TSSH Part 603
Concepts and Use of Technical Soil Services
Diversity of uses for soils information (603.00)
Technical soil services information provided by resource soil scientists ranges from specific items, such as measuring infiltration rates for irrigation and pond design, maintenance of the Field Office Technical Guide (FOTG), soil carbon determinations, determination of hydric soils, identifying the suitability of soils for various urban uses, gathering soils spatial and attribute data for Rapid Watershed Assessments, onsite soil erodibility, and in-field soil quality, to more broadly defined items, such as soil productivity for groups of crops, global climate change information, suitability of soils for wildlife, wetlands, and training in the use of soils information. The more precisely we define alternative conditions of soil use or manipulation, the more specific the predictions of results. For most soils that can be cropped, there are two or more alternative agricultural uses and several alternative combinations of management practices under each use. For conservation planning, soil scientists can assist in the in-field resource inventory, determining the soil-based resource concerns and making recommendations to the conservation planner as to the best conservation practices to apply to ameliorate degraded properties and behavior.
General users of soil surveys want to know how the soils on a tract of land can be expected to behave. First, they locate the tract of interest to them on the soil map. The map indicates the names of the soils on the tract. From the report, an individual can learn how these soils are expected to behave under the alternative uses, treatments, or systems of management they can support. Other users of soil maps need information for broad areas or for one or more kinds of soil wherever they may be found.
The main demand, however, is for information on specific tracts of land—fields, farms, ranches, watersheds, forests, subdivisions, roadways, construction sites, public parks, and the like. More and more, the users of soil surveys want quantitative information rather than the qualitative ratings of “good,” “fair,” and “poor.” The predictions and interpretations given in soil surveys for all land uses and management practices must be practical and verifiable. They will not be practical unless they can also be implemented and are scientifically sound.
Soil interpretations in soil survey reports and soil databases are predictions of soil behavior under stated conditions, not recommendations for specific tracts or fields. Interpretations of the soils indicate the reasonable alternatives for their use and management and the expected results. Soil interpretations are based on scientific data gathered over many years and on observations made during the extensive field mapping process. The National Soil Information System (NASIS) is an electronic information system implemented in the late 1990s to store, manage, interpret, and use soil survey information. NASIS and related information technology are tools used by resource soil scientists to develop new interpretations and deliver soils data to field conservationists in such systems as the NRCS Customer Service Toolkit. New soil interpretations based on the fuzzy logic concept can be developed by resource soil scientists and included in the Field Office Technical Guide.
New approaches to data collection and interpretations (603.01)
Also of increasing interest are dynamic soil properties, or those properties that change with land use and management. Collecting data, populating a national database like NASIS, and making interpretations such as are now being done for vegetative communities called “state and transition models” are new and exciting endeavors for NCSS soil scientists conducting initial and update soil surveys and for resource soil scientists assisting with the data collection and interpretation. When resource soil scientists are assisting field office planners and soil property notes are taken in the field as part of the resource inventory within the nine-step planning process, these data also need to be forwarded to the State Soil Scientist to aid in populating NASIS with regard to the specific management condition under which the data were collected. This information promotes the understanding of dynamic soil properties and may aid in documenting needs for updating the soil survey.
Interactions with other specialists and with land users (603.02)
Resource soil scientists are highly skilled in capturing the meaning of the experiences of land users. The increased exchange of information between soil scientists and those who live on the land allows better incorporation of local knowledge and expertise, thereby improving soil management and conservation at all levels of agricultural and nonagricultural uses. In the past, some people said, “It is the job of the soil scientist to get the facts, and someone else should interpret them.” Actually, this concept never worked out. Few people besides soil scientists know enough about soils, landscapes, and the interactions among the many soil characteristics that define each kind of soil to do the job by themselves. In addition, few other people were interested in all of the uses and interpretations. Once a kind of soil is defined and mapped, few people besides soil scientists are concerned with all of the interpretations needed. Experience shows that the soil scientist must be involved in developing and using soils information. Commonly, the soil scientist prepares a draft for others to review or provides reports that contain information and recommendations for others to incorporate in their plan or other work. The responsibility for ensuring that their work is properly interpreted is inherent in the duties of soil scientists.
Soil scientists must work with competent people in related fields. Agronomists, horticulturists, wildlife biologists, range conservationists, engineers, foresters, economists, and other specialists can help the soil scientist understand what combinations of characteristics and qualities are most important and can help assemble parts of the relevant data. To work with the specialists effectively, the soil scientist must learn something about their technical language and points of view. After the soil scientist has made drafts of the interpretations, specialists from the other disciplines can review the drafts and help the soil scientist test the interpretations in application.
Practical application of soils information (603.03)
Finally, the soil scientist’s results should be tested in practical application. In fact, soil scientists always live in an atmosphere of critique. If their soils information fails in its purpose, they hear about it. This criticism has been good for soil scientists and has resulted in considerably better soil information than would have otherwise been available.
Soil scientists working in technical soil services strike a balance between basic and applied soil science. There are those who think that soil classification and the research upon which it stands are strictly scientific activities—some say “pure” science. Basic soil research is essential to good soils information. A purely routine soil survey with no research, and especially with no research appreciation by the soil scientists, would almost certainly fail in its objectives. Further basic research and data collection involving the nature and behavior of soils as exemplified by the dynamic soil property or “soil change” effort promise much further advancement in the effective and sustainable use of soils than we have had in the past.
At the other extreme are those who say that scientific study and technical references are not needed. What they want is “practical” soils information in an electronic format and/or on a map. Neglecting the scientific base would result in strictly routine work that would leave important problems unresolved and would be unenlightened by scientific inquiry into soil genesis and behavior. Many problems would not be identified at all. Without full use of the basic principles of soil science and the skills of orderly inquiry, the soils information would soon prove to be disappointing. We cannot have reliable soils information without scientific curiosity and study, nor can we apply the results of scientific study without orderly interpretations. Both are essential. Competent soil scientists working in technical soil services are trained in both applied and basic science. They are expected to resolve the inconsistencies in applied and basic science and to provide accurate soils information to users.
Staying current with new developments (603.04)
Soil scientists providing technical soil services must stay current with changes in the criteria used in interpretations. In many cases these changes happen in less than a decade. With the emergence of new chemicals, new machines, new varieties of crops, new environmental issues, new government programs, geospatial-based land management decisions, and other new methods of soil use, changes are needed, including a few drastic changes in our evaluations of the performance of the various kinds of soil under different combinations of practices. Since soils respond unequally to new combinations of practices, we have both absolute and relative changes in their interpretations. Some interpretations are relatively stable, at least for long periods between technological breakthroughs.
Writing skills (603.05)
Resource soil scientists developing soils information for customers should be mindful of their readers. Soil scientists preparing reports of soils information have captive readers. If the customers use thematic maps and/or standard soil maps, they must read the soil scientist’s text whether it is well written, dull, or difficult to understand. The soil scientist who writes well will have appreciative customers, and the information is more likely to be used.
The resource soil scientist plays a critical role not only in raising awareness of the existence of soils information but also in distributing and applying the soil data. There are examples of poor project design or failure to obtain the needed soil data in every community. Many existing structures exhibit cracked walls, homes and other buildings have water in basements, homes slide downhill on mudflows, stormwater runoff floods streets and businesses, septic systems fail and effluent drains onto neighboring properties or into roadside ditches, and highways are closed because of soil blowing. Mitigation costs run into the hundreds of thousands of dollars. In most cases, good soil survey information and careful project planning could reduce and/or eliminate most of these costs. The use of soil survey information in USDA programs, such as the Conservation Reserve Program (CRP), has produced large savings of monies to taxpayers. A recent study by the Organization for Economic Cooperation and Development of the United States Department of Agriculture (OECD-USDA) showed that replacement of the Maximum Allowable Rental Rates (MARRs) with Soil Rental Rates (SRRs) resulted in a national savings of $1.2 billion over the 10-year life of CRP contracts.