WaterWare On-line Manuals: Soil classification

WaterWare
Reference &
User Manual

WaterWare On-line Manuals

Release Level

6.2

Release Date

2010 05

Revision Level

1.0

Last modified on: Monday, 20-Jul-09 14:05 CEST

Soil classification

There are numerous schemes for soil classification, including FAO (28 main groups), the US NRCS (11 groups), or the Canadian system (9 groups).

For WaterWare, a simple and easy to apply scheme combining texture and organic content is used.
The five texture classes:

very fine
fine
medium fine
medium
coarse

are combined with 3 levels or organic content:

low
medium
high

to result in a table of 15 soil types used to associate field capacity with, where field capcity decreases with coarseness and increases with organic content.

Field capacity:

in mm water / m soil, and by organic content,
compared with the simplified 3 level FAO classification

LIGHT (100); MEDIUM (140); HEAVY (180)

for use in CROPWAT specifies:

organic content very fine fine medium fine medium coarse
high 200 180 160 140 110
medium 180 160 140 110 100
low 160 140 110 100 80