VERTICAL DISTRIBUTION OF SOIL MICROARTHROPODS IN TWO TEA AGROECOSYSTEMS WITH DIFFERENT AGRONOMIC PRACTICES

Soil dwelling microarthropods occupied a very important component for maintaining the soil quality and soil health of an ecosystem. Different management practices greatly influence the abundance and distribution of edaphic microarthropods. The present study aims to elucidate the vertical distribution of mites and collembola in two tea agroecosystems with different agronomic practices viz- conventional and organic management in South Assam. The study revealed that organically managed system has higher abundance and density of both mites (17.54 and 17.54 ind./soil corer for WJTE; and 8.63 and 8.63 ind./soil corer for RTE) and collembolan (6.71 and

5.88 ind./soil corer for WJTE; and 4.86 and 4.25 ind./soil corer for RTE) as compared to the conventionally managed system. But the conventional tea agroecosystem showed higher percent composition (26.73% for 10- 20 cm; and 13.79% for 20-30 cm) with increasing soil depth as compared to organic tea garden (17.38% for 10- 20 cm; and 7.17% for 20-30 cm). This may be attributed as an adaptation strategy of soil arthropods to avoid the unfavourable conditions resulted from the management techniques. Negative correlation was revealed between soil depth and cryptostimata mite (r= -0.90 for WJTE and r= -0.89 for RTE) but not statistically significant (p=.28 for WJTE and p=.29 for RTE) for both sites. Similar result was reported for Collembola (r=-0.95 for WJTE and r=-0.94 for RTE; p=.19 for WJTE and p=.21 for RTE. The study revealed that there exist a significant influence of various management strategies on the distribution and diversity of the soil dwelling microarthropods.