Effect of management on soil aggregation in a tropical dry ecosystem

Abstract

Tropical dry forest (TDF) ecosystems have undergoneintense change in its land-use, mainly to agro-ecosystemswith pasture and cropland. The effects of land-use changesshould be integrally evaluated based on functionality,aptitude, and vulnerability in order to ensure that theresource quality will not be deteriorated; therefore, edaphicindicators that show early changes in soil conditions arerequired. The objective of this investigation was toevaluate soil aggregation as a quality indicator, in orderto detect land-use changes as a result of anthropogenicdegradation in aTDF ecosystem. The research was donein a representative morpho-edaphology unit of the TDFecosystem (hill slope on granite with eutric Regosol) onthe coast of the state of Jalisco, Mexico. The unit mainlypresents three land uses: conserved TDF, TDF withcattle, and pasture. An increase in the intensity of land-use causes an increase in bulk density, decrease intotalporosity, decrease in the internal porosity of macroaggregates, decrease in pH, organic carbon, and totalexchangeable bases of the soil. TDF with cattle andpasture show a number of macro aggregates larger than4.76 mm, and better resistance to soil erosion. ConservedTDF had more aggregates of 4.76 to 0.50 mm, resultingin better soil structure and improved edaphic conditionsfor tropical dry forests. The edaphic properties that, ingeneral, are related to aggregates were clay, organic carbon, calcium, and root volume. This study presentsimportant data that can suggest appropriate strategies forsoil conservation.