Wet Mollisol with Krotovina
Wet Mollisol with Krotovina This Mollisol from Minnesota has a relatively thick (10 inches) dark A horizon overlying a mottled Bw horizon. The "w" indicates the parent material has been changed but insufficient clay, iron or carbonate has been illuviated to form a horizon that merits a "t", "s" or "k" designation. Note the abrupt transition between the A and B. This is produced by cultivation. The mottles are produced by a fluctuating water table. During periods of high water, iron is reduced and mobilized. When the water table recedes, the iron is reoxidized. In places the iron is removed, leaving the uncoated mineral particles. In other places, the iron is concentrated, producing the orange mottles. Note the krotovina at 18 inches. This is an animal burrow that was filled with A horizon. In digging the pit and examining the soil, most of the material filling the animal burrow was removed.

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