Progress 09/01/02 to 06/30/07
Outputs
OUTPUTS: Hydropedology has become a well recognized interdisciplinary science that integrates pedology, hydrology, and geomorphology to study soil-water interactions and landscape-soil-hydrology relationships across spatial and temporal scales. An integrated approach of soil-landscape mapping, geophysics, hydropedology, hydrometry, and real-time monitoring of soil moisture, precipitation, and stream discharge has been used to understand subsurface flow networks and critical nodes (i.e., important junctions of flow networks in the subsurface that control the threshold behavior of hillslope subsurface stormflow) at our study site at the Shale Hills Catchment and Kepler Farm.
PARTICIPANTS: H.S. Lin, Associate Professor, Penn State University; X. Zhou, Graduate Student, Penn State University; and J. Zhang, Graduate Student, Penn State University. The students collected data and worked with the PI to analyze the data.
TARGET AUDIENCES: Soil scientists and hydrologists.
Impacts
The work at the Shale Hills Catchment has attracted interdisciplinary research and education interests across Penn State and beyond. As a result, a team of interdisciplinary scientists within and outside Penn State has received a large grant from NSF to establish this site as one of the 1st three National Critical Zone Observatories. Another significant impact of this project is the USDA funding received to host the 1st International Conference on Hydropedology to be held July 28-31, 2008, at Penn State.
Publications
- Zhou, X., H.S. Lin, and Q. Zhu. 2007. Temporal stability of soil moisture spatial variability at two scales and its implication for optimal field monitoring. Hydrol. Earth Syst. Sci. Discuss. 4:1185-1214.
- Schmidt, J. P., N. Hong, A. Dellinger, D. B. Beegle, and H.S. Lin. 2007. Hillslope-scale variability in corn response to nitrogen linked to in-season soil moisture redistribution. Agronomy Journal. 99:229-237.
- Lin, H.S. 2007. Cattle vs. ground beef: What is the difference? Soil Survey Horizons. 48:9-10.
- Lin, H.S. 2007. When it rains. Soil Survey Horizons. 48:47.
- Lin, H.S. 2007. Hydropedology: Its concept and opportunities. IUSS Bulletin. 111:12-15.
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Progress 01/01/06 to 12/31/06
Outputs
The emerging interdisciplinary research field of hydropedology attracts a substantial attention because of its promise to bridge pedology and hydrology. We continued to explore multiscale bridging frameworks in hydropedology using various approaches, including 1) conceptual hierarchies of soil mapping and soil process modeling, 2) bridging river basin scales and processes to assess human-climate impacts and the terrestrial hydrologic system, and 3) connecting pore- and pedon-scale soil structure and breakthrough measurement using X-ray computing tomography. We also developed an example of pedotransfer function relating soil structure and soil hydrologic parameters using the subset of 2,149 samples from the US National Soil Characterization database that had values of water content at -33 kPa and bulk densities on clods, structure characterized with grade, size and shape, textural class determined in the field and from lab textural analysis. Classification and
regression trees were used to group soil samples according to their water contents at -33 kPa. The structural parameters served as important grouping variables to define groups of soil samples with distinctly different average water retention for the groups.
Impacts
This study contributes to the development of an enhanced framework for modeling water flow and chemical transport in diverse structured soils, and has significant impacts on a number of issues of societal importance, (such as non-point source pollution prevention, watershed-based management, integrated agricultural systems, precision farming, nutrient dynamics in agroecosystems, sustainable land use, and ecosystem restoration and preservation). Defining and quantifying soil structure at various scales, including pore, pedon, hillslope and watershed scales, will also contribute to the development of scale-relevant PTFs at those scales.
Publications
- Lin, H.S., Bouma, J., and Pachepsky, Y. 2006. Revitalizing pedology through hydrology and connecting hydrology to pedology. Geoderma 131:255-256.
- Lin, H.S. 2006. Clarifying misperceptions and sharpening contributions. In A. Hartemink (ed.) The Future of Soil Science. International Union of Soil Sciences, Wageningen, The Netherlands. p. 80-83.
- Wilding, L.P. and Lin, H.S. 2006. Advancing the frontiers of soil science towards a geoscience. Geoderma 131:257-274.
- Pachepsky, Y. A., Rawl, W. J., and Lin, H.S. 2006. Hydropedology and pedotransfer functions. Geoderma 131:308-316.
- Reed, P., Brooks, R., Davis, K., DeWalle, D., Dressler, K., Duffy, C. , Lin, H.S, Miller, D., Najjar, R., Salvage, K. M., Wagener,T., and Yarnal, B. 2006. Bridging River Basin Scales and Processes to Assess Human-Climate Impacts and the Terrestrial Hydrologic System. Water Resource Research 42, W07418, http://www.agu.org/pubs/crossref/2006.../2005WR004153.shtml
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Progress 01/01/05 to 12/31/05
Outputs
An experiment was conducted to investigate quantitative relationship between preferential flow and soil structure using advanced X-ray computing tomography (CT) and real-time breakthrough curve in an agriculturally important soil in Pennsylvania. This study uses fractal analysis to quantitatively understand soil structure at multiple scales and their relations to dynamic soil hydrologic processes. The idea of structural fingerprinting in the soil is explored. Five positions of the intact soil column (Ap1, Ap2, Bt, and two boundaries between horizons) were scanned at three different stages with 78.1um 78.1um 86.7 m voxel size: 1) unsaturated, 2) saturated with water, and 3) injection of KI solution (as a tracer). Three dimensional pore volume, pore surface areas, pore hydraulic radius were computed from the CT images. Preferential flow pathways were segmented based on the higher CT number for the tracer. Preliminary results showed obviously different flow patterns at
the five positions in the soil column. Preferential flow pathways were mainly related to the macropores, especially the wormholes and those connected to the wormholes. In addition, the inter-pedal zone was also active in solute transport. This study illustrates the significance of soil structure in better understanding and modeling of water flow and solute transport in naturally-structured soils. The study also proves that industrial CT is a powerful tool to study intact soil structure and its impacts on water flow and solute transport.
Impacts
This study contributes to the development of an enhanced framework for modeling water flow and chemical transport in diverse structured soils, and has significant impacts on a number of issues of societal importance, such as non-point source pollution prevention, watershed-based management, integrated agricultural systems, precision farming, nutrient dynamics in agroecosystems, sustainable land use, and ecosystem restoration and preservation.
Publications
- Lilly, A., and Lin, H.S. 2004. Using soil morphological attributes and soil structure in pedotransfer functions. In Y. Pachepsky and W. Rawls (eds.) Development of Pedotransfer Functions in Soil Hydrology. Elsevier. p. 115-142.
- Luo, L., Lin, H. S., Grader, A., and Halleck, P. 2005. Soil Structure and Its Relationship to Preferential Flow Using Micro X-Ray CT. ASA-CSSA-SSSA Annual Meeting. Nov. 6-10, 2005, Salt Lake City, UT. CD-ROM.
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Progress 01/01/04 to 12/31/04
Outputs
I am currently working on a case study with a spatial statistician to apply Bayesian hierarchical modeling for predicting soil moisture across multiple scales. This approach integrates geostatistical and geospatial techniques to combine data from multiple sources and scales of spatial support. Under the Bayesian inferential paradigm, the effects of all sources of variation, including those attributed to model components and those attributed to the process of data collection, on uncertainty of model predictions are readily quantified. I am also collaborating with other scientists in developing improved pedotransfer functions that could be used to derive input parameters or prior knowledge for multiscale Bayesian hierarchical modeling. In addition, I have co-organized (with Jan Hopmans of UC-Davis and others) a national symposium on "Landscape Processes: Mapping, Monitoring, and Modeling" on Nov. 2, 2004, at the ASA-CSSA-SSSA International Annual Meetings in Seattle,
WA.
Impacts
Enhanced spatio-temporal predictions of soil moisture and other soil properties can be achieved through a combined use of ground-based point observations, GIS-based vector or raster maps of various scales, and remote sensing imagery, together with pedologic and hydrologic expertise of landscape-soil-water relationships. This research is beneficial to the dissemination/utilization of soil survey information and the applications of diverse geospatial landscape data.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
We are testing a new approach that integrates geostatistical and geospatial techniques into a Bayesian hierarchical multiscale modeling framework. In this framework, the importance of soil map, DEM, land use, and other geospatial data is emphasized in enhancing the use of geostatistics and in predicting the spatio-temporal pattern of soil properties. Combining data collected at different scales of spatial support is achieved by partitioning the modeling effort into separate process modeling and data modeling stages. The process modeling stage is comprised of modeling the joint probability distribution of all variables at the point scale. Given such a model, the joint distribution of the data collected at different scales of spatial support may be derived in the data modeling stage. Under the Bayesian inferential paradigm, the effects of all sources of variation, including those attributed to model components and those attributed to the process of data collection, on
uncertainty of model predictions are readily quantified. Moreover, prior beliefs regarding the spatial distribution of landscape-soil-water systems may be readily incorporated into the Bayesian hierarchical modeling framework.
Impacts
Enhanced spatio-temporal predictions of soil moisture and other soil properties can be achieved through a combined use of ground-based point observations, GIS-based vector or raster maps of various scales, and remote sensing imagery, together with pedologic expertise about soil-landscape relationships. This research is beneficial to the dissemination/utilization of soil survey information and the applications of diverse geospatial landscape data.
Publications
- Lin, H.S. and Rathbun, S. 2003. Hierarchical frameworks for multiscale bridging in hydropedology. In Y. Pachepsky et al. (eds.) Scaling Methods in Soil Physics. CRC Press, Boca Raton, FL. p. 353-371.
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