SOIL-PH EFFECTS ON GROWTH AND MINERAL CONCENTRATION OF BIRDSFOOT-TREFOIL

Birdsfoot trefoil (Lotus corniculatus L.) accessions G 31276 and G 312 72 exhibit rhizomatous growth and were collected from alkaline soils ( pH 8.0-8.5). Nothing is known about the adaptation of rhizomatous bird sfoot trefoil to more acid soils. Our objective was to determine the e ffects of soil pH on plant growth and mineral concentration of rhizoma tous and domestic non-rhizomatous birdsfoot trefoil. Three entries, No rcen, AU Dewey, and RBRC (a bulked reciprocal cross of G 31276 and G 3 1272), were grown at soil pH levels of 5.0, 6.0, 7.0 and 8.0 in a glas shouse. Dry-matter (DIM) production and concentrations of Al, Ca, K, P , Mg, Mn and Zn in tissues were determined. No significant entry x soi l pH interaction was found for either DM accumulation or mineral conce ntration, indicating the RBRC responded to acidic soil pH like the dom estic 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 gre atest at soil pH 5.0 and declined with increasing pH. Calcium concentr ation in leaves and stems was highest at soil pH 8.0. Magnesium concen tration was not affected by soil pH. Phosphorus concentration in leave s 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 signif icantly 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 birds foot trefoil populations derived from accessions G 31276 and G 31272 w ill not likely be limited by soil pH.