|Huang, Chi hua|
Submitted to: Soil Tillage Research Organization International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/10/2006
Publication Date: 8/1/2006
Citation: Norton, L.D., Mamedov, A., Huang, C., Levy, G.J. 2006. Soil aggregate stability as affected by long-term tillage and clay type. In: Proceedings of the Soil Tillage Research Organization International Conference. 17th Triennial Conference, Sustainability-its Impact on Soil Management and Environment, August 28-September 3, 2006, Kiel, Germany. p. 1521-1526. 2006 CDROM. Interpretive Summary:
Technical Abstract: Soil aggregate stability and dispersivity depend on clay mineralogy. However, little is known about the effect of soil mineralogy on soil crustability for long-term cultivated soil. The effect of long-term tillage on aggregate stability was the objective of our study. More than 20 soil samples characterizing a range of important agricultural (virgin, long-term no-till and tilled) soils of the humid and semi-arid zones with predominantly illitic, smectitic and kaolinitic clay mineralogy were studied. We measured aggregate stability using the high energy moisture characteristic method (HEMC), where the destructive force used to break down aggregates was accurately controlled by either a slow or fast wetting rate. Stability ratio was calculated from the changes in pore size distribution following the wetting as it was a sensitive measure of stability. The virgin soils, and soils predominantly with kaolinitic mineralogy were more stable independent of texture. Long-term tillage was more effective (harmful) for illitic and smectitic soils, whereas, effect of long-term no-till mostly were valuable on these soils with a relative high clay content. Long-term tillage significantly decreased volume of infiltration (drainable) pores, structural index and aggregate stability (10-30%). The aggregate stability indices were correlated with previously published seal formation data. Generally correlation was well with soil clay and/or organic matter content, seal formation and erosion data. Soil mineralogy should be considered on runoff and erosion prediction. The mechanisms describing the effect of soil mineralogy and texture and tillage and their interaction on aggregate stability, runoff and erosion are discussed.