INFLUENCIA DEL USO DEL SUELO EN LA COMPOSICIÓN QUÍMICA DE SUELOS FORESTALES EN EL SUROESTE DE LOS ESTADOS UNIDOS DE AMÉRICA Y NORTE DE MEXICO

Abstract

A comparative study to determine the influence of land-use history on the physical and soil chemical characteristics of forest ecosystems was developed. The study was located in two mountain ranges, one in Animas Mountains, New Mexico and the other one in Sierra de los Ajos, Sonora, Mexico. Land-use differences between mountain ranges apparently affected many soil characteristics such as du:ff depth, organic matter, total nitrogen, pH, cation exchange capacity, exchangeable cationes (Mg⁺², Na⁺, Ca⁺², K⁺), phosphates, and soluble ions (Ca⁺², Mg⁺², CO₃^-2, HCO₃^-, SO₄^-2, Cr). Soil characteristic differences could be explained in terms of differential fue frequency, timber harvesting, and cattle grazing. Sorne of the expected effects of frequent tires on soil characteristics in Sierra de los Ajos may have been negated or overriden by effects of soil erosion as related to livestock grazing, timber harvesting, and mining activities. Within a mountain range, precipitation-induced differences in elevation explained many, but not all, soil physical and chemical patterns. More detailed knowledge of historical land uses and a richer comparative literature would strengthen the ability to interpret patterns observed in this study.