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ERIC Number: EJ893695
Record Type: Journal
Publication Date: 2010
Pages: 5
Abstractor: As Provided
Reference Count: 8
ISBN: N/A
ISSN: ISSN-1059-9053
A Simple Approach for Demonstrating Soil Water Retention and Field Capacity
Howard, A.; Heitman, J. L.; Bowman, D.
Journal of Natural Resources and Life Sciences Education, v39 p120-124 2010
It is difficult to demonstrate the soil water retention relationship and related concepts because the specialized equipment required for performing these measurements is unavailable in most classrooms. This article outlines a low-cost, easily visualized method by which these concepts can be demonstrated in most any classroom. Columns (62.5 cm tall) were constructed using 25, 2.5 cm tall sections of 7.62-cm (3-inch) i.d. polyvinyl chloride pipe, which were connected using transparent tape. Three different soil materials were packed to specified bulk densities in the columns, and saturated with water. These vertical columns were then allowed to drain into a simulated water table 2.5 cm above the bottom of the soil volume until drainage ceased. After drainage, columns were sectioned to determine water content distribution with depth along the column. It was assumed that matric potential was inversely related to height above the water table. Therefore, water content measurements and assumed potentials for each section provided data for a water retention curve with minimum potential of approximately -60 cm. During drainage, measurements of soil matric potential were taken at regular intervals using tensiometers installed within the column, validating assumptions about matric potential. Among soil materials tested, those with narrow particle-size distributions, [approximately]100% sand, gave the widest distribution of water contents in the observed matric potential ranges. This method, with proper explanation and execution, may be a valuable learning tool by which visual, auditory, and kinesthetic learners may be better able to understand the concepts pertaining to soil-water retention relationships. (Contains 1 table and 5 figures.)
American Society of Agronomy. 677 South Segoe Road, Madison, WI 53711. Tel: 608-273-8080; Fax: 608-273-2021; Web site: http://www.jnrlse.org/
Publication Type: Journal Articles; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A