Evaluación de las prácticas de conservación de suelo en la Subcuenca Presa Jalpan, Querétaro, México

Abstract

This paper's main objective is to evaluate water erosion, and its effect on soil management and conservation practices in the subbasin Jalpan Dam, located at The Sierra Gorda Biosphere Reserve in the State of Queretaro in northern Mexico. This paper was elaborated in four stages: 1) Analysis of soil conservation practices at the study area, with information collected through semi-structured interviews and field verification; 2) Measurement of the effect in soil’s conservation practices on soil’s erodibility, by taking soil samples and in situ measurements on paired plots; 3) Estimation of water erosion and identification of priority areas for its management, by applying the USLE model of Wischmeier and Smith (1978) and the use of GIS (Geographic Information Systems); 4) Estimation of sediment contribution to the Jalpan dam, using the methodology of Aveldaño et al. (1994). As a result, 40 polygons with soil’s conservation practices were located within the Jalpan Dam sub-basin, distributed mainly in the high functional zone. 22 of the 40 polygons were visited, in which 6 types of practices were spotted: reforestations with pine-cedar, maguey lines, agricultural terraces, stone barriers, stone dams and brushwood check dams. The results show deterioration on the structures, more than 30% of them require maintenance and 20% are clogged. Vegetative practices have had little success, reflected in low plant densities and low survival. As a result of the conservation practices evaluations in soil’s erodibility, it was found that in 8 of the 9 sites evaluated, the practices decreased the susceptibility of the soil to erode. It is important to establish systematic supervising mechanisms to ensure proper evaluation of every soil conservation practice condition and function.