Changes in foliar nutrient content and resorption in Fraxinus excelsior L., Ulmus minor Mill. and Clematis vitalba L. after prevention of floods

Abstract

This paper focuses on the impact of flood on tree mineral nutrition through measurement of resorption (i.e. transfer of nutrients from leaves to perennial organs). Nutrient (N, P, K, Mg, Ca) concentrations in leaves of three representative species, Fraxinus excelsior L., Ulmus minor Mill. and Clematis vitalba L. were measured before and after abscission on flooded and unflooded hardwood forests of the upper Rhine plain. The nutrient concentrations in the soils, which were measured in the top layer of the study sites, were higher in the flooded sites for P but slightly lower for N and K, and identical at both types of site for Ca and Mg. The summer foliage concentrations were higher for N and P in the flooded areas, and probably related to the flooding process, which contributes to regular nutrient inputs in the flooded forest, causes high fluctuations of water level and increases bioavailability of certain nutrients. Resorption occurred for all nutrients in the three species, and was higher for N, P and K (40-70 %) than for Ca and Mg (0-45 %), but not significantly different at the two sites. This paper stresses the variability of the test species response (nutrient content and resorption) to the soil and flood water nutrient sources, and tries to specify parameters which control resorption, i.e. soil fertility, tree species or flood stress. © 1999 Inra/Editions scientifiques et medicales Elsevier SAS.