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Home , Soil biology, Soil functions, Soil life, Soil texture

Organic & Biological properties of

Structure Clumps / clods peds Density weight / volume Texture pore space / Carbon N P K + pH

Acidity Air and water movement / / soil profile movement and Air water Organic Properties Soil formation of Soil – biology in action!

Nutrient cycling & availability bio-chemical, bio-physical, & ecological processes

Structure: peds & pores Soil development processes, from parent “dirt” &

Soil horizons & their evolution

• Substratum (C) or bedrock (R) weathers physically & chemically to (B)

• Primarily biological processes create (A) and organic (O) horizons

USDA - NRCS http://soils.usda.gov Understanding Soil Biology provides essential functions

Soil is alive!

USDA-NRCS “Soil Biology Primer” S. Rose & E.T. Elliott http://soils.usda.gov/sqi/ Common in the soil foodweb

Fungi

Earthworms

Protozoa What Fuels the Soil Foodweb?

Plant : Sunlight  living and dead organic matter

Plants exude 20-30% of their photosynthetic energy as released in the root zone to feed beneficial soil organisms (bacteria & fungi). Restoring soil life, to restore

Soil organisms create: • • fertility = cycling • disease protection • Bio-filtration • control • stormwater detention & moisture capacity

Compost kickstarts the soil ! (Provides food and home for organisms) How does soil life create soil structure?

• Bacteria secretions glue clays, and together into micro-aggregates. • Micro-aggregates are bound together by fungal hyphae, root hairs and roots. • Spaces are made by moving arthropods & , and decaying roots. • Only when all organisms are present can roots and water move into the soil with ease.

S. Rose & E.T. Elliott How does soil life and increasing organic matter increase plant-available storage?

Increased structure, pore space, and soil colloids.

Organic Matter % How does soil life provide fertility (nutrient cycling)? • Soil foodweb stores nutrients in living & dead organic matter • Nutrients are released in root zone as organisms eat and excrete “waste” (, etc.) • Mycorrhizal fungi bring nutrients and water to roots of

Dr. Michael P. Amaranthus, Mycorrhizal Applications Inc. How does soil life provide plant disease protection? Diversity  predation, parasitization & competition with the few disease-causing organisms

• Bacteria cover leaf surfaces, block infection

• Ecto- and endo- mycorrhizae

prevent root Soil Foodweb Inc. infection

• Many organisms prey on the few disease-causing organisms

SSSA How does soil life filter out urban pollutants?

• Creates structure • Breaks down hydrocarbons, pesticides • Converts to stable forms, so they are available to plants but won’t wash away • Binds heavy metals in soil, so they don’t wash into streams How does soil life control erosion? • Creates pore spaces, increases • Sticks soil particles & aggregates together with bacterial slime, fungal hyphae, & root hairs (bigger aggregates are harder to move)  “aggregate stability” • Promotes rapid plant growth & deep root development How does soil life provide stormwater detention / infiltration? • Builds soil structure, moisture-holding capacity • Increases surface

UW trials, turf on glacial till soil

Compost- amended till soil – up to 50% reduction in storm water runoff How can we enhance & restore soil , to improve plant growth, water quality, and reduce runoff?

• Prevent /reduce compaction (keep heavy machinery off) • Reduce intensive use of pesticides & soluble fertilizers • Incorporate compost into soil, and mulch regularly, to feed soil life

organic matter + soil organisms + time creates  soil structure, biofiltration, fertility, & stormwater detention Protecting and restoring soil functions • Plan to preserve existing soil & vegetation where possible • Minimize grading, cut and fill • Minimize traffic off road bases • Even a low-organic subsoil can be substantially restored by amending 10-25% (by volume) with mature, stable compost.

16 Clearing up the confusion about “% organic”

“% Content” in lab soil tests is by loss-on-ignition method - Most /plant materials are 40-70% organic content by this method. ?

Recommended soil amendment rates (for low-organic soils or soil/compost topsoil mixes): • At least 3% Soil Organic Matter (by lab test) for soils = 10-15% compost amendment into soil by volume • 5-8% Soil Organic Matter (by lab test) for Turf/Landscape =15-25% compost amendment by volume • 10% Soil Organic Matter (by lab test) for Stormwater bioretention soil mixes

= 30-40% compost amendment by volume 17 Restoring soil in place • Place sub-drainage if req’d • Range of equipment for different-sized sites • If compacted, rip (scarify) to 12-18” depth before or while amending • 2-4” compost mixed into upper 8-12” of soil

18 Add Compost: Most of it in the top layer of the soil profile – mimic natural profile!

19 How to Select Compost Know your supplier!

Field tests: Mfr.-supplied info: – earthy smell - not sour, – State permitted composting facility stinky, or ammonia – Meets US Compost Council (STA) – brown to black color “Seal of Testing Assurance” – uniform particle range TMECC lab test methods, specs: – stable temperature (does not • C:N ratio get very hot if re-wetted) • Weed-seed trials – not powdery or soaking wet • Nutrients, salinity, contaminants Soil/compost lab test info: • Size: “screen”, % fines – Nutrients Stability /Maturity: - use Solvita test on-site (> 6) – Salinity or – pH - rely on mfr’s TMECC tests: CO2 – % organic content (OM) evolution and seedling growth 20 Carbon to Nitrogen ratio of composts • For turf & most landscapes C:N ratio of 20:1 to 25:1 - good nutrient availability for first year of growth (no other needed)

• For native plants and C:N ratio of 30:1 to 35:1, and coarser (1” minus screen) – less Nitrogen better for woody natives, discourages weeds – for streamside, unlikely to leach nitrogen Match Compost feedstocks for tree soil amendment compost C:N and nutrients • Generally, yard waste &/or bark compost to plant – Higher carbon, lower nitrogen – Maturity / stability very important needs • Possibly biosolids, manure fully composted with wood – Watch the nutrients, C:N, stability/maturity – caution! 21 Compost Based BMPs

• EPA-approved BMPs: blankets, berms, and socks see www.buildingsoil.org • “2 for 1” value – use compost for erosion control, then till in at end to restore soil: - No disposal costs - Faster planting, better growth • Costs: blankets similar to rolled products, but savings on disposal, plus 2 for 1 benefits

More info at www.BuildingSoil.org 22 Resources to learn more: WSU www.puyallup.wsu.edu/soilmgmt/Soils.html see videos and factsheets on “Collecting a soil sample”, “ “Determining by hand”, “Understanding soil tests”; plus more info for gardeners at www.puyallup.wsu.edu/soilmgmt/Gardening.html

Building Soil Manual: construction best practices www.BuildingSoil.org or www.SoilsforSalmon.org

Low Impact Development Manual for Puget Sound http://www.psp.wa.gov/LID_manual.php Soil Biology Primer http://soils.usda.gov/sqi/concepts/soil_biology/biology.html

Up by Roots: by James Urban: practical and strategies for successful urban landscapes (available on Amazon)