LAR 512 – Fall 2002

PROBLEM #4 – BASICS IN WATER STORAGE & DRAINAGE

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http://www.bsyse.wsu.edu/saxton/soilwater/

Go to this Washington State University soil/water web site and complete the following questions:

1. What is the bulk density of a soil consisting of 100% sand? __________

This bulk density approximates the density of quartz rock.

2. What is the total porosity in the above soil?__________

3. What is the bulk density of a soil consisting of 90% clay and 10 % sand? __________

4. What is the total porosity in the above soil? __________

5. What is the bulk density of a soil consisting of 10% sand and 10% clay? __________

What component of the soil makes up the other 80%? __________

6. What is the total porosity in the above soil? __________

7. Lets take consider the following soil:

Wagram Series, 0 to 28-inches is a fine sand, and 28 to 62-inches is a sandy clay loam

Using the diagram on the website click on fine sand and determine:

Total porosity __________

Water content at saturation __________

Water content at field capacity ___________

Water content at wilting point __________

Available water content __________

Using the diagram on the website click on sandy clay loam and determine:

Total porosity __________

Water content at saturation __________

Water content at field capacity ___________

Water content at wilting point __________

Available water content __________

8. Lets consider the following soil:

Congaree Series, 0 to 5-inches is a silt loam, 5 to 42-inches is a silty clay loam

Using the diagram on the website click on silt loam and determine:

Total porosity __________

Water content at saturation __________

Water content at field capacity ___________

Water content at wilting point __________

Available water content __________

Using the diagram on the website click on silty clay loam and determine:

Total porosity __________

Water content at saturation __________

Water content at field capacity ___________

Water content at wilting point __________

Available water content __________

9. Lastly, use the website and choose the soil texture you will want for the topsoil in your garden that will provide the:

Maximum available water __________

Maximum saturated hydraulic conductivity __________

Lowest bulk density __________

Which soil texture do you want for your garden topsoil? __________