ADDRESSING CONCEPTUAL AND TECHNOLOGICAL BOTTLENECKS TO ADVANCE SUBSURFACE HYDROLOGY

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0229960
• Project Start Date: Jul 1, 2012
• Project End Date: Jun 30, 2016
• Program Code: [(N/A)]- (N/A)

Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802

Performing Department
Ecosystem Science & Management

Non Technical Summary
Preferential flow and its network have become a frontier in subsurface hydrology. Preferential flow (PF) is a generic term that refers to the process whereby water (and materials carried by water) moves by preferred pathways in an accelerated speed through a fraction of a porous medium, thus bypassing a portion of the matrix. Non-uniform flow is another term commonly used interchangeably with PF. Over the past decades, a variety of PFs have been reported in the literature, including flows caused by macropores or pipes or fractures, soil structure, interfacial layers (especially restrictive layers within or underneath soil profiles), instability of wetting front, water repellency, topography gradient, biological activities, and land use disturbance. Despite significant progress made in the past decades, our ability to determine and predict preferential flow patterns, velocities, and pathways in the subsurface across space and time remains limited. All PFs are fundamentally important as they influence runoff, erosion, water quality, nutrient cycling, biogeochemical processes, ecological functions, gas emission, and contaminant fate in the environment. The value of PFs to ecosystem services has been estimated to be some $304 billion per year globally. Despite the importance and the long recognition of PF in soils, a theory of PF is still lacking, and a firm inclusion of PF in hydrologic models remains a challenge. This is in part due to the lack of a theoretical underpinning for PF occurrence, plus the classical perception that PF is the exception rather than the rule (we call this the conceptual bottleneck). Another reason is the difficulty in observing or monitoring PF in situ and in imaging PF-related subsurface heterogeneity across scalesespecially nondestructively, continuously, and with high enough spatial-temporal resolutions (we call this the technological bottleneck). These two bottlenecks result in the neglect or inadequate treatment of PF in many existing models. This project addresses a fundamental soil hydrological process across various land uses that will have significant impacts on our understanding and practices in watershed management, land use, stormwater management, flooding or drought protection, nutrient cycling, contaminant prevention, and wastewater recycling.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0110	2061	50%
112	0110	2050	50%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 112 - Watershed Protection and Management;

Subject Of Investigation
0110 - Soil;

Field Of Science
2050 - Hydrology; 2061 - Pedology;

Keywords

hydropedology

pedology

soil physics

hydrology

hillslope hydrology

watershed hydrology

lateral flow

subsurface flow

stormflow

soil structure

macropore network

flow network

threshold

soil type

soil distribution

Goals / Objectives
The overall objective of this project is to tackle the two bottlenecks in advancing subsurface hydrology - theoretical and technical bottlenecks. On the theoretical front, a set of new theories (including non-equilibrium thermodynamics, constructal theory, and evolving network theory) will be explored and tested in understanding and modeling preferential flow (PF) occurrence in various soils and landscapes. On the experimental front, a set of cutting-edge technologies (including computed tomography, ground penetrating radar, and electromagnetic induction) will be used in combination with real-time soil moisture monitoring to detect and image/map the generation and evolution of PF network in contrasting soil-landscape systems.

Project Methods
Theoretical Investigations: (1) non-equilibrium thermodynamics will be used to study the open, dissipative system of field soils. The dual-partitioning of pedogenesis will be used to explain organizing and dissipating processes in complex soil systems, which can explain the genesis and evolution of soil architecture (structure + matrix) and ubiquitous heterogeneity formed in diverse soils, thus leading to widespread potential for PF occurrence; (2) constructal theory suggests a tendency for dual-flow regime in natural flow systemsone with high resistivity (Darcy flow) and the other with low resistivity (preferential flow). Together, they form PF configuration that provides the least global flow resistance. This theory will be studied and relevant data will be collected to test its applicability in explaining and predicting dynamic PF occurrence in soils; (3) the theory of evolving networks will be examined to shed light on diverse PF networks observed in field soils, which increase the efficiency or effectiveness of energy and mass transfer in the subsurface. We plan to collect a series of network related data through experimental studies of this project to investigate this intriguing theory and its applicability in field soils. Experimental Studies: Noninvasive tools, particularly computed tomography and ground-penetrating radar, electromagnetic induction, will be used for subsurface hydrologic investigations to obtain spatially-exhaustive maps about spatial and temporal heterogeneity not otherwise attainable. With careful calibration, these maps can be translated to give estimates of hydrologic processes and properties. We plan to obtain extensive database for developing a PF theory (in combination with the theoretical studies of this project). This project will be conducted in the Penn State Experimental Watershed (the Shale Hills Catchment), the Penn State's Rock Spring Agricultural Research Center (the Kepler Farm), and the Penn State's Living Filter (the Astronomy Site). Coupling geophysics with hydropedology is an area that has not yet been explored. In this project, we will emphasize the use of pedologic insights (e.g., soil types, layers, and structural phases) to help constrain or zone the geophysical inversion. Moreover, 3D and 4D visualization of the complex subsurface PF can be accomplished through time-lapse GPR imaging. This is especially effective when it is combined with in situ hydropedologic investigations and real-time soil hydrologic monitoring.

Progress 07/01/12 to 06/30/16

Outputs
Target Audience:Researchers, educators, students, and practitioners in the areas of soil science and hydrology. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have offered training and professional development opportunity for four graduate students and three undergraduate students at Penn State as well as five visiting scholars from China. How have the results been disseminated to communities of interest?Project results have been disseminated in the following invited presentations: Lin, H.S. 2016. Soil and Water Resources: Tackling the Last Hydrologic Frontier. An invited talk at the workshop of Soils -- The Foundation of Life by the U.S. National Committee for Soil Sciences, National Academies of Sciences, Engineering, and Medicine, Washington, DC. Lin, H.S. 2016. Hot Spots and Hot Moments: Linking Hydropedology and Biogeochemistry in the Critical Zone. AGU Fall meeting, 2016, San Francisco, CA. What do you plan to do during the next reporting period to accomplish the goals?This project has ended.

Impacts
What was accomplished under these goals? Three journal articles have been published.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Wiekenkamp, I., J.A. Huisman, H.R. Bogena, H.S. Lin, and H. Vereecken. 2016. Spatial and temporal occurrence of preferential flow in a forested headwater catchment. J. of Hydrology 534:139149.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Wiekenkamp, I., J.A. Huisman, H.S. Lin, H.R. Bogena, and H. Vereecken. 2016. Deforestation effects on soil moisture patterns and water fluxes in a headwater catchment J. of Hydrology (in press).
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Zhang, Z.B., H. Zhou, H.S. Lin, and X. Peng. 2016. Puddling intensity, sesquioxides, and soil organic carbon impacts on crack patterns of two paddy soils. Geoderma 262:155-164.

Progress 10/01/14 to 09/30/15

Outputs
Target Audience:Researchers, educators, students, and practitioners who are interested in the interface between soil science and hydrology, and other related bio- and geo-sciences. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have used the Shale Hills Critical Zone Observatory and two other landscapes near Penn State (the Penn State's Kepler Farm and Living Filter) as platforms to enrich the experience of three visiting scholars from China as well as the training for four graduate students and three undergraduate students at Penn State. How have the results been disseminated to communities of interest?Project results have been disseminated in a number of presentations, including the following invited presentations at 13 international and 1 national professional meetings: Invited presentations: 13 international and 1 national Lin, H.S. 2015. Soil Change and The Nature's Method. July 21, 2015, Beijing Normal Univ., Beijing, China. Lin, H.S. 2015. Mesoscopes for Hydropedology in the Critical Zone. July 21, 2015, Beijing Normal Univ., Beijing, China. Lin, H.S. 2015. Frontiers of hydropedology and Critical Zone science. July 27-31, 2015, Tsinghua Univ., Beijing, China. Lin, H.S. 2015. Hydropedology and Critical Zone science. Progress in Soil Physics and Soil and Water Resources Protection, Soil Physics Division of the Chinese Soil Science Society. Aug. 2-3, 2015. Qingdao, China. Lin, H.S. 2015. Critical Zone science and hydropedology. Sino-Germany CZ Symposium on Coupled Hydrological and Nutrients Transport across Scales in Earth's Critical Zone: Monitoring and Modeling, Sept. 10-14, 2015, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China. Lin, H.S. 2015. Towards an International Network of Critical Zone Observatories (CZOs). 20th International Soil & Tillage Research Organization (ISTRO) Conference, Sept. 14-18, 2015, Nanjing, China. Lin, H.S. 2015. Hydropedology and Critical Zone Science: Exciting New Opportunities for Soil Science. The 12th International Conference of the East and Southeast Asia Federation of Soil Science Societies (ESAFS). Sept. 18-20, 2015, Nanjing, China. Lin, H.S. 2015. A New Kind of Physics for Understanding Soil Architecture and Preferential Flow across Scales: A Preliminary Exploration. Keynote at SUSTAIN - IUSS Conference on the International Year of Soils, Sept. 23-26, 2015, Kiel, Germany. Lin, H.S. 2015. Ecosystem Evolution and Preferential Flow. Keynote at the Symposium of Observing Ecosystem Transition: 10 Years Hühnerwasser/Chicken Creek Catchment, Sept. 28-29, 2015, Cottbus, Germany. Lin, H.S. 2015. Critical Zone Services: Complement and Enrich Ecosystem Services. Sino-U.S. CZO Workshop, Oct. 5-10, 2015, Guiyang, China. Richter, D., Lou Derry, Suzanne Anderson, Praveen Kumar, William McDowell, Tim Filley, and H.S. Lin. 2015. What makes a CZO a CZO? A U.S. Perspective. Sino-U.S. CZO Workshop, Oct. 5-10, 2015, Guiyang, China. Lin, H.S. 2015. Frontiers of Soil Science: Hydropedology, Critical Zone Science, and Food-Water-Soil Nexus. Invited seminar at China Agriculture University, Oct. 17, 2015, Beijing, China. Lin, H.S. 2015. Update on the Sino-U.S. CZO Workshop and its outcomes. Conference and Workshop Critical Zone Science, Sustainability and Services in a Changing World, Organic Matter Flux and Stabilization in the Critical Zone, and Joint Annual Conferences of the US-China EcoPartnership for Environmental Sustainability (USCEES) and the China-US Joint Research Center for Ecosystem and Environmental Change (JRCEEC). Oct. 22-24, 2015, Purdue Univ., IN. National Lin, H.S. 2015. Soil poetry - a succinct way to convey the messages of soils. Annual meetings of ASA-CSSA-SSSA, Nov. 17, 2015, Minneapolis, MN. What do you plan to do during the next reporting period to accomplish the goals?We plan to refine the Hydropedograph toolbox for detecting and quantifying preferential flow occurrence using real-time soil moisture monitoring datasets and will investigate the underlying controls of preferential flow processes. We will synthesize the spatial-temporal pattern of preferential flow occurrence in multiple landscapes based on extensive datasets already collected in several watersheds across the U.S. and in Germany and China through collaborations.

Impacts
What was accomplished under these goals? A total of 8 journal articles and 1 book chapter have been published in 2015. In addition, three special issues related to hydropedology have been published in the Soil Science Society of America Journal, Hydrological Processes, and Ecological Modelling, respectively. We have enhanced quantitative assessment of the frequency and control of preferential flow (PF) occurrence across landscapes. We have identified considerable temporal consistence in both the frequency and the main controls of PF occurrence at the hillslope scale in the Shale Hills catchment. When upscaling to the entire catchment, topographic controls on PF occurrence and its spatial pattern became more evident, leading to the identification of a hidden subsurface PF network in this catchment. Our work has confirmed that the initiation and persistency of PF are controlled jointly by interactions among landform units, soil types, initial soil moisture conditions, precipitation features, and seasons.

Publications

• Type: Book Chapters Status: Published Year Published: 2015 Citation: Lai, J., H. Yu, and H.S. Lin. 2015. Role of Soil-specific Farming in Converting Blue Water into Green Water. Chapter 15. p. 373390. In R. Lal and B. Steward (eds.) Soil-Specific Farming Precision Agriculture. CRC. DOI: 10.1201/b18759-16.

Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Researchers, educators, students, and practitioners who are interested in the interface between soil science, hydrology, geomorphology, and other related bio- and geo-sciences. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? We have used the Shale Hills Critical Zone Observatory and two other landscapes near Penn State (the Penn State’s Kepler Farm and Living Filter) as platforms to enrich the experience of seven visiting scholars from China as well as the training for two graduate students and one undergraduate. How have the results been disseminated to communities of interest? Project results have been disseminated in the classroom teaching (Soils 405 Hydropedology and Soils 507 Environmental Soil Physics), a number of volunteered presentations given by my students and other group members, as well as the following invited presentations at international (11) and national (2) professional meetings: Invited presentations: 11 international and 2 national Lin, H.S. 2014. Formation of Preferential Flow and Architecture of Biogeochemistry in Soils. International Symposium on Biogeochemical Interfaces in Soils – Towards a Comprehensive and Mechanistic Understanding of Soil Functions. Oct., 6-8, 2014, Leipzig, Germany. Lin, H.S. 2014. Mesoscopes for Hydropedology in the Critical Zone. TERENO International Conference, Sept. 29-Oct. 2, 2014, Bonn, Germany. Lin, H.S. 2014. Critical Zone Science and Hydropedology. OCE Cutting Edge Science Symposium on Critical Zone Science Challenges and Opportunities, CSIRO Land & Water, September 16-18, 2014, Serafino Wines McLaren Vale, South Australia. Lin, H.S. 2014. A 3rd Principle and a Mosaic Theory of Water Flow in Real-World Soils — Revealing Underground Super-highway. A special seminar, June 15, 2014, Korea University, Seoul, South Korea. Lin, H.S. 2014. Towards the Uunification of soil formation and soil functions. Special seminar series at Beijing Normal University, June 28, 2014, Beijing, China. Lin, H.S. 2014. A 3rd Principle and a Mosaic Theory of Water Flow in Real-World Soils — Revealing Underground Super-highway. Special seminar series at Beijing Normal Univ., June 27, 2014, Beijing, China. Lin, H.S. 2014. New Interdisciplinary Science of the Earth’s Critical Zone and Hydropedology: Opportunities for China. Special seminar series at Beijing Normal Univ., June 17, 2014, Beijing, China. Lin, H.S. 2014. Green water: Essential in combating looming global freshwater crisis. International Workshop on Water Use Efficiency in Agriculture, China Agricultural Univ., June 1, 2014, Beijing, China. Young, M, T. Caldwell, and H.S. Lin. 2014. Thermodynamic and pedogenic differences between desert microsites. European Geosciences Union meeting, April 27-May 2, Vienna, Austria. Zhu, Q., K. Liao, J. Doolittle, and H.S. Lin. 2014. Using Electromagnetic Induction Technique to Detect Hydropedological Dynamics: Principles and Applications. European Geosciences Union meeting, April 27-May 2, Vienna, Austria. Lin, H.S. 2014. New Interdisciplinary Science of the Earth’s Critical Zone and Hydropedology: Opportunities for China. An invited special seminar at the Institute of Earth Environment, the Chinese Academy of Sciences, March 11, 2014, Xi’an, China. National Lin, H.S. 2014. Soil Change and a New Worldview of Soils. Annual meetings of ASA-CSSSA-SSSA, Long Beach, CA. Lin, H.S. 2014. Hydropedology: Synergistic Integration of Soil Science and hydrology. NSF REU on the Critical Zone summer school. July 2, 2014, University Park, PA. What do you plan to do during the next reporting period to accomplish the goals? We plan to continue the advancement of quantifying and synthesizing preferential flow occurrence in various landscapes and under diverse conditions. We will particularly seek to improve the quantification of the frequency and control of preferential flow occurrence across scales from the pedon to the hillslope and to the catchment scales. We also plan to synthesize spatial-temporal patterns of preferential flow occurrence in relation to soil, terrain, vegetation, precipitation, and season using our extension datasets collected over the past several years. In addition, we plan to refine the new time-lapsed GPR protocol and the Hydropedograph toolbox for detecting and quantifying preferential flow occurrence.

Impacts
What was accomplished under these goals? My group has produced 10 journal articles (7 published and 3 accepted) and one book chapter in 2014 in the area of hydropedology and preferential flow. We have developed a new protocol to reconstruct subsurface lateral preferential flow networks with centimeter resolution. This is the first time that a detailed subsurface lateral preferential flow network and its dynamics have been revealed non-invasively along a hillslope using time-lapsed ground-penetrating radar. In addition, a new worldview of complex soil systems and the potential of using entropy to quantify soil complexity have been developed. Our work addresses a grand challenge in hydropedology/soil hydrology, i.e., to develop basic hydrologic principles and tools to further understand flow and transport processes through an irregular and interconnected real-world soils and landscapes.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Lin, H.S. 2014. A new worldview of soils. Soil Science Society of America Journal doi:10.2136/sssaj2014.04.0162.
• Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Lin, H.S. 2014. Thermodynamic entropy fluxes reflect ecosystem characteristics and succession. Ecological Modelling (accepted).
• Type: Book Chapters Status: Published Year Published: 2014 Citation: Lin, H.S., W. Zhang, H. Yu. 2014. Hydropedology: Linking Dynamic Soil Properties with Soil Survey Data. p. 23-50. In: Application of Soil Physics in Environmental Analyses. Springer.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Quijano, J., and H.S. Lin. 2014. Entropy in the Critical Zone: A Comprehensive Review. Entropy 16:3482-3536.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Zhang, Z.B., H., Zhou, Q.G., Zhao, H.S., Lin, X., Peng. 2014 Characteristics of cracks in two paddy soils and their impacts on preferential flow. Geoderma 228:114-121.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Yu, X., C. Duffy, D. Baldwin, and H.S. Lin. 2014. The role of macropores and multi-resolution soil survey datasets for distributed surface-subsurface flow modeling. J. Hydro. http://dx.doi.org/10.1016/j.jhydrol.2014.02.055.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Wu, Y., L. Guo, X. Cui, J. Chen, X. Cao, and H.S. Lin. 2014. Ground Penetrating Radar-based Automatic Reconstruction of Three-Dimensional Coarse Root System Architecture. Plant and Soil 383:155-172.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Guo, L., H.S. Lin, and J. Chen. 2014. Subsurface Lateral Flow Network on a Hillslope Revealed by Time-lapse Ground Penetrating Radar. Water Resource Research 10.1002/2013WR014603.
• Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Lin, H.S., H.J. Vogel, J. Phillips, and B. Fath. 2014. Complexity of soils and hydrology in ecosystems. Ecological Modelling (accepted).
• Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Zhang, Z.B., X. Peng, H. Zhou, H.S. Lin, H. Sun. 2014. Characterizing preferential flow in cracked paddy soils using computed tomography and breakthrough curve. Soil and Tillage Research (accepted).

Progress 10/01/12 to 09/30/13

Outputs
Target Audience: Researchers, educators, students, and practitioners who are interested in the interface between soil science, hydrology, geomorphology, and other related bio- and geo-sciences. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? We have used the Shale Hills Critical Zone Observatory as a platform to enrich the experience of five visiting scholars from China as well as the training for two graduate students and two undergraduates. How have the results been disseminated to communities of interest? Project results have been disseminated in the classroom teaching (Soils 405 Hydropedology and Soils 507 Environmental Soil Physics), a number of volunteered presentations given by my students and other group members, as well as the following invited presentations at international and national professional meetings: Invited presentations Lin, H.S. 2013. Soil Architecture and Preferential Flow. International Workshop on Soil Structure and Its Functions in Ecosystem Services, Sept. 9-10, 2013, Nanjing, China. Lin, H.S. 2013. Critical Zone Science & Hydropedology: Emerging New Interdisciplinary Sciences. An invited special seminar at the Institute of Earth Environment, the Chinese Academy of Sciences, July 12, 2013, Xi’an, China. Lin, H.S. 2013. Hydropedology, Critical Zone Science, and Water Flow in Real-World Soils. An International Workshop on Observation and Modeling of Ecohydrological Processes in Inland River Basins: A Vision for Transformative Science, July 6-8, 2013, Beijing, China. Lin, H.S. 2013. Critical Zone Science & Hydropedology: Emerging New Interdisciplinary Sciences. An invited special seminar at Tsinghua University, July 3, 2013, Beijing, China. Lin, H.S. 2013. Linking Soil Mapping and Soil Functions— Needs and New Opportunities in Hydropedology and Critical Zone Science. An invited special seminar at the Institute of Geographic Sciences and Natural Resources, the Chinese Academy of Sciences, July 2, 2013, Beijing, China. Lin, H.S. 2013. A 3rd Principle and a Mosaic Theory of Water Flow in Real-World Soils. International Workshop on Hydropedology and Integrated Natural Resources Management, June 29-30, 2013, Beijing, China. Lin, H.S. 2013. Critical Zone Observatories: Shale Hills as an Example, June 10-12, 2013, Karlsruher Institut für Technologie (KIT), Garmisch-Partenkirchen, Germany Lin, H.S. 2013. Hydropedology: Combining soil survey data with models of hydrological regimes. Second Brazilian Soil Physics Meeting, May 6-10, 2013, Rio de Janeiro, Brazil. Lin, H.S. 2012. Looking beneath the surface for sustainability: Future of soil science in the new era. Keynote speech at the 12th Congress of Chinese Soil Science Society, Sept. 24-27, 2012, Chengdu, China. Lin, H.S. 2012. Complex Soil Systems and Hydropedology: Bridging Time, Space, and Systems. Invited presentation at the 2nd International Conference on Hydropedology, July 22-27, 2012, Leipzig, Germany. Lin, H.S. 2012. Soil Moisture Patterns and Preferential Flow Dynamics in Two Contrasting Landscapes. Keynote at the 55th Annual Manitoba Soil Science Society Conference, Feb. 2-3, 2012, Winnipeg, MB, Canada. National Lin, H.S. 2013. A New Systems Thinking of Complex Soils in Ecosystems. Chapman Conference on “Soil-mediated Drivers of Coupled Biogeochemical and Hydrological Processes across Scales.” Oct. 21-24, 2013, Biosphere II, Tucson, AZ. Lin, H.S. 2013. What do we need in between microscope and telescope for enhanced understanding of catchments? – Mesoscope for Hydropedology! 2013 Gordon Research Conference Catchments Through the Looking Glass: From Microscopes to Telescopes, June 16-21, 2013, Proctor Academy, Andover, NH. Lin, H.S. 2013. World Water Security Begins with an Adequate Blue Water Supply. Annual Meeting of American Association for the Advancement of Sciences, Feb. 14-18, 2013, Boston, MA Lin, H.S. 2012. Three Principles and a Mosaic Theory of Water Flow in Real-World Soils: The Opportunity for Geophysics in Subsurface Hydrology. Seminar at Temple University, Oct. 19, 2012, Philadelphia, PA. What do you plan to do during the next reporting period to accomplish the goals? To continue to meet the goals of this project, and thus to contribute to the advancement of hydropedology, hillslope/catchment hydrology, and hydrogeophysics. We hope to particularly focus on the following: 1) To reveal soil moisture spatial-temporal patterns as influenced by soil, terrain, vegetation, precipitation, and season, and 2) To investigate preferential flow dynamics from the pedon to the hillslope and catchment scales.

Impacts
What was accomplished under these goals? My group has produced 16 journal articles and one edited book during 2012-2013 period. Our real-time soil moisture monitoring networks established in three landscapers, with a strong focus on detecting preferential flow dynamics, have contributed valuable infrastructure for further interdisciplinary research and education. Some significant results include: 1) We have made important progress on macropore flow characterization using the X-ray tomography, ground-penetrating radar, and in situ monitoring. We have identified and proved flow in fractured shale bedrocks; 2) We have been able to fundamentally characterize the spatial-temporal patterns of soil moisture as well as preferential flow occurrence across the Shale Hills Catchment; 3) We have developed a toolbox called Hydropedograph for comprehensive and streamlined analysis of automatic soil moisture monitoring datasets, which allows the revealing of soil and hydrologic information in efficient and visually appealing ways, including preferential flow detection; 4) Subsurface lateral flow (SLF) has been observed to contribute substantially to hillslope and catchment runoff. We have developed time-lapse ground penetrating radar (GPR) and artificial infiltration experiment to shed light on the nature of SLF and its dynamics on hillslopes; and 5) Soil thickness acts as an important control for headwater hydrologic processes. We have developed a simple geomorphic-based analytical model from the dynamic equations of soil thickness evolution for the Shale Hills.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: 1. Guo, L., H.S. Lin, B. Fan, X. Cui, and J. Chen. 2013. Impact of root water content on root biomass estimation using ground penetrating radar: evidence from forward simulations and field controlled experiments. Plant and Soil 1-18. DOI 10.1007/s11104-013-1710-4. 2. Guo, L., H.S. Lin, B. Fan, X. Cui, and J. Chen. 2013. Forward simulation of roots ground penetrating radar signal: simulator development and validation. Plant and Soil 1-19. DOI 10.1007/s11104-013-1751-8 3. Guo, L., J. Chen, X. Cui, B. Fan, and H.S. Lin. 2013. Application of Ground Penetrating Radar for Coarse Root Detection and Quantification: A Review. Plant and Soil 362:1-23. DOI: 10.1007/s11104-012-1455-5. 4. Meinzer, R., D. R. Woodruff, D. M. Eissenstat, H.S. Lin, T. Adams, K. A. McCulloh. 2013. Above- and belowground controls on water use by trees of different wood types in an eastern United States deciduous forest. Tree Physiology 33:345-356, doi:10.1093/treephys/tpt012. 5. Naithani, K.J., D. Baldwin, K. Gaines, H.S. Lin, D.M. Eissenstat. 2013. Spatial distribution of tree species governs the spatio-temporal interaction of leaf area and soil moisture across a landscape. PLoS ONE 8:e58704. doi:10.1371/journal.pone.0058704. 6. Thomas, E, H.S. Lin, C. Duffy, P. Sullivan, G. Holmes, L. Jin, and S. Brantley. 2013. Spatiotemporal Patterns of Stable Isotope Compositions at the Shale Hills Critical Zone Observatory: Linkages to Subsurface Hydrologic Processes. Vadose Zone J. doi:10.2136/vzj2013.01.0029 7. Lawrence, G. B., I. J. Fernandez, D. D. Richter, D. S. Ross, P. W. Hazlett, S. Bailey, R. Oiumet, R. Warby, A. E. Johnson, H.S. Lin, A. G. Lapenis, T. Sullivan, and J. Kaste. 2013. Measuring environmental change by repeated soil sampling: a North American perspective. J. Environ. Quality 42:623-39, doi:10.2134/jeq2012.0378. 8. Zhu, Q., H.S. Lin, and D. Doolittle. 2013. Functional soil mapping for site-specific soil moisture and crop yield management. Geoderma 200201:4554. 9. Zhang, Z.B., X., Peng, L.L., Wang, Q.G., Zhao, and H.S. Lin. 2013. Temporal changes of shrinkage behavior of two paddy soils under alternative flooding and drying cycles and its consequences on percolation. Geoderma 192:12-20. DOI: 10.1016/j.geoderma.2012.08.009. 10. Zhang, Z.B., H., Zhou, Q.G., Zhao, H.S., Lin, X., Peng. 2013 Characteristics of cracks in two paddy soils and their impacts on preferential flow. Geoderma (accepted) 11. Zhang, J., H.S. Lin, and J. Doolittle. 2013. Soil Layering and Preferential Flow Impacts on Seasonal Changes of GPR Signals in Two Contrasting Soils. Geoderma (accepted) 12. Vogel, H.J., B. Clothier, X.Y. Li, and H.S. Lin. 2013. Hydropedology: A perspective on current research. Vadose Zone J. (accepted) 13. Castellano, M.J., J.P. Kaye, H.S. Lin, and J.P. Schmidt. 2012. Linking Carbon Saturation Concepts to Nitrogen Saturation and Retention. Ecosystems. doi: 10.1007/s10021-011-9501-3. 14. Tang, J., B. Zhu, T. Wang, X. Cheng, M. Gao, and H.S. Lin. 2012. Subsurface flow processes in sloping cropland of purple soil. Journal of Mountain Science 9:1-9. 15. Graham, C., and H.S. Lin. 2012. The Hydropedograph toolbox. Hydrol. Earth Syst. Sci. Discuss. 9:14231-14271, doi:10.5194/hessd-9-14231-2012.

Progress 07/01/12 to 09/30/12

Outputs
OUTPUTS: Published the 1st edited volume of hydropedology in August 2012 by Academic Press/Elsevier, which has been well received by the community. Served as a co-organizer of the 2nd International Conference on Hydropedology, which was successfully held in July 23-27, 2012 in Leipzig, Germany. PARTICIPANTS: Henry Lin TARGET AUDIENCES: Researchers, educators, students, and practitioners who are interested in the interface between soil science, hydrology, geomorphology, and other related bio- and geo-sciences. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Hydropedology is now well recognized as a promising interdisciplinary field that cuts across soil science, hydrology, geomorphology, ecology, and many other related bio- and geo-sciences. Improved theoretical underpinning and time-lapsed geophysical tools have significant potential in advancing our understanding and modeling of complex soil processes and functions across space and time.

Publications

• Lin, H. S. (Editor). 2012. Hydropedology: Synergistic Integration of Soil Science and Hydrology. Academic Press/Elsevier. pp. 844.
• Takagi, K. and H. S. Lin. 2012. Changing controls of soil moisture spatial organization in the Shale Hills Catchment. Geoderma 173-174:289-302.