Si
silt loam

Mapping Symbol: Sn 

The Si series consists of moderately well-drained soils that formed under grass and hardwoods in alluvium on stream terraces near North Bend. Slopes are 0 to 2%, annual precipitation is 70 to 80 inches, mean annual air temperature is about 50 degrees F, and the frost-free season is about 150 days.

Typical Profile:
Depth from Surface:
0 to 25 Inches: Dark grayish-brown silt loam
25 to 60 Inches: Mottled dark grayish-brown, very dark gray, and olive-gray stratified silt loam, loamy sand, and very fine sandy
loam

Permeability: Moderate

Rooting Depth: 60 inches +

Depth to Seasonal High Water Table: 2 to 4 feet

Available Water Holding Capacity: High

Runoff Potential: Slow 

Erosion and Slippage Hazard: Slight

Stream Overflow Hazard: Moderate

Use and Management: Primary uses are for row crops and pasture. Pasture forage yields are 5.0 tons/acre/year. Douglas-fir, Western Red Cedar, Red Alder, and Bigleaf Maple are important tree species. These soils have severe limitations for forestry because of plant competition. These soils have moderate to severe limitations on engineering uses and moderate limitations on recreational uses due to their seasonal high water table and flood hazard.

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