Seasonal changes in the inorganic nutrient concentrations in Deschampsia caespitosa (L.) beauv. in relation to its tolerance of contrasting soils in the Chiltern Hills

An analysis is presented of the inorganic nutrient relations of three populations of Deschampsia caespitosa growing on an acid mull, a calcimorphic brown earth and chalk rubble respectively. Nutrient concentrations in different fractions of the tussocks generally reflected the contrasting availabilities of exchangeable ions in the corresponding soils. However, pronounced seasonal patterns in nitrogen, phosphorus, potassium and, to a lesser extent, magnesium concentrations tended to be inversely related to a seasonal progression in the proportion of live shoot material per tussock. A concentration peak in winter was attributed to translocation from dying tissues to younger tissues and another in spring was attributed to ion uptake. Tolerance of oligotrophic soils in D. caespitosa is discussed in relation to its mode of growth and the adaptive value of internal nutrient cycling.