Soil biological quality by application of the QBS-ar Index

Feasibility of analysis and evaluation of costs

The biological quality of the soil

The assessment of soil degradation is done using chemical, physical and microbiological parameters: with such methods, although it is possible to parameterize – and determine – certain soil characters, it is often difficult to determine what the effects of any degradation are on the biotic component of the soil. In fact, it is well known that the soil biotic component is a reliable and trustworthy indicator of soil quality that is a direct expression of the functionality of the organisms that populate it.
The use of bioindicators therefore can be a valuable aid in identifying ongoing environmental changes. Among the approaches that consider multiple functional groups and the complex relationships between them is the QBS-ar index, developed by Parisi in 2001.

The assessment of soil biological quality through the QBS-ar index

The QBS-ar (Soil Biological Quality) index is based on the entire soil microarthropod community and uses the criterion of biological forms so as to have an indication of the level of adaptation to hypogeal life. This is a biological approach, which prioritizes the ecological aspect and makes it possible to overcome the difficulties of taxonomic analysis at the species level. Microarthropods extracted from soil clods of 10 cm side and 10 cm depth through the Berlese-Tüllgren system are divided into morphologically homogeneous groups. Each group is assigned an Ecomorphological Index (EMI) value between 1 and 20 depending on the level of soil adaptation; the sum of the EMIs assigned to each group provides the QBS-ar index value.
The main morphological characters of adaptation to soil life include:

• body miniaturization;
• reduction in pigmentation and simplification of livery;
• reduction in length of appendages;
• reduction of visual apparatuses until they disappear;
• atrophy or disappearance of wings.

Feasibility requirements

It is essential for successful monitoring that samples are taken, packaged correctly and delivered to the laboratory within 36, maximum 48 hours of collection. Compliance with this timeline is essential for the quality of the analytical result.
It is therefore necessary that samples are shipped from the place of collection to Timesis laboratories in the shortest possible time.
Each sample, to be meaningful, needs to be composed of 3 replicates. The extraction time ranges from 5 to 7 days in general.
Optimal times for sampling are either autumn (October to mid-November) or spring; however, it remains possible to take samples throughout the year.

Practical guide to performing withdrawals

Information and quotes

For any other information and quotes, you can contact us at qbs@timesis.it