Tropical Grasslands (2007) Volume 41, 191–199

Pasture establishment on old cropping country in southern Queensland

SID COOK

Queensland Murray Darling Committee, Dalby,Queensland, Australia

Abstract

Large areas of marginal cropping lands are being sown to permanent pasture after 30–50 and more years of cropping. Organic matter and overall fertility of these areas have been depleted and soil structural issues are common. Annual grass and broadleaf weeds are present in many of these old cultivations. However, the period of seed-bed preparation and sowing is the time where a land manager has the greatest opportunity to influence the conditions that will enhance the prospects of a successful establishment.
Pasture establishment is a ‘numbers game’, based on the germination, seedling emergence and survival of the number of seeds that are sown per unit area. The effects of seed quality and dormancy, soil moisture and sowing depth on germination and establishment are discussed. Best establishment is likely to be achieved by sowing the seed into a dry soil surface that has adequate stored moisture within 5–7 cm of the surface, rather than broadcasting it on the soil surface. On the other hand, optimum sowing depths for most small-seeded pasture species are often only 10–20 mm and sowing too deep will reduce emergence. Seedling growth and survival are dependent on moisture and fertility, but this can be heavily influenced by competition from aggressive annual weeds. Suggestions for applying the principles and achieving the best possible establishment outcomes under field conditions are discussed.

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