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Identification of functional horizons to predict physical properties for soils from alluvium in Canterbury, New Zealand.
- Article from:
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Australian Journal of Soil Research
- Article date:
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September 1, 2003
- Author:
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Copyright informationCOPYRIGHT 2003 CSIRO Publishing. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Lack of soil physical data, particularly soil water release data and hydraulic conductivity data, is recognised as one of the greatest limitations to the widespread application of simulation models, needed to address environmental issues. Because of the expense of generating new soil physical data pedotransfer functions may be used to predict soil physical data from existing information, notably soil morphology. Pedological horizon descriptions can then be used to estimate soil physical properties for many points in the landscape.
The soils used in this study were derived from a systematic sampling of soil profiles for soil physical characteristics for 8 soils series within 2 drainage ...
<20 mm, 20-49 mm,>
<0.15 of base
of A
Soils of the glacial surface
Lismore Well drained><0.002 mm diameter
(%)
Bulk density BD Dry mass per unit volume
(Mg/[m.sup.3])
Field capacity FC Water content at -10 kPa (%)
Wilting pointWP Water content at -1500 kPa (%)
MacroporosityMP Soil volume drained from 0 to
-5 kPa (%)
Total available waterTAW Water drained hetween -10 and
-1500 kPa (%)
Readily availableRAW Water drained between -10 and
water-100 kPa (%)
Saturated hydraulic [K.sub.S] Hydraulic conductivity under
conductivity 10 min head (mm/h)
Unsaturated hydraulic[K.sub.-40] Hydraulic conductivity under
conductivity -40 mm tension (mm/h)
Transformation
Soil property TopsoilSubsoil
Clay Logarithm Logarithm
Bulk density
Field capacity
Wilting pointLogarithm
MacroporositySquare rootSquare root
Total available waterSquare root
Readily available Logarithm
water
Saturated hydraulic Logarithm Logarithm
conductivity
Unsaturated hydraulicSquare rootLogarithm
conductivity
Table 3. Comparison of soil properties for topsoil functional horizons
CY, clay; BD, bulk density; FC, field capacity; WP, wilting point; MP,
macroporosity; TAW, total available water; RAW, readily available
water; [K.sub.S], saturated hydraulic conductivity; [K.sub.-40]
near-saturated hydraulic conductivity; wk, weak; sl, slightly; fi,
firm. Horizons with><15 sbk & gr wk
2 2015-25 sbk & bk wk-fi
3 1225-40 sbk & bk sfi-fi
4 14><40 20-30 [slightly firm]><40><20 [weak]
2 35 all 20-30 [slightly firm]
3 16 all><40 firm
4 46>