Ecosystem development on reclaimed china clay wastes. III. Leaching of nutrients.
Losses of nutrients from young grass/clover swards in an establishing phase and older swards in a maintenance phase on china clay wastes were examined in lysimeters simulating conditions to be found in full scale reclamation operations. Losses of Ca, Mg, P and K were high and continuous over the whole period of the experiment and only slightly affected by the presence of a vegetation cover. By contrast, N losses were very high in the 1st few months of the establishment phase and then fell to a very low level; losses from older swards were low but continuous. Losses throughout were generally more than atmospheric inputs and unless further supplies were ensured by fertilizing and biological fixation the nutrient capital of the developing ecosystems would decline with time.