Universität zu Köln

Hu, Zhengkun ORCID: 0000-0002-5697-6518, Zhu, Chunwu, Chen, Xiaoyun, Bonkowski, Michael ORCID: 0000-0003-2656-1183, Griffiths, Bryan, Chen, Fajun, Zhu, Jianguo, Hu, Shuijin, Hu, Feng and Liu, Manqiang ORCID: 0000-0001-6654-7795 (2017). Responses of rice paddy micro-food webs to elevated CO2 are modulated by nitrogen fertilization and crop cultivars. Soil Biol. Biochem., 114. S. 104 - 114. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 0038-0717

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Abstract

Elevated atmospheric CO2 concentrations (eCO(2)) often increase plant growth but simultaneously lead to the nitrogen (N) limitation in soil. The corresponding mitigation strategy such as supplementing N fertilizer and growing high-yielding cultivars at eCO(2) would further modify soil ecosystem structure and function. Little attention has, however, been directed toward assessing the responses of soil food web. We report results from a long-term free air CO2 enrichment (FACE) experiment in a rice paddy agro-ecosystem that examined the responses of soil micro-food webs to eCO(2) and exogenous nitrogen fertilization (eN) in the rhizosphere of two rice cultivars with distinctly weak and strong responses to eCO(2). Soil micro-food web parameters, including microfauna (protists and nematodes) and soil microbes (bacteria and fungi from phospholipid fatty acid (PLFA) analysis), as well as soil C and N variables, were determined at the heading and ripening stages of rice. Results showed that eCO(2) effects on soil micro food webs depended strongly on N fertilization, rice cultivar and growth stage. eCO(2) stimulated the fungal energy channel at the ripening stage, as evidenced by increases in fungal biomass (32%), fungi:bacteria ratio (18%) and the abundance of fungivorous nematodes (64%), mainly due to an enhanced carbon input. The eN fueled the bacterial energy channel by increasing the abundance of flagellates and bacterivorous nematodes, likely through alleviating the N-limitation of plants and rhizosphere under eCO(2). While eCO(2) decreased the abundance of herbivorous nematodes under the weak-responsive cultivar by 59% and 47% with eN at the heading and ripening stage, respectively, the numbers of herbivorous nematodes almost tripled (x2.9; heading) and doubled (x1.6; ripening) under the strong responsive cultivar with eCO(2) at eN due to higher root quantity and quality. Structural equation model (SEM) showed that lower trophic-level organisms were affected by bottom-up forces of altered soil resources induced by eCO(2) and eN, and effects on higher trophic level organisms were driven by bottom up cascades with 69% of the variation being explained. Taken together, strategies to adapt climate change by growing high-yielding crop cultivars under eCO(2) may face a trade-off by negative soil feedbacks through the accumulation of root-feeding crop pest species. (C) 2017 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Hu, Zhengkun UNSPECIFIED orcid.org/0000-0002-5697-6518 UNSPECIFIED Zhu, Chunwu UNSPECIFIED UNSPECIFIED UNSPECIFIED Chen, Xiaoyun UNSPECIFIED UNSPECIFIED UNSPECIFIED Bonkowski, Michael UNSPECIFIED orcid.org/0000-0003-2656-1183 UNSPECIFIED Griffiths, Bryan UNSPECIFIED UNSPECIFIED UNSPECIFIED Chen, Fajun UNSPECIFIED UNSPECIFIED UNSPECIFIED Zhu, Jianguo UNSPECIFIED UNSPECIFIED UNSPECIFIED Hu, Shuijin UNSPECIFIED UNSPECIFIED UNSPECIFIED Hu, Feng UNSPECIFIED UNSPECIFIED UNSPECIFIED Liu, Manqiang UNSPECIFIED orcid.org/0000-0001-6654-7795 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-213718
DOI:	10.1016/j.soilbio.2017.07.008
Journal or Publication Title:	Soil Biol. Biochem.
Volume:	114
Page Range:	S. 104 - 114
Date:	2017
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	0038-0717
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ATMOSPHERIC CARBON-DIOXIDE; SOIL NEMATODE COMMUNITIES; BELOW-GROUND COMMUNITIES; CLIMATE-CHANGE; ENRICHMENT FACE; PLANT-GROWTH; MYCORRHIZAL FUNGI; SEASONAL-CHANGES; GLOBAL CHANGE; HYBRID RICE Multiple languages Soil Science Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/21371