INFLUENCE OF THE QUALITY OF LITTER WITH EARTHWORMS ON THE DYNAMICS OFNITROGEN AND PLANT-PRODUCTION

Nitrogen transfer from two different litters (C/N = 9,5 and 42,6) to p lants was estimated and followed, in microcosms, with or without earth worms (Lumbricus terrestris L.), for 89 and 113 days depending the kin d of litter. In these experimental conditions, three principal results were obtained. (1) Accumulation in soil of total mineral nitrogen and nitrogen coming from litter with low C/N litter and earthworms; (2) W ith low C/N litter the percentage of nitrogen from litter was very clo se with or without Lumbricus terrestris (18,2% and 19,8%). In contrast , with high C/N litter, these proportions were always higher with eart hworms (17,9% and 14,5% without animals); (3) With any of the two litt ers, the earthworms enhanced the N accumulation but decreased the plan t production. To explain this last observation, the authors suggested four hypotheses: (1) Root eating by earthworms, (2) vegetation decreas e by NH4+ plant absorption, (3) physiological inhibition of plant grow th and (4) complexation of nutrients in microbial products.