western-queensland-gardening-guide.pdf - South West NRM

Chapter 1. Gardening with bore water
The first thing to remember when using bore water is that it may change the structure
of the soil. This is because bore water is generally high in salts and extremely alkaline.
Soil types
The main soil types found in gardens in western Queensland are the sandy soils,
sandy loams and clays.
Sandy soils are usually well drained and of a light, free texture. They are very easy to
manage when using bore water because, the salts in the bore water are so readily
leached out. The only physical problem encountered is the low water-holding
capacity. This can be easily rectified by the addition of organic matter like leaf mould,
flood debris, hay or compost.
Sandy soils are generally acidic but, like all soils, the pH is governed by the type of
water being used. In this soil it is relatively easy to control any excess alkalinity by the
addition of sulphur.
In the Charleville, Eulo and Bollon areas, mulga soil is very common. This sandy loam
is naturally very acidic and infertile but with good quality dam or river water,
appropriate fertilisers, and organic matter it can become quite a useful horticultural
soil.
Bore water can make sandy loams become alkaline and the surface can set as hard as
concrete and become impervious to water. This is caused by a chemical reaction
between the salts in the bore water and the salts in the soil. The combination of mulga
soil and bore water therefore needs special cultural practices and careful selection of
plant species.
Clays are common soil types in the Longreach, Winton, Richmond, Camooweal,
Isisford, Blackall, Cunnamulla and Augathella areas. They are fairly fertile and usually
alkaline and when bore water is added to these soils they quickly become very
alkaline. Like the mulga soils, clays set very hard which impedes the infiltration of
n rain falls, the drainage is seldom good enough to allow leaching of the
salts present in the soil and concentrated by the use of bore water. Therefore clay soils
are possibly the most difficult soils to manage.
The application of bore water is a very critical point of gardening. Probably the best
advice is to use as little as possible. ere practical, use those plants with a low water
requirement or which are adaptable to salty or alkaline conditions. Where other
species are required reduce the amount of water needed as much as possible by the
use of mulches to reduce the ount of evaporation loss, which in the western
Queensland climate can be enormous.