Soil biological characteristics and microbial community structure in a field experiment

Abstract

The influence of different fertilization treatments on soil biological characteristics and microbial community structure was investigated. Soil samples were taken from a long-term field experiment which was conducted to explore the effect of eight treatments: control (non-fertilized), NPK (nitrogen, phosphorus and potassium), FYM (farmyard manure), FYM + NPK, CSl + St (cattle slurry + straw), CSl + St + NPK, CSl, CSl + NPK. The highest values of invertase activity were found in treatment fertilized with farmyard manure combined mineral fertilizers, similarly to total N content, activity of urease, and C of microbial biomass. Dehydrogenase activity was lower in all treatments with mineral fertilization. Bacterial and actinobacterial T-RFLP profiles of 16S rRNA genes showed similar patterns in response to eight fertilization treatments. In both, the communities formed distinct groups, which were separated by organic fertilization i.e. cattle slurry and straw amendments along the x axes and by NPK amendments along the y axes using the Sammon's method of multidimensional scaling. Significant correlations were determined in several situations related to diversity: between invertase and 1/Db (dominance, bacteria), 1/Da (dominance, actinobacteria) and between T-RFLP profiles of actinobacteria, nitrogen and organic carbon content and bacterial E (evenness).