Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados
The effects of land-use change on the structure of Oxisols in the Brazilian savannas (also known as the Cerrados) are still insufficiently understood. We therefore studied loamy and clayey Oxisols under natural savanna, crop, pasture, and reforestation to (1) quantify management-induced changes in t...
| Main Authors: | , , , |
|---|---|
| Format: | Book Chapter |
| Language: | Inglés |
| Published: |
International Center for Tropical Agriculture
1999
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/10568/55127 |
| _version_ | 1855533544896462848 |
|---|---|
| author | Neufeldt, Henry Ayarza, Miguel Angel Resck, DVS Zech, W. |
| author_browse | Ayarza, Miguel Angel Neufeldt, Henry Resck, DVS Zech, W. |
| author_facet | Neufeldt, Henry Ayarza, Miguel Angel Resck, DVS Zech, W. |
| author_sort | Neufeldt, Henry |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | The effects of land-use change on the structure of Oxisols in the Brazilian savannas (also known as the Cerrados) are still insufficiently understood. We therefore studied loamy and clayey Oxisols under natural savanna, crop, pasture, and reforestation to (1) quantify management-induced changes in the quantity of water-stable aggregates, (2) identify the main aggregating agents, and (3) correlate aggregation with changes in pore-size distribution. Clayey soils showed a significantly higher macroaggregation than did loamy soils. Compared with natural savanna, macroaggregation was clearly reduced under crops, whereas aggregation of soils under pasture and tree plantations was only slightly affected. In both clayey and loamy soils, polysaccharides formed the main aggregating agent. In the clayey soils, lime very effectively disaggregated the soils by weakening the electrostatic forces between positively and negatively charged soil compounds. In the loamy soils, the role of roots in binding macroaggregates was significant. Because pastures provide strong rooting and high polysaccharide production, we recommend introducing crop/pasture rotations. Management-induced disaggregation strongly affected the pore-size distribution by compacting the soils, and thus reducing macroporosity and increasing mesoporosity. Microporosity, however, was unaffected by management and differed only between the two substrates. Considering the Oxisols` typically low pore space at plant-available matrix potentials, the increase in mesoporosity may be important for annual crops during the frequent dry spells in the rainy season. |
| format | Book Chapter |
| id | CGSpace55127 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 1999 |
| publishDateRange | 1999 |
| publishDateSort | 1999 |
| publisher | International Center for Tropical Agriculture |
| publisherStr | International Center for Tropical Agriculture |
| record_format | dspace |
| spelling | CGSpace551272024-01-09T09:49:09Z Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados Neufeldt, Henry Ayarza, Miguel Angel Resck, DVS Zech, W. savannas land use oxisols hygroscopicity sabanas utilización de la tierra oxisoles higroscopicidad The effects of land-use change on the structure of Oxisols in the Brazilian savannas (also known as the Cerrados) are still insufficiently understood. We therefore studied loamy and clayey Oxisols under natural savanna, crop, pasture, and reforestation to (1) quantify management-induced changes in the quantity of water-stable aggregates, (2) identify the main aggregating agents, and (3) correlate aggregation with changes in pore-size distribution. Clayey soils showed a significantly higher macroaggregation than did loamy soils. Compared with natural savanna, macroaggregation was clearly reduced under crops, whereas aggregation of soils under pasture and tree plantations was only slightly affected. In both clayey and loamy soils, polysaccharides formed the main aggregating agent. In the clayey soils, lime very effectively disaggregated the soils by weakening the electrostatic forces between positively and negatively charged soil compounds. In the loamy soils, the role of roots in binding macroaggregates was significant. Because pastures provide strong rooting and high polysaccharide production, we recommend introducing crop/pasture rotations. Management-induced disaggregation strongly affected the pore-size distribution by compacting the soils, and thus reducing macroporosity and increasing mesoporosity. Microporosity, however, was unaffected by management and differed only between the two substrates. Considering the Oxisols` typically low pore space at plant-available matrix potentials, the increase in mesoporosity may be important for annual crops during the frequent dry spells in the rainy season. 1999 2015-01-28T14:17:27Z 2015-01-28T14:17:27Z Book Chapter https://hdl.handle.net/10568/55127 en Open Access International Center for Tropical Agriculture Neufeldt, Henry; Ayarza, Miguel Angel; Resck, Dimas Vital Siqueira; Zech, Wolfgang. 1999. Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados. In: Thomas, Richard J.; Ayarza, Miguel Angel (eds.). Sustainable land management for the oxisols of the Latin American savannas: Dynamics of soil organic matter and indicators of soil quality. Centro Internacional de Agricultura Tropical (CIAT), Cali, CO. p. 51-63. (CIAT publication no. 312) |
| spellingShingle | savannas land use oxisols hygroscopicity sabanas utilización de la tierra oxisoles higroscopicidad Neufeldt, Henry Ayarza, Miguel Angel Resck, DVS Zech, W. Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados |
| title | Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados |
| title_full | Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados |
| title_fullStr | Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados |
| title_full_unstemmed | Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados |
| title_short | Distribution of water-stable aggregates and aggregating agents in oxisols of the Brazilian cerrados |
| title_sort | distribution of water stable aggregates and aggregating agents in oxisols of the brazilian cerrados |
| topic | savannas land use oxisols hygroscopicity sabanas utilización de la tierra oxisoles higroscopicidad |
| url | https://hdl.handle.net/10568/55127 |
| work_keys_str_mv | AT neufeldthenry distributionofwaterstableaggregatesandaggregatingagentsinoxisolsofthebraziliancerrados AT ayarzamiguelangel distributionofwaterstableaggregatesandaggregatingagentsinoxisolsofthebraziliancerrados AT resckdvs distributionofwaterstableaggregatesandaggregatingagentsinoxisolsofthebraziliancerrados AT zechw distributionofwaterstableaggregatesandaggregatingagentsinoxisolsofthebraziliancerrados |