Effect of agricultural practices on soil bacterial populations in cropping systems in Chihuahua, Mexico

Abstract

Sustainability is the biggest challenge faced by Mexico against a backdrop of bleak environmental degradation. It is necessary to acquire knowledge and to implement environment-friendly alternatives in order to preserve and maintain the natural resources of the country, a key factor in improving the profitability of agricultural production. In nature there is an unknown number of associations between microbial populations, which are influenced by environmental, physical and chemical factors. Microbial relationships determine the dominant or inhibited communities that exist in the soil, in the roots of the plants, and also those that coexist without affecting (positively or negatively) other populations. The factors determining microbial activity are important because of their influence in maintaining soil fertility and crop nutrition. Therefore, this work studied the bacterial populations present in locations with different soil and climatic conditions. This in order to evaluate the presence of bacterial populations potentially beneficial for the crops of interest in the region. Initially, the total bacterial population and the subpopulation with rhizobial group characteristics were estimated in samples from three localities of the state of Chihuahua in June 2007, from 11 composite samples of agricultural soils. Bacterial population density was evaluated at levels from 1X102 to 6.6X103 UFC g-1, very low values for agricultural soils, suggesting the negative effect of pesticide application on the microbial populations of the soil.