Correlation of Microbial Population with Enzymatic Activities and Nutrient Levels of Soil during Paddy Growth

The influence of growth stages of paddy on correlation of different microbial population with soil enzymatic activities (dehydrogenase, urease and alkaline phosphatase), available nutrient pool and organic carbon has been accessed. These soil parameters were investigated at four growth stages viz., at transplantation, tillering, reproductive and maturation stage. Results showed that total bacterial and diazotrophic population had a significant positive correlation with soil dehydrogenase, alkaline phosphatase, available NPK and organic carbon at each growth stage. Fungal and actinobacteria population, however; showed a variable trend with various soil parameters at different growth stages of the crop. Actinobacteria population showed significant positive correlation with soil enzymatic activities and available nutrient at the reproductive stage; whereas it showed a negative correlation with most soil parameters at other time intervals. A significant effect of paddy growth stages was recorded on microbial community structure and their activities. At tillering stage, fungal, bacterial and diazotrophic population have significant impact on soil enzymatic activities; However, at reproductive stage, actinobacteria population become greater contributor towards soil enzymatic activity as compared to fungal population. This study revealed a complex plant-soil relationship, owing to the role of alternating microbial dynamics in determining soil health and fertility.