Soil pH effects on growth and mineral concentration of birdsfoot trefoil

Abstract

Birdsfoot trefoil (Lotus corniculatus L.) accessions G 31276 and G 31272 exhibit rhizomatous growth and were collected from alkaline soils (pH 8.0-8.5). Nothing is known about the adaptation of rhizomatous birdsfoot trefoil to more acid soils. Our objective was to determine the effects of soil pH on plant growth and mineral concentration of rhizomatous and domestic non-rhizomatous birdsfoot trefoil. Three entries, Norcen, AU Dewey, and RBRC (a bulked reciprocal cross of G 31276 and G 31272), were grown at soil pH levels of 5.0, 6.0, 7.0 and 8.0 in a glasshouse. Dry- matter (DM) production and concentrations of Al, Ca, K, P, Mg, Mn and Zn in tissues were determined. No significant entry x soil pH interaction was found for either DM accumulation or mineral concentration, indicating the RBRC responded to acidic soil pH like the domestic entries. Across entries, total DM was lower at soil pH 5.0 than at a higher pH. Concentration of Al and Zn in leaves and stems was greatest at soil pH 5.0 and declined with increasing pH. Calcium concentration in leaves and stems was highest at soil pH 8.0. Magnesium concentration was not affected by soil pH. Phosphorus concentration in leaves was lowest at soil pH 5.0 and tended to increase with increasing pH, whereas P concentration in stems was highest at pH 5.0 and not significantly different at pH 6.0, 7.0 or 8.0. Leaf K concentration was not affected by soil pH, but K concentration in stems was highest at pH 5.0. Manganese concentrations in leaves and stems followed an irregular pattern. Similar responses to soil pH among entries suggest that birdsfoot trefoil populations derived from accessions G 31276 and G 31272 will not likely be limited by soil pH.