Abstract

MARTINEZ-TRINIDAD, S. et al. Effect of Management on Soil Aggregation in a Tropical Dry Ecosystem. Terra Latinoam [online]. 2008, vol.26, n.4, pp.299-307. ISSN 2395-8030.

Tropical dry forest (TDF)ecosystems have undergone intense changein its land-use, mainly to agro-ecosystems with pasture and cropland.The effects of land-usechanges should be integrally evaluated based on functionality, aptitude, and vulnerability in order to ensure that the resource quality will not be deteriorated; therefore, edaphic indicators that show early changes in soil conditions are required. The objective of this investigation was to evaluate soil aggregation as a quality indicator, in order to detect land-use changes as a result of anthropogenic degradation in a TDF ecosystem. The research was done in a representative morpho-edaphology unit of the TDF ecosystem (hill slope on granite with eutric Regosol) on the coast of the state of Jalisco, Mexico. The unit mainly presents three land uses: conserved TDF, TDF with cattle, and pasture. An increase in the intensity of land-use causes an increase in bulk density, decrease in total porosity, decrease in the internal porosity of macro aggregates, decrease in pH, organic carbon, and total exchangeable bases of the soil. TDF with cattle and pasture show a number of macro aggregates larger than 4.76 mm, and better resistance to soil erosion. Conserved TDF had more aggregates of 4.76 to 0.50 mm, resulting in better soil structure and improved edaphic conditions for tropical dry forests. The edaphic properties that, in general, are related to aggregates were clay, organic carbon, calcium, and root volume. This study presents important data that can suggest appropriate strategies for soil conservation.

Keywords : soil quality; land degradation; soil geomorphology.