Reality for a Functional Universal Soil Classification System

Reality for a Functional Universal Soil Classification System

By Micheal L Golden, Director USDA-NRCS Soil Survey Division and National Lead for the National Cooperative Soil Survey Program

The idea of a truly functional Universal Soil Classification (USC) System should be based on the best functioning system we have today and develop it into a universal system that can be accepted by all countries. The United States led Soil Taxonomy or Soil Classification System has been developed and improved for almost 50 years by incorporating improvements worldwide and should be considered as a starting point. It is a system that has developed and continuously improved to address soils properties around the world to encompass the possible soils into a common system.

The Soil Taxonomy and abbreviated Keys to Soil Taxonomy identify 12 soil orders and has 6 categories down to the series level. Soil orders, soil suborders, great groups, sub groups, family and series levels have been identified as a hierarchical approach to group appropriate soils worldwide by most scientists. Official soil series descriptions could and should be created and stored in a central or distributed repository. Soil Series have been widely used for over a hundred years as a way to geographically associate soil catena’s of like soils so man can regionalize the location of the soil properties in question. Soil moisture and soil temperature are characterisitcs of soils and climate and some have criticized using it in the Soil Taxonomy system. The Newhall and Epic models are supported by the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) and National Cooperative Soil Survey (NCSS) and are used as tools to identify soil moisture and soil temperature regimes worldwide. They provide a great first cut to the suborders worldwide.

Today over 90 countries use Soil Taxonomy as its primary soil classification system and another 47 countries use Soil Taxonomy in conjunction with other classification systems. They have adopted a system that is maintained and updated to scientific standards worldwide. 1_/ 2_/

I propose that the International Union of Soil Scientist (IUSS) working group for a USC System adopt the existing Soil Taxonomy that the NCSS of the United States has developed with input of soil scientists worldwide over the last 50 years. There have been at least 10 international committees that have come together and contributed to make Soil Taxonomy better and better over the years. The purpose of the Soil Taxonomy has always been a universal system of soil classification. We have always encouraged worldwide input and have accepted improvement to the system now and in the future.

As Director of the USDA NRCS and National lead for the NCSS Program in the United States I most urgently ask the working group to adopt the existing Soil Taxonomy and build improvements into the existing system where all soils worldwide can be adequately classified into a system we can support as a soil science. We are aware of some issues that have been identified by a few countries that would improve Soil Taxonomy. We would like to review those concepts to improve the USC system. If needed acceptable changes should be incorporated. As an example Australia has questions about the 3% increase in clay that signifies an argillic horizon (3% is within lab error), and some others question the Mollisol definition. These should be vetted and addressed with appropriate action in the USC.

The NCSS has a great infrastructure with National, State, Local, and Private Soil Scientists who have built and maintained the system we use today. I propose that the existing Soil Taxonomy System be adopted as the draft or first approximation of a USC System.

If the Soil Taxonomy is adopted a name change should happen immediately to the USC. The USDA-NRCS would volunteer to become the institutional guardian of the USC system with updates, changes and additional improvements from around the world to develop a truly worldwide system if the IUSS supports this offer.

The USDA-NRCS SSD would provide human capacity primarily thru the National Soil Survey Center (NCSS) in Lincoln Nebraska which currently has a staff of over 70 scientists and a dedicated standards staff to maintain the newly adopted USC System worldwide. It would continue to work thru the IUSS to address improvements to the existing system. Currently the National Leader for Standards has a staff of seven soil scientists to maintain the national cooperative soil survey standards which includes Soil Taxonomy. The World Soil Resources staff has trained soil scientists within the United States and soil scientists from around the world that has led to the adoption of Soil Taxonomy and other soil survey standards.

The USDA-NRCS Soil Survey Division and World Soil Resources Branch that was previously led by Dr. Hari Eswaran converted the FAO to Soil Taxonomy Worldwide at the 1 to 5 million scale. Some refinements are needed.

The USDA-NRCS would provide financial support with other international institutions to update and publish future updates to the USC System and make it available online and work with countries to translate it into major languages. Currently Soil Taxonomy has been translated from English into several languages worldwide and includes French, Spanish, Dutch, Indonesian and Arabic.

In closing I personally appeal to the IUSS Soil Working Group to adopt the existing Soil Taxonomy that is used in over 130 countries worldwide as the Draft or first version of the “Universal Soil Classification” System. I also appeal that if adopted it will be enhanced and built where all countries worldwide may make improvements or enhancements for soils locally. I volunteer the USDA-NRCS SSD and NSSC as the Institutional Guardian to maintain the standards including the USC of the future.

Reference:

1_/The Handbook of Soil Terminology, Correlation and Classification

2_/ Unofficial tally of Countries from Office of World Soil Resources, NRCS