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2001 DIVISION S-1 SYMPOSIA 2001 Soil Science Society of America National Meetings October 21-25, 2001 Charlotte, NC t |
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S-1
2001 SYMPOSIA TOPICS
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| 1.
Temperature Effects on Soil Hydraulic Properties While the discipline of soil physics is most often concerned with the transport of liquid water and solutes in soils, the study of energy transport in soils is no less compelling and some of the issues revealed by studying this topic have more general interest. Since liquid water or water vapor can carry latent energy, the transport of water under temperature gradients is an important aspect of a soil's energy budget. One of the most intriguing aspects of this mechanism are the pronounced effect temperature has on soil capillary pressures, saturated hydraulic conductivities, and apparent dielectric constants. While each of these effects have been the subject of detailed studies and while the mechanisms for the temperature effects would initially appear to be straightforward, the work thus far has failed to elucidate unambiguously the mechanisms responsible for these effects. This failure reveals an uncertainty in the understanding of the fundamental nature of water's interactions with soils. Further, measurements of temperature effects on soil hydraulic properties can provide insights into the fundamental interactions of water with the soil matrix that are otherwise inaccessible experimentally. Interest in the study of temperature effects on soil hydraulic properties has revived in recent years due to improvements in field instrumentation, improved appreciation the importance of temperature effects in the transport of energy and water-especially in arid environments, and the promise of in-situ thermal remediation technologies. While having diverse motivations, this convergence of work makes it a propitious time to convene a special session on the effect of temperature on soil hydraulic properties. A special symposium is planned for the coming ASA meeting to summarize the state of understanding of the effect of temperature on soil hydraulic properties, to define the critical gaps in knowledge, and to explore the most promising avenues for future research. The session shall take advantage of some of the excellent experimental investigations by agricultural scientists in Europe and Asia. The session shall also draw up the important related work in hydrology and civil, environmental, and petroleum engineering. The symposium will be organized into a morning session of 10-12 invited and volunteered oral presentations followed by an afternoon poster session. For more information please contact: Steven A. Grant, U.S. Army Engineering and Research Center, Hanover, NH 03755-1290 tel: 603-646-4446, e-mail:steven.a.grant@usace.army.mil |
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Quantifying Agricultural Management Effects on Soil Properties and Processes Over the last 30 years, soil physicists have taken on the challenge of addressing real-world problems, and moved on from laboratory scale studies to field and landscape scales. Spatial variability of soil-water-solute properties and processes has been a major focus of studies, and our knowledge and understanding of these processes has been considerably enhanced. At the same time, several studies have shown that temporal variability of these processes can also be very significant. Agricultural management practices, such as tillage and reconsolidation, other operations with heavy machinery, plants and crop rotations, no-tillage and surface residues, and grazing management, are a major source of temporal variability of soil properties and processes. Weather related factors, such as freezing- thawing and wetting-drying, may somewhat modify the management effects. Numerous field studies have shown evidence of the significant management effects on soil-water-solute-plant properties and processes. However, very small effort has been made to synthesize the site-specific effects into hypotheses and theories, and to quantify these effects for practical applications. This Symposium is aimed at stimulating research by soil physicists and other soil scientists on synthesis, quantification, and modeling of management effects. The Symposium will include oral presentations by both invited and volunteer speakers, and a poster session. Suggested topics include: Tillage and reconsolidation effects on soil hydraulic properties, crusting-sealing, and other processes; Wheel-Track effects on soil properties and root growth; Subsoil compaction and root growth; Subsoiling or Chiseling and ridge-tillage effects; Plant rooting effects on soil; No-tillage and residue level effects on soil surface, soil matrix and macropore regions; Grazing intensity effects on surface soil properties and processes in rangelands; Interactions between natural variability and management effects; other topics. For more information contact: Dr. Laj Ahuja, USDA-ARS Great Plains Systems Research, P.O. Box E, Ft. Collins, CO 80522, e-mail: Ahuja@gpsr.colostate.edu |
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Bridging Scales in Soil Physics A pervasive problem in soil hydrology, and in soil science in general, is the representation of processes at a scale different from the one at which observations and property measurements are made. This scale-transfer problem must be solved, in particular, to describe effectively the coupled fluxes of heat and moisture across land surfaces, to establish appropriate soil parameters for describing the long-term fate of pollutants, to interpret various remote sensing data, to delineate management zones in agricultural fields, to estimate water yield and geochemical fluxes in ungaged watersheds, to understand sources and importance of diversity and patchiness in terrestrial ecosystems, and to provide parameters for estimating biogeochemical trends related to the climate change. The multiscale characterization of soil hydrological processes and parameters needs to be addressed both as a research issue of scale dependencies in soil physical properties and as practical/operational issue of data assimilation or data fusion in environmental monitoring and prediction. Remote sensing technologies to estimate soil parameters at large scales, spatially intensive methods to measure indirect indicators of soil physical properties, and in situ measurement techniques to obtain a small scale soil hydraulic data are being developed. There are marked advancements in understanding and simulating scale dependence in soil properties and their spatial variability. Tools to integrate georeferenced data collected at various scales become available. There is a significant number of soil research groups facing and attacking scale problems in soil hydrology within frameworks of various projects in agronomy and evironmental protection. The symposium will be organized into a half day session of both invited and volunteered oral presentations followed by an afternoon poster session. For more information please contact: Yakov Pachepsky USDA:ARS:BA:NRI:HRSL Hydrology and Remote Sensing Lab Bldg. 007, Rm. 104, BARC-WEST Beltsville, MD 20705 Phone: 301-504-7468 Fax: 301-504-8931, e-mail: ypachepsky@asrr.arsusda.gov or ypachep@hydrolab.arsusda.gov |
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Don Nielsen Symposium: Soil Physical Properties and Processes and Their
Variability in Space and Time Division S-1, with co-sponsorship of other S and A Divisions will organize a symposium at the 2001 annual Soil Science Society Meeting in Charlotte, NC, entitled "Soil Physical Properties and Processes and Their Variability in Space and Time". The symposium will honor the career and the scientific contributions of Dr. Donald R. Nielsen, Professor Emeritus of the University of California at Davis, who has been a leading soil physical scientist for more than four decades. He was among the first soil scientists to apply basic physical principles to the study of miscible solute transport in soils and to use geostatistics and time-series analysis to study the spatial and temporal distribution of soil physical properties and processes. Furthermore, Dr. Nielsen is exceptionally active on foreign assignments as a teacher and advisor. Two half-day sessions will be devoted to research topics and teachings interests of Dr.Nielsen, such as (1) fundamental theory of water and solute transport in porous media, (2) mass and heat transfer in field soils, (3) application of regionalized variables theory, geostatistical methods, and state-space analyses at the field scale, and (4) collaborative international environmental studies. The symposium will provide a forum for invited and volunteer speakers. For further information contact either: Ole Wendroth (owendroth@zalf.de) or Jan Hopmans (jwhopmans@ucdavis.edu) |
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Monday,
October 22 |
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