Research Methods

• Study Design
• Sampling Earthworms
• Sampling Plants
• Sampling Trees
• Sampling Soils

More on Mottles

Traditionally, matrix or mottle colors with chroma of 2 or less (and value of 4 or more) have been interpreted as indicators of seasonally high water tables.  Evidence has been accumulating that in many soils in the northeast, mottles of chroma 3 in a high chroma matrix may also be indicators of wetness.  In describing mottled soil, the dominant soil color is described first.  Mottles colors are then determined and the mottles are also described in terms of quantity, size, contrast, and color.  Color of mottles is recorded according to the conventions used in describing soils in general; quantity, size, and contrast of mottles are described using the following conventions:

Mottle Quantity

NONE: if mottles are the same color as the rest of the soil, or not present
FEW: mottles occupy less than 2% of the exposed surface area
COMMON: mottles occupy 2 - 20% of the exposed surface area
MANY: mottles occupy more than 20% of the exposed surface area

Mottle Size

FINE: smaller than 5 mm
MEDIUM: 5-15 mm
COARSE: larger than 15 mm

Mottle Contrast

FAINT:  Indistinct mottles are evident and recognizable only with close examination.  The hue and chroma of the matrix and mottles are close.

DISTINCT: Although not striking, the mottles are readily seen.  The color difference between the matrix and the mottles vary 1 or 2 hues or several units in chroma or value.  The pattern may be a continuous matrix with mottles or a mixture of two or more colors.

PROMINENT: Mottles are obvious and mottling is one of the outstanding features of the horizon.  The matrix and mottles usually vary several units (2 or more) in hue, value, and chroma.  The pattern may be a continuous matrix with contrasting mottles or a mixture of two or more contrasting colors.