Grow Your Own, Nevada! Fall 2011: Soil Amendments, Composting and Cover Crops

Improving Nevada’s SoilsImproving Nevada’s Soils

What is healthy soil?

How does soil form?

How can you improve your soil?

– Compost

– Amendments

– Cover Crops

– Mulches

OSU Extension Service

Healthy soil has:Healthy soil has:

Good porosity

Good drainage

Good water-holding capacity

Good tilth, meaning they’re easy to work

Lots of organic matter

Lots of organisms

A pH of about 7

Low salinity and sodium levels

Test Your SoilTest Your Soil

Low cost testing through UNCE

– pH

– EC

– Soil Texture

Soil Labs – contact UNCE for a list of labs

How are soils formed?How are soils formed?

A. Miller

Nevada SoilsNevada Soils

Many challenges

– Climate

– Organisms

– Parent material

– Time

– Topography

comcast.net

scioly.org

ucanr.org

Compare horizonsCompare horizons


It’s not your fault!It’s not your fault!

Nevada soils are:

– Young, geologically

– Complicated by new inputs

– Formed in the desert, so alkaline (high pH)

– Formed in the desert, so low organic content

What are soils made of?What are soils made of?

Minerals

Air

Water

Organic matter (humus)

www.statlab.iastate.edu

USDA NRCS

Water = 20 to 30%

Air = 20 to 30%

Mineral Fraction

(sand, silt,clay) = 45 to 50%

Organic Matter = 0 to 5%

““Ideal” composition of a soilIdeal” composition of a soil

Soil Soil minerals minerals textural textural classesclasses

A. Miller

The The dreaded dreaded

soil soil textural textural triangle!triangle!

A. Miller

NRCS, Bozeman Mont.

Textural Textural triangletrianglefor the for the

graphically graphically challengedchallenged

Why determine soil texture?Why determine soil texture?

Soil texture influences:

Water infiltration rates

Water-holding capacity

Ease of tillage

Amount of pore space or porosity

Soil fertility or nutrient-holding capacity

Soil texture and drainageSoil texture and drainage

Soil textureInfiltration rate, inches per hour

Sand 2 - 4

Sandy loam 1 - 3

Silt loam, loams 0.25 – 1.5

Silty clay loams, clay 0.1 – 0.3

A. Miller

Water Water spreads spreads differently differently in in different different soil soil texturestextures

Deepest penetration

Moderate spread and infiltration

Wide, but more shallow, infiltration

CLAY

SILT

SAND

Sand versus ClaySand versus ClayClay - “Heavy” soil

- High water-holding capacity

- Slow infiltration

- High nutrient-holding capacity

Sand- “Light” soil

- Low water-holding capacity

- Fast infiltration

- Low nutrient-holding capacity

Where do plants get their water Where do plants get their water from in the root zone?from in the root zone?

Adapted from PNW 475 by A. Miller

Soil textureSoil texture

Sandy soil watering tips

Emitters close to the plant

Higher volume per hour emitters

Low duration

Increased frequency

Clay soil watering tips

Emitters further from the plant

Lower volume per hour emitters

Higher duration

Lower frequency

Can you change soil texture?Can you change soil texture?

No, not really!

Add sand to clay – mess!

Add clay to sand – mess!

Texture may limit your plant choices

How can you improve your soil texture? Add organic matter!

Soil organic matter consists of:Soil organic matter consists of:

Living organisms

Dead organisms

Plant matter

Other decomposing organic materials

Benefits of soil organic matterBenefits of soil organic matter

Improved water infiltration

Increased water- and nutrient-holding capacity

Formation of soil into stable aggregates

Reduced soil compaction

Nutrient-holding capacityNutrient-holding capacity

Water moleculeWater molecule

Nutrients Nutrients held in the held in the

soil are soil are available available for plant for plant growthgrowth

lesco.com

Platy structure

Granular structure

www.statlab.iastate.edu/soils/

Soil structure:Soil structure:How particles are grouped together into stable

collections by organic matter “glue,” also called “peds” or soil aggregates

Soil StructureSoil Structure

Composition of a compacted soilComposition of a compacted soil

Note the reduced air space in a compacted soil.

Before After

70%50%

Soil CompactionSoil Compaction

Soil compaction Soil compaction

Avoid walking or driving on wet soilAvoid working wet soil


extension.umn.edu

The wetter The wetter the soil, the the soil, the worse the worse the

compaction compaction effect by effect by

mechanized mechanized equipment equipment

on soilon soil

Adding organic matter:Adding organic matter:

Improves water infiltration

Increases water- and nutrient-holding capacity

Forms soil into stable aggregates

Reduces soil compaction

Also – feeds soil biota!

USDA NRCS

The living soilThe living soil

wormworm

USDA NRCS

Add organic matter to your soilAdd organic matter to your soil


What kind of organic matter?

Composted or well-rotted OM

What about manure?


Uncomposted manure can be high in salts (burns plants and seeds) and can contain weed seeds, diseases, and insect eggs and larva.

Household vegetable debris, fall leaves and grass clippings can also be used to make compost

UNCE Reno, Nev.

Types of compostingTypes of composting

Slow composting

– Less labor intensive

– Slower product production

– Good for folks that produce low volumes

Fast composting

– More labor intensive

– Quicker production

– Good for folks that produce higher volumes

Types of compostersTypes of composters

Compost piles

– Can be messy

– Easy access for animals

– Harder to turn?

Types of compostersTypes of compostersCompost tumblers

Bin composters

– Neater, cleaner

Steps to creating a compost pileSteps to creating a compost pilePick a site

– Level, well-drained

– Build on bare soil for bacteria

– Shade

– Near water and source of raw materials

– Esthetically pleasing?

Steps to creating a compost pileSteps to creating a compost pile

Pile size

– Cool or slow composting

– Hot or active composting

• At least a cubic yard (3’ x 3’ x 3’)

• Not more than 5’ cube


Ingredients

– Ratio of 1:2 (1:1) green to brown material

– Finer the size, quicker to compost

– Too fine and it will compact 1-1.5” is best

– Sprinkle some soil or finished compost every 8 to 12 inches as you build the pile

What to CompostWhat to CompostGreen Materials

– Grass clippings

– Animal manure (from herbivores only)

– Non-animal-based kitchen wastes

– Garden trimmings

Dry or Woody (“Brown”) Materials

– Fall leaves, dry cornstalks

– Wood chips or sawdust (caution)

– Hay or straw (soiled or clean)

What What notnot to compost to compost Yard trimmings or grass clippings treated with

pesticides. They may kill the beneficial organisms in the compost pile or later in your garden.

Weeds, if the pile will not be hot enough to kill the seeds.

Diseased or insect-infested plant parts. The diseases or insects may be transferred to the soil with the compost.

Parts of any plant known to contain poisons or toxins, such as black walnut.

Too much of any plant that contains tannins or resins that inhibit decomposition, such as junipers, pine, spruce, arborvitae, oak or cottonwood.

Meat or fish bones or scraps. Dairy products.

What What notnot to compost to compost Charcoal ash, as this may contain substances harmful

to plants.

Fireplace ashes, since they have a very high pH, as do our native soils. High pH levels can result in nutrient deficiencies and other plant problems.

Fats, grease, lard or oils. These do not break down quickly and may attract pests, vermin, dogs or large carnivores.

Pet wastes, such as dog or cat feces or soiled cat litter. They may contain parasites, bacteria or viruses harmful to humans.

Swine or other omnivore wastes. They also may contain parasites, bacteria or viruses harmful to humans.


Add

Water!


Mix the pile

– Weekly for hot or active composting

– Whatever for slow or cool composting

– Should reach 120 to 160 degrees

– After 6-8 weeks of cooking, pile needs to cure for another 4-8 weeks

– Turn pile while it is curing also

Preventing problemsPreventing problems

Nuisance insects and animals

Food wastes can attract them

May need to vermiculture or worm compost or compost tumble high volumes of food wastes

Compost troubleshootingCompost troubleshooting

Composting Pros and ConsComposting Pros and Cons

PROS Recycle nutrients back

into your soil

Reduces waste to your garbage can and landfill

It is a cost-effective method of improving your soil

Get good at producing it, you will have many friends wanting some

CONS Can be messy and/or

smelly

Can be labor intensive

Can attract vermin, predators, stray dogs, etc.

Can be weather dependent

Do you have space?

Do you have time to manage?

What if I don’t want to What if I don’t want to compost?compost?

How about buying soil amendments?

– Steer manure

– Compost

– Worm castings

– “Triple mix”

– Neighbor’s horse manure

– Fireplace ashes

– Gypsum

Use caution adding soil Use caution adding soil amendments!amendments!

A word about gypsumA word about gypsumGypsum is CaSO4

.H2O

Good source of Calcium and Sulfur

Good for Sodium-Affected Soils

NOT a panacea for clay soils!

Too much Ca can interfere with chemical balance in soil and can contribute to a magnesium deficiency and interfere with other micronutrient availability

Sulfur:Sulfur:

• Essential plant food for production of protein

• Promotes activity and development of enzymes and vitamins

• Helps in chlorophyll formation

• Improves root growth and seed production

• Helps with vigorous plant growth and resistance to cold

Amendment Pros and ConsAmendment Pros and Cons

PROS Good quality

amendments will improve your soil

No down time

Less labor involved

CONS Good quality

amendments cost $

May be introducing a new problem

Mineral amendments may not be needed

Cover Crops or Green ManureCover Crops or Green ManurePlants grown NOT for crops but for

incorporation back into the soil

– Improves soil organic matter content

• Improves fertility (legumes add nitrogen)

• Improves soil biota

• Recycles plant nutrients

– Helps control erosion

– Helps reduce runoff and weeds

– Prevents compaction (deep roots, such as alfalfa, sweet clover or mustards)

Ways to use cover cropsWays to use cover crops

Rotation 2-3 years

Winter cover crop

Summer cover crop

Strip cropping

Interplanting or companion planting

Cover Crop RotationCover Crop Rotation

2-3 year program

Plant crop one year, cover crop the next or every third year

Good for annual crops, not perennials

Winter Cover Crop Winter Cover Crop Plant cold tolerant cover

crops in late summer

Allow to grow until following spring

Cover crop is turned under and composts in place or mowed and mulched or composted

Careful to let start to decompose before planting crops 4-6 weeks

Summer Cover CropSummer Cover Crop

Plant summer annual after spring crop

Reduces weeds and compaction

Plan on planting a cover crop that is easily winter killed

Watch seed production

Interplanting or Companion PlantingInterplanting or Companion Planting

Plant strips of cover crops between garden rows to control weeds and reduce compaction

Can be perennial crop

Strip CroppingStrip Cropping

Plant cover crop in early spring

Till out strip for crop and sow crop

When crop is established, till cover crop under

Use caution that cover crop does not take over crop!

Managing Cover CropsManaging Cover CropsTest and prepare the soil like any other crop.

Irrigate the cover crop, just like any other crop.

Incorporate the cover crop before it blooms! Otherwise, you’ve planted a weed!

Mow, chop, rototill or disc into the soil to speed up the decomposition process. Young plants.

Remember, it will use soil nutrients as it decomposes, so plan ahead! 4-6 weeks!

You can chop, mow or pull and put it in a compost pile, if the mass is too large or the time before planting your crop is too small.

What to plant as a cover crop?What to plant as a cover crop?

Plants that produce a lot of leaves and stems and/or deep roots, BUT are easily killed by weather, chopping or pulling.

Plants that are easily knocked down with herbicides, if you decided to go that route.

Do you want to loosen your compacted soil? Plant deep-rooted cover crops such as oats, rye or alfalfa.

Plants that can serve as livestock fodder as a removal method.

What to plant as a cover crop?What to plant as a cover crop?Summer annuals (easily winter killed)

– Barley, buckwheat, oats, garden peas, sorghum-Sudan grass hybrids

Winter annuals (cold tolerant plants)

– Hairy vetch, winter rye, alfalfa, clover

Rotation cover crops

– Above mentioned, can add flowers too!

– Also short-lived annuals or bienials

Cover Crop Pros and ConsCover Crop Pros and Cons

PROS

Cycle nutrients

Loosen soil with deep rooted varieties

If use annuals that are easily killed, easy to manage

May aid pollination in early spring

May attract beneficial insects

CONS

Can be labor intensive

Irrigation cost?

Manage to prevent “weeds”

Winter cover crops may attract critters (voles, rabbits, etc.)

May require tilling - does this damage soil structure?

May require herbicide?

MulchesMulches

Cover soil

Reduces:

– Crusting

– Compaction

– Weeds

Insulate roots

Aesthetics – design element

xeriscapeweb.com

MulchesMulches

Organic

– Bark

– Straw

– Nut shells

Inorganic

– Rock

– DG – decomposed graniteSunset

Applying MulchApplying Mulch

Organic 3-4 inches

Inorganic 2-3 inches

2-inch layer? That’s 6 cubic yards for 1000 square feet (50 feet by 20 feet)

Weed barrier can be placed first

Leave a few inches mulch-free around base of woody plants

Organic MulchesOrganic Mulches

Pros Enhance soil structure

Increase soil fertility

Increase soil OM content

Moderate soil temperatures

Prevent compaction

Cons Can use nitrogen

during initial break down

Break down over time – will need to be replaced or replenished

Fire hazard?

Vermin cover

Inorganic MulchesInorganic MulchesPros

Prevent compaction

Moderate temperature

Don’t deplete nitrogen

Don’t break down, don’t need to be replenished

Can help provide drainage

Can help prevent erosion and runoff

Aesthetically pleasing(?)

Cons

Don’t improve soil fertility

Don’t add to OM content of soil

Pain to remove later

Adding Organic Content to Your Adding Organic Content to Your Soil - Which Method to Choose?Soil - Which Method to Choose?

All methods reduce erosion and runoff

All methods improve soil or plant growth

How much time do you have?

How much will it cost?

Comfort with the different methods?

How can I manage my soils to How can I manage my soils to improve them?improve them?

Avoid compaction by:• Reducing tillage of wet soils

• Reducing traffic on wet soils

• Establish paths

Reduce erosion and runoff

Increase the organic matter content by: • Adding compost

• Adding amendments

• Grow a cover crop

• Adding mulch

Documents

Grow Your Own, Nevada! Fall 2011: Soil Amendments, Composting and Cover Crops