Seed production, seedling regeneration and hardseeds breakdown of annual clovers

Seed production of four annual clover species, arrowleaf (Trifolium vesiculosum), balansa (Trifolium michelianum), gland (Trifolium glanduliferum) and Persian (Trifolium resupinatum) was quantified from four sowing dates in 2010. Following initial sowing rate at 4-6 kg/ha, these clovers produced seed yields up to similar to 2340 kg/ha for balansa and gland, 914 kg/ha for arrowleaf and similar to 814 kg/ha for Persian. After herbage was removed the clover seedlings that regenerated produced a maximum ground cover of 91% for balansa, 65% for gland, 17% for Persian and 6% for arrowleaf. The seeds of 'Mihi' Persian clover were all soft and none were recovered in the soil after three months of burial. In contrast, arrowleaf clover had the highest percentage of hardseededness (>97%) and therefore retained most of its viable seeds in the soil into the second year. The differences in hardseededness and regeneration potential mean different management strategies for their successful establishment into dryland farming systems.