Performance of annual pasture legumes in cropping rotations in the cool temperate zone of south-eastern Australia

Abstract

The relative performance of 3 alternative pasture legumes, in comparison with subterranean clover, grown in a 1:1 pasture:crop rotation was investigated during 1997–2001, at 2 sites in the high rainfall (>500 mm/year) zone of southern Australia. Seedling densities of the pasture legumes (before and after crop) were examined, along with herbage dry matter production, growth pattern and seed production. After 2 cycles of a 1:1 pasture:crop rotation, average seedling densities of balansa (Trifolium michelianum Savi var. michelianum), Persian (T. resupinatum L. var. resupinatum Gib. and Belli), arrowleaf (T. vesiculosum Savi.) and subterranean (T. subterraneum L.) clovers at the 2 sites were 6810, 2910, 680 and 630 plants/m2, respectively. Average cumulative herbage mass in 2001 was 7.49, 5.21, 8.53 and 7.76 t DM/ha.year, respectively. All clovers produced a large seed pool: balansa, 71.8 g/m2; subterranean, 38.9 g/m2; Persian, 35.5 g/m2; and arrowleaf, 35.4 g/m2. The results suggest that a 1:1 pasture:crop rotation is sustainable, in terms of pasture seed–seedling dynamics for each of the legumes, and that under this system the pasture legumes need to be sown only once.