| Samenvatting: | The effects of time of cultivation in soil from corn fields on the structure of the Collembola community and soil organic matter (SOM) were explorad. Samples were collected from nine corn fields at Balún Canal, a community placed in Los Altos de Chiapas, México. These corn fields representad triplicated stages of three categories of time soil use: recently open land, two years and more than seven years of continuous cropping. Sampling was conducted during the agricultural cycle of 1997 (February - September). Two sampling periods were considerad (February and August) to collect soil collembola and to evalúate soil moisture and SOM. Resulta have shown a reduction of %SOM as time of cropping increases which was clearly significant in February. Number of species, diversity and equitativity of soil Collembola were negatively affected by time of cultivation. The specific composition of soil Collembola was more similar in plots with two and more than seven years of continuous cultivation compared with recently open land. The presence of Isotomidae was more conspicuous in soil with higher time of cultivation than in soil from recently open land. Most species of this family of Collembola were often more abundant than any species of Poduromorpha in soil submitted to intensivo use. The posible use of soil Collembola as indicators of SOM depletion resulting from continuous cropping is suggested.
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