Dealing with salinity in Wheatbelt Valleys - Department of Water

Pannell
• the area of land protected from salinity per
hectare of land sown to perennials;
• the cost of establishing perennials;
• the interest rate;
• the time lag until salinity would have occurred;
Required profitability of perennials
(relative to annuals)
1
0.8
0.6
0.4
0.2
– 4 –
• the income from crops or pasture on the land
if not replaced with perennials; and
• the potential to earn income from grazing off
salinised land.
Bathgate & Pannell (2002) specify the assumptions
they made about these and other factors.
Delay before salinity
would have occured
20 years
10 years
0
0.5 1 1.5 2 2.5
Land protected (proportion of treated area)
Figure 2: Break-even levels of direct profit from perennial-based farming system required to match longrun
financial performance of traditional annuals, allowing for salinity-prevention benefits of perennials
Figure 2 shows how much direct profit would be
required from the perennials to justify their
inclusion on the farm, from a narrow financial
perspective. Consider the result for a lag of
10 years before salinity occurs. The figure shows
that if the area treated equals the area protected
(“land protected” = 1.0), the perennial would
need to generate profits at least 70% as large as
the traditional agricultural enterprise grown on the
land in question. As the protection of additional
untreated land increases, there is a fall in the
profitability required to break even, while longer
time lags before salinity result in a greater profit
requirement.
Even in the most favourable situation, perennials
must do better than covering their input costs.
For time lags of 20 years or more, the profitability
of perennials must nearly equal that of traditional
crops or pastures, even if land protected is greater
than land treated.
Overall, the results show that the indirect benefits
of perennials due to salinity prevention will be
small relative to their direct, short-term benefits
and costs. In wheatbelt valleys of Western
Australia, it appears that it is rarely possible to
implement treatments that protect much more
than the land on which they are situated (and
perhaps not even that much). This information
requires us to fundamentally re-think the nature of
the salinity abatement problem. It implies that for
adoption of perennials to be financially attractive
to farmers, the perennials need to be directly
profitable, without considering the benefits of
salinity prevention. (Alternatively, the indirect or