Grow Your Own, Nevada! Fall 2011: Soil Amendments, Composting and Cover Crops
-
Upload
university-of-nevada-cooperative-extension -
Category
Documents
-
view
500 -
download
1
Transcript of 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
OSU Extension Service
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
OSU Extension Service
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
OSU Extension Service
What kind of organic matter?
Composted or well-rotted OM
What about manure?
OSU Extension Service
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
Steps to creating a compost pileSteps to creating a compost pile
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.
Steps to creating a compost pileSteps to creating a compost pile
Add
Water!
Steps to creating a compost pileSteps to creating a compost pile
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