Soil Organic Matter Pools and Carbon‐13 Natural Abundances in Particle‐Size Fractions of a Long‐Term Agricultural Field Experiment Receiving Organic Amendments

• DOI: 10.2136/sssaj2001.652352x
• Publication Date: 2010-07-27T20:29:32Z
• Authors: Martin H. Gerzabek; Georg Haberhauer; Holger Kirchmann
• Keywords: Cambisol; Topsoil; Silt; Soil carbon

The present study combined a physical fractionation procedure with the natural abundance of 13 C (δ C) to evaluate effect organic fertilizer applications, mineral fertilization, and fallow on changes in (C org ) associated different particle‐size fractions. long‐term agricultural field experiment was conducted since 1956 Ultuna, Sweden, Eutric Cambisol. Organic both bulk soil samples size fractions changed significantly 1956. Fallow plots lost approximately one‐third their from topsoil layer (0–20 cm), whereas amendments based an equivalent 2000 kg ha −1 yr increased up twofold depending quality material applied (green manure < animal sewage sludge peat). Silt‐sized particles receiving or peat. responded treatments. Most found silt fraction. relative contribution silt‐sized total by 18% as 10.8 (fallow) 32.0 (peat) g soil; clay‐sized decreased similar proportion. Mass balance calculations showed that proportion originating particle sand were most sensitive continuous affected amendments. δ variations among larger than treatments can be used fingerprint for differentiation. Our results suggest acted medium‐term sink added sand‐sized useful indicators status response land management.