Dynamics of a salinity-prone agricultural catchment driven by markets, farmers’ attitudes and climate change

An agent-based simulation model has been

developed with CORMAS combining

simplified bio-physical processes of land cover,

dry-land salinity changes, rainfall, farm

profitability and farmer decisions on land uses

in a dry-land agricultural catchment (no

irrigation). Simulated farmers formulate

individual decisions dealing with land use

changes based on the combined performance

of their past land cover productivity and

market returns. The willingness to adapt to

market drivers and the ability to maximize

returns varies across farmers. In addition,

farmers in the model can demonstrate various

attitudes towards salinity mitigation as a

consequence of experiencing and perceiving

salinity on their farm, in the neighborhood or in

the entire region. Consequently, farmers can

adopt land cover strategies aiming at reducing

salinity impact. The simulation results using

historical rainfall records reproduces similar

trends of crop-pasture ratios, salinity change

and farm decline as observed in the last 20 years

in the Katanning catchment (Western

Australia). Using the model as an explorative

tool for future scenarios, the simulation results

highlighted the importance of rainfall changes

and wide-spread willingness of farmers to

combat dry-land salinity. Rainfall changes as a

consequence of climate change can lead to

prolonged sequences of dry and wet seasons.

Adaptation to these sequences by farmers seems

to be critical for farm survival in this catchment.