The aggregates stability indicator <ASItest> to evaluate soil spatiotemporal change in a tropical dry ecosystem

In this work, aggregate stability was evaluated as a quality indicator in soils of tropical dry deciduous forests (TDF) with relation to land use, the sampling position in the hillslope and the sampling season. The study was done on a representative morpho-edaphological unit of the tropical dry ecosystems (hillslope on granite with eutric regosol) on the coast of the state of Jalisco, Mexico. The evaluated soil aggregation indexes were: Aggregate stability index (ASI)test, maximum stability, minimum stability, relative index of variability, and the index of quality of aggregation change. These indexes showed differences in soil aggregation resulting from changes in land use (conserved TDF, grazed TDF, and cultivated pasture). The indexes showed that there is greater stability of the aggregates during the rainy season than in the dry season; as well as in the higher part of the slope than in the lower one. The relationship of the edaphic properties with the ASItest indicator was mainly with radical volume, and less so with exchangeable bases (calcium and magnesium), clay, and organic carbon. The proposed soil aggregation indexes allowed monitoring spatiotemporal changes in soil structure.