Effects of increased levels of soil CaCO₃ on Lupin (Lupinus angustifolius) growth and nutrition

Abstract

Little published evidence exists which relates narrow-leafed lupin growth to lime levels in soils when compared with growth on a soil with minimal or zero levels of lime. This pot experiment measured lupin growth and nodulation plus plant levels of Ca and Fe by using mixtures of a gilgaid black earth soil with varying quantities of free lime. A sand control allowed a plant growth comparison at minimal levels of lime. Iron sequestrene was added to all treatments to eliminate iron chlorosis. Plants harvested 68 days after sowing showed adequate levels of Fe. However, plant height, branch number, shoot and root dry weight and nodulation were markedly lower for plants grown on the low lime depression soil than those from the sand. Further major reductions in all aspects of growth occurred with increasing levels of the mound (high lime) soil. These effects were strongly related to soil and plant Ca levels; it is suggested that poor lupin growth on highly calcareous soils may be related to adverse direct effects of Ca.