The soils of Eastern Oregon that are being reclaimed by means of irri- 

 gation, are mostly light in character. As a result of their light nature and 

 low cohesive power, they are subject to erosion by wind or flowing water. 



Wind action, by hindering development and cultivation, becomes an 

 important factor in reclaiming land. These conditions, however, become less 

 serious as the land is worked and improved. 



By reference to Table I it can be seen that the average wind velocity for 

 this district is very low as compared with Amarillo, Texas, and Belle Fourche, 

 South Dakota. Readings were taken once a day. As severe winds at Her- 

 miston are seldom of 24 hours duration, their maximum velocity, as shown 

 below, is frequently modified by several hours of comparatively mild wind. 



TABLE I. SHOWING COMPARATIVE WIND VELOCITY DURING THE GROWING 

 SEASON AT STATIONS IN OREGON, TEXAS, AND SOUTH DAKOTA 



Although the total mileage and maximum velocity of wind at the Texas 

 and South Dakota stations is much greater than at Hermiston, crops are 

 seldom injured by soil erosion. The soils are fairly heavy and not as easily 

 disturbed. 



When the influence of wind velocity overcomes the effects of gravity and 

 cohesion of soil particles, blowing or soil erosion takes place. The amount 

 and the rapidity of erosion depend upon the following factors: (1) degree of 

 exposure; (2) severity and frequency of wind; (3) constancy of direction of 

 the wind; (4) humidity or relative weight and drying effect of the air; (5) 

 amount of moisture present in the soil; (6) size of soil particles; (7) slope of 

 land; and (8) extent of protection afforded by crops and other protective 

 agents. 



Moving soils hinder irrigation by filling furrows, thus obstructing the 

 flow of irrigation water and rendering necessary the refurrowing of the land. 



One of the most harmful effects of soil erosion, and one that is frequently 

 overlooked, results from the removal of fine particles from the soil. The 

 finer portions, which result from weathering of rock particles, and from decay 

 of vegetable matter growing upon the soil, are sifted out and carried away, 

 whenever movement occurs. This leaves behind the coarser and heavier 

 particles that are of the least agricultural value. When blowing is allowed 

 to continue, therefore, the condition of the soil cannot be improved, since the 

 fine particles cannot be accumulated. 



