Investigations into the availability to lucerne (Medicago sativa) of copper applied to yellow-brown pumice soils

Abstract

The relationship between topdressing rate and Cu concentration in lucerne grown on Hinemaiaia sand was investigated using dressings of 0, 0.5, 1, 1.5, 2, and 4 kg Cu/ha. The changes in Cu concentration in the foliage over two years, with three harvests in each, are reported. Differences between years, and among treatments, were significant. In the first year, 4 kg Cu/ha increased the average harvest concentration from 3.6 to 6.7 ppm Cu. In the second year, the effect from 4 kg Cu/ha applied only in year 1, was as good as that from 2 and from 4 kg Cu/ha applied in both years. Cu application did not increase yield. The annual DM production was 11 960 kg/ha in year 1, and 11 780 kg/ha in year 2.