PT Journal
AU Roggy, J
   Moiroud, A
   Lensi, R
   Domenach, A
TI Estimating N transfers between N-2-fixing actinorhizal species and the non-N-2-fixing Prunus avium under partially controlled conditions
SO Biology and Fertility of Soils
JI Biol. Fertil. Soils
PY 2004
BP 312
EP 319
VL 39
IS 5
DE actinorhizal trees; mixed culture; litter; N transfer by roots; N-15
AB Two methods of N transfer between plants-by litter decomposition and root-to-root exchange-were examined in mixed plantations of N-fixing and non-fixing trees. Nitrogen transfers from decaying litters were measured by placing N-15-labelled litters from four actinorhizal tree species around shoots of containerized Prunus avium. Nitrogen transfers by root-to-root exchanges were measured after foliar NO3-N-15 fertilization of Alnus subcordata and Elaeagnus angustifolia growing in containers in association with P. avium. During the first 2 years of litter decomposition, from 5-20% of the N, depending on the litter identity, was released and taken up by P. avium. N availability in the different litters was strongly correlated with the amount of water-soluble N, which was highest in leaves of E. angustifolia. In the association between fixing and non-fixing plants, 7.5% of the A. subcordata N and 25% of E. angustifolia N was transferred to P. avium by root exchange. These results showed that the magnitude of N transfers by root exchange depended on the associated N-2-fixing species. Among the species investigated, E. angustifolia displayed the highest capacity for exudating N from roots as well as for releasing N from litters. These qualities make this tree a promising species for enhancing wood yields in mixed stands.
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