| Revised Universal Soil Loss Equation 1.06 - RUSLE1.06c News |
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This News page is an "unofficial" and informal way of providing information on current RUSLE activities.
New Version of RUSLE1.06: A new version of RUSLE1, RUSLE1.06c, is available for downloading.
RUSLE1.06c is land use independent and applies to any land use where mineral soil is exposed to the erosive forces of raindrop impact and overland flow. RUSLE1.06c is not limited to construction sites, but applies to all land uses including cropland.
Significant changes were incorporated in RUSLE1.06c so that it would give comparable results with the newly released RUSLE2. If you have been using previous versions of RUSLE1, including RUSLE1.06, you should upgrade to RUSLE1.06c. Changes between RUSLE1.06b and RUSLE1.06c include:
1. New erosivity R-values based on modern climate data have been developed for RUSLE2. These new values should be used in RUSLE1.06c. The RUSLE1.06c citylist database that is downloaded from this site when RUSLE1.06c is downloaded contains the new R-values. Overall, erosivity based on modern climate data is about 10% higher than based on the climate data previously used in the USLE and RUSLE1. See the Bulletin section for additional information, including an erosivity map for the eastern US.
2. A new map for 10-Yr El values was developed for use in RUSLE1.06c. New values from this map have been included in the RUSLE1.06c database that is downloaded when RUSLE1.06c is downloaded from this Internet. See the Bulletin section for additional information, including the new map of 10-Yr El values for the eastern US.
3. Equation 5-9 in Agriculture Handbook (AH) 703, which was incorrectly programmed in previous versions of RUSLE1.06, has been corrected in RUSLE1.06c. Correction of this error has little effect except for high amounts of soil biomass.
4. An interaction between canopy and ground cover was added to RUSLE1.06c. This interaction is the same as the one described in AH537 for the USLE. RUSLE1.06c computes increased soil loss for high canopy covers close to the ground. Using a 100% canopy cover close to the ground can not be used in RUSLE1.06c to effectively "shut off" soil loss for conditions like a flooded rice field or plastic-covered soil.
5. RUSLE1.06c computes less reduction in soil loss for no-till cropping systems, especially for high ground cover values, than do previous versions of RUSLE1.06. Soil loss values computed by previous versions of RUSLE1.06 were judged to be too high for no-till cropping systems.
6. RUSLE1.06c does not use a temporal variation in the soil erodibility factor. This change can affect soil loss values by about 25% in certain locations including the Midwestern and Northeastern regions of the US.
7. A change in the cursor operation was made for the time invariant C factor to clarify selection of the b value for the ground cover effect. This change has no effect on computed soil loss.
8. An error was fixed that prevented saving an Req climate file where an Req value had been manually entered.
9. The Req EI distribution for Req areas was changed from a 95-5 distribution of soil loss from the winter priod to the summer period to an 87-13 distribution. The new distribution was based on recent analysis of erosion data.
