Sodic Soils
The Problem:
Sodic soils have over 6% exchangeable sodium levels,
which leads to soil structure breakdown, surface sealing
and crusting. Sodic soils are quite extensive in Australia
leading to lost production.
The Solution:
Sodic soils can be ameliorated by the use of gypsum.
As with applying lime to acid soils the application
of gypsum can often prove expensive and uneconomic because
of transport and application costs. Applying 2.5 tons/ha
of agricultural grade gypsum results in a coverage which
can take several years to break down and be fully utilised.
While the benefits of this type of application may last
several years the economic impact of bearing all the
cost in the first year leads, in some instances, to
no application taking place at all.
By applying gypsum using the suspension system that
Rural Air Work has to offer, the product is applied
in the first year, is immediately available and provides
an immediate economic return.
The product used is high grade (93%+) gypsum that is
finely ground to 100% < 80 microns. This ensures
a rapid integration into the soil thus providing immediate
benefits to the plants.
The system provides a very even spread of the fine
particles ensuring availability to all the plants in
the first instance.
Application Rates: Rates
of gypsum have been applied from 200kg/ha to 400kg/ha.
Trials carried out on cotton country in North West New
South Wales and Southern Queensland during the 2002/2003
cotton season gave an economic yield response. While
gypsum alone was applied, in the future it is envisaged
incorporating trace elements, such as Zinc, into the
mix will yield an even greater result - far superior
to results achieved with conventional means.
While there are no tried and proven application rates
at present, the results achieved with 200kg/ha and 400kg/ha
application rates, has meant an ongoing demand for this
type of application to Sodic soils in the North West
of New South Wales and Southern Queensland.
Because this system uses only high grade Gypsum (93%+)
as opposed to products of lesser quality it means transport
costs are significantly reduced, as product isn’t
being transported that will give no economic return.
Suspension System Benefits:
- Quick application.
- High quality product used.
- Ability to incorporate trace elements.
- 100% of application area is covered with an even
spread.
- No soil compaction.
- Immediate results.
- Return on investment in first year.
Trial
Results Applying Fine Gypsum on Cotton |
Location |
Untreated Area
|
400 kg/ha Area
|
Increase
|
| Boomi Trial 2003 |
9.56 bales/ha
(3.87 bales/ac)
|
10.24 bales/ha
(4.14 bales/ac) |
0.68 bales/ha
(0.28 bales/ac)
7.1% |
| Boomi Trial 2004 |
The same field with no
more fine gypsum applied resulted in a 6.9%
increased yield over the untreated areas. |
| Moree Trial 2004 |
9.06 bales/ha
(3.66 bales/ac) |
9.41 bales/ha
(3.81 bales/ac) |
0.35 bales/ha
(0.15 bales/ac)
3.8%
|
Comments from Growers: |
- Area treated with Fine Gypsum appear
to retain moisture longer than untreated
areas.
- Soil appeared to be more friable when
cultivating treated areas.
- Noticeable visual difference after
defoliation.
- The module builder operator commented
that he appeared to be in different variety
cotton when they changed from untreated
to the treated areas.
|
|
|
