In order to understand soil and water loss and its dynamic changes in the black soil region

the dynamic characteristics and causes of soil and water loss during aperiod of 50years(1950

1980and 2000)were analyzed in Heilongjiang Province

by investigating the historical information

small watershed survey

and remote sensing data analysis.The results indicated that:(1)The area of soil and water loss increased by 2.08×104 km2 in the past 50years

and water erosion contributed the most for the erosion.(2)During the period from 1950to 1980

the area of soil and water loss was 411.9km2

while it was 386.4km2 during the period from 1980to 2000.(3)The number of erosion gully increased 98 832during the past 50years

the area of erosion gully increased by 172.4%

and the density of gully increased by 2.83times.The deterioration of soil and water loess was attributed to the uncontrolled anthropic activities

policy direction by local government and deterioration of black soil physical properties in this region.