Volume 25, 37

Tropical Grasslands (1991) Volume 25, 37–46

The effect of seedbed and sowing time on establishment of Siratro and Gatton panic into native pasture

K.F. LOWE and T.M. BOWDLER

Pasture Management Branch, QDPI, Ipswich, Queensland, Australia.

Abstract

The effect of seedbed preparation, sowing time and the inclusion of a grass component on the establishment and subsequent production of native pastures oversown with siratro (Macroptilium atropurpureum cv. Siratro) were investigated over 4 years in sub-coastal, south-east Queensland.
It was concluded that environmental conditions following sowing, no matter what seedbed preparation was employed or what time of the year the sowing occurred, had a major influence on the success of sowings of Siratro into a native pasture sward. Reliable establishment of the legume component was only achieved by severe pasture renovation which reduced the original basal cover by at least 75 percent. Spring sowings were the most reliable but good establishment of Siratro was also achieved from mid-summer sowings. The grass component never established well (usually < 1 plant/m² ) , no matter what the seedbed preparation. However, small initial populations were sufficient to contribute significantly to pasture yield in subsequent years.
Increasing the severity of renovation reduced subsequent pasture yields; reduction of the initial population by at least 75 percent by rotary hoeing increased the sown pasture component in pasture yields but decreased the native pasture component, particularly when the renovation occurred in summer or autumn. Severe renovation increased the yield of broadleaved weeds