EFFECTS OF CONVERTING FOREST TO AVOCADO ORCHARDS ON TOPSOIL PROPERTIES IN THE TRANS-MEXICAN VOLCANIC SYSTEM, MEXICO

In the present work, land cover and land use changes between 2003 and 2008 were assessed in the Cupatitzio River sub-basin located in the Trans-Mexican Volcanic System and Balsas Depression in Mexico. The effects of land cover conversion from temperate forest to avocado orchards on soil properties were determined. Land cover and land use databases were built for the years 1975, 2003, and 2008 using available cartographic information and interpretation of panchromatic SPOT images for the year 2008. Additionally, soil sampling was carried out in 16 representative sites in the higher parts of the sub-basin, where avocado plantation dynamics have caused important changes in areas covered by temperate forests. Results show that (i) temperate coniferous and tropical low deciduous forests were reduced at an annual rate of 09 per cent (1,001hay(-1)) between 1975 and 2008; (ii) cropland areas expanded at an annual rate of 07 per cent between 1975 and 2008, representing a growth of 553hay(-1); (iii) wet soil aggregate stability, mechanical resistance to penetration and nitrate (N-NO3) concentration in the topsoil layer of Andosols were significantly affected by land use conversion to avocado orchards. Other soil properties such as organic matter, interchangeable K, and available P showed degradation tendencies. These results suggest the importance of implementing strategies for mitigating the accelerated process of transformation and degradation of natural resources in the Cupatitzio River sub-basin. The implementation of programs for deforestation reduction should be a priority in the restoration strategy. Copyright (c) 2012 John Wiley & Sons, Ltd.