@ Shiv, Soil microbiota, being ‘the biological engine of the Earth’, provides pivotal services in the soil ecosystem functioning. Hence, management practices protecting soil microbial diversity and resilience, should be pursued. Besides, any abnormal change in rate of innumerable soil biochemical processes, as mediated by microbial communities, may constitute early and sensitive warning of soil homeostasis alteration and, therefore, diagnoses a possible risk for soil sustainability. Among the vastness of soil biochemical processes and related attributes (bioindicators) potentially able to assess the sustainable use of soils, those related to mineralisation-immobilisation of major nutrients (C and N), including enzyme activity (functioning) and composition (community diversity) of microbial biomass, have paramount importance due to their centrality in soil metabolism. The impact of different agricultural factors (fertilisation, tillage, etc.) under either intensive and sustainable managements on soil microbial community diversity and functioning by both classical and molecular soil quality indicators, in order to outline the most reliable soil biochemical attributes for assessing risky shifts from soil sustainability. To my judgement most important biochemical indicators are: Soil enzymatic activities, C and N mineralisation-immobilisation, Microbial diversity, Nucleic acid and fatty acid based indicators

What do you want to do with a soil index outdoor? It must have an interest for knowing something in the agricultural production, an index produces nothing.

Quality indices are generally limited by cost. As a consequence, even many classical fertility tests are not performed

@ Shiv, Soil microbiota, being ‘the biological engine of the Earth’, provides pivotal services in the soil ecosystem functioning. Hence, management practices protecting soil microbial diversity and resilience, should be pursued. Besides, any abnormal change in rate of innumerable soil biochemical processes, as mediated by microbial communities, may constitute early and sensitive warning of soil homeostasis alteration and, therefore, diagnoses a possible risk for soil sustainability. Among the vastness of soil biochemical processes and related attributes (bioindicators) potentially able to assess the sustainable use of soils, those related to mineralisation-immobilisation of major nutrients (C and N), including enzyme activity (functioning) and composition (community diversity) of microbial biomass, have paramount importance due to their centrality in soil metabolism. The impact of different agricultural factors (fertilisation, tillage, etc.) under either intensive and sustainable managements on soil microbial community diversity and functioning by both classical and molecular soil quality indicators, in order to outline the most reliable soil biochemical attributes for assessing risky shifts from soil sustainability. To my judgement most important biochemical indicators are: Soil enzymatic activities, C and N mineralisation-immobilisation, Microbial diversity, Nucleic acid and fatty acid based indicators

Thank You Martin Buser and Paul Milham sir for your contribution.

J. C. Tarafdar very well said sir.

As the soil biochemical properties are important indicators of soil quality. Still these properties are not taken into consideration while calculating the Soil Quality Index under different management practices.

I just want to know the reason behind it.

and if I want to take these properties for quality index assessment through simple additive method or PCA analysis, what will be their "Level" and "Index" value?

@ Shiv, the attached file may be useful to you .

Thank You J. C. Tarafdar sir for your valuable contribution.

I agree with you, Shiv, and Dr. Tarafdar: biochemical parameters are still too much ignored in soil science, due to clivages between microbiological, chemical and physical disciplines, the soil science is not sufficiently considered from the microbiological and biochemical point of view. I there any mathematician among us who wants to work on the integration of major biochemical parameters in soil quality index?

Thank you Dr Christine Juge for your response.

I'm also looking for the same to draw a statistical quality index including soil biochemical properties with soil physical and chemical properties.

As I understand,some microbial/biological parameters like microbial biomass and dehydrogenase activity are being used in soil quality/soil health index computation.We normally include the soil properties which can easily be determined in the laboratory especially in Soil Testing Laboratory as ultimately the STLs are the place where soil health of farmers' fields has to be measured.Dr.Paul Milham as rightly point out the cost factor.In addition, the test has to be simple and less time consuming(rapid).You may pleasure mention some important microbiological/biochemical parameters which can easily be measured in Soil Testing Laboratories.Same is the problem with the determination of some important physical parameters in STLs.

@ Dr. Rao, I think some parameters can easily be estimated and included for example : Earthworm population, Particulate Organic Matter, .Potentially Mineralizable Nitrogen, Soil beneficial Enzymes, .Soil Respiration, .Total Organic Carbon etc.

Your idea is great and must be implemented, but many research centers have not the knowledge, skill and facilities to measure this parameter.

J. C. Tarafdar ,Earthworm population and total organic carbon(mostly oxidizable organic carbon) are being used as indicators of soil health. One can try particulate organic matter or labile organic matter as soil health parameter.Potentially mineralizable N has been promoted as soil test for N but not received good /required attention.The other methods/parameters suggested, though very good,may not be suitable for Soil Testing Laboratories.Rapid or easy version of some important parameters can be attempted using new tools like sensors or colour tests.

Are there any microbiological standards as an indicator of good soil health

Thank you Annangi Subba Rao and J. C. Tarafdar sir for your valuable contributions.

thank you Beza Shewangizaw for your appreciation.

Surendra Gopal K. sir, I don't think so.

Biological properties are the excellent indicators of soil health and there must be some sore or level to consider them for soil quality index assessment.

Surendra Gopal K. ,European countries are using a minimum data set of microbial indicators for monitoring soil health.The minimum set of parameters vary from country to country but the common indices used by various European countries are: Soil respiration , microbial biomass, soil enzymes (enzymes selected differ from country to country), Potential C mineralization/organic matter decomposition, N-mineralization, nitrification, microbial diversity, bio-sensor bacteria (heavy metals) etc.

J. C. Tarafdar Thanks sir for your nice description.

There are thousands of microbial activities involved in the soil system and difficult to access for very concerned. Organic matter contents in larger perspectives and also the parameters mentioned by Dr. Rao used under normal soil conditions. Though, it varies qualitatively from country to country and the crops indeed.

Based on the work done at Indian Institute of Soil Science (IISS) , Bhopal and published literature,@ Drs.M.C.Manna and D.L.N. Rao suggested four parameters viz. , particulate organic matter, soil respiration, microbial biomass and N mineralization to give a complete picture of soil biological quality.The following paper may be consulted for more information and references to work done on this aspect at IISS,Bhopal.

Maintenance of soil biological health under different crop production systems.

M.C.Manna, A.Subba Rao and A.Mandal Indian Journal of Soil Conservation

41(2) 127-135 ,2013.

Thank you so much Bikas S Mahapatra sir for your valuable contribution.

Thank you Annangi Subba Rao sir for your informative contribution.

Because biological properties are directly related with microbial activity of soil, which is difficult to be assessed and at the same time microbial activity also changes instantly in response to surrounding environmental conditions as compared to soil organic matter.

Rhizosphere microorganisms directly and indirectly influence the composition and productivity of natural plant communities. Hence below ground microbial species richness has been proposed as a predictor of above ground plant diversity and productivity. Therefore soil biological properties are important and must be considered while computing soil quality indices.

We can not omit the biological properties of the soil in determing the soil quality index. Soi physical processes and properties as well as its chemical processes and properties are influenced by microbial activiyies.

Thank you Manpreet Jaidka sir for your contribution.

Thank you A. S. Tayade sir for your informative reply.

Thank you Nenita E Dela Cruz for your contribution

Soil quality is measured by physical, chemical and biological indicators. Soil biological properties like microbial biomass carbon, microbial biomass nitrogen, soil respiration, mineralizable nitrogen and sulphur, soil microorganisms, etc. are import soil health indicators. Biological diversity is also considered in soil quality index computation.

I request you to refer to the three relevant PDFs attached. Good day!

Soil health/Soil quality dictated by all the three ie physical, chemical and biological conditions. The more we address the issues, more the components adheres for health/quality assessments.

Thank you Dilip Kumar Pal and Bikas S Mahapatra Sir for your valuable inputs.

Soil properties defining a particular crop rhizosphere need a critical revisit , where rhizopshere mciorbiology is important , the most missing link , perhaps...despite the fact that some good work has been done this issue...

Rightly said. Thank You Prava Kiran Dash

Biological properties - Its a living quality subject to change every now and then and varies from field to field. It is not fixed

Other are Non-living.