Diagnosis of the microbiological state of soils according to the resilience of its bacterial population

摘要

The method comprises: sampling soil from agricultural land and/or agricultural islands, or forest land; measuring the dynamics of relative or absolute bacterial fraction of the soil in terms of diversity, activity and/or abundance with various pH values included with interior of a range of values corresponding to the extent of the exchangeable acidity of the soil; comparing the measured values and optimal values to note a significant variation; and diagnosing microbiological state of the soil based on the variation to recommend an agronomic practice so as to reinforce bacterial populations. The method comprises: sampling soil from agricultural land, agricultural islands and/or forest land; measuring the dynamics of relative or absolute bacterial fraction of the soil in terms of diversity, activity and/or abundance with various pH values included with interior of a range of values corresponding to the extent of the exchangeable acidity of the soil; comparing the measured values and optimal values to note a significant variation; and diagnosing microbiological state of the soil based on the variation to recommend an agronomic practice to reinforce bacterial populations in the soil. The measure of resilience is obtained by superposition of a variable curve describing the variation of the dynamic bacterial fraction of the microflora of the soil based on the different pH values imposed with a horizontally fixed curve at an optimum pH and/or assumed for optimal relative or absolute bacterial dynamics in terms of diversity, activity and/or abundance. The soil sample is incubated in the presence of a minimum amount of carbonaceous substrate. The measurement of the dynamics of the bacterial fraction is based on metabolism of the carbonaceous substrate, the count of viable bacterial cells with various pH values, and an index of diversity of the microflora with various pH values. The comparison step comprises a confidence interval applicable to the two curves beyond which the variable curve significantly deviates from the fixed curve. The bacterial populations are little or non-resilience if the variable curve significantly deviates from the fixed curve so that the reinforcement of populations is recommended by bacterial inoculation such as Azotobacter inoculation.