Daniel Seitz, Johannes Lehmann, Marcus Garcia, Werner Hanagarth, Klaus H. Hoffman, Wolfgang Zech:
A Microcosm Experiment to Evaluate Influence of Nutrient Release as Mediated by Diplopods from Litter of Agroforestal Species Using ¹⁵N Marker

DANIEL SEITZ¹, JOHANNES LEHMANN², MARCUS GARCIA³, WERNER HANAGARTH⁴, KLAUS H. HOFFMAN¹, WOLFGANG ZECH^5
1University of Bayreuth, Chair of Animal Ecology, Germany
²Cornell University NY, Department of Crop and Soil Science, United States of America
³Embrapa Amazonia Ocidental, Brasil
⁴State Museum of Natural Sciences, Department of Zoology, Germany
⁵University of Bayreuth, Institute of Soil Science, Germany

Understanding the ecology of the soil faunal community is essential for management of nutrient cycling by litter in sustainable agriculture. In central Amazonia, diplopods are the main decomposers for many litter types in agroforest plantations. A new approach of microcosm study is introduced here to examine the effect of litter quality on interactions of macrofauna with microfauna in decomposition and nitrogen release. Litter marked with ¹⁵N was used in integrated microcosms with standardised soil and collection of percolating water. Microcosms were developed that were cheap and easy to maintain so that high replicate numbers could be employed.

Plastic tubes of 20 cm diameter were used, giving sufficient space for incubation with macrofauna. Litter moisture was controlled by water application, which proved a critical factor in animal vitality. Leafs marked with ¹⁵N were cut fresh and artificially aged to produce homogenous litter of a quality found in the field. Animals were collected and artificial populations established. Microfauna regrew in soil and litter after remoisting. By including sieved soil from field study sites, effects of interactions between litter, microfauna and diplopods could be studied. Percolating water could be collected, without extensive collection systems. Nitrogen pathways were elucidated by using the isotope labelling technique.

The method employed is considered suitable for studying soil ecosystems by controlled experiments. Interactions between compartments can be tested directly within an integrated environment, which can be extended by adding further components.

Keywords: Decomposition, diplopods, litter quality, microcosm, nitrogen tracer, nutrient cycling, soil fauna

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Contact Address: Daniel Seitz, University of Bayreuth, Chair of Animal Ecology, Hübschstraße 20, 95448 Bayreuth, Germany, e-mail: daniel seitzyahoo.com