| | Background | Objectives | Orientation
Background
In 1984 the Senate Standing Committee on Agriculture, Fisheries and Forestry (1984) released the report "Soil at Risk" which documented a number of situations leading to soil degradation. This report and others like it (e.g. ASSW 1981) suggested that the agricultural landbase was in critical condition. These reports were responsible for the initiative of a number of provincial and federal studies to address the concern. The largest single program was the National Soils Conservation Program (NSCP), a federal-provincial program which ran from 1988 to 1993. It included a major research study, the Soil Quality Evaluation Program (SQEP). The summation of this project, "The Health of our Soils" (Acton and Gregorich 1995), reported on soil degradation factors such as erosion and salinity and concluded that there was indeed a continuing degradation concern but that it was not the crisis as suggested 10 years earlier. The report also introduced the concepts of "soil health" and "soil quality".
One of the more important findings from SQEP was that soil conditions change slowly and, as they are often variable to start with, are difficult to monitor on a real-time basis. That is, by the time a change can be measured, it is often too late to initiate remedial changes to management. There are ways around this. We have a significant amount of information at individual sites and we know some of the impacts of individual tillage practices. Therefore, we should be able to model or predict what might happen over-time under different kinds of management. This would allow those concerned with land management to concentrate on practices which were predicted to cause a deterioration of the land base. And, the focus of research would change from detailed monitoring all over the country to testing the models at specific locations.
In 1993, a replacement for the NSCP was negotiated on a provincial basis across Canada. It continued many of the initiatives started under the NSCP but was based on the broader concept of environmental sustainability. The program in Alberta, the Canada-Alberta Environmentally Sustainable Agriculture agreement or CAESA, included a soil quality monitoring component. The principal objectives of this component were to develop and test specific landscape process models, to monitor selected agricultural landscapes and to develop procedures for regional assessments of soil quality.
The latter objective became the focus of the present study, to develop ways to evaluate soil quality assessment and trends at an Ecodistrict level (SQAT). It was assumed that some kind of modeling approach would be used taking advantage of the significant gains that have been made in developing predictive models. There are models for crop growth (eg. CERES (Ritchie and Otter 1985)), wind erosion (Woodruff and Siddoway 1965), water erosion (Wischmeier and Smith 1978) and compaction and water movement (Leonard et al. 1987). There are also methods to calculate 'soil quality' (eg. MacDonald et al. 1995), but these are conceptually a little more difficult because quality must be tied to a use and it must be based on a point in time, such as "rainfed agriculture in 1991". There are others, such as EPIC (Williams et al. 1990), which attempt to integrate crop growth, management, degradation and economics. These are good for predicting change, and hence sustainability, but they do not define ‘quality’ or ‘health’ and because of the number of inputs, work best for restricted sites or specified conditions. Two basic issues inherent in all the analysis are those of scaling and the integration of many disparate data types and sources.
The general objectives of the present study (SQAT) were to first investigate and develop appropriate methods of data management at a broad scale and then to apply and evaluate those methods for use in assessment of agricultural sustainability in Alberta.
Objectives
The overall objectives as outlined in the 1993 project proposal were:
1. To develop and document techniques to evaluate generalized soil quality trends, and
2. To prepare a map showing soil quality trends at an Agroecological Resource Area level.
As the project progressed, it became apparent that the greatest challenges, and probably the most significant benefits, were in the areas of database compilation and data management for rolling up (scaling) information for large area representation. So, while the overall objectives remained, this additional aspect became the focus of much of the project activity.
Orientation
The original objectives were targeted at general sustainability analysis and information to support policy and program initiatives. In contrast, the data compilation and management results are seen as being most useful to those who are applying or extrapolating research results and models to areas larger than individual plots, fields or farms.
The kinds of results and audiences were felt to be different enough that separate reports should be considered. This report will address broad scale soil quality assessment and trends. Other reports will concentrate on topics such as inputs for EPIC, EPIC analysis, discussions of scaling and extrapolating land based data and programs for automating assessment procedures.
This information is provided by W.W. Pettapiece, K.L. Haugen-Kozyra and L.D. Watson. |
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