ECOSYSTEM DEVELOPMENT ON RECLAIMED CHINA CLAY WASTES. II. NUTRIENT COMPARTMENTATION AND NITROGEN MINERALIZATION.

The accumulation of biomass and nutrients in three compartments (plant shoots, roots and surface soil) in developing ecosystem in two types of reclaimed china clay waste, sand tips and mica dam walls was measured. Biomass and nitrogen accumulated mainly in the root compartment whereas all other elements measured with the exception of potassium in mica dam wall soils, accumulated in the soil fraction. The accumulation of nutrients in the shoot and root pools was not due to redistribution of nutrients from the soil pool as accumulation was demonstrated in all three pools. Soil nitrogen mineralization tests showed an increase in mineralization nitrogen in the reclaimed waste compared to the raw waste. A significant correlation with age since treatment was demonstrated for sand tip soils. The importance of nutrient cycling and of nitrogen cycling in particular in recently established ecosystems, such as reclaimed china clay wastes is emphasized. The relative contributions to nitrogen cycling from mineralization and grazing sources are discussed. [ABSTRACT FROM AUTHOR]