ISSN:
1432-0789
Keywords:
Decomposition
;
Litter
;
Microarthropods
;
Nitrogen
;
15N
;
Litterbags
;
Cornus florida
;
Quercus prinus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Surface additions of (15NH4)2SO4 were used to measure the immobilization and subsequent movement of exogenous N added to two litter types of contrasting quality (Cornus florida and Quercus prinus). Litterbaskets were used to measure the litter mass loss and N dynamics and to follow the movement of the 15N label through litter, F layer, and soil pools. Half of the litterbaskets of each species were treated with naphthalene to reduce microarthropod densities. The faster decomposing C. florida litter maintained a higher excess atom % 15N, and a greater relative concentration of the labeled input (μg 15N g−1) than did Q. prinus litter. In both litter types the excess atom % 15N, relative concentration (μg 15N g−1), and absolute amount of label recovered in the litter declined over time. This occurred during a period of net accumulation of total litter N, implying simultaneous release of the initial input and immobilization of N from other sources. The concentration of 15N in the soil increased over time, while the F layer apparently acted as an intermediary in the transfer of 15N from litter to soil. Naphthalene effectively reduced microarthropod numbers in all horizons of the litterbaskets and significantly reduced the decay rates of Q. prinus, but not C. florida litter. Naphthalene did not appear to affect total N dynamics in the litter. However, with all horizons taken together, the naphthalene-treated litterbaskets retained more total 15N than the control litterbaskets. Naphthalene also changed the vertical distribution of 15N within litterbaskets, so that the litter retained less of the 15N-labeled input and the F layer and soil horizons retained more of the labeled input than in control litterbaskets. Our major conclusions are: (1) the N pool of decomposing litter is dynamic, with simultaneous N release and immobilization activating N turnover even during the net accumulation phase; (2) litter quality is an important determinant of immobilization and retention of exogenous N inputs and, therefore, turnover of the litter N pool; and (3) microarthropod activity can significantly affect the incorporation and retention of exogenous N inputs in decomposing litter, although these changes are apparently not reflected in net N accumulation or release during the 1st year of decomposition. However, the naphthalene may have affected microbially mediated N dynamics and this possibility needs to be considered in interpreting the results.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00336039
Permalink
