Soil health

Soil health is a state of a soil meeting its range of ecosystem functions as appropriate to its environment. Soil health testing is an assessment of this status.[1] Soil health depends on soil biodiversity (with a robust soil biota), and it can be improved via soil conditioning (soil amendment).


The term soil health is used to describe the state of a soil in:

Soil Health has partly if not largely replaced the expression "Soil Quality" that was extant in the 1990s. The primary difference between the two expressions is that soil quality was focused on individual traits within a functional group, as in "quality of soil for maize production" or "quality of soil for roadbed preparation" and so on. The addition of the word "health" shifted the perception to be integrative, holistic and systematic. The two expressions still overlap considerably.

The underlying principle in the use of the term “soil health” is that soil is not just an inert, lifeless growing medium, which modern farming tends to represent, rather it is a living, dynamic and ever-so-subtly changing whole environment. It turns out that soils highly fertile from the point of view of crop productivity are also lively from a biological point of view. It is now commonly recognized that soil microbial biomass is large: in temperate grassland soil the bacterial and fungal biomass have been documented to be 1–2 t (2.0 long tons; 2.2 short tons)/hectare and 2–5 t (4.9 long tons; 5.5 short tons)/ha, respectively.[3] Some microbiologists now believe that 80% of soil nutrient functions are essentially controlled by microbes.[4][5] If this is consistently true, than the prevailing Liebig nutrient theory model, and Mitscherlich modifications of it, all which exclude biology, are perhaps dangerously incorrect for managing soil fertility sustainably for the future.

Using the human health analogy, a healthy soil can be categorized as one:

  • In a state of composite well-being in terms of biological, chemical and physical properties;
  • Not diseased or infirmed (i.e. not degraded, nor degrading), nor causing negative off-site impacts;
  • With each of its qualities cooperatively functioning such that the soil reaches its full potential and resists degradation;
  • Providing a full range of functions (especially nutrient, carbon and water cycling) and in such a way that it maintains this capacity into the future.




Soil health is the condition of the soil in a defined space and at a defined scale relative to a set of benchmarks that encompass healthy functioning. It would not be appropriate to refer to soil health for soil-roadbed preparation, as in the analogy of soil quality in a functional class. The definition of soil health may vary between users of the term as alternative users may place differing priorities upon the multiple functions of a soil. Therefore, the term soil health can only be understood within the context of the user of the term, and their aspirations of a soil, as well as by the boundary definition of the soil at issue.


Different soils will have different benchmarks of health depending on the “inherited” qualities, and on the geographic circumstance of the soil. The generic aspects defining a healthy soil can be considered as follows:

  • “Productive” options are broad;
  • Life diversity is broad;
  • Absorbency, storing, recycling and processing is high in relation to limits set by climate;
  • Water runoff quality is of high standard;
  • Low entropy; and,
  • No damage to, or loss of the fundamental components.

This translates to:

  • A comprehensive cover of vegetation;
  • Carbon levels relatively close to the limits set by soil type and climate;
  • Little leakage of nutrients from the ecosystem;
  • Biological and agricultural productivity relatively close to the limits set by the soil environment and climate;
  • Only geological rates of erosion;
  • No accumulation of contaminants; and,
  • The ecosystem does not rely excessively on inputs of fossil energy

An unhealthy soil thus is the simple converse of the above.


On the basis of the above, soil health will be measured in terms of individual ecosystem services provided relative to the benchmark. Specific benchmarks used to evaluate soil health include CO2 release, humus levels, microbial activity, and available calcium.[6]

Soil health testing is spreading in the United States, Australia and South Africa.[7] Cornell University, a land-grant college in NY State, has had a Soil Health Test since 2006. Woods End Laboratories, a private soil lab founded in Maine in 1975, has offered a soil quality package since 1985 that contains physical (aggregate stability) chemical (mineral balance) and biology (CO2 respiration) which today are prerequisites for soil health testing. in the United States, six commercial soil labs are registered for "Soil Health" testing under the NRCS website. The approach of all the labs is to add into common chemical nutrient testing a biological set of factors not normally included in routine soil testing. The best example is adding biological soil respiration ("CO2-Burst") as a test procedure; this has already been adapted to modern commercial labs.

There is resistance among soil testing labs and university scientists to adding new biological tests, primarily since interpretation of soil fertility is based on models from "crop response" studies which match yield to test levels of specific chemical nutrients. These soil test methods have evolved slowly over the past 40 years and are backed by considerable effort. However, in this same time USA soils have also lost up to 75% of their carbon (humus), causing biological fertility to drop drastically. Many critics of the current system say this is sufficient evidence that the old soil testing models have failed us, and need to be replaced with new approaches. These older models have stressed "maximum yield" and " yield calibration" to such an extent that related factors have been overlooked. Thus, surface and groundwater pollution with excess nutrients (nitrates and phosphates) has grown enormously, and is reported presently (in the United States) to be the worst it has been since the 1970s, before the advent of environmental consciousness.[8] [9] [10]

See also


  1. ^ NRCS 2013
  2. ^ "Archived copy". Archived from the original on 2017-01-23. Retrieved 2018-03-21.CS1 maint: Archived copy as title (link)
  3. ^ "Microbial diversity and soil functions" (PDF). European Journal of Soil Science. 54: 655–670. December 2003. doi:10.1046/j.1365-2389.2003.00556.x. Archived (PDF) from the original on 2016-04-12.
  4. ^ The Role of Soil Biology in Improving Soils Archived 2014-03-12 at the Wayback Machine Webinar
  5. ^ "Listing 17 microbes and their effects on the soil and plant health functions". Explogrow, Dr Malherbe, BSc, BSc Hons., MSc, Pr.Sci.Nat. 22 December 2016. Archived from the original on 25 June 2016.
  6. ^ "Healthy Soil". Archived from the original on 19 December 2016. Retrieved 26 April 2018.
  7. ^ Kick, Chris (18 February 2014). "New soil test measures soil health - Farm and Dairy". Archived from the original on 1 December 2017. Retrieved 26 April 2018.
  8. ^ Bernard T. Nolan; et al. (January 1998). "A National Look at Nitrate Contamination of Ground Water". Water Conditioning and Purification. 39 (12): 76–79. Archived from the original on 2014-03-13.
  9. ^ Estimating Soil Carbon, Nitrogen, and Phosphorus Mineralization from Short-Term Carbon Dioxide Respiration Communications. in Soil Science and Plant Analysis, 39: 2706–2720, 2008
  10. ^ Soil CO2 respiration: Comparison of chemical titration, CO2 IRGA analysis and the Solvita gel system. Renewable Agriculture and Food Systems: 23(2); 171–176

Further reading

  • Kristin Ohlson (2014). The Soil Will Save Us: How Scientists, Farmers, and Foodies Are Healing the Soil to Save the Planet. Rodale Books. ISBN 978-1609615543.

External links

Forest cover

Forest cover in general refers to the relative (in percent) or sure (in square kilometers/square miles) land area that is covered by forests or the forest canopy or open woodland.

Forest cover is one category of terrestrial land cover. Land cover is the observed physical features, both natural and manmade, that occupy the earth’s immediate surface ... forest cover is defined as 25% or greater canopy closure at the Landsat pixel scale (30-m × 30-m spatial resolution) for trees >5 m in height

Global forest cover, however crucial for soil health, the water cycle, climate and air quality it is, is severely threatened by deforestation everywhere, as a direct consequence of agriculture, logging, and mining all of which can be attributed to human overpopulation.

Forest cover can be increased by reforestation and afforestation efforts, but loss of old-growth forests is irreversible in terms of its ecological services.

Global forest cover has been estimated to be 30% or 40 million square kilometres (4.3×1014 sq ft) in 2006 with 12-yearly losses (2000-2012) amounting to 2.3 million square kilometres (2.5×1013 sq ft) and reforestation gains about 0.8 million square kilometres (8.6×1012 sq ft).

In particular, forest cover may refer to

Forest cover by state in the United States

Forest cover by state or territory in Australia

Forest cover by province or territory in Canada

Forest cover by state in India

Forest cover by federal subject in Russia

Green waste

Green waste, also known as "biological waste," is any organic waste that can be composted. It is most usually composed of refuse from gardens such as grass clippings or leaves, and domestic or industrial kitchen wastes. Green waste does not include things such dried leaves, pine straw, or hay. Such materials are rich in carbon and considered "brown wastes," while green wastes contain high in concentrations of nitrogen. Green waste can be used to increase the efficiency of many composting operations and can be added to soil to sustain local nutrient cycling.

Michael Jeffery

Major General Philip Michael Jeffery (born 12 December 1937) is a retired senior Australian Army officer who was the 24th Governor-General of Australia, serving from 2003 to 2008, and the 30th Governor of Western Australia, serving from 1993 to 2000.

From Perth, Jeffery graduated from the Royal Military College, Duntroon, and served in the Malayan Emergency and the Vietnam War, being awarded the Military Cross during the latter conflict.

He was at various stages commander of the Special Air Service Regiment and the 1st Division, and subsequently Deputy Chief of General Staff, before retiring from active service in 1993. After serving for seven years in the equivalent viceregal role in Western Australia, Jeffery was appointed governor-general in 2003, following the resignation of Peter Hollingworth. He was the first career Australian Army officer to hold the position, and was succeeded by Dame Quentin Bryce.

National Initiative on Climate Resilient Agriculture

National Innovations on Climate Resilient Agriculture (NICRA) was launched during February 2011 by Indian Council of Agricultural Research (ICAR) with the funding from Ministry of Agriculture, Government of India. The mega project has three major objectives of strategic research, technology demonstrations and capacity building. Assessment of the impact of climate change simultaneous with formulation of adaptive strategies is the prime approach under strategic research across all sectors of agriculture, dairying and fisheries. Evolving climate resilient agricultural technologies that would increase farm production and productivity vis-à-vis continuous management of natural and manmade resources constitute an integral part of sustaining agriculture in the era of climate change. The four modules of NICRA – natural resource management, improving soil health, crop production and livestock – is aimed making the farmers self-reliant.


Soil is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Earth's body of soil, called the pedosphere, has four important functions:

as a medium for plant growth

as a means of water storage, supply and purification

as a modifier of Earth's atmosphere

as a habitat for organismsAll of these functions, in their turn, modify the soil.

The pedosphere interfaces with the lithosphere, the hydrosphere, the atmosphere, and the biosphere. The term pedolith, used commonly to refer to the soil, translates to ground stone in the sense "fundamental stone". Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). Accordingly, soil scientists can envisage soils as a three-state system of solids, liquids, and gases.Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness, soil ecologists regard soil as an ecosystem.Most soils have a dry bulk density (density of soil taking into account voids when dry) between 1.1 and 1.6 g/cm3, while the soil particle density is much higher, in the range of 2.6 to 2.7 g/cm3. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, although fossilized soils are preserved from as far back as the Archean.Soil science has two basic branches of study: edaphology and pedology. Edaphology studies the influence of soils on living things. Pedology focuses on the formation, description (morphology), and classification of soils in their natural environment. In engineering terms, soil is included in the broader concept of regolith, which also includes other loose material that lies above the bedrock, as can be found on the Moon and on other celestial objects as well. Soil is also commonly referred to as earth or dirt; some scientific definitions distinguish dirt from soil by restricting the former term specifically to displaced soil.

Soil Health Card Scheme

Soil Health Card Scheme is a scheme launched by the Government of India in 19 February 2015. Under the scheme, the government plans to issue soil cards to farmers which will carry crop-wise recommendations of nutrients and fertilisers required for the individual farms to help farmers to improve productivity through judicious use of inputs. All soil samples are to be tested in various soil testing labs across the country. Thereafter the experts will analyse the strength and weaknesses (micro-nutrients deficiency) of the soil and suggest measures to deal with it. The result and suggestion will be displayed in the cards. The government plans to issue the cards to 14 crore farmers.

Soil carbon

Soil carbon includes both inorganic carbon as carbonate minerals, and as soil organic matter. Soil carbon plays a key role in the carbon cycle, and thus it is important in global climate models.

Soil management

Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance (such as soil fertility or soil mechanics). It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.

Soil water (retention)

Soils can process and hold considerable amount of water. They can take in water, and will keep doing so until they are full, or until the rate at which they can transmit water into and through the pores is exceeded. Some of this water will steadily drain through the soil (via gravity) and end up in the waterways and streams, but much of it will be retained, despite the influence of gravity. Much of this retained water can be used by plants and other organisms, thus contributing to land productivity and soil health.

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