Predicting Rainfall Erosivity in Honduras
1997
Mikhaĭlova, E. A. | Bryant, R. B. | Schwager, S. J. | Smith, S. D.
Iso-erodent maps can be used in soil conservation planning to identify regions with high rainfall erosive potential. This study was conducted to determine the significance of elevation in predicting the rainfall erosivity index (R) in addition to the average annual precipitation and to develop an iso-erodent map for Honduras. With previously calculated R-factor values for eight climatic stations in Honduras, a regression relationship was established for estimating the rainfall erosivity index as a function of average annual precipitation and elevation with R² of 0.972. This regression model was used to estimate the rainfall erosivity index for each of the 344 Honduran climatic stations without calculated rainfall erosivity indices. Due to the limited number of data points and their geographic clustering, the best estimates of mean rainfall erosivity indices were for stations with average annual precipitation in the range from 831 to 1313 mm and elevation between 360 and 1080 m. A provisional iso-erodent map of Honduras at a scale 1:1 000 000 was compiled in Arc/Info format, using a basemap obtained from the digital chart of the world. Iso-lines for the 95% prediction intervals for new rainfall erosivity indices are displayed on the map to show the accuracy of the new estimates. Elevation was found to be highly significant in predicting the rainfall erosivity in addition to the average annual precipitation. Data from Costa Rica, Sri Lanka, and the southeastern USA supported this finding. Contribution from the Cornell Univ. Agric. Exp. Stn., Cornell Univ., Ithaca, NY 14853.
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