Copyright © 1997 Province of British Columbia
Published by the Resources Inventory Committee
3.0 PRE-FIELD ACTIVITIES
[Back to TOC] [Previous] [Next]
3.1 Confirming Purpose and Objectives
[Back to TOC] [Previous] [Next]
The initial phase of the planning process has been discussed in Chapter 2. At this juncture, it is presumed that the basic objective of the soil inventory and the user groups have been identified and adequate funding provided. It is important now to re-confirm these items and begin detailed planning for the project. These tasks are usually the responsibility of the Project Leader (or Party Chief) in close consultation with the Project Manager. At this point, the completed Project Plan should be referred to and amended where necessary to incorporate the detailed plans. For example, it is necessary to ensure that personnel and equipment are assembled to achieve the aims of the project, that necessary funding is allocated, and that the schedule for completion is understood and accepted by all agencies and individuals involved.
Factors that must be examined by the Project Leader and the Project Manager and, if necessary, more explicitly described, are discussed under the following sub-headings.
3.1.1 Schedule and Budget
A detailed schedule indicating key milestones, personnel allocation (person-days), tasks and costs should be prepared and agreed upon. At a minimum, the key milestones should include:
· Starting date of the field work.
· Completion date for the field work (multi-year projects should show this detail).
· The date when base maps and aerial photography will be required for field work and the production of the final map.
· The date when the manuscript maps will be ready for drafting (and/or digitizing) and when they are required to be completed.
· The date the draft report will be available for editing.
· The date for final publication.
3.1.2 Determination of Survey Area
In order to avoid any confusion regarding the area to be surveyed, a map (most often a National Topographic Series Map) should be prepared that clearly outlines the boundaries of the map area. The size of the map area (ha, acres or km2) should be determined from this map.
3.1.3 Interpretations
The interpretations required from the soil survey should be specified and the methods to be employed in performing the interpretations should be documented. In addition, those individuals or agencies responsible for undertaking the interpretations should be specified. Special studies, as well as data other than that provided by the soil inventory, should be identified and the responsibility assigned to an individual or agency. These requirements should be factored into the project schedule.
3.1.4 Relationship to Other Surveys
The soil inventory may be one component of an overall survey of the project area. There may be several other inventories taking place (e.g. Forest Inventory, Terrain, Wildlife Habitats, etc.) and the relationship and use of the soil inventory with respect to its integration with these other inventories must be fully described and understood.
3.1.5 Differentiating Criteria for Map Units and Format of Map Legend
The soil related criteria and parameters which will be used to differentiate map units such as wetness, texture, stoniness, slope, etc., and their class limits, must be decided upon and recorded. In most cases, these values will be determined by the interpretations that are required from the soil map and data base. The type of soil map legend (e.g. open, closed) should be determined.
The publication Describing Ecosystems in the Field (Luttmerding, et al, 1990) is an excellent source document for the definition of various criteria which are often used to describe soils and landscape characteristics and to differentiate map units. As an example, for detailed soil survey (SIL 1 or 2), ten classes of slope may be used ranging from 0% (level) to greater than 100% (very steep) whereas these classes can be grouped for less detailed survey (e.g. 5 classes for SIL 3).
3.1.6 Kind and Intensity of Field Procedures
The Survey Intensity Level (SIL) should be decided upon as a function of the accuracy required. Standards of accuracy and precision are fundamental requirements for the survey program and will be subject to critical review during the correlation phase of the project and any statistical testing of the survey results.
3.1.7 Minimum Size Delineation and Map
The individuals responsible for the soil survey and the user group(s) must decide on the minimum size for a map unit delineation as well as the map scale. As outlined in Chapter 2, the minimum size delineation should be approximately 0.5 cm2. Map scale, and by corollary Survey Intensity Level, should be chosen so that the required legibility is not compromised and fits the needs of the map users.
3.1.8 Special Equipment
Depending upon the objectives of the soil survey and the nature of the landscape being examined, it may be necessary to assemble equipment that is not part of a normal soil survey. Such items might include backhoes for excavation, special equipment for measuring infiltration rates or helicopters for access to remote sites.
3.1.9 Soil Sampling, Laboratory Analysis and Research
Obtaining samples of soil within the map area, either prior to or during the conduct of the field mapping, is normally done to properly characterize the map units or support the interpretations to be made from the survey. Special sampling and analysis may also be done for research or purely scientific purposes but this is usually beyond the objectives of a standard soil survey. The publication Soil Sampling and Methods of Analysis (Canadian Society of Soil Science, 1993) provides a thorough description of recommended techniques.
The types of physical and chemical analysis required for characterizing the soils and map units should be specified and a laboratory selected to perform the work. An estimate of the number of samples and analytical procedures should be made and incorporated into the budget and schedule. Any research or special studies that are needed to support map unit characterization or interpretations of the data should also be identified and addressed in the budget and schedule.
Some of the more common analyses that are conducted for the purpose of verifying field estimates and providing information for taxonomic needs are listed as follows. Where a new soil is being defined (e.g. a new Soil Series), a minimum of three soil profiles should be sampled for analysis, and more comprehensive analytical work may be required. If the soil has been previously defined and characterized, including chemical and physical analyses, then sampling one soil profile is usually sufficient.
· pH (0.01M CaC12)
· particle size (% sand, silt and clay) and coarse fragment content
· organic matter (% organic carbon)
· iron and aluminum (sodium pyrophosphate extractable)
· electrical conductivity (mS/cm2)
· available water storage capacity (cm H2O/metre of soil)
· exchangeable cations (Ca, Mg, Na, K) and cation exchange capacity
3.1.10 Map and Report Publication and Dissemination
Since the map publication format affects the legend format and often the type of map unit symbol, it is important to decide on the scale and type of map bases that will be utilized for the manuscript and published (if required) maps. In this regard, decisions are required on:
· Type of base map (topographic, cadastral, photo mosaic, etc.).
· Digitizing the map polygons, symbols, sample site data, etc.
· Database characteristics: polygon numbers, acreage, statistics, etc.
· Colour or black and white; or combination of colour and black and white.
· Graphics and photos required for the report.
· How will the report and maps be reproduced (diazo; microfiche; printed by offset press; photocopied; computer plotted).
· How many copies are required, who will distribute them, who will receive them and where will copies be stored for future distribution.
3.2 The Use of Existing Information and Preliminary Field Studies
[Back to TOC] [Previous] [Next]
As in any orderly research program, it is necessary to assemble the existing information about the soil survey area that is pertinent to the objectives of the survey in order to save the time and money associated with duplicating previous work and to avoid costly errors. Accuracy and efficiency can be greatly aided by assembling background information, reviewing it for applicability and validity, and utilizing it in the survey program. In fact, the gathering and review of existing information should be undertaken early in the planning process since it can have impacts on scheduling and budgeting. The examination of such information should not be restricted to only that available for the intended survey area, but should also include surrounding areas for which soils and other information will be of benefit in understanding landscape relationships and during correlation activities. For example, many of the soils in the survey area may already be defined in adjacent areas.
In B.C., the most useful background data sources include, but are not limited to, the following:
· Previous soil survey and interpretive maps and data; these are usually from older surveys and often at smaller scales.
· Aerial photography, mosaics and remote sensing imagery; the age and scale of the photography should be considered in determining their usefulness for the survey and new aerial photography should be ordered well in advance of the survey if the quality, age, or scale of the existing photography is inadequate; LANDSAT and SPOT satellite images should be examined for their usefulness in meeting the survey objectives.
· Topographic (NTS), TRIM (Terrain Resource Information Management) and Cadastral/Planimetric map bases; these map bases and the digital files associated with the TRIM program, and some others, are available for parts of B.C. from Maps-BC and appropriate versions of them should be obtained for field use and perhaps final map production.
· Natural resource information (maps and reports) other than soil surveys are often valuable aids in understanding landscape relationships; these include: forest cover; terrain and surficial geology; bedrock geology; ecological/biophysical/biogeoclimatic; hydrological; and climatological maps and information.
· Research studies; often research institutes (e.g. Agriculture Canada; Canadian Forest Service; research branches of various provincial ministries) as well as Universities and Colleges have undertaken research studies (often as post-graduate thesis studies) within or adjacent to the survey area; these studies should be obtained and reviewed.
· Information gathered by the private sector; these include studies conducted by consultants, private companies (e.g. forestry and mining companies) and Crown Corporations for the purpose of land development or environmental impact assessment; where available, these studies should be obtained and reviewed.
· Cultural and land use information; maps of land use, zoning, land ownership and cultural features (e.g. highways, roads, airports, etc) are often of value in planning the soil survey and, in the case of Regional Districts and Municipalities, often contain information on landscape features that are valuable for understanding soil and land use relationships.
A critical review of these and perhaps other background information will enable the surveyor to determine where data gaps exist and allow sufficient time for the studies or tasks needed to fill the gaps to be undertaken. For example, these may include the requirement for new aerial photography to be flown or for new base maps to be prepared. Should specific studies be necessary that cannot be undertaken by the soil survey organization, they can be identified and a contract or funding mechanism organized for the work. These plans must be incorporated into the overall schedule and budget plan.
It is usually valuable to incorporate preliminary field studies into the project plan in order to supplement and verify the information available from existing sources and to enable the survey leader to gain a preliminary understanding of the landscape that is to be mapped. The purpose of the preliminary field studies is to gain a perspective on the broad patterns of soils and their relationship to soil landscapes (e.g. relief, aspect, parent materials, drainage), land use and vegetation. This examination, in addition to the background information (if any exists), enables the soil surveyor to prepare a preliminary or rough draft of a soil legend, and in some instances, to prepare a small scale, first-approximation of broad soil map units. In addition, it provides the soil surveyor with information on problems that may be encountered during the field survey such as complex soil patterns and access issues. All of the information gathered during this field examination should be recorded for future reference. One of the most important reasons for undertaking a preliminary field examination is to aid in the fine-tuning of the Project Plan in terms of schedule and cost. It is often of value to complete this exercise well in advance of the actual field mapping program so that necessary changes can be incorporated into the Project Plan and be discussed and agreed upon by the funding organization(s) and user group representatives.
3.3 Identifying and Designing Soil Mapping Units
[Back to TOC] [Previous] [Next]
As stated in Chapter 2, the classes of soil taxonomy as defined by the Canadian System of Soil Classification and the methods outlined in Describing Ecosystems in the Field (Luttmerding, et.al. 1990) provide the basic set of soil properties that help define the soil mapping units. The objectives of the soil survey, and hence the SIL, will, among other things, help define the level of soil taxonomy that should be applied to meet the needs of the project (e.g. Subgroup, Family or Series). The boundaries of a polypedon are sometimes difficult to precisely locate and therefore map units are identified by more than one taxa. This results in the use of the terms "complexes" and "associations" where there are two or more taxa and possibly nonsoil areas included in the map unit. Where it is necessary, due to project objectives, to recognize in the mapping procedures a soil property that is more refined than the soil taxon, then a phase can be used. For example, it is possible to recognize a Ferro-Humic Podzol - very stony phase if this is of importance to the interpretations to be made from the survey.
In B.C., it has been and is likely to continue to be common, to map Soil Associations and Soil Series and phases of them, depending on the intensity of the survey. Soil Series and Soil Associations are usually named for the geographic location (e.g. a mountain, lake, river, community, etc.) near where they are first described. The name is used to provide an easily recognizable description that implies a wealth of information about the soil in order to aid in communication. These concepts are discussed in more detail in Chapter 4. However, it should be remembered that the SIL will determine the kinds of map units and level of taxa to be used. Ranges of soil properties can be narrow or broad. The important point here is for the soil surveyor to design the map units that provide the greatest uniformity and usefulness for the purposes of the survey. During the planning stage, it must be determined if the mapping unit:
· Can be mapped as a reasonably pure delineation of soil taxa.
· Is too narrowly defined to be useful for the survey purpose.
· Has properties that range too widely to serve the purposes of the survey.
This means soil surveyors must not just gather facts about the soil but must also focus their efforts on gathering relevant facts and presenting them so that they are readily identifiable and useable. At broad levels of soil inventory (SIL 3,4 and 5), the surveyor is faced with the difficult task of organizing map units that best reflect the complexity of soils found over large areas and what combinations or associations of soils are best to characterize useful and mappable units.
3.4 Initial Legend Formulation
[Back to TOC] [Previous] [Next]
During the examination of relevant background information and through initial field studies, it is usually possible to prepare a preliminary soil survey legend that broadly defines mapping units as well as characteristics of the soils and related landscape features within the survey area. Since it is not likely to have a complete legend at the start of a field survey, the preliminary legend will likely be modified and added to as the survey progresses (if available, a legend from an adjacent mapped area may be useful to use as a preliminary legend). However, by providing the preliminary legend to all of the field mappers it is possible to establish a number of tentative map units to which comparisons can be made in the field and to which additional mapping units can be logically and carefully added as the survey progresses.
3.5 Mapping Bases
[Back to TOC] [Previous] [Next]
Since one of the major end-products of a soil inventory is the soil map and legend, the appropriate selection of a base map to portray the soil map units is critical. The base map will influence accuracy and, due to factors such as the degree of ground control and age, the amount of field effort that must be applied in the survey, as well as the quality and usefulness of the final published or manuscript map. The term "ground control" or "control" implies the degree of accuracy which the base map portrays relative to actual ground conditions. Consequently, serious effort needs to be applied to the selection of not only the map bases used for field survey work but also those that will be used for the final soil map.
During the field survey, aerial photography of appropriate scale, backed up by topographic maps, are often used to assist the soil survey team. These tools allow for the stereoscopic interpretation of the ground surface from aerial photos and for ground-control and elevational relationships in the case of topographic maps. In many cases, soil surveyors will map directly on the aerial photographs during the course of the field survey. In addition, several types of remote sensing other than photography (e.g. satellite images) can prove useful.
For final map production, several choices of base maps are available such as topographic maps, controlled aerial photo mosaics and cadastral/planimetric maps. The choice of the appropriate one will depend on cost, availability and the intended use of the survey information. In all instances, however, the base map must have accurate horizontal ground control so that there is little or no distortion or error throughout the entire map area. The degree of horizontal ground control will greatly influence the scale of the map, its accuracy, and its orientation and location relative to the surface of the earth. The Party Chief must be well aware of the degree of ground control and the location of permanent ground control stations (markers) relative to the base map being used for the soil survey. In the case of aerial mosaics, the use of digitally corrected images offer great potential, particularly when the soil map units are to be digitized.
[Back to TOC] [Previous] [Next]