حشمت الله آقارضی
جمال قدوسی
افشین پورمتین

Universal soil loss equation which is contain of six factor rainfall erosion (R) , Soil erodibility (K) Length slope (L), Slop percent (S) . Canopy cover (C) and . protection' measures J has been obtained in climUle of U.SA by wichmeier and smith . Since this equation is 'used for estimation of erosion rate in Iran, It is necessary to study aboUl value of soil' loss in this equation and in flew measures and contrasting between them. TIle aim of this project is stUdy about some factors of the equation such as effect of thirty minutes: rainfall intensity on erosion. . The method of perfonnance of this project is as follow. There were four piece of land with the slop of 9, 15, 20 25 percent in the place of perfonnance of project and each slope had three treatment J crop pasture and tillage in three replicate during each rainfall, the value of runof and sediments ill treatment and their repelicatio11S have been collected nad thd rate of sediments have been measured. obtained results show that erosion rate and soil loss that have estimated by U.S.L.E withowt any exception are more than field value measures and at least should adjust in the proportion of means that has given in table 8.