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Mineral nitrogen cycling through earthworm casts in a grazed pasture under elevated atmospheric CO 2
Author(s) -
CHEVALLIER ALEXIS J. T.,
LIEFFERING MARK,
CARRAN R. A.,
NEWTON P. C. D.
Publication year - 2006
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2005.01087.x
Subject(s) - earthworm , lumbricus rubellus , pasture , cycling , biomass (ecology) , nitrogen , chemistry , nitrogen cycle , zoology , environmental chemistry , mineral , agronomy , environmental science , biology , archaeology , organic chemistry , history
We used the New Zealand grazed pasture free air CO 2 enrichment experiment to determine the effects of elevated CO 2 on earthworm ( Aporrectodea caliginosa and Lumbricus rubellus ) cast production and mineral nitrogen (N) concentration over a 5‐week period in the spring. Elevated CO 2 did not affect earthworm biomass or the amount of cast material produced. However, cast mineral N concentrations were 18% lower, resulting in 27% less mineral N being deposited on the soil surface under elevated CO 2 . An analysis of the earthworms' potential diet showed that a reduction in the N content of sheep dung at elevated CO 2 was the most likely cause of the lower cast N concentrations. Earthworm casts made only a small contribution to mineral N cycling in our system; however, their quality may act as a sensitive indicator of reduced N availability under elevated CO 2 which is consistent with the hypothesised process of progressive N limitation.