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The below‐ground perspective of forest plants: soil provides mainly organic nitrogen for plants and mycorrhizal fungi
Author(s) -
Inselsbacher Erich,
Näsholm Torgny
Publication year - 2012
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.1469-8137.2012.04169.x
Subject(s) - environmental science , biogeochemical cycle , taiga , ecosystem , soil water , nitrogen cycle , terrestrial ecosystem , biogeochemistry , soil organic matter , decomposer , terrestrial plant , agronomy , nitrogen , environmental chemistry , ecology , biology , chemistry , soil science , organic chemistry
Summary• Nitrogen (N) availability has a major impact on a wide range of biogeochemical processes in terrestrial ecosystems. Changes in N availability modify the capacity of plants to sequester carbon (C), but despite the crucial importance for our understanding of terrestrial ecosystems, the relative contribution of different N forms to plant N nutrition in the field is not known. Until now, reliably assessing the highly dynamic pool of plant‐available N in soil microsites was virtually impossible, because of the lack of adequate sampling techniques. • For the first time we have applied a novel microdialysis technique for disturbance‐free monitoring of diffusive fluxes of inorganic and organic N in 15 contrasting boreal forest soils in situ . • We found that amino acids accounted for 80% of the soil N supply, while ammonium and nitrate contributed only 10% each. In contrast to common soil extractions, microdialysis revealed that the majority of amino acids are available for plant and mycorrhizal uptake. • Our results suggest that the N supply of boreal forest soils is dominated by organic N as a major component of plant‐available N and thus as a regulator of growth and C sequestration.