Natural 13C abundance: a tool to trace the incorporation of dung-derived carbon into soil particle-size fractions
✍ Scribed by Wulf Amelung; Roland Bol; Christina Friedrich
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 50 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0951-4198
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✦ Synopsis
During the decay of 13 C enriched dung patches, the ; 13 C signal of surface soil (1-5 cm) increased with a temporary maximum after 42 d. To understand the underlying processes, we investigated the incorporation of dung-derived C into soil particle-size fractions. Dung, collected from beef steers fed on maize ( 13 C = À15.36%) or ryegrass ( 13 C = À25.67%), was applied in circular patches to a C3 pasture at North Wyke, UK. Triplicates were sampled from surface soil (1-5 cm) at 14, 28, 42, and 70 d after application, pooled, separated into fine (0.2 mm) and coarse clay (0.2-2 mm), silt plus fine sand (2-250 mm), and coarse sand (250-2000 mm), and analyzed for total C, N, and 13 C. As particle-size diameter decreased, the C/N ratios decreased and 13 C values increased at all plots due to increasing microbial alteration of soil organic matter. After dung application, ca. 60 % of dung-derived C in soil was recovered in the 0.2-250 mm fractions during the whole experiment. The proportion of dung-derived C in the fine clay peaked 42 d after dung application, coinciding with the 13 C maximum in the bulk soil and the maximum leaching rate measured in lysimeters at this time in another study at the same sites. The percentage of dung-derived C as particulate C in the coarse sand fraction increased until the end of the experiment. We conclude that incorporation of C into soil from decomposing dung patches involved both temporary sorption of leached dung C to 0.2 mm fractions and continuous accumulation of particulate C (b250 mm).