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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT TECHNOLOGIES FOR ARID RANGELANDS Title: Fine gravel controls hydrologic and erodibility responses to trampling disturbance for coarse-textured soils with weak cyanobacterial crusts.

Authors
item Herrick, Jeffrey
item Van Zee, Justin
item Belnap, Jayne -
item Johansen, J -
item Remmenga, Marta -

Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 10, 2010
Publication Date: October 1, 2010
Repository URL: http://handle.nal.usda.gov/10113/58395
Citation: Herrick, J.E., Van Zee, J.W., Belnap, J., Johansen, J.R., Remmenga, M. 2010. Fine gravel controls hydrologic and erodibility responses to trampling disturbance for coarse-textured soils with weak cyanobacterial crusts. Catena. 83:119-126.

Interpretive Summary: Soil surface disturbance nearly always increases the susceptibility of soil to erosion and often reduces infiltration rate. These two effects combine to increase runoff and water erosion. However, few studies have evaluated the effects of disturbance on sandy soils with high amounts of fine gravel at the surface. These soils, which are derived from granite, are very common in many arid regions. This study was completed in the Mojave Desert in southern California, USA. It showed that lug-soled boot trampling disturbance significantly reduced final infiltration rate and total infiltration and increased sediment generation from small (0.5 m2) rainfall simulation plots. It had similar effects on soils with both low and very low levels of cyanobacterial biomass. Trampling appears to reduce infiltration by significantly reducing the cover of gravel and coarse sand on the soil surface. This creates favorable conditions for the development of a physical crust during rainfall events.

Technical Abstract: We compared short-term effects of lug-soled boot trampling disturbance on water infiltration and soil erodibility on coarse-textured soils covered by a mixture of fine gravel and coarse sand over weak cyanobacterially-dominated biological soil crusts. Trampling significantly reduced final infiltration rate and total infiltration and increased sediment generation from small (0.5 m2) rainfall simulation plots (p<0.01). Trampling had no effect on time to runoff or time to peak runoff. Trampling had similar effects at sites with both low and very low levels of cyanobacterial biomass, as indicated chlorophyll a concentrations. We concluded that trampling effects are relatively independent of differences in the relatively low levels of cyanobacterial biomass in this environment. Instead, trampling appears to reduce infiltration by significantly reducing the cover of gravel and coarse sand on the soil surface, facilitating the development of a physical crust during rainfall events. The results of this study underscore the importance of carefully characterizing both soil physical and biological properties to understand how disturbance affects ecosystem processes.

Last Modified: 12/21/2014
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