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Plant diversity influenced gross nitrogen mineralization, microbial ammonium consumption and gross inorganic N immobilization in a grassland experiment

Lama, Soni; Velescu, Andre; Leimer, Sophia; Weigelt, Alexandra; Chen, Hongmei; Eisenhauer, Nico; Scheu, Stefan; Oelmann, Yvonne; Wilcke, Wolfgang

Abstract:
Gross rates of nitrogen (N) turnover inform about the total N release and consumption. We investigated how plant diversity affects gross N mineralization, microbial ammonium (NH4+) consumption and gross inorganic N immobilization in grasslands via isotopic pool dilution. The field experiment included 74 plots with 1–16 plant species and 1–4 plant functional groups (legumes, grasses, tall herbs, small herbs). We determined soil pH, shoot height, root, shoot and microbial biomass, and C and N concentrations in soil, microbial biomass, roots and shoots. Structural equation modeling (SEM) showed that increasing plant species richness significantly decreased gross N mineralization and microbial NH4+ consumption rates via increased root C:N ratios. Root C:N ratios increased because of the replacement of legumes (low C:N ratios) by small herbs (high C:N ratios) and an increasing shoot height, which was positively related with root C:N ratios, with increasing species richness. However, in our SEM remained an unexplained direct negative path from species richness to both N turnover rates. The presence of legumes increased gross N mineralization, microbial NH4+ consumption and gross inorganic N immobilization rates likely because of improved N supply by N2 fixation. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000123323
Veröffentlicht am 04.09.2020
Originalveröffentlichung
DOI: 10.1007/s00442-020-04717-6
Scopus
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Geographie und Geoökologie (IFGG)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 07.2020
Sprache Englisch
Identifikator ISSN: 0029-8549, 1432-1939
KITopen-ID: 1000123323
Erschienen in Oecologia
Band 193
Heft 3
Seiten 731–748
Nachgewiesen in Web of Science
Scopus
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