New Zealand Journal of Agricultural Research abstracts
Available water capacities of key soil layers in the Gisborne-East Coast
region, New Zealand
M. MCLEOD
W. C. RIJKSE
Landcare Research
Private Bag 3127
Hamilton, New Zealand
email: mcleodm@landcare.cri.nz
M. R. JESSEN
Landcare Research
Private Bag 11052
Palmerston North, New Zealand
Abstract Soil water storage values are required in many
climate-driven ecological models. Using targeted soil profile layers we have
modified an existing "building block" method whereby available water capacities
can be rapidly provided for soil classes. This building block approach allows
available water capacity estimates to be generated inexpensively and rapidly on
a regional scale. In the case of the Gisborne-East Coast region,
regionalisation can be achieved via soil Subgroup polygons in the 1:50 000
scale second edition of the New Zealand Land Resource Inventory. Replicated
undisturbed soil samples were taken from 45 key soil profile layers and
analysed for available water capacity, % gravel, and bulk density. The analyses
have been used as "building blocks" to determine the available water capacity
of whole soil profiles by simple addition of the available water capacity of
appropriate key layers and adjusting for % gravel. Soil layers containing
tephra generally have high available water capacities, as do coastal dune sand
and loamy alluvium. Bentonitic clay subsoil material had very high available
water capacity, nearly double that of tephric material.
Keywords soil; readily available water; total available
water; tephra; Gisborne-East Coast; New Zealand Land Resource Inventory
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 195-203
0028-8233/99/4202-0195 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (726K); (scanned from paper original: notes about this process)
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