Department of Primary Industries, Meiers Road, Indooroopilly, Qld 4068
Ladino and Haifa cultivars of Trifolium repens were grown with T. semipilosum cv. Safari in eight pot experiments to measure their relative responses to phosphorus, potassium, sulphur, lime, copper, zinc and molybdenum.
In rate of nutrient experiments with phosphorus, potassium, sulphur and lime, yields at the nil rate were so low that relative responses could only be compared on the basis of the rates required for 90% of maximum yields. This comparison showed little difference between the three cultivars. In rate experiments with molybdenum and zinc, relative yields of the nil rates were calculated as well as the rates required for 90% of maximum yields. Both methods of comparison showed that there was little difference between Ladino and Safari in their responsiveness to molybdenum but for zinc, Safari had a lower relative yield and required a higher rate of zinc than Ladino or Haifa, indicating greater sensitivity of Safari to zinc deficiency. In the absence of copper, yields of all three cultivars were 10 to 15% of the complete treatment.
Nutrient concentrations in Ladino and Haifa were generally similar, but less than those in Safari. Lower dry matter yields of Safari are considered responsible for the higher nutrient concentrations except in the case of potassium where Safari appears to accumulate higher concentrations than the other clovers.