Growth and nutrition of legumes on a high country yellow-brown earth subsoil

Abstract

The growth and phosphate response patterns of a range oflegumes growing on an acid, infertile, high country yellow-brown earth subsoil were compared in two pot trials. All species responded strongly to added P, but foliage and soil analyses indicated that aluminium toxicity as well as P deficiency may have limited the growth of some species. Lotus peduneulatus, L. cornieulatus, the inter-specific lotus hybrid G4712, and Lupinus polyphylius had low shoot Al concentrations, suggesting tolerance of Al toxicity. In contrast Trifolium repens, T. ambiguum, Coronilla varia, and Astragalus cieer had high shoot Al concentrations, and the growth of these species may have been affected by Al toxicity. T. repens was lower yielding than Lotus peduneulatus cultivars at both low and high rates of added P. Surface-applied fertiliser P remained close to the soil surface and depressed KC1- exchangeable Al levels in the surface (0-2 cm) horizon, but had no effect on Al levels in the sub-surface horizons. Relative P accumulation rates were higher in species with a strongly developed surface rooting habit than in species that developed a tap root, or had few roots close to the soil surface.

Keywords:

• high country yellow-brown earth subsoil
• leguminosae
• phosphate
• aluminium
• toxicity
• Astragalus cieer
• Coronilla varia
• yLotus peduneulatus
• L. eornieulatus
• L. peduneulatus x L. eornieulatus
• Lupinus polyphylius
• Trifolium ambiguum
• T. repens
• plant nutrients
• plant nutrient deficiencies
• root systems
• roots
• soil horizons
• fertilisers