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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #336808
Title: Modeling land management effects on the size distribution of eroded sediment

Author
item LIU, GANG - Northwest Agricultural & Forestry University
item Dabney, Seth
item YODER, DANIEL - University Of Tennessee
item Wells, Robert - Rob
item Vieira, Dalmo

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2019
Publication Date: 4/18/2019
Citation: Liu, G., Dabney, S.M., Yoder, D.C., Wells, R.R., Vieira, D.A. 2019. Modeling land management effects on the size distribution of eroded sediment. Soil & Tillage Research. 192:121-133. https://doi.org/10.1016/j.still.2019.04.012.
DOI: https://doi.org/10.1016/j.still.2019.04.012

Interpretive Summary: Land management that increases organic matter additions to soil, increases root growth, and decreases disturbance by tillage in expected to improve soil tilth and structure. However, current erosion models to not consider these effects when estimating sediment aggregate size. We modified a computerized conservation planning tool to overcome this deficiency. The new estimates of increased aggregation agreed with observations made when cropland was restored to native warm season prairie in the central U.S.A. The improved conservation planning tool will give more appropriate conservation credit to conservation systems that improve soil health.

Technical Abstract: Land management that improves soil quality is known to increase the amount of water-stable soil aggregates, but many current soil erosion models do not consider land management effects when estimating the size distribution of eroded sediment. A literature search identified 274 soil aggregate size distributions where soil clay and soil organic carbon were also reported. The median value and log-normal standard deviation were estimated for each distribution. Median value was found to be linearly related to soil clay fraction and quadratically related to soil carbon content. Algorithms were derived and incorporated into the RUSLE2 model to estimate increased aggregation for managements that increased biomass inputs and residue cover of the soil. The resulting estimates of macro-aggregates were similar to observations made when cropland was converted to prairie in the central U.S.A. More data is needed to assess the generality of the algorithms and parameter estimates presented.