Soil phosphorus cycling across a 100-year deforestation chronosequence in the Amazon rainforest
© 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd.
| Veröffentlicht in: | Global change biology. - 1999. - 30(2024), 1 vom: 04. Jan., Seite e17077 |
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| Weitere Verfasser: | , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2024
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| Zugriff auf das übergeordnete Werk: | Global change biology |
| Schlagworte: | Journal Article Amazon XANES chronosequence deforestation phosphatase phosphorus phosphorus fractionation reforestation Soil mehr... |
| Zusammenfassung: | © 2023 The Authors. Global Change Biology published by John Wiley & Sons Ltd. Deforestation of tropical rainforests is a major land use change that alters terrestrial biogeochemical cycling at local to global scales. Deforestation and subsequent reforestation are likely to impact soil phosphorus (P) cycling, which in P-limited ecosystems such as the Amazon basin has implications for long-term productivity. We used a 100-year replicated observational chronosequence of primary forest conversion to pasture, as well as a 13-year-old secondary forest, to test land use change and duration effects on soil P dynamics in the Amazon basin. By combining sequential extraction and P K-edge X-ray absorption near edge structure (XANES) spectroscopy with soil phosphatase activity assays, we assessed pools and process rates of P cycling in surface soils (0-10 cm depth). Deforestation caused increases in total P (135-398 mg kg-1 ), total organic P (Po ) (19-168 mg kg-1 ), and total inorganic P (Pi ) (30-113 mg kg-1 ) fractions in surface soils with pasture age, with concomitant increases in Pi fractions corroborated by sequential fractionation and XANES spectroscopy. Soil non-labile Po (10-148 mg kg-1 ) increased disproportionately compared to labile Po (from 4-5 to 7-13 mg kg-1 ). Soil phosphomonoesterase and phosphodiesterase binding affinity (Km ) decreased while the specificity constant (Ka ) increased by 83%-159% in 39-100y pastures. Soil P pools and process rates reverted to magnitudes similar to primary forests within 13 years of pasture abandonment. However, the relatively short but representative pre-abandonment pasture duration of our secondary forest may not have entailed significant deforestation effects on soil P cycling, highlighting the need to consider both pasture duration and reforestation age in evaluations of Amazon land use legacies. Although the space-for-time substitution design can entail variation in the initial soil P pools due to atmospheric P deposition, soil properties, and/or primary forest growth, the trend of P pools and process rates with pasture age still provides valuable insights |
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| Beschreibung: | Date Completed 29.01.2024 Date Revised 29.01.2024 published: Print Citation Status MEDLINE |
| ISSN: | 1365-2486 |
| DOI: | 10.1111/gcb.17077 |