Production and persistence of temperate perennial grasses and legumes at five saline sites in southern Australia

Abstract

Herbage production and persistence of 24 perennial legumes from 20 species and 19 perennial grasses from 10 species were measured at five sites across southern Australia that differed in annual rainfall and extent of salinity and waterlogging. At Cranbrook, Western Australia, a site with occasional waterlogging and a summer salinity [estimated by electrical conductivity (ECe)] of 6.9 dS/m in the surface 10 cm of soil, strawberry clover (Trifolium fragiferum L.) and Lotus uligonosis Schkuhr produced 2.7 t/ha in the second year and had the highest legume plant frequencies in year 3, while herbage production of L. tenuis Waldst. & Kit. ex Willd. and L. corniculatus L. was not significantly lower. No grasses produced more than 0.3 t/ha in the second year, but tall wheatgrass (Thinopyrum ponticum (Podp.) Z.-W. Liu & R.-C. Wang) was the most persistent. At Girgarre, Victoria, another site with occasional waterlogging and a summer ECe of 8.0 dS/m, phalaris (Phalaris aquatica L.) produced 8.5 t/ha in the second year, while production of tall wheatgrass and perennial ryegrass (Lolium perenne L.) was not significantly lower. Sulla (Hedysarum coronarium L.) was the only legume that produced more than 1 t/ha. Phalaris, tall wheatgrass and sulla had the highest densities in the third year. At Duranillin (Western Australia) and Keith (South Australia), which both experienced extensive winter waterlogging and had summer ECe >30 dS/m, puccinellia (Puccinellia ciliata Bor) and tall wheatgrass were the only grass or legume species that persisted beyond the first summer. Puccinellia was the only species to produce useful quantities of herbage (1.0 t/ha) in year 3 at Duranillin. No perennial grasses or legumes produced more than 0.35 t/ha in either year 2 or year 3 at Tammin, Western Australia, the lowest rainfall site (330 mm mean annual rainfall) with summer ECe of 10.9 dS/m. Genotypic differences within sites were indicated for several species, suggesting opportunities to develop cultivars better adapted to saline soils