A Rainfall Erosion Index for a Universal Soil-Loss Equation
A Rainfall Erosion Index for a Universal Soil-Loss Equation
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DOI：
10.2136/sssaj1959.03615995002300030027x
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发表时间：
1959-05
影响因子：
2.9
通讯作者：
W. H. Wischmeier
中科院分区：
文献类型：
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作者：
W. H. Wischmeier
对基本的土壤流失数据进行了广泛的回归分析，以确定风暴侵蚀土壤能力的最佳指标。作为这种指示器的暴雨特征是其值是降雨能量和暴雨最大30分钟强度（指定为EI）的乘积的变量。这一变量解释了从72%到97%的变化，在个别风暴侵蚀耕作连续休耕6土壤。季节性降雨侵蚀指数值计算增加的EI值的风暴> 0.5英寸解释高达94%的总土壤流失在夏季休耕的年偏差。对连续行作物在四个相距甚远的位置，每一个10年或更长时间的地块的数据进行测试，EI值的总和解释了72%至85%的土壤流失在相应的覆盖期内的年度变化。该指数的预期年度值和侵蚀潜力的季节性分布可以很容易地从当地的降雨记录计算。在东部31个州的60个地点开展了这项工作。目前正在分析大约8 000个样地-年的基本侵蚀数据，以评估一个通用土壤流失方程的因素，该方程以预期的当地降雨量的侵蚀潜力为基础。试验表明，以这种方式计算的平均侵蚀损失的估计是足够准确的保护农场规划作为健全的基础。
Extensive regression analyses of basic soil-loss data were designed to determine the best indicator of the capacity of a storm to erode soil. The rainstorm characteristic found to be outstanding as such an indicator is the variable whose value is the product of the rainfall energy and maximum 30-minute intensity of the storm (designated as EI). This variable explained from 72 to 97% of the variation in individual-storm erosion from tilled continuous fallow on 6 soils. Seasonal rainfall erosion index values computed by adding the EI values of storms > 0.5 inch explained as high as 94% of the yearly deviation in total soil loss from fallow during the summer season. Tested against data from plots in continuous row crop for 10 or more years at each of four widely separated locations, the summed EI values explained from 72 to 85% of the yearly variation in soil loss within corresponding cover periods. Expected annual values of the index and seasonal distribution of the erosion potential may be readily computed from local rainfall records. This has been done for 60 locations in the 31 Eastern States. About 8,000 plot-years of basic erosion data are being analyzed to evaluate factors for a universal soil-loss equation for which the erosion potential of expected local rainfall serves as the base. Tests show that estimates of average erosion losses computed in this manner are sufficiently accurate to serve as sound bases for conservation farm planning.