Hi Rhoda, there are many parameters to measure soil quality indicators. Basically, there are different physical, chemical, and biological parameters (in terms of soil quality) to measure. The basic parameters are an organic matter which describes a lot about soil quality if you are considering conservation practice. There are also commonly used parameters, example: bulk density, hydraulic conductivity, water holding capacity/soil moisture available etc (as a physical parameter), the growth of biological community (as biological parameter, recently Phospholipid fatty acid (PFLA) analysis Indicates the amount of microbial biomass and proportions of microbial types such as mycorrhizal fungi, gram-positive fungi). These are indicators of soil quality in terms of conservation agriculture.

If you wish you can read this journal article:

Introducing the North American project to evaluate soil health measurements

Article Introducing the North American project to evaluate soil heal...

Thank you.

Ajoy

Its most important to identify minimum set of soil properties to define the rhizosphere properties of a given crop , regardless of soil properties. But , i agree , unless the biological properties of soil are taken into account , the functionality of soil will never be addressed.

Organic matter and maybe its management.

The diversity of the beneficial microorganisms such as the arbuscular mycorrhiza, soil promoting rhizobacteria and phosphate solubilizers bacteria, plant hormone producers(PGR),agents of biological control of plant diseases and microorganisms related to the formation of stable soil aggregates for example arbuscular mycorrhiza can produce chitin which act as a glue to stick the soil particles together .

What are the most relevant parameters to measure as soil quality indicators?

The most relevant parameters to measure as soil quality indicators depend on soil biological, physical and chemical characters. The parameters include soil organic matter, pH, CEC, particle density, bulk density, water holding capacity, electrical conductivity, soil moisture, microorganisms, surface tension etc.

What are the most relevant parameters to measure as soil quality indicators?

The recommended soil parameters are soil density, soil porosity, organic matter in the soil and soil management.

Well, soil quality is related with specific soil functions and management objectives. So, please specify your management objective, and accordingly select a minimum dataset, which can be any of the soil attributes and/or index.

Soil quality indicators include Physical, chemical and biological parameters. Physical parameters include Aggregate stability, available waterholding capacity, bulk density,infiltration, soil structure and macropores. Chemical parameters include, soil pH, EC, reactive carbon, mineralization nitrogen, SOM , available P,

Biological parameters include microbial biomass carbon, enzymes such as dehyrogenase, cellulase phosphatase,sulfates, urease and FDAse,

Soil quality indicators are physical, chemical, and biological properties, processes, and characteristics that can be measured to monitor changes in the soil. The types of indicators that are the most useful depend on the function of soil for which soil quality is being evaluated. These functions include: - providing a physical, chemical, and biological setting for living organisms; - regulating and partitioning water flow, storing and cycling nutrients and other elements; - supporting biological activity and diversity for plant and animal productivity; - filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials; and - providing mechanical support for living organisms and their structures.

Soil quality indicators are important to: - focus conservation efforts on maintaining and improving the condition of the soil; - evaluate soil management practices and techniques; - relate soil quality to that of other resources; - collect the necessary information to determine trends; - determine trends in the health of the Nation’s soils; - guide land manager decisions

Physical, chemical and biological properties.

It is very important to measure soil enzyme activities, depending on the use of soil you could measure the ones important to characteriza fertility or as biological indicators of pollution with heavy metals, pesticides, and hydrocarbons.

Basically soil physio-chemical proprties. Physical parameters include Aggregate stability, available waterholding capacity, bulk density,infiltration rate, soil structure. Chemical parameters include, soil pH, EC, reactive carbon, mineralization nitrogen. SOM is most important bcz OM increase when residue add in the soil for long term basis

All physical (structure texture bulk density porosity infiltration hydraulic conductivity soil water conserves and many more) , chemical(soil pH soil nutrient retention and availability status buffering action of soil and many more) and biological (organic carbon

Soil organic matter

Beneficial microorganisms viz bacteria fungi actinomycetes

Earthworms)

All productive soils are healthy soil while all fertile soils may not be healthy as it only denotes supplying capacity of nutrients in an adequate amount with suitable proportion irrespective of optimization in physical chemical and biological properties in question...

Some of the most relevant paraments like pH, EC, CEC, bulk density, soil moisture holding capacity, mean weight diameter, SOC, TOC, Labile C pool, soil microbial biomass carbon, particulate organic matter, Available N, P, K, dehydrogenase activity can easily be estimated and included.

Soil quality can be effectively measured when all the three aspects; physical, chemical and biological parameters are considered and measured. Yes, I recommend most of the answers above.

In the Pacific Islands Soil physical properties are aggregate stability, percolation rates, penetration/compaction; chemical properties are pH and nutrient availability, and biological properties are soil organic C and earthworm count. Most of these can be done with simple methods.