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| Rural Industries |
Objectives
Background
The Shepparton Irrigation Region, which covers 500,000 hectares, is responsible for much of Victoria's dairy and horticultural production. Approximately 40% of the region is subject to shallow water tables which translates to an estimated loss in agricultural production approaching $20 million.
Research
The feasibility study investigated two sites, one
where pumped groundwater was concentrated through one stage of
saltbush on a heavy soil type, the second where tile drainage
water is concentrated on a light soil type, firstly through a
plantation of River Red Gums integrated with salt tolerant grasses,
followed by a crop of saltbush.
At each site the SBC system was designed to allow intermittent ponding of the irrigation water to promote leaching during the summer and reduce salt accumulation. Tile drains were designed to collect drainage water predominantly over irrigation season to reduce the volume of artesian flow intercepted and avoid the need for winter storage dams. Crystallisation ponds were incorporated into evaporation basin design to prolong their lifespan and aid in salt harvesting.
Outcome
Until the Region exceeds its salt disposal entitlement,
the SBC system is likely to be isolated to areas where there is
no access to disposal and there is low productive land available
for concentration of the drainage water.
The study revealed a deficiency in the technical knowledge on the leaching fractions on the duplex soils when irrigated with highly saline irritation water. Also, there is limited information on the proportion that artesian flow contributes to tile drainage flow in shallow water table conditions which may be a critical factor in obtaining concentration of the drainage water. A pilot project would need to address these issues, especially with regard to the sustainability of the system on heavy soil types.
Implications
The SBC concept, developed in California, provides
a system for managing moderate to highly saline water in irrigation
regions.
The SBC system will apply mainly to the dairying
industry in the region since it has both the financial capacity
to pay for salinity mitigation and land available for the salt
tolerant crops to concentrate the drainage water.
Economically, it would be more attractive to utilise
the heavier soil types since a single concentration phase would
achieve the desired reduction in the volume of drainage water.
However, the sustainability of the system is unknown and needs
to be investigated in the field.
Saltbush or a combination of salt tolerant grasses
would be the crops most appropriate for the SBC system. If the
nutritional value of saltbush, for cattle as a pure stand could
be improved, then saltbush would be the preferable choice in all
situations due to its high salt tolerance and productive capacity
A pilot study would need to address the problems
of a lack of awareness in the farming community, deficiency in
technical knowledge on the leaching fractions on the duplex soils
and a lack of knowledge as to the proportion that artesian flow
contributes to tile drainage flow in shallow watertable conditions.
RIRDC Project No: DAV-62A
RESEARCHERS: Mr Alfred Heuperman and Mr J Heath
ORGANISATION: Institute of Sustainable Irrigated Agriculture
Horticulture and Resource Management Centre Ferguson Road TATURA VIC 3616PHONE: 058 33 5222
FAX: 058 33 5299
Last updated: 10 October 1996
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