| Abstract: | We examine soil organic matter (SOM) turnover and transport using C and N isotopes in soil profiles sampled circa 1949, 1978, and 1998 (a period spanning pulse thermonuclear 14C enrichment of the atmosphere) along a 3-million-year annual grassland soil chronosequence. Temporal differences in soil ??14C profiles indicate that inputs of recently living organic matter (OM) occur primarily in the upper 20-30 cm but suggest that OM inputs can occur below the primary rooting zone. A three-pool SOM model with downward transport captures most observed variation in ??14C, percentages of C and N, ??13C, and ??15N, supporting the commonly accepted concept of three distinct SOM pools. The model suggests that the importance of the decadal SOM pool in N dynamics is greatest in young and old soils. Altered hydrology and possibly low pH and/or P dynamics in highly developed old soils cause changes in soil C and N turnover and transport of importance for soil biogeochemistry models. |
| Genre: | Article |
| ProdID: | 70023833 |
| Citation Author: | Baisden, W. T.; Amundson, R.; Brenner, D. L.; Cook, A. C.; Kendall, C.; Harden, J. W. |
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| Citation End Page: | 1 |
| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Global Biogeochemical Cycles |
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| Citation Number Of Pages: | -80 |
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| Citation Search Results Text: | A multiisotope C and N modeling analysis of soil organic matter turnover and transport as a function of soil depth in a California annual grassland soil chronosequence; 2002; Article; Journal; Global Biogeochemical Cycles; Baisden, W. T.; Amundson, R.; Brenner, D. L.; Cook, A. C.; Kendall, C.; Harden, J. W. |
| Citation Start Page: | 82 |
| Citation Volume: | 16 |
| Citation Year: | 2002 |
| Type: | citation/reference |
| Text: | A multiisotope C and N modeling analysis of soil organic matter turnover and transport as a function of soil depth in a California annual grassland soil chronosequence; 2002; Article; Journal; Global Biogeochemical Cycles; Baisden, W. T.; Amundson, R.; Brenner, D. L.; Cook, A. C.; Kendall, C.; Harden, J. W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 2002 00:00 -0600 |
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