At Helmstedt the accumulated biomass of alfalfa varied
between 4.7 tha−1 dry matter in the mineral fertiliser treatment
and a maximum of 8.5 tha−1 dry matter, for compost
treatments. Yields of 7.0 tha−1 dry matter were attained for
mixtures of mineral fertiliser and compost (Fig. 5b). These
results correspond with the positive growth response of most
tree species for same treatments and underline the significance
of organic matter amendments for the productivity of
sites