Resumo

LUGO-MORIN, Diosey Ramón  e  REY, Juan Carlos. Evaluation of the vulnerability to agroenvironmental degradation through the use of the MicroLEIS system in soils of the central plains of Venezuela. Rev. Int. Contam. Ambient [online]. 2009, vol.25, n.1, pp.43-60. ISSN 0188-4999.

The agricultural ground degradation in Venezuela is dramatically increasing, mainly due to problems related to inadequate practices in handling different farming usages. In order to make an evaluation of the risk or vulnerability to the hydric erosion and the agrocontamination of the Orituco River-Chaguaramas Sector of the Guarico State of Venezuela, fourteen land units of the zone of interest were evaluated within four different farming usages: maize (Zea mays), sorghum (Sorghum bicolor) and pasture with-without fertilization. The evaluation was done with Raizal and Pantanal models, a land evaluation decision support system (MicroLEIS) which allowed to determine the potential, present and handling vulnerability, according to the erosion (water) and agrocontamination risks. The results indicated that the present vulnerability to the hydric erosion under the uses of maize and sorghum, was high and very high in 30 % of the area of study due to the ground confluence with high erosionability and the use of conventional handling practices; however, for the pasture the present vulnerability to the hydric erosion was low in all the area, due to the good cover it offers and to the low animal load used by the cattle systems of the zone. On the other hand, the present vulnerability to agrocontamination by phosphorus, nitrogen, heavy metals and pesticides for the uses of maize, sorghum and pasture with fertilization was high in more than 65 % of the area due to the excessive use of high persistence agrochemicals in combination with the susceptibility of grounds to the high surface run-off, the low absorption capacity of cations (texture and mineralogy) and the low biodegradation capacity of the pesticides (low levels of organic matter). Through maps, the most vulnerable areas are located where is recommended the implementation of practices such as the usage of protective cultures (pasture) in rotation with cleaner cultures (maize and sorghum), the use of mulch, conservationist tillage systems and tillage in contour with alive barriers for the maize and the sorghum, intercalating strips of land with clean crops, the use of agroforestry for cattle operations and the rational use of agrochemicals to avoid problems of environmental pollution.

Palavras-chave : Zea mays; Sorghum bicolor; pasture; erosion; agrocontamination; MicroLEIS.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )