On the basis of field fixed-spot survey and investigation

soil erosion by water in rural settlements

soil erosion by earth discarding during new cave(or house) construction and soil erosion caused by cave collapse were studied in the loess hill area of North Shaanxi Province.From June of 2004 to October of 2004

the annual average soil erosion by water in rural settlements was 5 434.3 t/km2.The annual average soil erosion by water on roads(between houses)

open spaces(between houses) and yards was 7 348.0

6 873.2 and 2 081.7 t/km2

respectively.The average amount of discarded earth for a new-built cave or house was 34.9 m3

being 23.6% of the dug earth.The annual amount of discarded earth for all new caves(or houses) averaged over recent 20 years in the abundant and coarse sediment area of Yulin and Yan'an was as much as 7.96×10-7 m3

with annual soil loss by earth discarding up to 5.17×106 m3(7.76×106 t).According to the accumulated volume formed by 102 caves(houses) investigated

the annual earth loss per cave(or house) collapse was 46.3 m3.The annual amount of earth loss caused by cave collapse in Yulin was as much as 1.25×10-7 m3 (1.87×10-7 t).The above data show that the development of rural settlements brings out the more serious soil erosion.More attentions must be paid to the study

prevention and control of soil erosion in the region.