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Dry land salinisation is a significant cause of land and water degradation in Australia.Changing land use from annual to perennial crops has been widely proposed as ameans to reduce land degradation and increase the productivity of saline land.However, in many areas annual crops are financially more attractive than perennialcrops. Increases in perennial crops might also reduce local stream flows with adverseeffects on in-stream values. As such salinity control is likely to involve significanttradeoffs between public and private costs and benefits. This paper considers theimpact of planting differing areas of pastoral and woody perennials on farmprofitability (P), and water (W) and salt (S) exports from the Little River catchment inNew South Wales (NSW), Australia. The analysis uses two linear programming (LP)models. The first model represents a mixed crop and sheep system and the outputs ofthis model are integrated to provide inputs to a second catchment level model. Thestructure of the LP models is described and an analysis of the potential for perennialsto assist in salinity management is presented. The implications of the analysis forfarm systems and catchment scale changes in land use are considered.The study highlighted the importance of targeting management decisions to individualsub-catchments and of using relatively detailed farm level models as part of acatchment level study. The potential for perennials to contribute to profitable androbust farm systems and to reduce degradation to land from salt scalds and to streamsarising with elevated discharge and wash-off of salt is demonstrated.
