EDAFOCLIMATICS VARIABLES ASSOCIATED TO DESERTIFICACIÃ'N

Desertification is a land degradation process generated by climatic variations and human activities. Mexico evidences a 64 % of degraded land, caused by deforestation, overgrazing, and change of land use. The aims of this research were to determine the degree of desertification of agricultural watershed in Baja California Sur and to correlate it with climatic variables and soil physical-chemistries. Samples of soil at two depths were collected (0-10 cm and 10-30 cm) and analyzed to determine texture, pH, organic matter, electrical conductivity, sodium, nitrogen, potassium and phosphorus. We calculated evapotranspiration and estimated the tendencies for average temperature and precipitation from 1978 to 2008. Soils are sandy loam, clear color, pH from 7.10 to 8.05. Organic matter content was low, with salinity varying from 33 to 8100 µS cm-1. The content of other chemical elements were low except for sodium, which values were high because of inadequate management of agricultural irrigation. Annual average temperature oscillates between 21.7 and 25.4 ºC. It is concluded that the agricultural lands of these watershed tend to deteriorate as a consequence of resources overexploitation, and also due to low precipitation, which oscillates from 150 to 180 mm per year, with high annual evapotranspiration.