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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY-SOUND PEST, WATER AND SOIL MANAGEMENT STRATEGIES FOR NORTHERN GREAT PLAINS CROPPING SYSTEMS

Location: Agricultural Systems Research Unit

Title: New Method for the Characterization of 3D Preferential Flow Paths at the Field

Authors
item Abou-Najm, Majdi -
item Jabro, Jalal "jay"
item Iversen, William
item Mohtar, Rabi -
item Evans, Robert

Submitted to: Water Resources Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 16, 2009
Publication Date: February 4, 2010
Repository URL: http://hdl.handle.net/10113/46541
Citation: Abou-Najm, M., Jabro, J.D., Iversen, W.M., Mohtar, R., Evans, R.G. 2010. New Method for the Characterization of 3D Preferential Flow Paths at the Field. Water Resources Research. VOL. 46, W02503, doi:10.1029/2009WR008594.

Interpretive Summary: Preferential flow paths development in the field is the result of the complex interaction of multiple processes relating to the soil’s structure, moisture condition, stress level, and biological activities. Visualizing and characterizing the cracking behavior and preferential paths evolution with soil depth has always been a key challenge and a major barrier against scaling up existing hydrologic concepts and models to account for preferential flows. This paper reviews the current methods used for visualizing and characterizing preferential paths and discusses the barriers against the coupling of morphometric methods into hydrologic models. Then, the paper presents a new and simple methodology to quantify soil preferential paths at the field scale using liquid latex. The evolution of the preferential flow paths behavior in terms of (1) volume, (2) volume ratio, and (3) specific volume of preferential flow paths at different soil depths and moisture conditions are assessed. Results from different soil types (the savage soil vs. the Chalmers soil) and different landuses (corn/tilled field vs. soy bean no-till fields in the Chalmers soil) are presented. The objectives of this paper are to (1) review the various methods and concepts by which preferential paths have been addressed in soil science and hydrology; and (2) propose a new method for 3D visualization and characterization of the preferential paths volume at the field scale. In addition, the paper will briefly (1) address the disconnect between various morphometric methods used to characterize preferential paths and the existing hydrologic models; and (2) propose means for the coupling of preferential flow paths characterization and hydrologic modeling. The paper starts with a review of the various methods and concepts that dealt with cracking from different disciplines and across various scales. Then, methodologies for (1) the monitoring of the evolution of surface cracks using digital imagery and (2) the 3D visualization of the preferential path network in soils using liquid latex will be presented. Results from the Savage soil in Montana and the Chalmers soil in Indiana will be presented with discussion covering some of the factors contributing to the evolution of preferential paths at the field scale. The following is a brief summary of the outcomes of this study: 1. Although cracking pattern may be repetitive for large and deep cracks, digital imagery analysis showed that this observation may not be extended to soils with surface shallow cracks as preferential path patterns were not repetitive; 2. Soil type and field conditions (water table) play major role in preferential path structure; 3. Soil management has direct effect on biological activities at the field. Field observations and preferential path-latex frames showed that biological preferential paths are more active in no-till fields compared to fields with conventional tillage. 4. Vegetation type showed major effect on preferential path patterns with mud-like preferential paths in the soybean field compared to a linear large preferential paths parallel to the middle row of corn fields. 5. Total preferential path volume (per soil depth layer) may be estimated by water displacement method. Further classification of preferential paths can be estimated accurately by latex-destructive method.

Technical Abstract: Preferential flow paths development in the field is the result of the complex interaction of multiple processes relating to the soil's structure, moisture condition, stress level, and biological activities. Visualizing and characterizing the cracking behavior and preferential paths evolution with soil depth has always been a key challenge and a major barrier against scaling up existing hydrologic concepts and models to account for preferential flows. This paper reviews the current methods used for visualizing and characterizing preferential paths and discusses the barriers against the coupling of morphometric methods into hydrologic models. Then, the paper presents a new and simple methodology to quantify soil preferential paths at the field scale using liquid latex. The evolution of the preferential flow paths behavior in terms of (1) volume, (2) volume ratio, and (3) specific volume of preferential flow paths at different soil depths and moisture conditions are assessed. Results from different soil types (the savage soil vs. the Chalmers soil) and different land uses (corn/tilled field versus soy bean no-till fields in the Chalmers soil) are presented.

Last Modified: 8/30/2014
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