# Commission Directive 2004/73/EC of 29 April 2004 adapting to technical progress for the twenty-ninth time Council Directive 67/548/EEC on the approximation of the laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (Text with EEA relevance), Division ANNEX 1: WATER TENSION, FIELD CAPACITY (FC) AND WATER HOLDING CAPACITY (WHC)(1)

Extent: E+W+S+N.I.

pF = log of cm water column.
1 bar = 105Pa.
Corresponds to an approximate water content of 10% in sand, 35% in loam and 45% in clay.
Field capacity is not constant but varies with soil type between pF 1.5 and 2.5.
Height of Water Column [cm]
pF
bar
Remarks
107
7
104
Dry Soil
1.6 · 104
4.2
16
Wilting point
104
4
10
103
3
1
6 · 102
2.8
0.6
3.3 · 102
2.5
0.33
102
2
0.1
Range of Field capacity
WHC (approximation)
Water saturated soil
60
1.8
0.06
33
1.5
0.033
10
1
0.01
1
0
0.001
Water tension is measured in cm water column or in bar. Due to the large range of suction tension it is expressed simply as pF value which is equivalent to the logarithm of cm water column.
Field capacity is defined as the amount of water which can be stored against gravity by a natural soil 2 days after a longer raining period or after sufficient irrigation. It is determined in undisturbed soil in situ in the field. The measurement is thus not applicable to disturbed laboratory soil samples. FC values determined in disturbed soils may show great systematic variances.
Water holding capacity (WHC) is determined in the laboratory with undisturbed and disturbed soil by saturating a soil column with water by capillary transport. It is particularly useful for disturbed soils and can be up to 30 % greater than field capacity (1). It is also experimentally easier to determine than reliable FC-values.

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Source: https://www.legislation.gov.uk/eudr/2004/73/annex/2I/division/ANNEX (the official version)
Page: https://openlegislation.uk/eu-directive-2004-73/annex-2I/division-ANNEX
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.