Variation in Potassium Available to Trees Within an Outwash Soil

Abstract

AbstractThirteen deep soil pits were sampled by strata, 40 forest floor samples were collected, and tube samples were taken at 119 locations of the surface 15‐cm layer and at 30‐cm intervals to a soil depth of 2.1 m. The sampling was done on an 0.8‐ha area supporting good and poor growing 37‐year‐old red pine (Pinus resinosa Ait.) separated by an old fenceline. The soil has formed in slanted and discontinuous strata of different physical and chemical properties. Acid‐extractable K data from the 13 pits indicate the magnitude but not the pattern of variability. Data from the pit samples were used to predict acid‐extractable K for the tube samples. Regression techniques were used on the 0‐ to 15‐ and 15‐ to 45‐cm layers. An ocular textural classification technique was employed for deeper soil layers. Results indicate K variability is pronounced in the soil volume studied and is associated with the occurrence of discontinuous finer‐textured strata at differing depths. K variability as measured by these techniques was found to be only partly related to red pine growth.