Sediment Removal by Prairie Filter Strips in Row-Cropped Ephemeral Watersheds
- Matthew J. Helmersa,
- Xiaobo Zhou *a,
- Heidi Asbjornsenb,
- Randy Kolkac,
- Mark D. Tomerd and
- Richard M. Crusee
- a Dep. of Agricultural and Biosystems Engineering, Iowa State Univ., Ames, IA 50011
b Dep. of Natural Resources and the Environment, Univ. of New Hampshire, Durham, NH 03824
c USDA Forest Service, Northern Research Station, Grand Rapids, MN 55744
d USDA–ARS, National Lab. for Agriculture and the Environment, Ames, IA 50011
e Dep. of Agronomy, Iowa State Univ., Ames, IA 50011. Assigned to Associate Editor Phil Haygarth
Twelve small watersheds in central Iowa were used to evaluate the effectiveness of prairie filter strips (PFS) in trapping sediment from agricultural runoff. Four treatments with PFS of different size and location (100% rowcrop, 10% PFS of total watershed area at footslope, 10% PFS at footslope and in contour strips, 20% PFS at footslope and in contour strips) arranged in a balanced incomplete block design were seeded in July 2007. All watersheds were in bromegrass (Bromus L.) for at least 10 yr before treatment establishment. Cropped areas were managed under a no-till, 2-yr corn (Zea mays L.)–soybean [Glycine max. (L.) Merr.] rotation beginning in 2007. About 38 to 85% of the total sediment export from cropland occurred during the early growth stage of rowcrop due to wet field conditions and poor ground cover. The greatest sediment load was observed in 2008 due to the initial soil disturbance and gradually decreased thereafter. The mean annual sediment yield through 2010 was 0.36 and 8.30 Mg ha-1 for the watersheds with and without PFS, respectively, a 96% sediment trapping efficiency for the 4-yr study period. The amount and distribution of PFS had no significant impact on runoff and sediment yield, probably due to the relatively large width (37–78 m) of footslope PFS. The findings suggest that incorporation of PFS at the footslope position of annual rowcrop systems provides an effective approach to reducing sediment loss in runoff from agricultural watersheds under a no-till system.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2012. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.