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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #108526
Title: EVALUATING SOIL QUALITY-SOIL REDISTRIBUTION RELATIONSHIP ON TERRACES AND STEEP HILLSLOPES

Author
item LI, YONG - CAAS BEIJING CHINA
item Lindstrom, Michael

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2001
Publication Date: 9/1/2001
Citation: N/A

Interpretive Summary: Soil erosion by water is recognized as an important process that reduces the production potential of soils. It is now being determined that soil redistribution by tillage implements can have an equally important effect on soil properties and crop production potentials. The objectives of this study were to quantify changes in soil properties due to soil redistribution by water and tillage erosion on terraced and steep cultivated hillslopes. Total soil redistribution was determined by using a mass balance model through cesium-137 techniques. A tillage erosion prediction model determined soil redistribution by tillage. Water erosion was calculated by difference between the two techniques. Results from this study showed that water erosion was the primary cause for the overall decline in soil properties on the steep cultivated hillslope while tillage erosion had a comparable or greater contribution to the decline on terraces. Soil accumulation at concave slope positions was found to be the controlling factor in variation in soil properties for both hillslope conditions. Results from this study will be useful to land managers in explaining soil property variations and crop yields commonly observed in terraced and steep cultivated hillslopes.

Technical Abstract: Soil redistribution from tillage and water erosion have the potential to modify the spatial patterns of soil quality on terraced and steep cultivated hillslopes. However, few studies have investigated this relationship. Our objectives were to quantify soil quality parameters along terraced and steep hillslopes and determine the relationship between soil redistribution from tillage erosion and water erosion on soil quality parameters in the Chinese Loess Plateau. Soil quality indicators, i.e. soil organic matter (OM), available phosphorus (P), nitrogen (N), bulk density (BD), and clay and silt contents were measured at 5 m intervals on terraced field and at 10 m intervals on a steep cultivated hillslope in a down slope transect. Soil redistribution rates from tillage and overland flow were obtained by cesium-137 (137Cs) technique integrated with a tillage erosion prediction model (TEP). Water erosion is the primary cause for the overall decline in soil quality on steep cultivated hillslope while tillage erosio has a comparable or greater contribution to overall level in soil quality on terraces. Soil accumulation due to tillage controls the spatial patterns in OM, N and P on both terraced and steep cultivated hillslope. Water erosion caused a linear decrease in clay content of 0.02% m**-1 and corresponding increase in silt content of 0.04% m**-1 downslope on the steep cultivated hillslope. The effectiveness of tillage erosion on OM, N and P on the steep cultivated hillslope can be assessed using the change in adjacent slope gradients (X) through a soil quality-topography regression model, Y=aX+b.