Sedimentation of Prairie Pothole Wetlands: The Need for Integrated Research by Agricultural and Wildlife Interests
Soil Erosion and Sedimentation of Prairie Wetlands
During 1993-1995, we examined sedimentation rates in wetlands with watersheds (i.e., catchments) in native prairie with no prior history of tillage, land in CRP, and summer fallow land-use treatments (Gleason and Euliss 1996). Preliminary results from June-July 1993 indicated that sedimentation rates (g • m-2 • d-1) were up to 70 times greater in summer fallow (
=269.88) than in native prairie (=15.74) and CRP (=3.81) (Gleason 1996). Other investigators also have documented accelerated sedimentation of wetlands in agricultural landscapes. Adomaitis et al. (1967) demonstrated that the aeolian mixture of snow and soil ("snirt") in wetlands surrounded by cultivated fields accumulated at twice the rate as in wetlands in vegetated fields. Similarly, Martin and Hartman (1987) and Dryer et al. (1996) found that prairie wetlands with cultivated watersheds accrued sediments at twice the rate of wetlands surrounded by grassland, and Dieter (1991) demonstrated that turbidity in tilled wetlands was significantly higher than in partially tilled (wetlands with a filterstrip of vegetation along their periphery) and non-tilled wetlands. Catastrophic sedimentation events also have been observed in the PPR in which wetlands have completely filled with sediment during a single episodic rainfall event (Gleason and Euliss, personal observations). Wetlands in cultivated fields are thus shorter lived than wetlands in grasslands landscapes and significant soil loss occurs in agricultural lands under conventional tillage practices.
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