Home' Grower : April 2011 Contents The South Australian Grower -- April 2011
Figure 1: Salinity of recycled domestic
effluent relative to threshold tolerance of
almond. Wet winters lead to higher leakage
of saline groundwater into the sewer
system and salinity in the subsequent
summer. Data WRSV 2009
MIXING occurs between the pass-
ing water front or draining water
and the outermost layers of soil
water which are held at the lowest
energy. Mixing rapidly spreads out
Passive movement of solutes
occurs by a process called diffusion.
Diffusion can be readily seen by
placing a drop of food dye to the
top of a glass of water. Over time
the dye will spread evenly in the
glass. The process, however, is much
slower than mixing. Net movement
of solutes is from areas of higher
concentration to lower concentra-
tion, whereas overall movement of
water is the opposite, from areas of
lower solute concentration to areas
of higher solute concentration.
The relative importance of the two
processes depends on soil properties
and timeframes associated with
Leaching efficiency is
•Avoids pooling at the surface --
soil wets up better.
•Allows time for salt to move pas-
sively into the draining water.
•Continually adds 'fresh' water to
promote efficient removal of salt.
•Ensure enough water is applied
to drain the leached salt from the
NIGHT TIME application
•Minimal plant uptake resulting in
more water available for drainage
Soil water monitoring devices can
show whether the water front and
the leached salt it contains, have
moved below the root zone.
Effective leaching management is
essential to maintain crop produc-
tivity. Leaching strategies will be
covered in part 4 of this series.
• Anthony Fox is senior land management
adviser, Adelaide and Mount Lofty Ranges,
NRMB, and Jeanette Chapman is compli-
ance officer for the Environment Proection
• Details: 08 8523 7718 or
Next month: Targeting salinity manage-
ment within crop root zones
Figure 2: Different wetting patterns due to
rainfall and drip irrigation. (Graphic:
Jeanette Chapman, 2009)
Rainfall can also spread accumulated salt
from the edges of irrigated soil back
towards the plant from where it can be
potentially taken up by the root system.
Rapid irrigation will push the salt back out
to the edges
Figure 3: Mechanisms of removal of
salt by leaching. (Graphic: Jeanette
Removal of salt by leaching
WHEN two different sources of water come
into contact, the solutes they contain will
tend to spread out evenly between them.
Many irrigators commonly mix or 'shandy'
two or more sources of irrigation water to
lower overall salinity.
During irrigation, the applied water moves
into and around the spaces between the
solid particles. Existing soil water and the
solutes it contains is held in various 'layers'
at increasing energies as they become closer
to the surfaces of clay and other solid parti-
cles. Solutes and water molecules move in
and out of these layers by two main process-
es, mixing and passive movement (Figure
TEL. (08) 8389 8233 Fax (08) 83898133
Lobethal Rd. & Cold Store Rd. Lenswood S.A. 5240
Suppliers to fruit growers & farmers
Plant Nutrition -- Fertilisers Programmes --
Organic Fertilisers -- Crop Protection Products
Soil -- Leaf -- and Water Testing
Warm Farm clothing -- Boots -- Gloves
Harvest bags - Ladders --Bird Netting
Irrigation Products Tanks -- troughs -- Pipe & fittings
High quality pruning equipment
Livestock Drenches -- Vaccines
We provide excellent service and good advice
Just Ask Us
BLUEPRINTS TO BETTER AGRICULTURE
Re-sow / Over-sow
No Drill Rows!!!
Air Seeder available
Inter Row and in the Row
Vegetables -- Herbs etc.
Row Crops Weed Controll:
03 3548 2669
M. 0418 508 573
F. 03 5348 2075
Other weed control implements
Field crops weed management 5m to
24m working width Pre &Post
Weed management evenly spaced
crops potatoes, Maize, etc
PHONE KATHY TODAY
PHONE: (02) 9606 0522 MOBILE: 0407 942 868
We have a wide range of artichoke,
beetroot, broccoli, cabbage,
chinese cabbage, cauliflower,
capsicum, sweet and hot chilli,
carrot, cucumber, eggplant, lettuce,
endive, kale, kohlrabi, leek, spring
onion, pumpkin, radicchio,
rockmelon, silverbeet, squash,
tomato, cherry and grape tomato,
turnips, watermelon, zucchini and
herbs for micro mixes, salad mixes.
We also do ou
best to fulfill
supplier of hybrid vegetable
and herb seeds that imports from around
the globe and deals direct to the growers.
See us at
May 5th & 6th
Links Archive March 2011 May 2011 Navigation Previous Page Next Page