The economics of lucerne as an option for dryland salinity control in low rainfall environments.

The replanting of trees and other high water use perennial plant options has been the major focus of dryland salinity management in recent times. Hydrologists have indicated that unless these options are taken up on a very large scale, little can be done to control ongoing land salinisation in southern Australia. The scale of the problem is further exacerbated with very few economic options for salinity management in low rainfall agricultural environments (< 350mm/year) which in Western Australia includes 40-50% of our agricultural areas. Phase farming with lucerne (Medicago sativa L.) is an increasingly noted option for dryland salinity management in Australia. The benefits of phase farming systems with lucerne is currently considered to offer both hydrologic and economic benefits for sustainable farming systems. In many areas it may be profitable to change farming systems in order to achieve recharge reductions and therefore manage salinity at a local scale- suggested to be possible in up to 30% of the agricultural landscape in Western Australia (Pannell et al., 2001). Our aims in this paper are (a) to review the advantages and disadvantages of lucerne management, (b) to present results from a case study of lucerne in south-west Western Australia by Bathgate and Pannell (2001) and (c) to assess the relevance of the case study findings for environments with lower annual rainfall.