fertilizers and organic amendments; (2) K left in residues; (3) K partitioning differences among species; (4) soil texture; (5) soil pools that act as temporary sources or sinks for K. In this chapter, the role of cash and cover crops and organic residues on K cycling are explored to better understand how these factors could be integrated into making K fertilizer recommendations.
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Zhong, Shunqin, Jianming Xu, Jiachun Shi, and Jianjun Wu. "Does Iron Plaque Improve the Uptake and Translocation of Lead by Broad-leaf Cattail in Lead-contaminated Soils." In Molecular Environmental Soil Science at the Interfaces in the Earth’s Critical Zone, 148–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-05297-2_45.
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Richardson, S., and S. Wohnlich. "Characterization of the Unsaturated Zone Using Carbon Monoxide as a Tracer Gas to Improve Soil Venting Systems." In Field Screening Europe, 147–52. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-1473-5_34.
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Surbeck, Cristiane Q., and Jeff Kuo. "Vadose Zone Soil Remediation." In Site Assessment and Remediation for Environmental Engineers, 121–72. First edition. | Boca Raton, FL : CRC Press/Taylor & Francis Group, LLC, 2021. |: CRC Press, 2021. http://dx.doi.org/10.1201/9780429427107-5.
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Jeffrey, David W. "Saltmarshes and the coastal zone." In Soil~Plant Relationships, 235–56. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-011-6076-6_18.
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Chen, Wilfred, and Ashok Mulchandani. "Engineering of Improved Biocatalysts in Bioremediation." In Soil Biology, 235–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-06066-7_10.
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Gupta, Raj K., I. P. Abrol, Charles W. Finkl, M. B. Kirkham, Marta Camps Arbestain, Felipe Macías, Ward Chesworth, et al. "Soils of the coastal zone." In Encyclopedia of Soil Science, 711–34. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-3995-9_562.
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Beltrame, Philippe. "Soil Wettability." In Soils as a Key Component of the Critical Zone 3, 53–84. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119438045.ch2.
Full textConference papers on the topic "Zone of improved soil"
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"Can assimilating remotely-sensed surface soil moisture data improve root-zone soil moisture predictions in the CABLE land surface model?" In 19th International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand (MSSANZ), Inc., 2011. http://dx.doi.org/10.36334/modsim.2011.e4.pipunic.
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Kutuzova, Anel, Elena Provornaya, and Galina Stepanova. "AGROENERGY EFFICIENCY OF IMPROVED TECHNOLOGIES FOR CREATION AND USE OF ALFALFA-CEREAL HAYMAKING IN THE NON-CHERNOZEM ZONE." In Multifunctional adaptive fodder production 26 (74). ru: Federal Williams Research Center of Forage Production and Agroecology, 2021. http://dx.doi.org/10.33814/mak-2021-26-74-9-17.
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On the basis of field experience in the creation of alfalfa-grass stands on sod-podzolic soil of the Non-Chernozem zone, a high agroenergetic efficiency of improved technologies has been established, including two zoned varieties of alfalfa changeable (Lugovaya 67 and Pastbishchnaya 88) in combination with agrotechnical methods (change in the composition of leguminous species in the previous period and pre-sowing inoculation of alfalfa seeds with complementary strains of Sinorhizobium meliloti). As a result of the application of the agro-energy method for assessing the production of exchangeable energy and total anthropogenic costs in uniform indicators according to the international SI system (GJ/ha), their payback was established — 8–11 times. This was achieved due to a high share of natural factors (88–91% of total costs), additional nitrogen input into the production process due to increased symbiotic fixation (141–171 kg/ha per year) and long-term use — for 7 years. The productivity of 1 hectare was 62–64 GJ/ha metabolic energy, the collection of protein was 956–1120 kg/ha, the saving of anthropogenic costs due to the exclusion of the use of nitrogen fertilizers was 17–21 GJ/ha.
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Henniges, M., S. Meister, H. Rhee, C. Theiss, H. Robers, M. Grehn, D. Stolarek, L. Zimmermann, and U. Woggon. "Integrated fresnel zone plate in the SOI backend for improved laser to chip coupling efficiency." In 2017 IEEE Optical Interconnects Conference (OI). IEEE, 2017. http://dx.doi.org/10.1109/oic.2017.7965512.
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Ilchenko, Y. I., O. A. Biryukova, A. V. Kucherenko, and A. M. Medvedeva. "YIELD OF WINTER WHEAT WHEN USING DIRECT SEEDING IN THE CONDITIONS OF THE ROSTOV REGION." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.342-345.
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The article presents the results of a three-year study of the effect of mineral fertilizers on the yield of winter wheat in the No-till system in the soil and climatic conditions of the southern zone of the Rostov region. The combined introduction of ammophos and kalimagnesia before sowing with two fertilizing with ammonium nitrate in the tillering and outlet phases of the tube helps to improve the nutritional regime of the soil and ensures maximum yield of winter wheat.
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Shiri, Hodjat, and Mark Randolph. "The Influence of Seabed Response on Fatigue Performance of Steel Catenary Risers in Touchdown Zone." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20051.
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The significant influence of the riser-seabed interaction on the fatigue performance of steel catenary risers is now widely accepted. Most design, however, is still carried out using linear seabed springs, and assuming a flat seabed. Improved nonlinear hysteretic seabed models have recently been proposed, which automatically simulate the different stiffness in the seabed response through the touchdown zone. A further consideration, however, is the influence of the trench that forms at the seabed. ROV surveys have shown that trenches several diameters deep can develop beneath the riser in the early stages of the SCR life, and a critical question is how this affects the fatigue life. A non-linear soil hysteretic model has been used to model gradual trench development in the touchdown zone. Initially, the seabed model parameters are adjusted to allow trenches of varying depth to be developed over a moderate number of displacement cycles of the SCR. Design wave spectra are then applied, simulating a generic Spar system, after correcting the model parameters to more typical values normal range. The paper presents results that show the impact of trenches of different depths on the fatigue performance of SCRs in the touchdown zone.
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Keaton, Jeffrey R., Theodore H. Parks, Luther H. Boudra, and Lee D. Walker. "Enhancing Pipeline Project Management With Improved Rock Excavation Forecasting." In 2012 9th International Pipeline Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ipc2012-90143.
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Accurate rock-excavation forecasting is one of the geotechnical risk factors that challenge successful management of cross-country pipeline projects. Rock excavation requirements commonly are estimated by pipeline construction personnel with local experience. Construction bid and contract documents typically call for excavation of “ditch” rock to be paid per lineal foot, whereas “area” or right-of-way grading (ROWG) rock is paid per cubic yard. Rock excavation forecasting tends to be used for economic feasibility more than for selecting contractors or preparing contracts. Recent pipeline projects in Pennsylvania and New Jersey used geotechnical estimates of rock excavation to update detailed cost and schedule projections after construction was underway because ROWG rock excavation exceeded the expected volume. Geotechnical estimates of rock excavation were based on a rapid desktop study followed by field observations and measurements. The desktop study used available digital data manipulated with geographic information management software (GIS). Topographic data (digital elevation models) at 10-m resolution and the pipeline centerline in 10-m-long segments were used to plot alignment elevation profile and ground slope, as well as to calculate slope aspect and apparent ground slope across the ROW perpendicular to centerline. The centerline was plotted in Google Earth Pro for a virtual geologic field reconnaissance to identify areas where rock was likely or unlikely to be encountered within ditch depth. Digital geology was used to assess bedrock type along the alignment and digital soil survey data were classified to identify soil units with shallow cemented zones or bedrock. These complementary data types were combined into an overall rock excavation index factor (0 = uncemented soil; 1 = cemented soil; 2 = weathered rock near ditch bottom; or 3 = nearby rock outcrop, weathered rock near top of ditch, or unweathered rock at any ditch depth). GIS polygons of “rock factors” were converted to a grid so that values could be extracted at points along the pipeline centerline. Ground-condition variability was considered subjectively for each rock factor by assigning length-based and area-based percentages where rock was considered likely to be encountered for both “average” and “maximum” rock conditions. Rock factor areas were used to select locations for 115 or 230-ft-(35 or 70-m-) long seismic refraction surveys. Seismic velocities > 4,000 to 4,500 ft/s (1,220 to 1,370 m/s) were considered blast rock in trench excavations. Locations where the 4,000-ft/s contour was shallower than ditch depth were used to refine subjective ground variability estimates. Additional construction records of actual blasting details are needed to further improve the rock excavation model. Unique aspects of geology may require model parameters to be modified for other settings.
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Tannoury, George A., and Steven D. Schrock. "Introduction to Chemical Stabilization of Unstable Trackbeds." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5779.
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Trackbeds are typically composed of all granular materials comprised of ballast and subballast over compacted subgrade. Most poor performances of railroads can be attributed to poor and unstable subgrade conditions. Below the surface, the instability of the subgrade material can propagate through the granular zone leading to excessive settlements and deformations of the railway. Conventional subgrade restoration in the trackbed system requires the removal of the granular materials and over-excavation of soft unstable subgrade materials, moisture adjustment, re-compaction, and sometimes chemical stabilization of the subgrade soils. Since these procedures are considered very expensive in terms of construction equipment, railway outage time, and labor force, alternative solutions for consideration and evaluation are essential. Injection of expansive foam (polymer based) materials is a relatively recent method that has been used in various applications of soil stabilization in the roadway industry. This technique relies on the injection of rigid-polyurethane foam, which is a high-density, expanding, thermoset, hydro-insensitive and environmentally neutral polyurethane-resin product, into the soft and unstable soil to improve their shear strength and stability index. In addition, the stabilized zone acts as a waterproof membrane protecting moisture sensitive subgrade, and acting as a separation layer to eliminate pumping and contamination of the granular subballast at saturated fine grained conditions. The objective of this paper is to evaluate the practicability of polyurethane stabilized soft and unstable subgrade under unbounded granular trackbeds to mitigate future deformation, restore railway foundation, and reduce trackbed repair cost and outage time.
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Aggarwal, Rajiv K., Marcio M. Mourelle, Steinar Kristoffersen, Henri Godinot, Pedro Vargas, Michael Else, Ronald W. Schutz, et al. "Development and Qualification of Alternative Solutions for Improved Fatigue Performance of Deepwater Steel Catenary Risers." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29325.
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Several initiatives have been undertaken by the operators, engineering companies, product manufacturers, and regulatory bodies to enable increased use of steel catenary riser (SCR) design in development of deepwater and ultra-deepwater fields. Some of these efforts focus on improvement in understanding of soil-structure interaction at SCR touch down zone (TDZ) and its impact on fatigue damage estimates through analytical studies, laboratory testing, or in-field monitoring of SCR behavior. Through recent studies and laboratory testing work for floating platforms with SCR, the need for significant enhancement of SCR design at TDZ through implementation of alternate solutions has been identified. This paper presents a summary of the work undertaken in a Joint Industry Project (JIP) during 2004 to 2007 [1, 2] to develop solutions and undertake qualification tasks for four alternatives with potential to improve fatigue performance at TDZ by factor of up to 10 or more. The solutions considered at SCR TDZ include: thick light-weight coating over steel riser sections; steel riser sections with upset ends; high strength steel riser sections with integral connectors; and a titanium segment. The major qualification tasks undertaken for each solution will be identified and discussed. The qualification program undertaken for each solution varied and in some cases, it also included manufacturing of samples, laboratory and full-scale fatigue testing, and post-failure evaluation. Through significant qualification activities undertaken in this JIP, progress has been made to bring these solutions to project ready state for their consideration at the frond end engineering design (FEED) stage. Such design enhancements would enable increase in selection of SCR design for production and export riser applications under severe operating conditions, harsh environment, and floating systems with high motions.
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Hill, Stephen D., and Prateen Desai. "Plasma Torch Interaction With a Melting Substrate." In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47199.
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A model of a partially ionized, high pressure plasma in stagnation flow as it melts a nonhomogeneous solid is presented. It encompasses both the analysis of the multi-fluid plasma to ascertain its bulk temperature and the heat flux profile, as well as its interaction with a receding melt interface in and around the stagnation domain. The model examined in this study couples the plasma motion, bulk energy, electron and ion densities and temperatures, with impinging jet theory to determine the amount of heat transfer into the particular substrate material — soil. “Multi-fluid” equations are derived for an axially symmetric plasma from the Boltzmann equations for Maxwellian velocity distributions. By examining the dominant effects, the equations are scaled and the roles of the driving dimensionless parameters are established. For specified values of these parameters, various numerical methods are used to couple and solve the two distinct models. The first one, to ascertain the moving boundary phase change heat transfer characteristics, is developed by adopting a form of the enthalpy method. The second model, characterizing the plasma jet is solved via and adaptation of the commercially available code, CHEMKIN, developed by the Sandia National Laboratories. A parametric study is performed, leading to evaluation of such important torch characteristics including mass flow rate of the Argon gas, temperature of the plasma bulk, and proximity of the plasma torch to the surface, as it influences the substrate melt zone. The extremely high temperatures produced by the plasma irreversilby changes the material structure of the sample. This new structure, when cooled, forms a predominantly glassy product. Such a vitrification process has been proven to improve the construction properties of the soil and to reduce a toxic sample of the soil into a leachable solid. From the calculations of solid/liquid interfacial location, radii of the melt zones, and depths of the melt zones an overall perspective of the vitrification process is assessed.
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Quéau, Lucile M., Mehrdad Kimiaei, and Mark F. Randolph. "Lazy Wave Catenary Risers: Scaling Factors and Analytical Approximation of the Static Stress Range in the Touchdown Zone." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10273.
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Offshore exploration and production of oil and gas continue to increase and move into ever deeper water. Steel catenary risers (SCRs) are one of the most cost effective type of risers in deep water. However, high sensitivity to vessel motions and hydrodynamic loading in the touchdown zone may limit the feasibility of SCR applications. In recent years, there has been a growing interest in the use of Lazy-wave catenary riser (LWR) due to their better fatigue performance in the touchdown zone through the damping effect of the buoyancy section. The design of LWR involves numerous parameters that lead to a wide range of configurations. Each of these configurations needs to be evaluated against several criteria with respect to geometry, strength and fatigue for instance. This paper presents how tools recently proposed to improve the design of standard SCRs can be extended to benefit LWR applications. The dimensionless groups governing the structural response of LWRs are established in the aim of easing sensitivity analysis to key input parameters for LWR design, assisting experiments and reducing the number of numerical simulations. Moreover, the DAF (dynamic amplification factor) approach for dynamic response which has previously been explored for SCRs could also be used to simplify design of LWRs. As DAF relies on the analytical determination of static response, this framework shows that analytical boundary layer solutions in conjunction with the use of a Winkler type soil model can efficiently and accurately predict the static stress range of LWRs observed in the TDZ.
Reports on the topic "Zone of improved soil"
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Bonfil, David J., Daniel S. Long, and Yafit Cohen. Remote Sensing of Crop Physiological Parameters for Improved Nitrogen Management in Semi-Arid Wheat Production Systems. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7696531.bard.
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To reduce financial risk and N losses to the environment, fertilization methods are needed that improve NUE and increase the quality of wheat. In the literature, ample attention is given to grid-based and zone-based soil testing to determine the soil N available early in the growing season. Plus, information is available on in-season N topdressing applications as a means of improving GPC. However, the vast majority of research has focused on wheat that is grown under N limiting conditions in sub-humid regions and irrigated fields. Less attention has been given to wheat in dryland that is water limited. The objectives of this study were to: (1) determine accuracy in determining GPC of HRSW in Israel and SWWW in Oregon using on-combine optical sensors under field conditions; (2) develop a quantitative relationship between image spectral reflectance and effective crop physiological parameters; (3) develop an operational precision N management procedure that combines variable-rate N recommendations at planting as derived from maps of grain yield, GPC, and test weight; and at mid-season as derived from quantitative relationships, remote sensing, and the DSS; and (4) address the economic and technology-transfer aspects of producers’ needs. Results from the research suggest that optical sensing and the DSS can be used for estimating the N status of dryland wheat and deciding whether additional N is needed to improve GPC. Significant findings include: 1. In-line NIR reflectance spectroscopy can be used to rapidly and accurately (SEP <5.0 mg g⁻¹) measure GPC of a grain stream conveyed by an auger. 2. On-combine NIR spectroscopy can be used to accurately estimate (R² < 0.88) grain test weight across fields. 3. Precision N management based on N removal increases GPC, grain yield, and profitability in rainfed wheat. 4. Hyperspectral SI and partial least squares (PLS) models have excellent potential for estimation of biomass, and water and N contents of wheat. 5. A novel heading index can be used to monitor spike emergence of wheat with classification accuracy between 53 and 83%. 6. Index MCARI/MTVI2 promises to improve remote sensing of wheat N status where water- not soil N fertility, is the main driver of plant growth. Important features include: (a) computable from commercial aerospace imagery that include the red edge waveband, (b) sensitive to Chl and resistant to variation in crop biomass, and (c) accommodates variation in soil reflectance. Findings #1 and #2 above enable growers to further implement an efficient, low cost PNM approach using commercially available on-combine optical sensors. Finding #3 suggests that profit opportunities may exist from PNM based on information from on-combine sensing and aerospace remote sensing. Finding #4, with its emphasis on data retrieval and accuracy, enhances the potential usefulness of a DSS as a tool for field crop management. Finding #5 enables land managers to use a DSS to ascertain at mid-season whether a wheat crop should be harvested for grain or forage. Finding #6a expands potential commercial opportunities of MS imagery and thus has special importance to a majority of aerospace imaging firms specializing in the acquisition and utilization of these data. Finding #6b on index MCARI/MVTI2 has great potential to expand use of ground-based sensing and in-season N management to millions of hectares of land in semiarid environments where water- not N, is the main determinant of grain yield. Finding #6c demonstrates that MCARI/MTVI2 may alleviate the requirement of multiple N-rich reference strips to account for soil differences within farm fields. This simplicity will be less demanding of grower resources, promising substantially greater acceptance of sensing technologies for in-season N management.
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Kamai, Tamir, Gerard Kluitenberg, and Alon Ben-Gal. Development of heat-pulse sensors for measuring fluxes of water and solutes under the root zone. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604288.bard.
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The objectives defined for this study were to: (1) develop a heat-pulse sensor and a heat-transfer model for leaching measurement, and (2) conduct laboratory study of the sensor and the methodology to estimate leaching flux. In this study we investigated the feasibility for estimating leachate fluxes with a newly designed heat-pulse (HP) sensor, combining water flux density (WFD) with electrical conductivity (EC) measurements in the same sensor. Whereas previous studies used the conventional heat pulse sensor for these measurements, the focus here was to estimate WFD with a robust sensor, appropriate for field settings, having thick-walled large-diameter probes that would minimize their flexing during and after installation and reduce associated errors. The HP method for measuring WFD in one dimension is based on a three-rod arrangement, aligned in the direction of the flow (vertical for leaching). A heat pulse is released from a center rod and the temperature response is monitored with upstream (US) and downstream (DS) rods. Water moving through the soil caries heat with it, causing differences in temperature response at the US and DS locations. Appropriate theory (e.g., Ren et al., 2000) is then used to determine WFD from the differences in temperature response. In this study, we have constructed sensors with large probes and developed numerical and analytical solutions for approximating the measurement. One-dimensional flow experiments were conducted with WFD ranging between 50 and 700 cm per day. A numerical model was developed to mimic the measurements, and also served for the evaluation of the analytical solution. For estimation WFD, and analytical model was developed to approximate heat transfer in this setting. The analytical solution was based on the work of Knight et al. (2012) and Knight et al. (2016), which suggests that the finite properties of the rods can be captured to a large extent by assuming them to be cylindrical perfect conductors. We found that: (1) the sensor is sensitive for measuring WFD in the investigated range, (2) the numerical model well-represents the sensor measurement, and (2) the analytical approximation could be improved by accounting for water and heat flow divergence by the large rods.
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Lieth, J. Heiner, Michael Raviv, and David W. Burger. Effects of root zone temperature, oxygen concentration, and moisture content on actual vs. potential growth of greenhouse crops. United States Department of Agriculture, January 2006. http://dx.doi.org/10.32747/2006.7586547.bard.
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Soilless crop production in protected cultivation requires optimization of many environmental and plant variables. Variables of the root zone (rhizosphere) have always been difficult to characterize but have been studied extensively. In soilless production the opportunity exists to optimize these variables in relation to crop production. The project objectives were to model the relationship between biomass production and the rhizosphere variables: temperature, dissolved oxygen concentration and water availability by characterizing potential growth and how this translates to actual growth. As part of this we sought to improve of our understanding of root growth and rhizosphere processes by generating data on the effect of rhizosphere water status, temperature and dissolved oxygen on root growth, modeling potential and actual growth and by developing and calibrating models for various physical and chemical properties in soilless production systems. In particular we sought to use calorimetry to identify potential growth of the plants in relation to these rhizosphere variables. While we did experimental work on various crops, our main model system for the mathematical modeling work was greenhouse cut-flower rose production in soil-less cultivation. In support of this, our objective was the development of a Rose crop model. Specific to this project we sought to create submodels for the rhizosphere processes, integrate these into the rose crop simulation model which we had begun developing prior to the start of this project. We also sought to verify and validate any such models and where feasible create tools that growers could be used for production management. We made significant progress with regard to the use of microcalorimetry. At both locations (Israel and US) we demonstrated that specific growth rate for root and flower stem biomass production were sensitive to dissolved oxygen. Our work also identified that it is possible to identify optimal potential growth scenarios and that for greenhouse-grown rose the optimal root zone temperature for potential growth is around 17 C (substantially lower than is common in commercial greenhouses) while flower production growth potential was indifferent to a range as wide as 17-26C in the root zone. We had several set-backs that highlighted to us the fact that work needs to be done to identify when microcalorimetric research relates to instantaneous plant responses to the environment and when it relates to plant acclimation. One outcome of this research has been our determination that irrigation technology in soilless production systems needs to explicitly include optimization of oxygen in the root zone. Simply structuring the root zone to be “well aerated” is not the most optimal approach, but rather a minimum level. Our future work will focus on implementing direct control over dissolved oxygen in the root zone of soilless production systems.
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, October 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
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Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.
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Heiser, John, and Michael Furey. Application of Polymeric Agents for Improved Soil Decontamination. Office of Scientific and Technical Information (OSTI), September 2008. http://dx.doi.org/10.2172/973599.
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Chorover, Jon, Karl T. Mueller, K. G. Karthikeyan, A. Vairavamurthy, and R. Jeff Serne. Interfacial Soil Chemistry of Radionuclides in the Unsaturated Zone. Office of Scientific and Technical Information (OSTI), June 2001. http://dx.doi.org/10.2172/833610.
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Chorover, Jon, Karl T. Mueller, K. G. Karthikeyan, A. Vairavamurthy, and R. Jeff Serne. Interfacial Soil Chemistry of Radionuclides in the Unsaturated Zone. Office of Scientific and Technical Information (OSTI), June 2002. http://dx.doi.org/10.2172/833612.
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Chorover, Jon, Karl T. Mueller, K. G. Karthikeyan, A. Vairavamurthy, and R. Jeff Serne. Interfacial Soil Chemistry of Radionuclides in the Unsaturated Zone. Office of Scientific and Technical Information (OSTI), June 2003. http://dx.doi.org/10.2172/833614.
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Karl T. Mueller, Don Chorover, Peggy O'Day, R. Jeff Serne, Garry Crosson, Geoffrey Bowers, and Nelson Rivera. Collboration: Interfacial Soil Chemistry of Radionuclides in the Unsaturated Zone. Office of Scientific and Technical Information (OSTI), December 2006. http://dx.doi.org/10.2172/896844.
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Crowley, David E., Dror Minz, and Yitzhak Hadar. Shaping Plant Beneficial Rhizosphere Communities. United States Department of Agriculture, July 2013. http://dx.doi.org/10.32747/2013.7594387.bard.
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PGPR bacteria include taxonomically diverse bacterial species that function for improving plant mineral nutrition, stress tolerance, and disease suppression. A number of PGPR are being developed and commercialized as soil and seed inoculants, but to date, their interactions with resident bacterial populations are still poorly understood, and-almost nothing is known about the effects of soil management practices on their population size and activities. To this end, the original objectives of this research project were: 1) To examine microbial community interactions with plant-growth-promoting rhizobacteria (PGPR) and their plant hosts. 2) To explore the factors that affect PGPR population size and activity on plant root surfaces. In our original proposal, we initially prqposed the use oflow-resolution methods mainly involving the use of PCR-DGGE and PLFA profiles of community structure. However, early in the project we recognized that the methods for studying soil microbial communities were undergoing an exponential leap forward to much more high resolution methods using high-throughput sequencing. The application of these methods for studies on rhizosphere ecology thus became a central theme in these research project. Other related research by the US team focused on identifying PGPR bacterial strains and examining their effective population si~es that are required to enhance plant growth and on developing a simulation model that examines the process of root colonization. As summarized in the following report, we characterized the rhizosphere microbiome of four host plant species to determine the impact of the host (host signature effect) on resident versus active communities. Results of our studies showed a distinct plant host specific signature among wheat, maize, tomato and cucumber, based on the following three parameters: (I) each plant promoted the activity of a unique suite of soil bacterial populations; (2) significant variations were observed in the number and the degree of dominance of active populations; and (3)the level of contribution of active (rRNA-based) populations to the resident (DNA-based) community profiles. In the rhizoplane of all four plants a significant reduction of diversity was observed, relative to the bulk soil. Moreover, an increase in DNA-RNA correspondence indicated higher representation of active bacterial populations in the residing rhizoplane community. This research demonstrates that the host plant determines the bacterial community composition in its immediate vicinity, especially with respect to the active populations. Based on the studies from the US team, we suggest that the effective population size PGPR should be maintained at approximately 105 cells per gram of rhizosphere soil in the zone of elongation to obtain plant growth promotion effects, but emphasize that it is critical to also consider differences in the activity based on DNA-RNA correspondence. The results ofthis research provide fundamental new insight into the composition ofthe bacterial communities associated with plant roots, and the factors that affect their abundance and activity on root surfaces. Virtually all PGPR are multifunctional and may be expected to have diverse levels of activity with respect to production of plant growth hormones (regulation of root growth and architecture), suppression of stress ethylene (increased tolerance to drought and salinity), production of siderophores and antibiotics (disease suppression), and solubilization of phosphorus. The application of transcriptome methods pioneered in our research will ultimately lead to better understanding of how management practices such as use of compost and soil inoculants can be used to improve plant yields, stress tolerance, and disease resistance. As we look to the future, the use of metagenomic techniques combined with quantitative methods including microarrays, and quantitative peR methods that target specific genes should allow us to better classify, monitor, and manage the plant rhizosphere to improve crop yields in agricultural ecosystems. In addition, expression of several genes in rhizospheres of both cucumber and whet roots were identified, including mostly housekeeping genes. Denitrification, chemotaxis and motility genes were preferentially expressed in wheat while in cucumber roots bacterial genes involved in catalase, a large set of polysaccharide degradation and assimilatory sulfate reduction genes were preferentially expressed.