An approach to quantitative classification of nutrient regimes of forest soils

Abstract

Many workers have classified nutrient regimes of forest soils, but there have been few attempts to provide an objective means of defining soil nutrient regimes. This objective was accomplished in the present study by numerical analysis conducted on 195 soil samples of vegetation and soils from coastal British Columbia. The differentiating characteristics used in the classification were pH (H2O) and the C/N ratio of the humus forms; and total soil nitrogen (kg/ha) and sum of exchangeable calcium, magnesium, and potassium (kg/ha) within the soil rooting zone. Numerical analysis distinguished seven soil groups. These groups were related to the floristic composition of understory vegetation and to forest productivity as indicated by site index. These vegetation – soil relationships were then used to assign the soil groups into five soil nutrient regime classes: very poor, poor, medium, rich, and very rich.