A Simple Approach for Demonstrating Soil Water Retention and Field Capacity

Autor/inn/en	Howard, A.; Heitman, J. L.; Bowman, D.
Titel	A Simple Approach for Demonstrating Soil Water Retention and Field Capacity
Quelle	In: Journal of Natural Resources and Life Sciences Education, 39 (2010), S.120-124 (5 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	1059-9053
DOI	10.4195/jnrlse.2009.0036n
Schlagwörter	Intervals; Soil Science; Natural Resources; Energy; Experiments; Water; Agronomy; Plants (Botany) + Suchen Sie Ihr Suchwort? Bodenkunde; Natural Ressource; Natürliche Ressource; Energie; Erprobung; Wasser; Agarwissenschaft; Pflanze
Abstract	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.) (As Provided).
Anmerkungen	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/
Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10