Soil health cannot be determined by measuring only crop yield, water quality, or any other single outcome. Soil health cannot be measured directly . Knowledge of soil health requires knowledge of its physical, chemical and biological properties

Physical Properties

• Physical Indicators
• Aggregate Stability
• Available Water Capacity
• Bulk Density
• Infiltration
• Slaking
• Soil Crusts
• Soil Structure and Macropores

Chemical Properties

• Chemical Indicators .
• Reactive Carbon.
• Soil Electrical Conductivity .
• Soil Nitrate .
• Soil pH .

Biological Properties

• Biological Indicators.
• Earthworms.
• Particulate Organic Matter .
• Potentially Mineralizable Nitrogen .
• Soil Enzymes .
• Soil Respiration .
• Total Organic Carbon.

Dear Bruno Sir,

Please follow the below given ResearchGate link and PDF attachments.

https://www.researchgate.net/post/What_are_the_three_most_important_soil_properties_physical_chemical_biological_that_can_be_used_to_construct_a_Soil_quality_health_indicator

Good luck!

Soil organic matter/carbon.

Beside the suggestions given by Dr. Singh, I personally believe that soil organic matter and microbial biomass/population is the best indicator of soil health.

I also agreed with dr. tarafdari sir, definitely organic carbon percent and beneficial microbial population are the best indicator for healthy soil.

Soil health cannot be determined by measuring only crop yield, water quality, or any other single outcome. Soil health cannot be measured directly . Knowledge of soil health requires knowledge of its physical, chemical and biological properties

Physical Properties

• Physical Indicators
• Aggregate Stability
• Available Water Capacity
• Bulk Density
• Infiltration
• Slaking
• Soil Crusts
• Soil Structure and Macropores

Chemical Properties

• Chemical Indicators .
• Reactive Carbon.
• Soil Electrical Conductivity .
• Soil Nitrate .
• Soil pH .

Biological Properties

• Biological Indicators.
• Earthworms.
• Particulate Organic Matter .
• Potentially Mineralizable Nitrogen .
• Soil Enzymes .
• Soil Respiration .
• Total Organic Carbon.

Physical Properties

• Physical Indicators
• Aggregate Stability
• Available Water Capacity
• Bulk Density
• Infiltration
• Slaking
• Soil Crusts
• Soil Structure and Macropores

Chemical Properties

• Chemical Indicators .
• Reactive Carbon.
• Soil Electrical Conductivity .
• Soil Nitrate .
• Soil pH .

Biological Properties

• Biological Indicators.
• Earthworms.
• Particulate Organic Matter .
• Potentially Mineralizable Nitrogen .
• Soil Enzymes .
• Soil Respiration .
• Total Organic Carbon

physio-chemical properties......(pH, EC, OC etc)

In addition, redox potential of the soil system (Eh7) is a good indicator.

Put some water in a test soil and observe the extent of frothing , that will give an indication of soil microbial load in a most practical mannner. Despite all these , i think , soil pH will reveal everything....including soil health...

Microbial biomass carbon / soil respiration is is the best indicator of soil health.

It was defined as the ecological equilibrium and the functionality of a soil and its capacity to maintain a well balanced ecosystem with high biodiversity above and below surface, and productivity. Its indicators can be chemical or physical. Chemical indicators are related with the ability of the soil to provide nutrients for plants and at the same time retains chemical elements or compounds harmful to the environment and plant growth. Physical indicators texture, bulk density, porosity and aggregate stability

Thank you all for your well thought answers to my question. Could you please explain what type of indicator is the one you calledEh7 Dr. Yanni?

Thanks for your question. The Eh7 is the redox potential of the soil. It is the resultant of the oxidative and negative charges in the soil system. It can be measured using a calomel and a platinum electroded. This is the redox potential or the oxidation-reduction potential. Using tabulated figured it then be corrected to the oxidation-reduction potential calculated at ph7. This figure is used as an indicator of the oxidative or reductive status of the soil system. It is measured a mile volts. The oxidative status of the system means that the aerobic conditions is prevailed and the root system can work well. The reductive status means anaerobic conditions in which the elements in the soil system are in its reduced state which mostly toxic to plant growth. Further detales can be obtained from soil chemistry and biology references and a lot of research papers and chapters describing the importance of this value to

Describe the soil physical, chemical and biological status of the soil and its health.

Many thanks for your clear and very fast answer to my question about Eh7.

Infact , most of the soil properties , they work in tandem with each other , and one soil property has cascading effects on many of the other soil properties . For example, organic carbon , which influences whole range of soil properties , starting from soil structure, water transmission properties, soil aggregate stability , soil fertility to soil microbial population in all dimensions, all defining the status of soil health at one or other point of time. So eventually , which are those minimum set of soil properties that define the soil health in most of the soil conditions..??

It depends on for what you need the soil.

Indeed. What we expect out of soil health, is it the nutrient supply level of the soil or soil as a ecosystem service provider , which is again a huge topic of debate, or defining the soil health as a comprehensive tool to support productive life of commercial crops, or serving to the needs of different ecosystems...like that its a vast area..But , i was willing to know from our learned colleagues, some minimum dataset is required to define soil health or we can rely on soil microbial population/soil microbial communities/microbial biomass nutrients/ enzyme activities etc....Bruno has raised a very pertinent question....

Those Soils which provides nutrients and water for plants and other organisms, cleans and filters water, and recycles essential plant nutrients is considered to be a the best indicator of soil health. In addition organic carbon indexing is the main check to see the soil health

Good answers from my colleagues here.

I assume the question is intended for agricultural purposes. But in any case, according to soil quality (health) experts, no single soil property is a complete and perfect indicator. Although soil organic matter (organic carbon) in most cases is one of the important ones. The best is a combination of properties from categories mentioned by Dr. Alhayani. Since there is numerouse soil properties, usually a few important ones, related to the purpose of the land use, and the needs, are chosen, which is the minimum number of indicators for the intended purpose.

Good luck

Soil organic matter is the super structure for growth dynamics of crop science.

Besides all these superb responses, friends we have to keep in mind, every crop can be grown in any soil or vice-versa. And when we say that rhizosphere health is perhaps more important , more so in perennial crops than any other field crops...

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.

What are some indicators?

Indicators of soil quality can be categorized into four general groups: visual, physical, chemical, and biological.

Visual indicators may be obtained from observation or photographic interpretation. Exposure of subsoil, change in soil color, ephemeral gullies, ponding, runoff, plant response, weed species, blowing soil, and deposition are only a few examples of potential locally determined indicators. Visual evidence can be a clear indication that soil quality is threatened or changing.

Physical indicators are related to the arrangement of solid particles and pores. Examples include topsoil depth, bulk density, porosity, aggregate stability, texture, crusting, and compaction. Physical indicators primarily reflect limitations to root growth, seedling emergence, infiltration, or movement of water within the soil profile.

Chemical indicators include measurements of pH, salinity, organic matter, phosphorus concentrations, cation-exchange capacity, nutrient cycling, and concentrations of elements that may be potential contaminants (heavy metals, radioactive compounds, etc.) or those that are needed for plant growth and development. The soil’s chemical condition affects soil-plant relations, water quality, buffering capacities, availability of nutrients and water to plants and other organisms, mobility of contaminants, and some physical conditions, such as the tendency for crust to form.

Biological indicators include measurements of micro and macro-organisms, their activity, or byproducts. Earthworm, nematode, or termite populations have been suggested for use in some parts of the country. Respiration rate can be used to detect microbial activity, specifically microbial decomposition of organic matter in the soil. Ergosterol, a fungal byproduct, has been used to measure the activity of organisms that play an important role in the formation and stability of soil aggregates. Measurement of decomposition rates of plant residue in bags or measurements of weed seed numbers, or pathogen populations can also serve as biological indicators of soil quality

How are indicators selected?

Soil quality is estimated by observing or measuring several different properties or processes. No single property can be used as an index of soil quality. The selection of indicators should be based on:

- the land use;

- the relationship between an indicator and the soil function being assessed;

- the ease and reliability of the measurement;

- variation between sampling times and variation across the sampling area;

- the sensitivity of the measurement to changes in soil management;

- compatibility with routine sampling and monitoring;

- the skills required for use and interpretation.

When and where to measure?

The optimum time and location for observing or sampling soil quality indicators depends on the function for which the assessment is being made. The frequency of measurement also varies according to climate and land use. Soil variation across a field, pasture, forest, or rangeland can greatly affect the choice of indicators. Depending on the function, such factors as the landscape unit, soil map unit, or crop growth stage may be critical. Wheel tracks can dramatically affect many properties measured for plant productivity. Management history and current inputs should also be recorded to ensure a valid interpretation of the information. Monitoring soil quality should be directed primarily toward the detection of trend changes that are measurable over a 1- to 10-year period. The detected changes must be real, but at the same time they must change rapidly enough so that land managers can correct problems before undesired and perhaps irreversible loss of soil quality occurs.

THE SOURCE: USDA Natural Resources Conservation Service

(Prepared by the National Soil Survey Center in cooperation with the Soil Quality Institute, NRCS, USDA, and the National Soil Tilth Laboratory, Agricultural Research Service, USDA)

Best regards

Nehal

Hello Nehal,

Great insight. That is why the future of agronomy is integrated nutrients management for crop science and why i promote climate smart agriculture today. visit www.aratibiotech.com/climate smart agricuture

The idea of the assessment of soil health and soil quality is to investigate inherent and dynamic soil properties that are mostly affected by management practices. These soil health and quality factors are targeted through (Physical, chemical and biological) indicators plus some crop features. Mr Al Alhayany already listed these indicators which could be measured in the field and laboratory. I think reliable health test results could be employed to determine fertilizer needs and other similar limitations as reflected by different indicators.

Yes Subhan, soil pH dictates the entire health of the soil...