The Effect of Organic Amendments and Chemical Fertilizers On Microbial Diversity.

The microbial ecosystem in soil is important for maintaining productive soil and having a better understanding of the biodiversity.  Changes in the microbial ecosystem provides information on the plant microbe interaction, nutrient availability, and carbon cycles.  Denaturing gradient gel electrophoresis (DGGE) is a useful technology in assessing the microbial diversity in a soil environment.  In this study the affect of nitrogen on the biodiversity is observed, the affect of manure on the biodiversity is observed.  The nitrogen sources in this experiment are ammonium nitrate and a polymer base slow release fertilizer.  The chemical fertilizers were applied at two rates, the low rate was 100 lb N/ AFS and the high rate was 400 lb N AFS.  The two fertilizers at the two rates were applied to three plots with varying levels of manure application.  The high level plot containing over twenty years of dairy manure effluent applied, a low level plot containing manure applications for fertilizer, and a no manure plot.  A control was put in for every plot with manure and no chemical fertilizer.  Samples were collected at time of application and five time points following.  DNA extraction from the soil was completed with a kit from MoBio.  The V2-V3 region of the 16s rDNA were PCR amplified with the eubacteruim specific primers 341 fgc-GC clamp and the 534r.  DGGE banding patterns were then compared for all the treatments.  There were differences in banding patterns between different manure plots and between chemical fertilizers, however rates of application seemed to have similar banding patterns.  This information indicates that manure application and chemical fertilizers can change the biodiversity.