Effects of Probiotics on Soil Microbial Community and Biomass Under Cover Crops.

Although use of agro-chemicals over the past few decades has increased land productivity, frequent use of agro-chemicals have resulted in some negative impacts on the environment and soil microbial biodiversity.  Therefore, use of alternative management approaches is necessary to promote and maintain soil health.  Use of probiotics is a promising alternative to promote soil biodiversity and soil nutrient cycling.  However, very few research studies have been conducted to evaluate the significance of probiotics on soil microbial community and biomass.  This research study was conducted at the NRCS soil health farm, Chariton County, Missouri to quantify probiotic effects on soil biological diversity and nutrient cycling.  Soils in the study site are classified as Armstrong loam (fine, smectitic, mesic Aquertic Hapludalfs).  The study design consists of four soil application concentrations of Bio-Ag (SCD Probiotics) at 0, 60, 90 and 120 L ha^-1 year^-1 with three replications and two equal split applications.  Soil microbial biomass and community structure were greater with high probiotic concentrations as compared to the control treatment analyzed by phospholipid fatty acids (PLFA) detection method.  Total PLFA can be used as an indicator of microbial biomass as it detects essential fatty acid components present in cellular membranes of all living organisms.  Furthermore, using signature biomarker fatty acids, higher and more diverse microbial communities are expected in probiotics treatments.  Soil enzyme activities were also greater with higher concentrations of probiotic application.  Results of the study imply that application of probiotics favor soil microbial diversity.

Keywords: PLFA, cover crops, probiotics, soil enzymes