Elements of a functional definition of oligotroph humus based on the nitrogen nutrition of forest stands.
Describes a study of the oligotrophic humus of sols brun acides under forest in the Belgian Ardennes [cf. FA 30, 5110; 33, 1896]. Three incubation techniques were used to measure the net N mineralization in soil from under native Beech and planted Spruce stands. It is concluded that moder can be distinguished from mor by the net rate of N mineralization. In the case of moder, however, the quality of the site and efficiency of N nutrition are not necessarily related to N availability. The concept of absorbing power is discussed in this connexion.