Grow Your Own, Nevada! Fall 2011: Soil Amendments, Composting and Cover CropsPresentation Transcript
Improving Nevada’s SoilsWhat is healthy soil?How does soil form?How can you improve your soil? – Compost – Amendments – Cover Crops – Mulches
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 OSU Extension Service Low salinity and sodium levels
Test Your SoilLow cost testing through UNCE – pH – EC – Soil TextureSoil Labs – contact UNCE for a list of labs
How are soils formed? A. Miller
Nevada SoilsMany challenges – Climate – Organisms – Parent material – Time – Topography
Compare horizons OSU Extension Service
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? Minerals Air Water www.statlab.iastate.edu Organic matter (humus)USDA NRCS
“Ideal” composition of a soil Mineral Water = 20 to 30% Fraction (sand, silt,clay) = 45 to 50% Air = 20 to 30% Organic Matter = 0 to 5%
Soilmineralstexturalclasses A. Miller
Thedreaded soiltexturaltriangle! A. Miller
Textural triangle for thegraphicallychallenged NRCS, Bozeman Mont.
Why determine soil texture?Soil texture influences:Water infiltration ratesWater-holding capacityEase of tillageAmount of pore space or porositySoil fertility or nutrient-holding capacity
Soil texture and drainage A. Miller Infiltration rate, Soil texture inches per hourSand 2-4Sandy loam 1-3Silt loam, loams 0.25 – 1.5Silty clay loams, clay 0.1 – 0.3
Water spreads CLAY differently Wide, but more shallow, infiltration in SILT different Moderate spread and soil infiltration textures SAND Deepestpenetration
Sand versus ClayClay - “Heavy” soil - High water-holding capacity - Slow infiltration - High nutrient-holding capacitySand - “Light” soil - Low water-holding capacity - Fast infiltration - Low nutrient-holding capacity
Where do plants get their water from in the root zone? Adapted from PNW 475 by A. Miller
Soil textureSandy soil watering tips Clay soil watering tips Emitters close to the Emitters further from plant the plant Higher volume per Lower volume per hour emitters hour emitters Low duration Higher duration Increased frequency Lower frequency
Can you change soil texture?No, not really!Add sand to clay – mess!Add clay to sand – mess!Texture may limit your plant choicesHow can you improve your soil texture? Add organic matter!
Benefits of soil organic matter Improved water infiltration Increased water- and nutrient- holding capacity Formation of soil into stable aggregates Reduced soil compaction
Nutrients held in the soil are available for plant growthlesco.com
Soil structure: How particles are grouped together intostable collections by organic matter “glue,” also called “peds” or soil aggregates www.statlab.iastate.edu/soils/ Platy Granular structure structure
Composition of a compacted soil Before After 50% 70% Note the reduced air space in a compacted soil.
Avoid walking or driving on wet soil Avoid working wet soilOSU Extension Service
The wetter the soil, the worse the compaction effect by mechanized equipment on soilextension.umn.edu
Adding organic matter:Improves water infiltrationIncreases water- and nutrient-holding capacityForms soil into stable aggregatesReduces soil compaction Also – feeds soil biota!
The living soil USDA NRCS
worm USDA NRCS
Add organic matter to your soil What kind of organic matter? Composted or well-rotted OM OSU Extension Service
OSU Extension Service What about manure?Uncomposted manure can be high in salts(burns plants and seeds) and can contain weedseeds, diseases, and insect eggs and larva.
UNCE Reno, Nev.Household vegetable debris, fallleaves and grass clippings can also be used to make compost
Types of compostingSlow composting – Less labor intensive – Slower product production – Good for folks that produce low volumesFast composting – More labor intensive – Quicker production – Good for folks that produce higher volumes
Types of compostersCompost piles – Can be messy – Easy access for animals – Harder to turn?
Types of compostersCompost tumblersBin composters – Neater, cleaner
Steps to creating a compost pile Pick 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 pilePile 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 pileIngredients – 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 Compost Green 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 not 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 not 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 pile A d d W a t e r
Steps to creating a compost pileMix 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 problemsNuisance insects and animalsFood wastes can attract themMay need to vermiculture or worm compost or compost tumble high volumes of food wastes
Composting Pros and Cons PROS CONS Recycle nutrients back Can be messy and/or into your soil smelly Reduces waste to your Can be labor intensive garbage can and landfill Can attract vermin, It is a cost-effective predators, stray dogs, etc. method of improving Can be weather dependent your soil Do you have space? Get good at producing it, you will have many Do you have time to friends wanting some manage?
What if I don’t want to compost?How about buying soil amendments? – Steer manure – Compost – Worm castings – “Triple mix” – Neighbor’s horse manure – Fireplace ashes – Gypsum
Use caution adding soil amendments!
A word about gypsumGypsum is CaSO4.H2OGood source of Calcium and SulfurGood for Sodium-Affected SoilsNOT 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:• 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 ConsPROS CONS Good quality Good quality amendments will amendments cost $ improve your soil May be introducing a No down time new problem Less labor involved Mineral amendments may not be needed
Cover 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 cropsRotation 2-3 yearsWinter cover cropSummer cover cropStrip croppingInterplanting or companion planting
Cover 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 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 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 Planting Plant strips of cover crops between garden rows to control weeds and reduce compaction Can be perennial crop
Strip 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 Crops Test 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? 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?Summer annuals (easily winter killed) – Barley, buckwheat, oats, garden peas, sorghum-Sudan grass hybridsWinter annuals (cold tolerant plants) – Hairy vetch, winter rye, alfalfa, cloverRotation cover crops – Above mentioned, can add flowers too! – Also short-lived annuals or bienials
Cover Crop Pros and ConsPROS CONS Cycle nutrients Can be labor intensive Loosen soil with deep Irrigation cost? rooted varieties Manage to prevent If use annuals that are “weeds” easily killed, easy to Winter cover crops may manage attract critters (voles, May aid pollination in rabbits, etc.) early spring May require tilling - May attract beneficial does this damage soil insects structure? May require herbicide?
Applying MulchOrganic 3-4 inchesInorganic 2-3 inches2-inch layer? That’s 6 cubic yards for 1000 square feet (50 feet by 20 feet)Weed barrier can be placed firstLeave a few inches mulch-free around base of woody plants
Organic MulchesPros Cons Enhance soil structure Can use nitrogen Increase soil fertility during initial break down Increase soil OM Break down over time – content will need to be replaced Moderate soil or replenished temperatures Fire hazard? Prevent compaction Vermin cover
Inorganic Mulches Pros Cons Prevent compaction Don’t improve soil Moderate temperature fertility Don’t deplete nitrogen Don’t add to OM content of soil Don’t break down, don’t need to be replenished Pain to remove later Can help provide drainage Can help prevent erosion and runoff Aesthetically pleasing(?)
Adding Organic Content to Your Soil - Which Method to Choose?All methods reduce erosion and runoffAll methods improve soil or plant growthHow much time do you have?How much will it cost?Comfort with the different methods?
How can I manage my soils to improve them?Avoid compaction by: • Reducing tillage of wet soils • Reducing traffic on wet soils • Establish pathsReduce erosion and runoffIncrease the organic matter content by: • Adding compost • Adding amendments • Grow a cover crop • Adding mulch