Changes in soil bacterial community as affected by soil compaction, soil water content and plant roots

Abstract

The present study assessed the effects of compaction on temporal dynamics of soil microbial communities and whether these changes were influenced by the presence of plant roots and soil water content. A pot trial comprised three levels of compaction (1.1 gcm-3 – un-compacted; 1.25 gcm-3 – moderately-compacted; 1.4 gcm-3 – heavily-compacted), two levels of irrigation regimes (60 and 80% FC), and two soil conditions (planted soil versus free root soil) was established. Soil microbial attributes investigated included bacterial activity and diversity, which were obtained from five sampling times (5; 10; 15; 20; 30 days). The results showed that bacterial activity and diversity changes over time and were higher in un-compacted soil treatment at day-20. Bacterial activity and diversity were higher in moderately-compacted soil with high soil moisture level (80% FC). Microbial activity and diversity were weakly correlated with the presence of plant roots particularly when soil was heavily compacted. Given the changes of microbial communities that followed changes in soil moisture availability, it was, therefore, concluded that management of the timing of irrigation inputs is needed in order to maintain microbial communities in soil.