Residual effect of copper applied to lucerne on a yellow-brown pumice soil

Abstract

The effect of copper sulphate applied to an established stand oflucerne (Medicago sativa L.) on a yellow-brown pumice soil was measured over a 4-year period. Dry matter yields were unaffected but plant and soil copper (Cu) were increased by Cu application. Plant Cu concentrations were maintained for 4 years at 7–8 mg/kg, which is adequate for sheep and beef cattle, by application of 3-4 kg Cu/ha. Extractable soil Cu values indicated that the residual effect of Cu application may last for a considerable time. It is concluded that a single application of Cu to lucerne when it is established is sufficient to provide herbage that contains adequate Cu for livestock for at least 4 years.

Keywords:

• copper
• lucerne
• fertilisers
• animal requirements
• residual value
• soil