Soil and water resources  Certified farms are actively involved in long-term conservation of soil and water resources

Why Consider Long Term Site Productivity?  It is Basic  Increasing costs from problems with insects and diseases over time.  Need to stay competitive with other CT growing regions. First rotation field

2003 Productivity Study First Rotation D. Fir Third Rotation D. Fir

Types of Analyses Done  pH  Nutrients  Soil carbon  Atrazine/Velpa r residues  Aggregate stability  Soil density

Soil surface lacks good structure

Compaction on Christmas Tree Sites

Study Summary for Physical Properties  No widespread decline in physical properties for all sites examined.  Some sites need treatment now.  Other sites have already been restored by tillage, cover crops, or other means.

Physical Properties and Erosion  Loss in aggregate stability and\or increasing compaction can lead to erosion of surface soil.

Erosion- Poor Drainage or Concentration

Soil Erosion and PNW Climate  Most erosion occurs during rain “events” during the fall and winter.  Overland flow of water is the main culprit.

Loss of surface soil layer

Soil Erosion Following Harvest Rototilled Site Erosion After Storm Event

Treatment Strategies  Rest between planting  Plant grass cover crop  Barriers  Incorporate organic material  Don’t rip/till when wet  Minimize traffic  Deep ripping/tillage

Why Aggregate Stability Might Drop?  Excessive tillage/traffic  Erosion  Loss of organic matter

ADVANTAGES OF SOIL TILLAGE Useful when compaction is unavoidable Can treat existing compacted area Can yield other site preparation benefits Costs may be reasonable & justifiable

Winged Subsoilers shank & tine mounting & design vary

Add wings, loosen more soil

Deep Ripping Between Rotations

Mulches

Straw bales

Cover Crops

Fourth rotation field

There are many options