Agronomy and Soil Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, 2350.
White clover has been the primary legume used in improved pastures of the Northern Tablelands over the past 90 years, however data is lacking on the ability of white clover varieties and ecotypes to yield under low and high P conditions. An evaluation was undertaken that examined the yield performance of 5 white clovers when grown under P application rates of 0, 10, 20, 40 and 80 kg P/ha applied each year for just under 2 years. At the first harvest taken 7 months after sowing Ladino produced the highest yield at P0 and Tablelands the lowest with responsiveness to P in the order New Zealand > Clarence > Algerian > Ladino > Tablelands. Yields at P80 ranged from 33 kg/ha for Tableland to 242 kg/ha for Clarence. Responsiveness to P over the 4 harvests taken over the experimental period was in the order New Zealand > Clarence =Algerian > Ladino = Tablelands. Yields at P80 ranged from 2013 kg/ha for Tableland to 5226 kg/ha for Ladino.
Data like that reported here is becoming increasingly important as fertiliser prices rise. The lack of investment in public research to objectively evaluate new germplasm leaves producers without clear guidelines about replacement species. Significant value could be gained from developing well adapted and productive white clover cultivars that are significantly more P efficient.