Mary Bianchi University of California Cooperative Extension

Our agenda for today  Basic soil principles  The things we add to our soils  Amendments  Mulches  Compost  Fertilizers

Soils for the Gardener  Why are Soils Important to Sustainability?  Landscapes with local conditions in mind  Optimal growing conditions, or  The right plant in the right place!  Landscapes that conserve and protect  Water, air and soil quality  Energy  Landscapes that send less to the landfill  Composting, recycling, water and fertilizer conservation

Soils for the Gardener  The Soil Habitat  Webster’s Dictionary definition of habitat:  the site where a plant normally lives and grows

Copyright 1999 Oregon State University Soils for the Gardener

Soil Profile

What will the roots experience in this soil? Photo by Jim Fortner, USDA NRCS

Soils for the Gardener  What would a root need to thrive in the soil habitat?  Space  Air  Water  Food  Diversity!!

Soils for the Gardener  What would a root need to survive in the soil habitat?  Space

Do these roots need different spaces? Copyright 1999 Oregon State University Soils for the Gardener

Courtesy of Southern Nevada Water Authority Roots Under Perfect Growing Conditions

Soils for the Gardener  What would a root need to survive in the soil habitat?  Space  Think vertically!  How can you give a root more room to grow vertically?

Soils for the Gardener  What would a root need to survive in the soil habitat?  Air  Respiration

Soils for the Gardener  Pore space  Pore space is the conveyor of oxygen, water, dissolved nutrients and provider of space for root growth  Soil texture and soil structure influence the amount of pore space in the soil

 Soil texture is the percentage of  Sand  Silt  Clay

Soils for the Gardener Can you change soil texture?  Remember soil texture is the percentage of  Sand  Silt  Clay

Soils for the Gardener Courtesy of Soil Science Society of America Soil Textural Triangle % clay % silt % sand 100% clay 100% sand 100% silt

Soils for the Gardener Courtesy of Soil Science Society of America Soil Textural Triangle clay silt sand

Soils for the Gardener Courtesy of Soil Science Society of America Soil Textural Triangle

Soils for the Gardener Courtesy of Soil Science Society of America Soil Textural Triangle Sandy loam

Soils for the Gardener Courtesy of Soil Science Society of America Soil Textural Triangle Loam 50-70% clay 30-50% silt 25-50% sand

Estimating Soil Texture

From Colorado State Master Gardener Fact Sheet #214

 Soil texture affects pore space  Sandy soils have fewer, larger pore spaces  Clay soils have more, smaller pore spaces Advantages? Disadvantages?

Water infiltrates in Hagerstown silt loam – Penn State Soils 101

Wetting front advances through the Hagerstown and a bit into the high clay soil to the right in this photograph.

The wetting front has reached the coarse sand. What is happening here?

Another view as the wetting front reaches the boundary between the Leetonia and the coarse sand.

Look at what is happening at the Leetonia/coarse sand boundary!

Finally the water breaks through the coarse sand layer.

The water has made it through the coarse sand and gravel and is advancing into the Hublersburg.

A good final shot of the wetting front.

Soils for the Gardener  Soil structure  Soil structure refers to form of aggregates  Except for sands, soil particles don’t exist as single particles but as aggregates

 Soil structure  Soil structure refers to form of aggregates  Except for sands, soil particles don’t exist as single particles but as aggregates

Soils for the Gardener  We want to improve pore space  Air  Space for roots  Water  Nutrients  How can we do it?

 Structure and diversity go hand in hand  Organic matter in the soil affects soil structure  Humus, plant and microbial exudates, and earthworm activity act as “binding” agents for improving soil structure.

Soils for the Gardener Lumbricus spp. - Nightcrawler

SOILS FOR THE GARDENER  A wonderful earthworm website

Soils for the Gardener  What would a root need to survive in the soil habitat?  Water

Soils for the Gardener er  Wat er  There’s two kinds of people in the world:

Soils for the Gardener  Water  There’s two kinds of people in the world:  Those that over-water  Those that under-water

Water Conservation  Know your soil reservoir  Rooting depth of the plant

How deep to water  Leafy vegetables and annual bedding plants  6 inches to 1 foot  Small shrubs, cool-season turf, corn, tomatoes  1 to 2 feet  Large shrubs, trees, warm-season turf  1.5 to 5 feet

Water Conservation  Know your soil reservoir  Rooting depth of the plant  Soil water holding capacity

Soil water characteristics for typical soil texture classes Soil TexturePlant-available water per foot of soil depth Gallons of water per cubic foot of soil Sand0.5 – – 0.66 Sandy loam1.0 – – 1.00 Clay loam1.5 – – 1.33 Clay1.5 –

Water Conservation  Know your soil reservoir  Soil water holding capacity  Rooting depth of the plant  Track storage capacity of the reservoir  “Feel Test” pg 79 MG Handbook

Water Conservation  Know your soil reservoir  Soil water holding capacity  Rooting depth of the plant  Track storage capacity of the reservoir  “Feel Test” pg 79 MG Handbook  Soil Moisture Meters

Water Conservation  Know your soil reservoir  Soil water holding capacity  Rooting depth of the plant  Track storage capacity of the reservoir  “Feel Test” pg 79 MG Handbook  Soil Moisture Meters  Set Priorities

What about fruit trees?

Soils for the Gardener  What are the impacts of over-watering on the habitat of the plant?  Remember the roots need  Space  Air  Water  Food

Soils for the Gardener  What are the impacts of over-watering on the habitat of the plant?  Pore spaces are filled with water  Roots can’t respire  Nutrient uptake reduced  Disease incidence may increase  Impacts on other soil microflora and fauna

Soils for the Gardener  What are the impacts of under-watering on the habitat of the plant?

Soils for the Gardener  What are the impacts of under-watering on the habitat of the plant?  Water requirements of plant not met  Less root growth  Less nutrient uptake  Impacts on other soil microflora and fauna

 It’s time to switch presentations and take time to stand and stretch!!

Soils for the Gardener  What would a root need to survive in the soil habitat?  Food - Is the root a fussy eater?

 Plant nutrients  the root does not care whether its nutrients were derived from organic or inorganic sources – advantages?

NUTRIENTS  PLANTS NEED MANY BASIC ELEMENTS FOR PLANT GROWTH – -NITROGEN (N) -MANGANESE (Mn) -PHOSPHORUS (P) -BORON (B) -POTASSIUM (K) -CHLORINE (Cl) -CALCIUM (Ca) -COPPER (Cu) -SULFUR (S) -MOLYBDENUM (Mo) -MAGNESIUM (Mg) -OXYGEN (O) -IRON (Fe) -CARBON (C ) -ZINC (Zn) -HYDROGEN (H) -NICKEL (Ni)

Soils for the Gardener  Plant nutrient deficiencies  Absolute deficiency  Nutrient is absent from soil  What type of soils?  Addition of organic matter may not provide all that the root needs  will increase the ability of the soil, especially sandy soils, to hold onto nutrients

Soils for the Gardener How does the deficiency of zinc affect the roots? Courtesy of Ohio State University How does that affect the deficiency in zinc?

Soils for the Gardener  Plant nutrient deficiencies  Induced deficiency  Nutrient is present in adequate amounts  Something is preventing its uptake  ?

 Induced deficiency  Nutrient is present in adequate amounts  Something is preventing its uptake  Low water availability  Low oxygen availability  Damage to root system from disease  Soil pH

Soil pH measures active acidity (Source: "Nutrient Management for Agronomic Crops in Nebraska," EC01-155)

pH of the soil  Relative acidity or alkalinity  Function of hydrogen ion concentration  Acid soils have pH =< ?  Alkaline soils have pH=> ?

pH of the soil  Most plants prefer pH = ?  What are some exceptions?  Why is a neutral pH preferred?

Effect of soil pH on nutrient availability

Our next topic for today  Basic soil principles  The things we add to our soils  Amendments  Mulches  Compost

Fertilizers and Soil Amendments  Which one is it?  Fertilizers affect plant growth directly  improve the supply of available nutrients  Amendments affect plant growth indirectly  improve the soil’s physical condition

Amending Landscape Sites Courtesy of UC OHRIC

Fertilizers and Soil Amendments  When should you amend a landscape soil?  Amendments affect plant growth indirectly  improve the soil’s physical condition

Amending Landscape Sites Courtesy of UC OHRIC

Amending Individual Planting Sites Courtesy of UC OHRIC

Amending Annual Planting Sites Courtesy of Aggie Horticulture, TAMU

Photo courtesy of Gary Johnson University of Minnesota Extension Service Amending planting sites for trees and why we don’t recommend it

Fertilizers and Soil Amendments  When should you amend a landscape soil?  Not all sites require amendments  Important to clearly identify the problem  Chemical  Physical

Fertilizers and Soil Amendments  Chemical Problems in Landscape Soils  Where soil pH is high - sulfur  takes time - mediated by microorganisms  temperature and moisture dependent  Where soil pH is low - lime  can increase rather quickly  Soluble Salts

Soluble salts come from several sources  Salt moves with water  Salts that ARE dissolved in water  Salts that are ADDED to water  Salts that GET dissolved in water

A – Components of Salinity Cations: Ca ++ Mg ++ Na + (toxic ion) K + Anions: Cl - (toxic ion) SO 4 -- CO 3 -- HCO 3 - NO 3 - (nitrates) pHSpecific Ion Toxicity: Na, Cl, Boron Alkalinity: CO HCO 3 -

A - Salts in water 1 acre-ft of water with an EC =1 contains 1 ton of salt or 2 tablespoons of salt per 10 gallons

Salt Accumulation with Drip Irrigation Drip line Salt Accumulation Balancing deep percolation with distribution uniformity with...

What is Compost???? UC definition of Compost: “Compost is the biologically active material that results from microbial decomposition of organic matter under controlled conditions.” (Compost Production and Utilization, UC ANR Pub. #21514)

Felder Rushing’s Two Rules of Composting: 1)Stop throwing that stuff away! 2)Pile it up somewhere!

A Compost Pile is an Ecosystem Function = decomposition of organic matter

The Compost Process depends on:  Organic Matter Composition  Carbon (Browns)  Nitrogen (Greens)  Microorganisms  Macroorganisms  Water  Oxygen  Temperature

Organic Matter: Carbon or “Browns”  Carbon rich sources are called “browns”  Usually dry, low moisture content, lightweight  Examples: dry leaves, straw, sawdust, wood chips, corn stalks

Organic Matter: Nitrogen or “Greens”  N is needed to get the decomposition process started and keep pile “cookin”  Examples: vegetable and fruit scraps, grass clippings, coffee grounds, manures, and alfalfa hay

Carbon:Nitrogen Ratio  Optimal C:N ratio is 30:1 at an elemental level  Carbon supplies energy for bacteria and Nitrogen supplies nutrients (proteins).  Balance material ratios to get 30:1 ratio: e.g. 1/5 oak leaves 26:11/5 poultry manure 10:1 1/5 pine needles 85:11/5 grass clippings 20:1 1/5 food scraps 15:1 C:N ratio = ~31:1 Approximately equal volumes of greens and browns provides a good C:N ratio

Microorganisms  Bacteria begin breakdown process – aerobic bacteria feed on plant sugars and respire to “heat up” pile  In the right conditions, population growth is amazing—bacteria can double every hour!

Microorganisms Four Types of Bacteria  Psychrophilic: work at lower temperatures  Mesophilic: thrive between 70-90°F  Thermophilic: work from °F short “work week” 3-5 days, turn pile to reactivate  Anaerobic  Closed air bins, wet piles or too dense - not aerated  Fermentation & odors from anaerobic decomposition  Pile does not heat up, so doesn’t kill pathogens/weeds

More Microorganisms…  Fungi: active in end stages of composting - live on dead or dying material  Actinomycetes: halfway between bacteria & fungi – gray-white cobweb type material in compost pile, also active in later stages of composting actinomycetes

Macroorganisms  As temperatures decline, population diversity increases:  Nematodes:  sightless, brainless roundworms, <1 mm long. prey on bacteria, protozoa, fungal spores  Fermentation or mold mites  Springtails  tiny white insects

Macroorganisms  Wolf spiders:  build no webs, run free hunting their prey  Centipedes:  flattened body, long legs, fast moving  Millipedes:  worm-like body with hard plates, up to 6” long. Slow moving vegetarians that help in breaking down OM.  Sowbugs & pillbugs  (Isopods) small, fat-bodied decomposers with gills. Pillbugs roll into a ball, sow bugs don’t. Feed on rotting woody materials Pillbug Sowbug

Macroorganisms  Beetles:  rove beetle, ground beetle, and feather winged beetle  Earthworms:  native redworms  Enchytraeids,  (Ehn kee tray' id) white or pot worms, ¼ - 1” long, white & segmented  Flies:  feed on any organic matter. Bury kitchen scraps well, keep fatty foods out of the pile to control. Whiteworms

Macroorganisms  Snails and Slugs:  Feed on living plant material, garbage and plant debris.  Fruit beetle larvae:  large grubs, 2” long & C-shaped; translucent white, head is dark brown.  Ants:  feed on aphid honeydew, fungi, seed, sweets, scraps, other insects, and other ants. Compost provides food and shelter. Ants usually mean pile is too dry.  Earwigs:  predators of all stages of insects, mites & nematodes, also algae, fungi & plants.

Water & Oxygen  Balance oxygen and water in the compost pile: 50% moisture + 50% O 2  Consider moisture content of added materials (food scraps!)  Compost should be about as moist as a well wrung-out sponge. It should be moist to touch but yield no liquid when squeezed.

Water in the Pile  Wet pile:  pull it apart, loosen it, incorporate dry materials and remake it.  Dry pile:  turn & rewet material as it is being turned (some browns are hard to moisten)  Seasonal considerations!!!

Oxygen  Aerobic composting is preferable  Anaerobic decomposition or fermentation  may produce compounds toxic to plants  produces ammonia & methane gas – smelly!  Passive aeration: air is warmed by the compost process, rises through the pile, pulls in fresh air from the sides.  Active aeration: turn and mix the compost, or build the pile effectively so surface air diffuses in

Temperature!  Temperature is a function of: pile size, oxygen & moisture content  Temperature affects biological activity: Most microorganisms active between ºF Best decomposer bacteria thrive at ºF. Above 140ºF kills pathogens & weed seeds, but slows decomposition.

Temperature  Optimum is 2 weeks of temperatures around 135º  Turning the compost whenever temperatures get above or below the optimum range produces high quality compost in the shortest possible time.  If compost is properly moist and turning does not cause temperatures to rise, the compost is finished or needs more nitrogen.

“It depends” on:  Density of material  Particle size (amount of exposed surface area)  C & N content  Moisture content  Aeration  Volume  Insulating materials around the pile How long does it take?

Making the Pile

What kind of bin should I use?

Making the Pile: Important Considerations  Size of pile should be 3’x3’x3’ to 5’x5’x5’  Do you have all the organic material (batch) or will you add continuously (continuous)?  Have you chopped up your materials?  Moisture and aeration: what’s the rule?  Compost tools: hay fork, aerator…

Composting Methods Standard Method:  Need a variety of materials  Turn it each week  4-6 weeks for finished compost (summer)

Rapid Composting Method  Need large supply of organic materials  Requires substantial chopping and shredding and more turning of the pile  Can take less than one month in ideal conditions.

Slow, Continuous or Static Method – It’s not a moral issue  If a steady supply of organic materials is not available  Takes very little time or labor  Requires 6 months to 2 years to produce compost  Smaller compost area needed, because pile is built as materials are available  Little if any heat is produced, so weeds & pathogens are not killed

 Grass clippings  Yard waste  Leaves, pine needles  Vegetable trimmings  Food scraps  Wood chips (shredded to size)  Newsprint  Sawdust What goes in the Pile?

 Disease infected plants  Plants with severe insect attack  Ivy, morning glory and succulents  Pernicious weeds, e.g. Bermuda grass, oxalis, cheeseweed  Cat and dog manures  Meat and fish scraps  Wood ash (add after composting is finished) What does NOT go in the Pile?

BUT… What are some issues that complicate composting??? Compost Happens!

Composting issues  Rodents  Raccoons  CC&Rs  Smell  Other???

Correcting Physical Problems in landscape soils  Physical Problems in landscape soils  Adding sand -- just remember the components of concrete!!  What can we add to correct physical problems?

Physical Problems in landscape soils  Correcting Physical Problems  Organic materials

Benefits of organic matter as an amendment  Reduces compaction  ‘Humus’ -- derived from OM and resistant to further decomposition  aids in formation of soil aggregates  Organic Matter provides food source for earthworms and saprophytic organisms

When can the addition of OM cause problems in the home garden?  Cyclic relationship between activities of decomposers and availability of nutrients  Especially NO 3 -  Induced deficiencies

Nitrogen Immobilization NO 3 - depletion time Time Activity of decay organisms High C:N Addition Nitrogen level of soil

What about OM as a mulch?  Mulches are not incorporated into the soil  Petunia example!!

Petunia Example Petunias planted and then mulched Petunias planted – no mulch applied Mulch applied and then petunias planted

Petunia Example Petunias planted and then mulched Petunias planted – no mulch applied Mulch applied and then petunias planted

Mulches can save water  Materials put on top of soil  Reduce water evaporation – why?  Prevent weed problems  Buffer soil temperatures  Be careful with native plants!!  Desert pavement serves as a mulch

Depth of mulch depends on materials – why?

Depth of mulch depends on materials Coarse - 4 to 6 inches Medium - 2 to 4 inches

Depth of mulch depends on materials Fine mulches need only about 1” depth

Desert Pavement as a mulch

Yamanaka et al 2004

Should I use fertilizers?  Garden soils rarely contain all required nutrients  Equally rare for garden soil to be deficient in several  Add only the ones that are deficient  Careful with nitrogen in cold climates

 Don’t apply fertilizer before projected rain event

Nitrogen deficiency curcurbit

Phosphorus deficiency tomato

Potassium deficiency sunflower

Fertilizers and Soil Amendments  How much should I fertilize?  “Two kinds of people in the world”

Problem: Contamination of surrounding water bodies Nitrates, Phosphorous Nitrates Eutrophication Lake Groundwater

Apply Fertilizers Efficiently  Time Fertilizer Application to Plant Uptake - Grapes N partitioning N Time

Fertilizers and Soil Amendments  How much should I fertilize?  “What is the most limiting factor for plant growth - is it really nutrients?”

Soils for the Gardener How might this affect plant growth? Courtesy of Ohio State University

Fertilizers and Soil Amendments  Types of Fertilizers  Inorganic Fertilizers: CSFML says not derived from plant or animal residues  Advantages  fast-acting  low in cost  Disadvantages  leaching  salt effects

Fertilizers and Soil Amendments  Types of Fertilizers  “  “Complete” fertilizers: contain at least  Nitrogen (N)  Phosphorus (P)  Potassium (K)

Fertilizers and Soil Amendments  By law, guaranteed content of fertilizer must be stated on bag  Expressed as % of each plant nutrient applied  N - P - K

Fertilizers and Soil Amendments  N - P - K   First number: % nitrogen (N)  Second number: % phosphoric acid P 2 O 5  Third number: % potash K 2 O

 Nitrogen (N)  No conversions required

Fertilizers and Soil Amendments  PHOSPHORUS (P)  Expressed as phosphoric acid P 2 O 5  Phosphoric acid contains only 43% P  To convert from P 2 O 5 to P  P= P 2 O 5 x 0.43

Fertilizers and Soil Amendments  POTASSIUM (K)  Expressed as potash, or K 2 O  Potash contains only 83% K  To convert from K 2 O to K  K= K 2 O x 0.83

Efficient fertilizer applications

Courtesy of Aggie Horticulture, TAMU