Roxana Vidican

A Short Review about Using MicroResp Method for the Assessment of Community Level Physiological Profile in Agricultural Soils

MicroResp is a colorimetric method developed by Campbell et al., (2003), used for assessing the community level physiological profile of the microbial population. MicroResp can be used to assess soil health, pollution induced community tolerance, also for toxicity testing, pesticide degradation profiles, bioremediation evaluation and water ecology and toxicity. The aim of the present review was to look over the results of recent papers and to highlight the importance and efficiency of the MicroResp method in assessing the physiological profile of the microbial community. The method advantages and limitations were also assessed. We focused on agricultural soil in order to deepen our understanding about changes of microbial community induced by agricultural practices. To achieve this goal, academic literature was analyzed using an academic database. There were set a total of six keywords, used to make a search algorithm, achieving five search terms. For each search, the first four articles of interest were chosen to be reviewed. After the searches for each of the terms, between 72 and 210 articles were found, 20 of them being chosen for final evaluation. Following the undertaken research, it can be stated that MicroResp method is an important tool to assess the physiological profile of the microbial community, featuring a series of advantages that place it ahead of other competing methods.

Number of microorganisms in the soil cultivated with legume-Grass mixtures supplied with phytohormones and nitrogen.

The study concerned the number of microorganisms colonizing the humus layer and under plough soil from the cultivation of perennial ryegrass mixtures with red clover, which were fed by biostimulant based on the phytohormones and different doses of nitrogen. Nitrogen was applied at four levels-control (no nitrogen), 50, 100 and 150 kg N∙ha-1, biostimulant in two combinations with and without preparation. Soil material to assess the size of individual groups of microorganisms was collected from each experimental plot in autumn 2010 from the humus (0-20 cm) and under plough layers (20-40 cm). The analysis of soil samples for a total number of bacteria, actinomycetes and fungi was conducted at the Department of Agricultural Microbiology IUNG-PIB in Pulawy. Results of studies have shown that more colonies of bacteria, actinomycetes and fungi were colonized the humus horizon. Biostimulant application in this cultivation led to a decrease of the total number of colonies of the all soil microorganisms groups but improved the ratio of bacteria to fungi. Increasing doses of mineral nitrogen by the limiting of the bacteria number and intensive development of soil fungi, helped to narrow the B/F ratio.