Dear DR.,

Soil quality index (SQI) calculations

A total 13 parameters used for developing SQIs were pH, EC, BD, WSA, GMD, MWD, PR, SOC concentration, N concentration, C-Stock, N-Stock, AWC, and soil water content.

As some of these parameters were synthesized and redundant, only nine parameters were chosen omitting MWD, C and N concentrations, and water content from the SQI-1 and SQI-2 calculations to avoid redundancy.

However, SQI-3 was not a primarily additive approach and redundancy of the parameters was eliminated through the processes of elimination as prescribed before. Thus, all 13 parameters were initially included in SQI-3 model and only four non-redundant soil parameters with maximum variations in the dataset were finally retained in the model as described in the following section. The average and standard deviation values of these parameters grouped by soil types are presented in

SQI proposed framework an ideal soil would have SQI value of 1 for the highest quality soil and 0 for the severely degraded soil.

PFA, 

http://www.isealalliance.org/sites/default/files/Soil%20Quality%20Indicators.pdf

http://www.sciencedirect.com/science/article/pii/S0167198714002025

https://dl.sciencesocieties.org/publications/sssaj/abstracts/79/1/224

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0105981

These articles may be helpful to you, 

Thanks

VSM

http://www.isealalliance.org/sites/default/files/Soil%20Quality%20Indicators.pdf

Dear Habib,

You can use the 10 indicators (called parameters above) I used for SMAF to evaluate rangelands, however some of them are a bit difficult to measure and were developed for U.S. landscapes. The potentially minerizable N is a bit involved. You really do not need all of the parameters. You might evaluate a few of the parameters that include physical (wet aggregate stability, BD), chemical ( electrical conductivity, pH), and biological (soil organic carbon, microbial biomass carbon, beta-glucosidase activity) indicators.  However, these must be tested for your region.  You would need new calibrations for Iran. Alternatively, you might look at the methods presented in http://jornada.nmsu.edu/monit-assess/manuals/assessment. They should be more easily used for your purpose.

Best wishes,

Ted Zobeck 

Determination of soil quality index is nothing but the integration of representative highly performed minimum dataset which best reflects the soil function in terms of specific goal. Therefore , before quantifying the soil quality index  for specific management system , some exercise like, definition of goal, selection of minimum dataset defining that management system , scoring of indicators base on performance towards soil function and integration of indicators scores into soil quality index are mandatory to address this issue ,  you raised  Habib.