Best Practices—Nurturing Soil

• Build healthy soil, don’t replace it

• Clay is great—why?

• Mulch all plants

• Mix in compost to vegetable beds each growing season

• (Optionally) Add organic fertilizer to vegetable beds each growing season, but not to most ornamental beds

• Grow cover crops and then chop up and add to soil in vegetable beds (“green manure”)

• Prevent soil compaction (one tip: grow in beds, not rows)

Soil and climate change Much more carbon stored in soil than air, including but

not limited to wetlands, peat and permafrost

Erosion of rocks creates soil particles: clay, silt, and sand

Soil Texture—Test by Hand

Sandy Clayey

Solids + pore space = Soil Aggregates

“Something’s destroying my soil aggregates!”

• Tillage—sheers apart aggregates. Short term: increases large pores. Long term: decreases, and can lead to “tillage pans.” Severs earthworm channels. Severs fungi.

• Walking (and other compaction)—Breaks down and re-structures soil. Tip: use beds, not rows.

• Raindrops—Break down aggregates on surface, which can then form crust. Very difficult for water to enter crust, or seedlings to push up through crust. Also—can lead to erosion.

But wait! Something’s helping!

• Root growth promotes aggregation! Roots feed organisms. Roots wetting/drying causes (helpful) cracks. Decaying roots form channels for water and air.

• Adding organic material helps aggregation!—or, why to add compost. Critical to develop crumb and granular structures. Helps form large pores.

• Mulching protects soil from wind erosion, rain compaction. Helps retain water. Overall, helps maintain good soil structure.

What is mulch?

Mulch is anything that covers bare soil:

• Wood chips• Compost• Straw• Plastic

Why mulch?• Conserves soil moisture root growth

• Adds organic matter to soil

• Insulates roots from temperature extreme

• Keeps down weeds (caveat …)

• Prevents topsoil erosion

• Looks attractive

Dozens of mulches• Pine: Bark, Bays of needles, Nugget – acidic,

loved by rhodies and azaleas• Cypress or Cedar – aromatic• Straw bales• Dyed

Organic or synthetic mulch?

Non-organic mulches

Organic mulch

Organic mulch

How to Mulch

• Remove weeds

• Water

• Spread 2-6” of mulch across soil surface

• Keep 6-12” away from base of shrubs and trees

• Keep mulch on top of soil to avoid nitrogen tie-up

Do not make Mulch Volcanoes around trunks!

Mulch helps retain soil moisture

Prolonged moisture around trunk can lead to cankers and root rot

Mulch can interfere with respiration of cambium, phloem- it limits exchange of CO2 & O2 with air

© 2001-2006 Clay County© UC SAREP

Cover CropsCover Crops

Grasses and Grains as cover crops

Green Manure: Fava beans

Fava beans

How to dig in your green manure . . .

Fertilizing: Adding Essential Plant Nutrients to the Soil

from air, H2O primary secondary micronutrients

Nitrogen availability after adding high C/N ratio organic matter to soil

Myths

• “My plant’s problem is due to nutrient deficiency”

• “Compost tea is best”

• “I worry that city compost isn’t safe”

Avoid

• Peat—you don’t need it, don’t use it

SUMMARYSustainable Practices: Soil• “Grow” your soil, don’t replace it.

• Make compost at home.

• Use organic compost, mulch, fertilizer.

• Avoid pesticides and herbicides. Dig, hoe or smother weeds. Use hand labor when possible.

• Grow cover crops, turn in green manure.

• Add only the nutrients needed.

• Don’t over-till.

• Prevent soil compaction by growing in beds, not rows.