B.G. COOK¹, J.C. MULDER² and B. POWELL³

¹Department of Primary Industries, P.O. Box 395, Gympie, Q. 4570.
²Department of Primary Industries, P.O. Box 1085, Townsville, Q. 4810.
³Department of Primary Industries, Meiers Road, Indooroopilly, Q. 4068.

Abstract

Factors affecting persistence and vigour of Trifolium semipilosum cv. Safari were investigated in a survey of 41 pastures at 25 sites in south eastern Queensland. Only pastures where Safari had persisted for more than three years were surveyed. Average annual rainfall at survey sites ranged from 650 mm to 1775 mm, and altitude from 2 m to 680 m above sea level, with soil type and aspect also diverse.
Safari combined successfully with a number of different tussock and stoloniferous grasses. Its vigour appeared to be limited by available soil phosphorus and/or potassium, and although Sarfari frequency in the pasture varied from 8 to 100%, it was not meaningfully related to any management or environmental parameters tested. Maximum, minimum and mean values of nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, sodium, zinc, copper and manganese concentrations in dry matter are reported and discussed in relation to plant vigour, soil analyses, and pasture management. Soil seed levels were strongly related to clover frequency and ranged from 60 seeds m^-2 to 53 000 seeds m^-2