Qualification of soils through microbial activities measurements influence of the storage period on int-reductase, phosphatase and respiration

The storage of soils occurring before microbial activities measurements is liable to cause pronounced changes in their microbial populations. The bias thus introduced in not often taken into account during contaminated soils studies. The study of the influence of time and temperature of the storage period on three microbial activities and for three different soils shows that, in less structured ones certain activities decrease very quickly with the time of storage. Measurement of microbial activities for soil diagnosis must take place quickly after sampling, and storage is preferable at 4°C. Comparison of the results obtained from different soils is not possible as physico-chemical characteristics have a strong influence on the response levels of microbial activities.