The state of Rio Grande do Sul is an important tobacco producer. The crop is produced in three management systems: conventional tillage (CT), minimum tillage (MT) and no tillage (NT). To assess the impact of these systems on the soil fauna population, the epigeic fauna was sampled. Aside from the three cited systems, an area in conversion from tobacco to grape (TGr) and an area of native forest (NF) were evaluated. Ten Provid traps per area were used for sampling. The evaluated parameters were abundance of organisms, richness, Shannon's diversity index (H') and Shannon's Evennes Index (J). Due to its sensibility to environmental modifications, Collembola (Arthropoda: Hexapoda) was identified to the family level. Multivariate analysis were performed by the method of Hierarchical Cluster Analysis of Average Euclidean Distance and Principal Component Analysis and the indexes H' and J were compared by the Student´s t test. The total number of organisms was largest in NT, differentiated from the other areas in the Hierarchical Cluster Analysis. The richness values were very similar among the areas, particularly close between TGr and NF. No statistical differences were observed between the treatments CT, NT and TGr regarding H', with values of 1.58, 1.60 and 1.52, respectively. The value of H' was lowest in MT (1.18) and intermediate in NF (1.33). The statistical behavior for J was very similar to that of H'. For Collembola, the families Entomobrydae, Sminthuridae, Poduridae and Hipogastruridae were identified. All four families were observed in NT, while in the other areas only Entomobrydae and Sminthuridae were identified. The Principal Component Analysis (PCA) explained 32 % of the variability among the areas. Of this percentage, the axes 1 and 2 explained 59.3 %. The presence or absence of soil tillage and cover crop rotation were the most influential factors in epigeic fauna populations.
soil quality; soil management; epigeic fauna
