author(s)
Uthappa AR and Devakumar AS

abstract
The soil fauna was studied in three major seasons viz., summer, rainy and winter in different systems in semi-arid regions of Karnataka. Different diversity indices were derived to assess the diversity of soil fauna. The results revealed that highest number of soil fauna species were recorded during winter (18) and least was observed in summer season (11). Simpson (1-D) indices was highest under rainy (0.776) and lowest was under summer (0.610). Shannon-Weiner (1.888), Margalef richness (2.771) and Chao-1 (18.25) index was recorded highest in winter followed by rainy season and least in Summer season. The Pielou’s evenness index was highest in rainy (0.654), followed by winter season (0.653) while lowest value was recorded under summer (0.607). A total of 22 different taxa/ species of soil fauna were recorded in three seasons. The highest numbers of individuals were recorded in rainy season (722) followed by winter (462) and summer (141). Out of different species identified relative density of Mesostigmata (40%) was highest followed by Cryptostigmata (20.7%) and Onychiuridae (14.00%). Cluster analysis revealed that, soil fauna of winter and rainy season were more similar compared to summer season. Based diversity analysis it can be concluded that, winter season followed by rainy season is the best season to study the soil fauna in semi-arid regions of Karnataka.