Navigation Links
Students get a feel for soil-water relationships

MADISON, WI, August 2nd, 2010 - Using little more than PVC rings, a trashcan, and a scale, students can literally get a feel for soil water retention and field capacity, concepts that are important and useful in fields from farming to engineering.

The demonstration, developed by Adam Howard, Drs. Josh Heitman and Dan Bowman of North Carolina State University, was designed to illustrate concepts that can be difficult for students to visualize and understand, and the equipment for making measurements of these variables is expensive. They report their method in the 2010 Journal of Natural Resources and Life Sciences Education, published by the American Society of Agronomy, the Crop Science Society of America, and the Soil Science Society of America.

The demonstration begins by taping short rings of PVC pipe together into a tall column. That column is then filled with soil and placed in a trashcan, and filling the trashcan with water to saturate the soil column. Saturating the column represents a long, soaking rainfall event.

The column is then removed from the trashcan, and allowed to drain for a day or two. When the excess water in the soil is drained away, the water left is the water contained in the soil at field capacity. Then the rings of the column are separated and the soil in each ring is weighed. As the column is sectioned from the top to the bottom, students are able to feel the differences in the soil water content. The soil is then dried and weighed again to determine the water content in each ring.

The concept of field capacity is one that arises often in soil, crop, and horticultural science disciplines. Field capacity is generally defined as the water content of a soil after free water no longer drains from a thoroughly wetted soil.

Field capacity is generally reported as a single number, which would be the average of the water contents in the rings, but few who use this information know where that number originated. Nor do they realize that this there isn't one value throughout the depth of the soil, but a continuum of water concentration that increases as you move from the top of the column towards the bottom.

A number of factors influence this soil water content continuum, including the soil texture, or the size of the soil particles, structure, or the way those particles are arranged, and depth to the water table.

The water retention relationship is a valuable tool in many disciplines. This is a relationship that connects the energy status of soil water to the soil water content. The soil water energy status, or potential, is the driver behind water movement in soils. Potential is also what plant roots must overcome to extract water from the soil. Plants wilt at very negative potentials, because they can no longer overcome the tension in very dry soils that limit water movement.

Through this very simple and inexpensive demonstration, students are better able to understand the soil, water, and plant relationships that surround us every day.


Contact: Sara Uttech
American Society of Agronomy

Related biology news :

1. Middle school students co-author research on enzyme for activating promising disease-fighters
2. Students design early labor detector to prevent premature births
3. Tufts graduate students win $10,000 prizes
4. Perceptions of forestry students change through years of study
5. 3 UAB students awarded prestigious Goldwater scholarships
6. Students perceptions of Earths age influence acceptance of human evolution, says U of Minn. study
7. Biochemist researching computer models of protein structure that help high school, college students
8. Oregon State trains graduate students to be better TAs
9. Students learn environmental stewardship, improve science scores
10. UT Southwestern receives $700,000 from HHMI to promote medical education of Ph.D. students
11. K-State receives more than $780,000 to fund graduate students studying ecology, evolution, genomics
Post Your Comments:
Related Image:
Students get a feel for soil-water relationships
(Date:10/29/2015)... , Oct. 29, 2015   MedNet Solutions , ... entire spectrum of clinical research, is pleased to announce ... Tech Association (MHTA) as one of only three finalists ... "Software – Small and Growing" category. The Tekne Awards honor ... have shown superior technology innovation and leadership. ...
(Date:10/29/2015)... -- Connected health pioneer, Joseph C. Kvedar , MD, ... and wellness, and the business opportunities that arise from ... of Healthy Things . Long before health and ... Kvedar, vice president, Connected Health, Partners HealthCare, was creating ... from the hospital or doctor,s office into the day-to-day ...
(Date:10/27/2015)... , October 27, 2015 ... Automated Semantic Gaze Mapping technology (ASGM) automatically maps data ... Eye Tracking Glasses , so that they can ... --> Munich, Germany , October ... automatically maps data from mobile eye tracking videos created ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... Muncie, IN (PRWEB) , ... November 25, 2015 ... ... Aeronautics (AMA) and the Organization of Black Aerospace Professionals (OPBAP) has been formalized ... Mathewson and other AMA team leaders met with OPBAP leaders Capt. Karl Minter ...
(Date:11/24/2015)... KUALA LUMPUR, Malaysia , Nov. 24, 2015 ... the global contract research organisation (CRO) market. The ... to result in lower margins but higher volume ... With increased capacity and scale, however, margins in ... Contract Research Organisation (CRO) Market ( ...
(Date:11/24/2015)... 2015 /CNW/ - iCo Therapeutics ("iCo" or "the Company") ... for the quarter ended September 30, 2015. Amounts, ... and presented under International Financial Reporting Standards ("IFRS"). ... said Andrew Rae , President & CEO ... not only value enriching for this clinical program, ...
(Date:11/24/2015)... N.C. , Nov. 24, 2015  Clintrax Global, Inc., a ... North Carolina , today announced that the company has set ... represented a 391% quarter on quarter growth posted for Q3 of ... and Mexico , with the establishment ... in December 2015. --> United Kingdom ...
Breaking Biology Technology: