EXISTING AND POSSIBLE NEW GLEYSOLIC ORDER CRITERIA APPLIED TO FIVE PEDONS FROM BRITISH COLUMBIA

Abstract

Use of the current criteria for distinguishing Gleysolic soils from gleyed intergrades to other soil classes resulted in the apparent misclassification of some soils in British Columbia. Pedologists of the area selected five pedons encompassing several degrees of expression of gley features. Current classification criteria based on soil color and possible new differentiating features based on chemical and micromorphological analyses were applied in considering the classification of the soils. Application of the current specific color criteria involving low chromas and prominent mottling result in the classification of three pedons in the Gleysolic order and two in gleyed subgroups of other orders. This classification was appropriate in the view of B.C. pedologists except for one Gleysolic pedon in which the water table is rarely within 1 m of the surface. Prior to drainage, however, the soil was probably saturated to the surface and under reducing conditions for prolonged periods each year. Thus, classification as a Gleysolic soil is appropriate as it probably reflects the prevailing conditions and processes during most of the period of soil genesis.Segregation of iron and manganese as nodules and coatings was most marked in the Gleysolic pedons. Walls of some voids were bleached due to depletion of iron oxides. Though study of thin sections, bulk chemical analysis and analysis of specific features by scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDXRA) were useful in providing information on soil properties, they did not indicate an improved basis for differentiating Gleysolic soils from others. The color criteria used to distinguish soils of the Gleysolic order do not necessarily reflect the current soil water regime, and they are not intended to do so. The current criteria resulted in the appropriate classification of the five soils. Key words: Gleying, reduction, iron, manganese, micromorphology, SEM-EDXRA