Figure 17.—Indicator A12, Thick Dark Surface.
This photo accompanies Figure 17.—Indicator A12, Thick Dark Surface. [Field Indicators of Hydric Soils in the United States].
A close-up of the upper B horizon of a Tonka soil (vertical cross-section, broken along ped face). Note the many soft masses of oxidized iron and redox depletions. Masses of iron are mostly in ped interiors. The redox depletions are along root channels and elongated pores.
This soil is hydric based on Indicator A12 (Thick Dark Surface). Deep observation is needed to determine whether a soil meets the requirements of this indicator. In this soil, depth to the depleted matrix is about 55 cm.
Figure 17.—Indicator A12, Thick Dark Surface.
This photo accompanies Figure 17.—Indicator A12, Thick Dark Surface. [Field Indicators of Hydric Soils in the United States].
A close-up of the upper B horizon of a Tonka soil (vertical cross-section, broken along ped face). Note the many soft masses of oxidized iron and redox depletions. Masses of iron are mostly in ped interiors. The redox depletions are along root channels and elongated pores.
This soil is hydric based on Indicator A12 (Thick Dark Surface). Deep observation is needed to determine whether a soil meets the requirements of this indicator. In this soil, depth to the depleted matrix is about 55 cm.