Effects of a consortia probiotic inoculant on soil microorganisms and impacts on autoinducers employed in quorum sensing

Abstract

Soil microbial communities are key drivers of soil processes and contribute crucially to agricultural productivity. The goal of optimized agricultural productivity has long been fulfilled through manipulation of indigenous microbial communities for example by applying microbial inoculants. We hypothesized that application of SCD ProBio BalanceTM Plus (PBP), a particular consortia probiotic product, may enhance soil microbial diversity, thus improving pathogen control and amplifying crop residue turnover. To test the hypothesis, field experiment was established in Central Missouri on Mexico silt loam soils under two different management situations: (1) restored grassland; (2) standard corn/soybean rotation. During the 2012 growing season, soils were amended with the PBP product at the rate of 100L ha (treatment) or water (control). The treatment was replicated in triplicate and soils were sampled to the depth of 10cm and sampling was repeated eight times throughout the experiment. Soil microbial diversity was surveyed through 16srDNA DGGE. Furthermore, soil enzymatic activity was examined with respect to dehydrogenase activity and the capacity to digest fluorescein diacetate. Application of PBP correlated with no major changes in soil enzymatic activity or soil microbial diversity. Certain limitations may have obscured the actual impacts of