10
Pallic Soils
In regions with a summer drought
the Pallic Soils are about
with dense subsoils formed in loess
the winter wet may make one curse.
Abstract
Pallic Soils are prominent on the rolling downlands of the
lower North Island and eastern South Island. Pallic Soils,
the third-most extensive soil order, covering 12% of New
Zealand, occur in regions where there is normally a dry
summer with a mean annual rainfall of about 500–
1000 mm in the South Island and <*800 mm in the
North Island. Pallic Soils are often formed in loess, a
uniform silt-dominated material that is blown off river
floodplains and deposited onto the surrounding landscape.
A dense (soil dry bulk density *1.5 t m
−3 ) fragipan
often forms in the subsoil which can obstruct root
penetration and drainage. Thus Pallic Soils often suffer
winter wetness, as water perches above the fragipan, and
are also prone to summer drought. Subsoils are
pale-coloured (“pallic”) because of their low contents of
iron oxides and, in some cases, gleying. Pallic Soils are
most suitable for pastoral grazing, maize, and other
summer crops. Tree crops may be limited by winter
saturation and rooting depth. Subsoil drainage can be
effective in preventing winter or spring saturation. Some
Pallic Soils form in alluvium or slope debris and are
friable, without a strong fragipan, hence are deep rooting
and versatile.
10.1 Important Features of Pallic Soils
10.1.1 Concept and Key Features of the Soil
Order
Pallic Soils are generally fine-textured soils with dense,
pale-coloured subsoils (Fig. 10.1). Pallic Soils are formed
mainly in loess, a uniform, silt-dominated material that has
been blown off river floodplains and deposited onto the
surrounding landscape, at a relatively slow rate, during
glacial periods. A key feature that contributes to development of Pallic Soils is a summer drought. Thus, Pallic Soils
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
A. E. Hewitt et al., The Soils of Aotearoa New Zealand, World Soils Book Series,
https://doi.org/10.1007/978-3-030-64763-6_10
145
Pallic Soils
In regions with a summer drought
the Pallic Soils are about
with dense subsoils formed in loess
the winter wet may make one curse.
Abstract
Pallic Soils are prominent on the rolling downlands of the
lower North Island and eastern South Island. Pallic Soils,
the third-most extensive soil order, covering 12% of New
Zealand, occur in regions where there is normally a dry
summer with a mean annual rainfall of about 500–
1000 mm in the South Island and <*800 mm in the
North Island. Pallic Soils are often formed in loess, a
uniform silt-dominated material that is blown off river
floodplains and deposited onto the surrounding landscape.
A dense (soil dry bulk density *1.5 t m
−3 ) fragipan
often forms in the subsoil which can obstruct root
penetration and drainage. Thus Pallic Soils often suffer
winter wetness, as water perches above the fragipan, and
are also prone to summer drought. Subsoils are
pale-coloured (“pallic”) because of their low contents of
iron oxides and, in some cases, gleying. Pallic Soils are
most suitable for pastoral grazing, maize, and other
summer crops. Tree crops may be limited by winter
saturation and rooting depth. Subsoil drainage can be
effective in preventing winter or spring saturation. Some
Pallic Soils form in alluvium or slope debris and are
friable, without a strong fragipan, hence are deep rooting
and versatile.
10.1 Important Features of Pallic Soils
10.1.1 Concept and Key Features of the Soil
Order
Pallic Soils are generally fine-textured soils with dense,
pale-coloured subsoils (Fig. 10.1). Pallic Soils are formed
mainly in loess, a uniform, silt-dominated material that has
been blown off river floodplains and deposited onto the
surrounding landscape, at a relatively slow rate, during
glacial periods. A key feature that contributes to development of Pallic Soils is a summer drought. Thus, Pallic Soils
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
A. E. Hewitt et al., The Soils of Aotearoa New Zealand, World Soils Book Series,
https://doi.org/10.1007/978-3-030-64763-6_10
145