NUTRIENT STRESS IN BIRDSFOOT TREFOIL

Birdsfoot trefoil (Lotus corniculatus L.) is often grown on poorly drained, low fertility, and low pH soils under marginal management. The objective of this research was to document several aspects of single nutrient stresses in birdsfoot trefoil. Plants were grown hydroponically in the glasshouse through two vegetative cycles and one reproductive growth cycle. Nutrient deficient treatments included P, K, Ca, Mg, S, B, Fe, Mn, Zn, Cu and Mo; toxicity treatments included B, Mn, Zn, Cu and Mo. Dry mass of shoots, shoot branching, and leaf area were typically lower in stressed plants than in plants grown in complete nutrient solution and specific leaf mass was generally larger in stressed plants. Nodule function and appearance were more severely affected by macronutrient than by micronutrient (except B) deficiencies. A deficiency or excess of a given nutrient often increased concentrations of other nutrients, but concentrations of some elements also decreased in response to a stress in another. In a few instances, concentrations of a nutrient differed from the complete treatment in an opposite manner in shoots than in roots. Seed yield and yield components were less frequently affected by nutrient stress than were herbage yields. Visual symptoms were generally similar to those of alfalfa (Medicago sativa) and the clovers (Trifolium spp.).Key words: Lotus corniculatus L., mineral nutrition, nutrient deficiency, nutrient toxicity, hydroponic solution culture, birdsfoot trefoil