Soil and water resources

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

Why Consider Long Term Site Why Consider Long Term Site Productivity?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 Study2003 Productivity Study

First Rotation D. FirFirst Rotation D. Fir Third Rotation D. Fir Third Rotation D. Fir

Types of Analyses Done pHpH NutrientsNutrients Soil carbonSoil carbon Atrazine/Atrazine/

Velpar Velpar residuesresidues

Aggregate Aggregate stabilitystability

Soil densitySoil density

Soil surface lacks good structureSoil surface lacks good structure

Compaction on Christmas Tree Sites

Study Summary for Physical Properties

No widespread decline in physical properties for all sites No widespread decline in physical properties for all sites examined.examined.

Some sites need treatment now.Some sites need treatment now.

Other sites have already been restored by tillage, cover Other sites have already been restored by tillage, cover crops, or other means.crops, or other means.

Physical Properties and Physical Properties and ErosionErosion

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

Erosion- Poor Drainage or Concentration

Soil Erosion and PNW ClimateSoil 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 layerLoss of surface soil layer

Soil Erosion Following HarvestSoil Erosion Following Harvest

Rototilled SiteRototilled Site

Erosion After Storm Event

Treatment StrategiesTreatment 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 Why Aggregate Stability Might Drop?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 SubsoilersWinged Subsoilers

shank & tine mounting & design vary

Add Add wingswings, loosen , loosen moremore soil soil

WingedSubsoiler

DiskHarrow

Soil moisture dry moist to dry

Soil texture all but clayey(large clods)

all textures, including clayey

Rocks & roots up to heavy amounts OK

minimal

Slope limit - downhill

40% 20%

Slope limit - cross slope

15% 10%

Winged Subsoiling vs. Disking:Conditions for Effective Tillage

Andrus & Froehlich 1983

Deep Ripping Between Deep Ripping Between RotationsRotations

MulchesMulches

Straw bales

Cover Crops

Fourth rotation field

There are many options