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Site degradation occurs mainly through deterioration of the soil's capacity to capture and store water, as well as the loss of organic matter or the accumulation of salts or other toxic substances in the soil. This degradation process, leading to the reduction of the biotic potential of the site, is known as desertification. In this study, changes in bulk density, organic matter, and electrical conductivity are used as indicators of desertification in northeast Mexico. The hypotheses put forward here are that degradation processes are affecting extensive areas of the region, and that the type of processes and their magnitude differ according to specific land uses. Thirty-one sites under different land use systems (agriculture, rangeland, induced grassland, and a protected site) were sampled for bulk density, organic matter, and salinity. Soil samples for bulk density estimation were collected in 1996, 1997, and 1999, while those for organic matter and salinity were taken in 1993, 1997, and 1999. Soil bulk density and organic matter showed significant changes across time in rangeland sites. None of the sites showed significant changes in salinity. Organic matter was similar in agriculture, rangeland, and grassland sites across dates. Soil bulk density was similar in grasslands and rangelands and lower in agriculture sites. Values of organic matter were lower and those of soil bulk density were higher when compared to a protected native vegetation site.
