Current estimates are that almost one-third of southwestern Australia's arable land will be lost to salinisation if annual crops and pastures are not substantially replaced with perennial species.
Scientists are taking a hard look at herbaceous perennial legumes to identify those which allow the development of a high water-use farming system that includes cropping.
Geoff Moore, from Agriculture Western Australia and the Cooperative Research Centre for Legumes in Mediterranean Agriculture (CLIMA), said a project has been under way since 1998 to investigate and identify perennial pasture plants in addition to lucerne with the potential to combat further encroachment of salinity in the cropping zones of the WA wheatbelt.
Mr Moore said a large germplasm accumulation and seed-increase program of herbaceous perennial legumes was started in 1999 at Medina Research Station. "At that time we were looking at about 350 lines of 46 different species. This year we have an additional area of seed increase with three new bays (2,000 m of nursery rows) adjacent to the 1999 planting.
"About 200 new lines have been sown, with the material sourced from Kew Gardens, the International Centre of Agricultural Research in the Dry Areas (ICARDA), SARDI, Tasmania DPI and the old CSIRO Melilotus collection. We also used some lines that were collected in Italy last year as part of the CLIMA/Italian University joint project supported by the GRDC."
Those perennial legumes and grasses considered capable of growing and persisting in the wheatbelt could be used in a pasture phase between periods of intensive cropping. Once sufficient seed of the new perennial species has been produced and the legumes matched to an appropriate rhizobium, the most promising species will be tested in the field for adaptation to the general acid and infertile soils and compared to currently available options, particularly lucerne.
A list of species and priority lines of herbaceous perennial legumes at an advanced stage of development towards commercialisation, to meet a range of soil and climate niches, is to be prepared by June 2004.
Contact: Dr Mike Ewing 08 9380 1876, Mr Geoff Moore 08 9368 3293