Dry Aggregate Size Distribution of Sandy Soils as Influenced by Tillage and Precipitation
- T. M. Zobeck and
- T. W. Popham
Surface soil dry aggregate size distribution (ASD) has a significant effect on the amount and intensity of wind-induced soil erosion. The ASD of cropland varies through time primarily due to the effects of management and climatic factors. A method of predicting ASD is needed to make accurate estimates of wind erosion. The effects of tillage on ASD are described and models proposed to estimate changes in ASD after precipitation has further modified a sandy soil surface. The ASD and bulk density of the near-surface soil were measured on four west Texas sandy soils immediately after tillage and after up to 130 mm subsequent rainfall. Tillage methods included moldboard plow, lister, chisel, and tandem disk. Results indicated that the four tillage methods tested could be separated into two groups to produce reliable estimates of ASD. Moldboard plowing produced significantly larger aggregates than a tillage-tool group comprised of lister, chisel, and tandem disk. The combined effects of tillage and precipitation after tillage produced significant differences (P < 0.002) in ASD for each soil tested. Regression models to estimate ASD using bulk density in the near-surface soil and cumulative precipitation as independent variables accounted for up to 80% of the variation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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