Factors Causing Losses during the Establishment of Surface-Sown Pastures

Abstract

Seeds of four pasture species were surface-sown in winter, spring, and summer and losses of seeds, seedlings, and plants during germination, radicle-entry, establishment, and survival noted under various treatments. On an unprotected soil surface losses during germination, radicle-entry and establishment were least in winter and greatest in summer. Dead plant cover on the surface reduced losses during germination and radicle-entry in the summer, while sub-irrigation reduced losses during germination in summer and radicle-entry and establishment in spring and summer. Losses during survival were heavy in all seasons, usually because of moisture stress. Other reasons for losses included harvesting of seeds by ants, damage by soil fauna, residual herbicides, and competition from weeds.