Perennial legumes for the high rainfall zone of eastern Australia. 2. Persistence and potential adaptation zones

Abstract

Cultivars and accessions of a range of perennial legumes were evaluated in small plot field trials at 4 on-farm locations on the Northern Tablelands of New South Wales. Variable establishment from seed resulted in good stands at 2 sites, and moderate to poor stands at the other 2 sites. In spite of this, trends in behaviour of individual species were apparent even where stands were very poor. This was exemplified by the gradual improvement in frequency of Trifolium medium at the most montane site. Trifolium ambiguum and Coronilla varia were most persistent across all sites. Good stands of Lotus corniculatus, L. pedunculatus, T. pratense and Medicago sativa thinned out within several years with M. sativa most persistent. Astragalus cicer thinned out rapidly on the relatively acidic soils but maintained a good stand at 1 site on a deep, free-draining granite. From these results and known climatic responses, simple logical rules were constructed to predict potential legume adaptation zones for eastern Australia. The zones of adaptation for the range of species are compared with a nominal zone for T. repens to identify areas where legume persistence might be improved with additional species.