Ministry of Environment

Soils

Part 3 - The Soil Landscapes of British Columbia

3.1 Introduction

K.W.G. Valentine

The land of British Columbia is almost infinite in its variety. It contains many minerals and fossil fuels. Its vegetation ranges from rainforest to sagebrush and cactus. Parts of the south are subarid with hot summers and parts of the north have permafrost. So it is with the soils. Those of us who have attempted to map and describe the soils of British Columbia through the years have debated long and hard how best to express this complexity in a simple way in our maps and reports. The problem is compounded when a description of the soils of the whole province is attempted instead of the soils of the map sheet, which covers only a small area.

Actually there are two problems here. Firstly how can the province be divided into sections of manageable size within which the soil forming factors produce a particular and unique pattern of soils? Secondly what soil unit should be described? The problems were solved in this publication - if the reader agrees that they have indeed been solved! - partly by borrowing from previous work (to delineate physiographic regions) and partly by developing a concept of a large soil area (the "soil landscape").

Physiography in British Columbia influences climate, hydrology, vegetation and thereby soils. Five large physiographic regions were therefore defined as described in the Introduction to Part 1 and shown in Figure 1.1.1. They have been used periodically throughout this publication, but it is within Part 3 that they will be used most extensively as the initial divisions within which the soil landscapes are described.

A soil landscape is thought of as the total ecosystem with which a particular soil is associated, with emphasis placed on the soil itself. It could be used at any level of the soil classification, but here it is used as a great group. For instance the morphology and chemistry of the Ferro-Humic Podzol soils on the west coast are described within the context of coarse textured acid parent materials, high rainfall, a dense coniferous forest and rugged topography.

There may appear to be some duplication. Many soil landscapes occur in more than one physiographic region, but they usually have a different combination of the soil forming factors in the two regions. For instance Gray Luvisols in the Interior Plateau have developed on calcareous till and lacustrine deposits derived from basic lavas under a forest cover of Douglas-fir. In the Great Plains similar soils have developed from acid, calcareous or saline sandstones and shales under a forest of trembling aspen and white spruce.

The province-wide distribution of the soil great groups is shown initially by the soil map of British Columbia derived from the Atlas of British Columbia (Part 3.2). The soil landscapes of the five physiographic regions are then described by pedologists or geologists who have worked in those areas. In most cases it was possible to describe a single soil landscape that occupies the major portion of a large area. However, in other cases individual soil landscapes were so intimately mixed within an area (as in floodplains) or combinations of soils formed such a distinctive type of country (as in the grasslands or the alpine tundra) that it was more convenient or logical to discuss them together. The pattern of soil landscapes in each region is illustrated by cross sections and oblique air photographs. The vegetation associated with each soil landscape is also described using Krajina's biogeoclimatic zones and Rowe's forest regions (see Further Reading in Part 1.4 for references)