Enhanced A Horizon Framework and Field Form for detailed field scale monitoring of dynamic soil properties

2014 ◽  
Vol 94 (2) ◽  
pp. 189-208 ◽  
Author(s):  
Catherine A. Fox ◽  
Charles Tarnocai ◽  
Gabriele Broll ◽  
Monika Joschko ◽  
David Kroetsch ◽  
...  

Fox, C. A., Tarnocai, C., Broll, G., Joschko, M., Kroetsch, D. and Kenney, E. 2014. Enhanced A Horizon Framework and Field Form for detailed field scale monitoring of dynamic soil properties. Can. J. Soil Sci. 94: 189–208. Taxonomic protocols for A horizon description are limited when detailed monitoring of soil change in dynamic soil properties is required for determining the effectiveness of best management practices, remediation efforts, and assessing subtle impacts on soil properties from environmental and anthropogenic stressors. The A Horizon Framework was designed by consolidating protocols from national and international description systems and expert opinion to optimize descriptive capability through use of additional enhanced lowercase designators. The Framework defines new protocols and syntax resulting in a unique soil fingerprint code. Five levels of enhanced lowercase A horizon designators are defined: Level 1, Soil processes and environmental context; Level 2, Soil structure-bulk density; Level 3, Organic carbon; Level 4, pH and electrical conductivity; and, Level 5, Soil and landscape context (i.e., soil texture, surface conditions, current land use, slope character). An electronic Field Form based on the new Framework syntax automatically records the soil fingerprint code in an enhanced (all Levels included) and a minimum detail mode focused on the key dynamic properties. The soil fingerprint codes become a powerful tool by which to identify trends of soil change and small alterations in the dynamic soil properties. Examples of soil fingerprint codes from selected Canada and Germany long-term experimental studies are presented.

2018 ◽  
Vol 10 (3) ◽  
pp. 851 ◽  
Author(s):  
Katherine Merriman ◽  
Amy Russell ◽  
Cynthia Rachol ◽  
Prasad Daggupati ◽  
Raghavan Srinivasan ◽  
...  

Subwatersheds within the Great Lakes “Priority Watersheds” were targeted by the Great Lakes Restoration Initiative (GLRI) to determine the effectiveness of the various best management practices (BMPs) from the U.S. Department of Agriculture-Natural Resources Conservation Service National Conservation Planning (NCP) Database. A Soil and Water Assessment Tool (SWAT) model is created for Alger Creek, a 50 km2 tributary watershed to the Saginaw River in Michigan. Monthly calibration yielded very good Nash–Sutcliffe efficiency (NSE) ratings for flow, sediment, total phosphorus (TP), dissolved reactive phosphorus (DRP), and total nitrogen (TN) (0.90, 0.79, 0.87, 0.88, and 0.77, respectively), and satisfactory NSE rating for nitrate (0.51). Two-year validation results in at least satisfactory NSE ratings for flow, sediment, TP, DRP, and TN (0.83, 0.54, 0.73, 0.53, and 0.60, respectively), and unsatisfactory NSE rating for nitrate (0.28). The model estimates the effect of BMPs at the field and watershed scales. At the field-scale, the most effective single practice at reducing sediment, TP, and DRP is no-tillage followed by cover crops (CC); CC are the most effective single practice at reducing nitrate. The most effective BMP combinations include filter strips, which can have a sizable effect on reducing sediment and phosphorus loads. At the watershed scale, model results indicate current NCP BMPs result in minimal sediment and nutrient reductions (<10%).


2020 ◽  
Vol 63 (2) ◽  
pp. 513-522 ◽  
Author(s):  
Ritesh Karki ◽  
Puneet Srivastava ◽  
Tamie L. Veith

HighlightsThis review study identified five different ways of setting up a SWAT model for field-scale analysis.Model setup for each field-scale modeling method and examples of application are discussed.Benefits and limitations of each method are discussed.Abstract. Although the Soil and Water Assessment Tool (SWAT) has been widely used as a watershed/basin scale model, recently there has been considerable interest in applying it at the field scale, especially for evaluation of best management practices and for building stakeholder confidence. In this study, a thorough review of the literature on field-scale application of SWAT was conducted. It was determined that there is more than one way of setting up a field-scale SWAT model depending on the spatial scale of the research as well as the research question to be answered. This article provides a detailed review of the methods used for field-scale SWAT modeling along with a summary of applications. This article also discusses the limitations and advantages of each method along with future research needs. The overarching goal of this article is to provide a valuable and time-conserving resource for future researchers interested in field-scale SWAT modeling. Keywords: Arc-SWAT, Field level, Field-scale resolution, Field-scale SWAT, SWAT.


Author(s):  
Celestino Valle ◽  
Kenneth H. Stokoe

Comparisons of the dynamic properties of intact and remolded offshore clay specimens has been carried out. The clay specimens were obtained from Campeche Bay, offshore Mexico. Combined resonant column and torsional shear (RCTS) equipment at the University of Texas at Austin was used to determine the dynamic soil properties. Each soil specimen was tested twice, first in the intact condition and second as remolded material. Remolding was done by kneading the intact material and then reforming the specimen by compacting in a mold. The effects on the dynamic properties, expressed by shear modulus and material damping ratio, between intact and remolded conditions are discussed. As expected, shear modulus and material damping at small and large strains are affected by remolding. Interestingly, the normalized modulus degradation curves were changed very little by remolding up to strains between 0.06 and 0.1%. The results offer insight into the effects of sampling disturbance on linear and nonlinear dynamic soil properties.


2018 ◽  
Vol 9 (1) ◽  
pp. 78-98 ◽  
Author(s):  
Shiv Shankar Kumar ◽  
Arindam Dey ◽  
A. Murali Krishna

This article highlights the implication of site-specific properties on seismic ground response studies. One-dimensional equivalent linear ground response analysis was carried out using site-specific dynamic properties of locally available soils of Guwahati city, and the results are compared with those obtained using existing strain-dependent dynamic properties. Acceleration time histories from three strong motions were used. It was observed that an input motion having a higher peak bedrock acceleration, utilizing experimentally obtained dynamic soil properties, exhibits 38% and 24% lower peak ground acceleration and peak spectral acceleration, respectively, in comparison to the results obtained using standard VD-SI soil models. The amplification characteristics of the strong motions are observed to be significantly influenced by the degradation of damping ratio beyond 1% shear strain. The results highlight the necessity of conducting GRA of any region considering its regional dynamic soil properties to obtain more realistic outcomes.


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