Copper deficiency in lucerne (Medicago sativa. L.)

Abstract

In the course of these studies more questions have been posed than answered. It is clear that Lucerne production is being limited by low Cu levels in some areas. The relationships between yield and plant composition were rather different from those predicted from other studies; it is considered that this indicated that the present understanding of these relationships is far from adequate. A survey of Cu content of Lucerne growing on Eyre, Lismore and Wakanui soils showed the first two to supply just enough Cu for healthy plant growth at most sites. Wakanui soils grew Lucerne with more than adequate Cu contents. Variation within stands was not great, bulk sampling should give adequate information about the Cu status of any particular stand. Variation due to season was not marked. It is concluded that herbage Cu levels on all soils surveyed were sufficiently low to cause concern about animal health and that it is reasonable to assume similar or lower Cu levels in the other “old” shallow soils of Canterbury.