Soil Quality


Lawrence F. London, Jr. - Venaura Farm - Chapel Hill, NC, USA
mailto:london@sunSITE.unc.edu  http://sunSITE.unc.edu/InterGarden
mailto:llondon@nuteknet.com  http:nuteknet.com/london  Venaura Farm
Title: Soil Quality
What is Soil Quality or Soil Health?
Is there a difference between Soil Quality and Soil Health?

Contact: Dr. Bruce T. Bowman

FAQ Menu URL: http://res.agr.ca/lond/pmrc/faq/menu.html

"Soil Quality vs Soil Health"

In a recent publication from the Research Branch of Agriculture and Agri-Food Canada entitled "The health of our soils: toward sustainable agriculture in Canada" (D.F. Acton and L. J. Gregorich, editors; 1995), the editors state that the terms Soil Quality and Soil Health can be used interchangeably.

In a Statement on Soil Quality by the Soil Science Society of America [SSSA] (Agronomy News, June 1995, Page 7), the editors added the following Footnote on Soil Quality:

The terms soil quality (favored by scientists) and soil health (favored by farmers) tend to be used interchangeably, especially in the general press. Characterization of soil quality by scientists focuses on analytical/quantitative properties of soil with a separately defined quantitative link to the functions of soil quality.
Characterization of soil health by farmers focuses on descriptive/qualitative properties of soil with a direct value judgement (unhealthy to healthy)integrated into the options for a given property; in addition, interwoven into the properties of soil per se are value-based descriptive properties of plant, water, air, and animal/human systems considered by farmers to be an integral part of soil health characterization.

Soil Quality: A Conceptual Definition

(excerpted from Soil Science Society of America Agronomy News, June 1995, P.7)

Public interest in soil quality is increasing throughout the world as humankind recognizes the fragility of earth's soil, water, and air resources and the need to protect them to sustain civilization. To understand soil quality however, one must first be aware of the complexity of soil and its intrinsic value.

Soil is a living system that represents a finite resource vital to life on earth. It forms the thin skin of unconsolidated mineral and organic matter on the earth's surface. It develops slowly from various parent materials and is modified by time, climate, macro- and micro-organisms, vegetation, and topography. Soils are complex mixtures of minerals, organic compounds, and living organisms that interact continuously in response to natural and imposed biological, chemical, and physical forces. Vital functions that soils perform within ecosystems include:

(I) sustaining biological activity, diversity, and productivity;
(ii) regulating and partitioning water and solute flow;
(iii) filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric depositions;
(iv) storing and cycling nutrients and other elements within the earth's biosphere; and
(v) providing support for socioeconomic structures and protection for archeological treasures associated with human habitation.

Conceptually, the intrinsic quality or health of a soil can be viewed simply as "its capacity to function." More explicitly, SSSA defines soil quality as:

The capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.

By encompassing productivity, environmental quality, and health as major functions of soil, this definition requires that values be placed on specific soil functions as they relate to the overall sustainability of alternate land-use decisions. Although unstated, the definition also presumes that soil quality can be expressed by a unique set of characteristics for every kind of soil. It recognizes the diversity among soils, and that a soil that has excellent quality for one function or product can have very poor quality for another. The functions encompassed by soil quality integrate chemical, physical, and biological properties and processes occurring within every soil and are responsive to human use and management decisions.

Soil quality in its broadest sense is enhanced by land-use decisions that weigh the multiple functions of soil, and is impaired by land-use decisions that focus on single functions. Soil quality can be degraded by using inappropriate tillage and cropping practices; through excessive livestock grazing or poor timber harvesting practices; or by misapplication of animal manures, irrigation water, fertilizers, pesticides, and municipal or industrial by-products.

To enhance soil quality, everyone must recognize that the soil resource affects the health, functioning, and total productivity of all ecosystems. We must become more aware of potential side effects of soil management and land-use decisions. By addressing the integrative concept of soil quality, SSSA members can provide the leadership for better long-range, landscape-scale planning and land-use, thus helping to protect finite and living soil resources and fragile landscapes.

To evaluate soil quality for various land-uses, assessments will be required over time and across space. For the evaluations to be meaningful, research must develop soil quality indicators that are sensitive, reliable, reproducible, and capable of detecting changes in soil physical, chemical, and biological properties, processes, and their interactions. The indicators must be qualitative or semiquantitative for immediate use by farmers or land managers, and quantitative for the people responsible for developing long-range, process-based strategies that will improve land-use; enhance plant, animal, and human health; and sustain biological diversity within natural and fabricated ecosystems.

Numerous specific soil measurements are being evaluated, but to help identify the attributes that will be most useful for soil quality evaluations, research and education are needed to:

(i) identify the vital functions of soil for which assessments need to be made;
(ii) determine the appropriate methods, measurements, and criteria for interpreting those assessments,
(iii) develop and evaluate accessible databases as repositories for high quality, reliable soils information; and
(iv) design improved land use practices that will ensure the economic viability, environmental safety, social acceptability and value that is appropriate for each soil resource.

This is a great challenge, but our premise is that determining how to evaluate soil quality provides a unique and important opportunity for the SSSA to demonstrate the utility of our profession and to serve as a focal point for addressing complex environmental and land-use issues.

Developed by:

D.L. Allan, D.C. Adriano, D.F. Bezdicek R.G. Cline, D.C. Coleman, J.W. Doran, J. Haberern, R.F. Harris, A.S.R. Juo, M.J. Mausbach, G.A. Peterson, G.E. Schuman, M.J. Singer, and D.L. Karlen (Chair).

Other Related Web Sites

Soil Quality Working Group (S3), Soil Science Society of America

Soil Survey and Land Research Centre (SSLRC), Cranfield University, UK (The aim of SSLRC is to be a leading national and international centre for research and development, consultancy and training in soils and their use, management and protection in the UK and overseas.)

Mulch-Based Agriculture Group - under the auspices of Cornell International Institute for Food, Agriculture, and Development

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Last Revised: 11 November, 1996 08:55:05