Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass
It is generally assumed that phosphorus (P) availability for plant growth on highly weathered and P-deficient tropical soils may depend more on biologically mediated organic P (Po) turnover processes than on the release of adsorbed inorganic P (Pi). However, experimental evidence showing the linkage...
| Autores principales: | , , , , |
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| Formato: | Journal Article |
| Lenguaje: | Inglés |
| Publicado: |
Springer
2001
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| Materias: | |
| Acceso en línea: | https://hdl.handle.net/10568/43949 |
| _version_ | 1855530417273176064 |
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| author | Oberson, Astrid Friesen, Dennis K. Rao, Idupulapati M. Buhler, S Frossard, Emmanuel |
| author_browse | Buhler, S Friesen, Dennis K. Frossard, Emmanuel Oberson, Astrid Rao, Idupulapati M. |
| author_facet | Oberson, Astrid Friesen, Dennis K. Rao, Idupulapati M. Buhler, S Frossard, Emmanuel |
| author_sort | Oberson, Astrid |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | It is generally assumed that phosphorus (P) availability for plant growth on highly weathered and P-deficient tropical soils may depend more on biologically mediated organic P (Po) turnover processes than on the release of adsorbed inorganic P (Pi). However, experimental evidence showing the linkages between Po, microbial activity, P cycling and soil P availability is scarce. To test whether land-use systems with higher soil Po are characterized by greater soil biological activity and increased P mineralization, we analyzed the partitioning of P among various organic and inorganic P fractions in soils of contrasting agricultural land-use systems and related it to biological soil properties. Isotopic labeling was used to obtain information on the turnover of P held in the microbial biomass. Soil samples were taken from grass legume pasture (GL), continuous rice (CR) and native savanna (SAV) which served as reference. In agreement with estimated P budgets (+277, +70 and 0 kg P ha?1 for CR, GL and SAV, respectively), available P estimated using Bray-2 and resin extraction declined in the order CR > GL > SAV. Increases in Bray-2 and resin Pi were greater in CR than GL relative to total soil P increase. Organic P fractions were significantly less affected by P inputs than inorganic fractions, but were a more important sink in GL than CR soils. Extractable microbial P (Pchl) was slightly higher in GL (6.6 mg P kg?1) than SAV soils (5.4 mg P kg?1), and significantly lowest in CR (2.6 mg P kg?1). Two days after labeling the soil with carrier free 33P, 25, 10 and 2% of the added 33P were found in Pchl in GL, SAV and CR soils, respectively, suggesting a high and rapid microbial P turnover that was highest in GL soils. Indicators of P mineralization were higher in GL than CR soils, suggesting a greater transformation potential to render Po available. Legume-based pastures (GL) can be considered as an important land-use option as they stimulate P cycling. However, it remains to be investigated whether crops planted in pasture crop rotations could benefit from the enhanced Po cycling in grass legume soils. Furthermore, there is need to develop and test a direct method to quantify Po mineralization in these systems. |
| format | Journal Article |
| id | CGSpace43949 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2001 |
| publishDateRange | 2001 |
| publishDateSort | 2001 |
| publisher | Springer |
| publisherStr | Springer |
| record_format | dspace |
| spelling | CGSpace439492024-08-29T11:41:32Z Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass Oberson, Astrid Friesen, Dennis K. Rao, Idupulapati M. Buhler, S Frossard, Emmanuel soil deficiencies phosphorus soil biology land use deficiencias del suelo fósforo biología del suelo utilización de la tierra It is generally assumed that phosphorus (P) availability for plant growth on highly weathered and P-deficient tropical soils may depend more on biologically mediated organic P (Po) turnover processes than on the release of adsorbed inorganic P (Pi). However, experimental evidence showing the linkages between Po, microbial activity, P cycling and soil P availability is scarce. To test whether land-use systems with higher soil Po are characterized by greater soil biological activity and increased P mineralization, we analyzed the partitioning of P among various organic and inorganic P fractions in soils of contrasting agricultural land-use systems and related it to biological soil properties. Isotopic labeling was used to obtain information on the turnover of P held in the microbial biomass. Soil samples were taken from grass legume pasture (GL), continuous rice (CR) and native savanna (SAV) which served as reference. In agreement with estimated P budgets (+277, +70 and 0 kg P ha?1 for CR, GL and SAV, respectively), available P estimated using Bray-2 and resin extraction declined in the order CR > GL > SAV. Increases in Bray-2 and resin Pi were greater in CR than GL relative to total soil P increase. Organic P fractions were significantly less affected by P inputs than inorganic fractions, but were a more important sink in GL than CR soils. Extractable microbial P (Pchl) was slightly higher in GL (6.6 mg P kg?1) than SAV soils (5.4 mg P kg?1), and significantly lowest in CR (2.6 mg P kg?1). Two days after labeling the soil with carrier free 33P, 25, 10 and 2% of the added 33P were found in Pchl in GL, SAV and CR soils, respectively, suggesting a high and rapid microbial P turnover that was highest in GL soils. Indicators of P mineralization were higher in GL than CR soils, suggesting a greater transformation potential to render Po available. Legume-based pastures (GL) can be considered as an important land-use option as they stimulate P cycling. However, it remains to be investigated whether crops planted in pasture crop rotations could benefit from the enhanced Po cycling in grass legume soils. Furthermore, there is need to develop and test a direct method to quantify Po mineralization in these systems. 2001 2014-10-02T08:32:59Z 2014-10-02T08:32:59Z Journal Article https://hdl.handle.net/10568/43949 en Limited Access Springer |
| spellingShingle | soil deficiencies phosphorus soil biology land use deficiencias del suelo fósforo biología del suelo utilización de la tierra Oberson, Astrid Friesen, Dennis K. Rao, Idupulapati M. Buhler, S Frossard, Emmanuel Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass |
| title | Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass |
| title_full | Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass |
| title_fullStr | Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass |
| title_full_unstemmed | Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass |
| title_short | Phosphorus transformations in an oxisol under contrasting land-use systems: The role of the soil microbial biomass |
| title_sort | phosphorus transformations in an oxisol under contrasting land use systems the role of the soil microbial biomass |
| topic | soil deficiencies phosphorus soil biology land use deficiencias del suelo fósforo biología del suelo utilización de la tierra |
| url | https://hdl.handle.net/10568/43949 |
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