Baseline soil characteristics of a humid tropical silvopastoral system and changes in selected soil properties
We established fast-growing leguminous trees (Erythrina berteroana Urban) in native grass pastures in Costa Rica's Atlantic region to determine the effects of tree pruning and cattle grazing on soil phosphorus availability and pasture biomass production. The field experiment included a randomized complete block of four treatments which were replicated on five farms: grazing and trees, grazing-no trees, trees-no grazing, and no trees-no grazing (the control). In 1987, we conducted a complete baseline characterization of the study soil's chemical. physical and mineralogical properties (andic humitropept, series Neguev). Three years later, we remeasured exchangeable bases and acidity, soil pH, carbon and nitrogen contents, phosphorus forms and bulk density to evaluate both farm and treatment effects over time. The Neguev soil series is acid (pH 4.8 - 5.2), low in exchangeable bases (sum of bases -2.3 cmol/kg), high in exchangeable AI (>25% of ECEC), low in available P (2.8 mg P/kg midified Olsen extractable), yet high in total P (1385 mg P/kg). Soil bulk density was relatively low (0.84 - 0.91 g/cm3) and moisture retention capacity high (53% by volume at field capacity). The soil's mineralogy, dominated by kaolinite, gibbsite and irons oxides, is consistent with the oxic-andic nature exhibited by both chemical and physical properties. Over the three-years study period, soil organic C increased in the two no-grazing no tree control. Short-term changes in these parameters reflect the fallow-loke status incurred from no grazing. There were also significant declines in soil pH and exchangeable monovalent cations along with increases in exchangeable Al and Fe at the farm level. Concurrently, organic P reserves declined and NaHCO3- EDTA extractable P increased. Such changes may represent either gradual soil chemical changes associated with post-deforestation equilibrium shifts or normal fluctuations in the pasture ecosystem's inherent dynamic equilibrium.
| Main Authors: | , |
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| Format: | Artículo biblioteca |
| Language: | English |
| Published: |
IICA, San José (Costa Rica)
1993-01
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| Subjects: | ERYTHRINA POEPPIGIANA, ÁRBOLES DE PROPÓSITO MÚLTIPLE, AGROFORESTERIA, VARIEDADES DE ALTO RENDIMIENTO, SISTEMAS AGROPASCICOLAS, LEGUMINOSAS FORRAJERAS, PASTIZALES, PODA, PASTOREO, FÓSFORO, SUELO, BIOMASA, ANDOSOLES, TIPOS GENETICOS DE SUELOS, NO METALES, ELEMENTOS QUÍMICOS, DENSIDAD DEL SUELO, PH DEL SUELO, ZONA TROPICAL, COSTA RICA, |
| Online Access: | https://repositorio.catie.ac.cr/handle/11554/9610 |
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