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Soil microbial community structure and organic matter transformation processes in organic and integrated farming systems

Fliessbach, Andreas; Dubois, David; Esperschütz, Jürgen; Gunst, Lucie; Mäder, Paul; Oberholzer, Hansruedi; Schloter, Michael and Gattinger, Andreas (2005) Soil microbial community structure and organic matter transformation processes in organic and integrated farming systems. Paper at: Researching Sustainable Systems - International Scientific Conference on Organic Agriculture, Adelaide, Australia, September 21-23, 2005. [Unpublished]

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Summary

The DOK long-term field trial in Switzerland started in 1978 (Mäder et al., 2002). Biodynamic (BIODYN), bioorganic (BIOORG) and integrated (CONFYM) farming systems with manure fertilization, an integrated system based on mineral fertilizer only (CONMIN) and an unfertilized control (NOFERT) were investigated for changes in soil organic matter and on the structure of the soil microbial communities. Soil organic matter (SOM) in the Ap-horizon (0-20 cm) was analysed from the beginning of the DOK field trial in 1978. Roughly 20% of the initial SOM was lost when no manure was applied for 21 years as in the CONMIN and the NOFERT system, whereas SOM increased slightly by 4% in the BIODYN system that makes use of composted farmyard manure, corresponding to 1.4 livestock units per hectare (LSU). The BIOORG and the CONFYM system lost about 7%.
Soil microbial biomass analysed from 2000 and 2003 samplings revealed higher values in organically fertilised plots. Bacterial and eukaryotic biomasses followed the order: CONMIN < CONFYM ≤ BIOORG ≤ BIODYN. Phospholipid etherlipids, indicative for micro-organisms of the domain Archaea occurred in abundance compared to other organically fertilised soils and followed the order: CONMIN < BIODYN = BIOORG = CONFYM. Clear differences in PLFA based microbial community structure among the four farming systems were observed. Organic fertilization compared to no manure had the strongest effect, followed by organic farming compared to integrated, and finally the kind of organic farming management (BIODYN with composted manure vs. BIOORG with rotted manure). The incorporation of maize-derived carbon – with higher 13C content – to some of the PLFA was detected and highlights the functional role of the corresponding microbial groups in carbon transformation processes. Contrasting 13C values in the PLFA-biomarkers for Archaea in organic and conventional soils support the assumption that carbon transformation processes are affected by the farming systems.
Our results suggest that changes in SOM are indicated by changes in soil microbial biomass. The functional role of microbial groups will be further investigated. The enhanced chemical and biological soil quality found in the field plots fertilized with manure and manure compost maintains key soil functions, on which low input farming systems rely.


EPrint Type:Conference paper, poster, etc.
Type of presentation:Paper
Keywords:farming systems, soil quality, organic matter, soil microbial communities, phospholipid fatty acids, DOK, Bodenfruchtbarkeit
Subjects: Soil > Soil quality
Research affiliation: International Conferences > 2005: 1st ISOFAR Conference > 2005: 1st ISOFAR Conference
Switzerland > FiBL - Research Institute of Organic Agriculture Switzerland > Soil Sciences
Related Links:http://orgprints.org/4013/, http://www.isofar.org/adelaide2005, http://orgprints.org/view/projects/int-conf-isofar-2005.html, http://www.fibl.ch/english/research/annual-crops/dok/index.php
Deposited By: ISOFAR,
ID Code:4342
Deposited On:23 Nov 2005
Last Modified:12 Apr 2010 07:30
Document Language:English
Status:Unpublished
Refereed:Peer-reviewed and accepted
Additional Publishing Information:The paper presented here is the final paper submitted by the authors to the conference Researching Sustainable Systems.
The final edited papers are available with the following publication:
Köpke, Ulrich; Niggli, Urs; Neuhoff, Daniel; Cornish, Peter; Lockeretz, Willie und Willer, Helga, (Hrsg.) (2005) Researching Sustainable Systems. Proceedings of the First Scientific Conference of the International Society of Organic Agriculture Research (ISOFAR), Held in Cooperation with the International Federation of Organic Agriculture Movements (IFOAM) and the National Association for Sustainable Agriculture, Australia (NASAA), 21 – 23 September 2005, Adelaide Convention Centre, Adelaide, South Australia.. Research Institute of Organic Agriculture FiBL, CH-Frick, and International Society of Organic Agriculture Research (ISOFAR), c/o Institute of Organic Agriculture (IOL), DE-University of Bonn. http://orgprints.org/4013/
Distribution: Paper copies may be ordered from FiBL at a cost of 28 Euros plus mailing costs (see FiBL shop at http://www.fibl.org/shop); FiBL order number 1394. A PDF version is available free of charge for ISOFAR members via the member area of www.isofar.org.

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