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An overlooked carbon source for grassland soils: loss of structural carbon from stubble in response to elevated pCO 2 and nitrogen supply
Author(s) -
Schneider Manuel K.,
Lüscher Andreas,
Frossard Emmanuel,
Nösberger Josef
Publication year - 2006
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2006.01796.x
Subject(s) - lolium perenne , perennial plant , agronomy , nitrogen , grassland , carbon fibers , soil water , soil carbon , field experiment , environmental science , chemistry , soil science , biology , mathematics , organic chemistry , algorithm , composite number
Summary• In grasslands, the loss of structural carbon (C) from nonharvested plant parts is a primary C source for the soil. The amount of input depends not only on the size of structural C pools but also on their loss rates. • In the field, we examined the effects of elevated atmospheric partial pressures of CO 2 (pCO 2 ) and nitrogen (N) supply on pool size and rates of structural C loss in stubble and roots of perennial ryegrass ( Lolium perenne ) by using multiple‐pulse labelling and steady‐state labelling. • Stubble retained structural C for roughly half the time it was retained in roots. Elevated pCO 2 combined with low N supply enlarged the pools of roots and stubble. These conditions also stimulated the rate of structural C loss from stubble and, thus, the amounts available for further transformation. • The potential of multiple‐pulse labelling as a field technique is highlighted. The stimulation of structural C loss from stubble by elevated pCO 2 at low N provides a missing link between increased C assimilation and low yield response and indicates a potentially higher input of structural C into the soil.