Soils Notes - Maia

Development of natural soils Horizons/ soil profile: layers and composition of soil: O (organic) topsoil: less dense, more decaying organic matter A ( surface): B (subsoil): main storage for nutrients and moisture C (substratum): carbonate layer/ parent material R (bedrock): more dense 5 Soil forming factors: COPT/T Parent material Repeated floods over large portions of the interior plains of North America Over several hundred million years This resulted in sedimentary bedrock formation ( soils aren’t identical provincially) Glaciation Huge masses of ice moved by their weight The ice grinds the rock below it and redistributed it across the continent Glacial till deposits: an unsorted mixture of stones, boulders, sand, silt, and clay Deglaciation: down melting of glaciers Deposits Fluvial deposits (flowing water): where the river once flowed, sand and gravel were deposited Lacustrine deposits: where glacial lakes once stood; fine materials like silts and clays Eolian deposits: where the wind has resorted material; like sand dunes (fine sand, silts, clays) 4 types of parent material: Glacial till: mixture of clay, silt, sand, sharp gravel, stones, boulders Fluvial: fast streams would deposit gravel first, then sands deposited as stream speed lessens Lacustrine: deposits in lakes that drained away; contains mainly silt/ clay Eolian: sand dunes; fine sands and silts 2. Climate: Eats away at the rock to break it down Components of soil: Water 25% Air 25% Organic matter: 5% Mineral 45%: dictate the soil chemistry, influence soil Ph salinity, fertility, and structure Primary minerals (sand and silt): Secondary Minerals (clays): Unchanged in composition since it was formed in cooling lava Coarse particle size Contribute to air and water movement Iron oxides, gypsum, quartz, feldspars, dolomite, and apatite Sand: small total surface area per volume Results from the decomposition of a primary mineral Forms sheets or layers that hold most minerals for plant growth Fine particle size <0.002mm Good water holding capacity and fertility It has very high surface area Carbonate minerals originate in limestone bedrock (calcium and dolomite). Dead fish, shells, laid-down and left-overs all contain carbonates. Many precipitate and recrystallize in a modified form. Maintain an alkaline pH (>7) in soils It may interfere with plant growth when in high amounts Saturation: when all the pores of soil are filled with water. Gravitational water: water is pulled down from the macropore space into the micropore space. - macropores are filled with air. Field capacity: the capacity of soil to hold water. When at field capacity water is classified as available water Evapotranspiration: a combination of water evaporating from the soil and transpiring out from the leaves. The way that water leaves the system. Permanent wilting point (PWP): when water runs out from the water pores (only hygroscopic water is remaining. Hygroscopic water: water that is adhered to the particles but not available to the plants Soil reservoir: water is attracted to the sides of soil particles. Soil water: soil water is held against the downward pull of gravity in the pore spaces by adhesion and cohesion Pore space: diameters of soil pores Range from several millimeters to less that 0.001 millimeter Large pores = rapid movement of water Small pores = tortuous routes for water to move. Soil Air: is not interconnected- its composition varies from place to place Some gasses are consumed by plants and some are released. Co2 concentration is often 100x higher in soil than in the atmosphere. Soil water influences air content Low water content allows for more air High water content traps air in small pockets and microbes may produce toxic gasses. Organic matter in soil: residues from plants, animals, and microbes Influences a soil’s fertility by improving water holding capacity Increased the diversity of pore size Primary food source for soil microorganisms Improving soil texture: do not add clay or sand, it will turn to cement Instead add organic matter; does not affect texture but does improve structure. Texture Influences by the percentage of sand, silt and clay (Organic matter does not change the texture) Signifies air, water, nutrients and erodibility: Sand + Silt + clay = 100% Flocculation (like a flock of birds): formation of balls (aggregates) - when soil wets and dries, during freezing and thawing, from roots or animals Cementation: when a component makes the aggregates more stable. Are stabilized by agents such as bacteria and fungi that are released from organic matter breaking down. Organic matter glues and gums to make the aggregates more stable. Divalent cations: linking cations that hook onto the negative charges of clay and link together the aggregates (Ca 2+ and Mg 2+) However cementation is primarily caused by organic matter, gums and glues Deflocculation: the separation of aggregates caused by Na+ (sodium) Soil Structure The formation of aggregates based on mineral content Loams: wide range of compositions and properties, some set like concrete some like powder, some form surface crusts Aggregates: freezing+thawing/ swelling+shrinking, will push these particles together to form aggregates Sand and silt particles cohere together as clay particles coat them and hold them together Formed from flocculation Aggregates are porous with voids between the grains (micropores) Flocculation: particles of various sizes come together as aggregates, here is also help from cations in the soil, (calcium) Aggregate stability: Unstable aggregates break up easily Susceptible to compaction Have “weak” structure Stable aggregates: do not break up easily said to have strong structure. Organic matter: as it break down it releases gummy glue These act as cementing agents and coat the sand and silt Larger pores, macropores, exist between the aggregates Most of the water movement and root growth occurs in these macropores Deflocculation: Na+ destroys soil structure by pushing particles apart. Naturally formed structures: In grassland soils Granular (topsoil): rounded aggregates less than 1cm Allows good water movement and airflow Resists soil erosion Prismatic (B horizon): provide good conditions for air and water to move into the subsoil Blocky (B horizon): provide good conditions for air and water to move into the subsoil Columnar (B Horizon) solonetzic (sodium): provides poor infiltration, percolation, and root penetration. Structureless (amorphous) Massives: soils that are moved or worked when they are wet will tend to lose their structure After soil is dug up, transported, spread, graded, and compacted, it may fail to drain or support plant growth Water infiltrates very slowly Does not drain through fast enough to allow roots to have oxygen Prevents growth of roots Plants drown out with high rainfall or dry out under dry conditions Because roots cannot penetrate to grow deep in the soil. Soil interface: abrupt boundary Roots and water have difficulty penetrating the interface Perched water table: if water sits on top of the interface Color in soil always has to do with the mineral content (black is high organic matter though) Soil Compaction and Bulk Density Soil Compaction: occurs as the volume of a fixed amount of soil decreases Highly compacted soil is better suited as a road base than for planting landscape plants. Results in an increase in bulk density: Soil aggregates are pushed together and crushed, filling the pore spaces, especially macropores. Same amount of soil, lower volume (air is pushed out of pore spaces) As the ratio of weight to volume increases, the higher the bulk density is. Bulk Density Formula: Oven dry weight (g) 600g = 6.0g/cm3 Volume (cm3) 100 cm3 *memorize this formula* Physical changes Shift in pore size distribution Well-aggregated: Compressed soil: Large macropores - air-filled Medium to small micropores - water-filled Reduced volume - loss of macropore space Some macropores become micropores Reduction of pore space As Db increases, macropore space decreases The structural aggregates are crushed (in sand they’re “pressed or rearranged”) increase resistance to root penetration Water infiltration is reduced: Less water is absorbed for plant use Runoff is increased/ soil erosion Reduced drainage: roots will rot and die Reduction of gas exchange: diffusion of oxygen is limited Ventilation of gasses is reduced (toxicities) Reduction in aeration: gaseous aeration only occurs in macropores Compaction changes pore pattern arrangement Increases tortuosity of the diffusion pathway O2 decreases; CO2 increases How much can a soil be compacted? Depends on: Soil texture Organic matter content Soil moisture at the time of compaction Different textures: Similar to bulk densities affect rooting depth differently in soils of different textures. Fine textured soil: Collapse or deformation of the material Soil particles get forced apart, bonds are broken, particles slide, becomes plastic Water from pore spaces gets discharged Sandy soils: Particles are not compressible Have little to no structure development Usually single grained Particles just get reoriented but don't lose pore space Sandy soils: rely on friction between particles for strength Get stronger as they get wetter, water forms bonds Strength is lost when saturated Sandy loam: Become rearranged and reoriented Finer particles are packed between coarse grains. Engineer: manipulated soil for use as a foundation Must be consolidated to a certain density 90-95% compaction Able to meet loa bearing specifications Proctor test: Measures moisture density relationship of soil sample Plot of soil density vs soil water content is produced in this test Optimum water content produced maximum soil density, which plots as the apex of the soil density vs water content curve Horticulturist: Load-bearing density is greater than any plant could tolerate Natural vs urban soils: Soil has natural processes that increase porosity and reduce soil density Natural processes are not able to occur or exist in urban soil therefore compaction dominates in the urban soil situation Causes of compaction: Foot traffic Heavy rain/snow/floods Vehicles Heavy equipment Vibration Tilling transporting/piling Soil Chemical Properties: 1st row: alkali metals: +1 charge (H, Na, K) 2nd row: alkaline earth metals: +2 charge (Ca, Mg) Above the metalloids: Anions Available in water: C, H, O Primary macronutrients: N,( NH4+, NO3-), P (always picks up phosphorous in a negative form: H2PO4-, HPO4-2), K, K+ Secondary Macronutrients: Ca (Ca+2), Mg (Mg+2), S (SO4-2) **Ending in “Ate” leech into the soil** Micronutrients: Fe+2, Cu+2, Zn,+2 Mn+2 ( if you have an excess of one, you will have a deficiency of the rest) Also micronutrients: Bo-3, MoO4-, Cl-2 Cation exchange capacity: soils ability to exchange and hold onto cations (bigger the negative charge, higher the cation exchange capacity) clays and really OM have a negative charge . Cations are easily exchangeable with other cations Cations: positively charged ions Calcium Ca++ Magnesium Mg++ Potassium K+ Sodium Na+ Ammonium NH+4 Makes them plant available Nutrients are picked up in solution CEC represents total amount of exchangeable cations that a soil can absorb Mainly: Ca, Mg, K (and Na in drier climates) CEC: expressed in meq/100g (milli-equivalents per 100 grams of soil) Contributors to CEC: clay and organic matter particles are negatively charged (attract positive cations) Clay: charges do not change, they are permanent Organic Matter: 4-100x higher CEC than clay per volume - depends on break down of OM (surface area) - amount of charges are pH-dependent ** as pH increases, CEC decreases** Root surfaces: Cations are attracted to charged surface cells within the root, called cortex cells Plant root releases a hydrogen ion pH of immediately surrounding soil decreases Cation aggressiveness: as valence increases, agression increases * hydrogen is most aggressive despite only having one valence cation* Mass action: aggression is important 1 on 1 All of you against me - pack mentality If you overapply NH4+ it will bump Ca off the exchange sites Implications: Higher the CEC, more clay or organic matter in the soil, less susceptible to leaching losses of these cations With this there is usually a greater water holding capacity than low CEC (sandy) soils For low CEC soils, a large one time addition of cations (fertilizers) can lead to large leaching losses Soil isnt able to hold excess cations More frequent additions of smaller amounts is better Base Saturation: a measurement that indicates the relative amounts of case cations in the soil Percentage of Ca, Mg, K, and Na, that make up the total cation exchange capacity A base saturation of 75% means 75% of the cation exchange capacity is occupied by base cations Base saturation in prairie soils is relatively high (100%) pH increases as base saturation increases Soil reaction: pH pH: a measure of the hydrogen ion concentration of the soil solution pH affects: Availability of nutrients Toxicity of nutrient Microorganism activity Structure 0-5.5: Fe, Al (iron and aluminum are so available that they become toxic) 5.5-6.5: micronutrients are the predominant cations, Fe, Cu, Zn, Mn, B ** 6.5-7.5: predominant cation NPK** Ideal pH *7-8.5: predominant cation CaCO3 and MgCO3* (limited phosphorous because of high calcium *8.5-14: H2NaCO 6-8: most microorganism activity Pools of acidity: Active acidity: H+ activity in the solution - Exchangeable on the colloids (clays and organic matter) - Have an immediate effect on soil pH Reserve acidity: H+ is bound by organic matter and clays Buffering Capacity; ability to resist a change in pH Ensures stability in the soil pH Prevents drastic pH fluctuations It takes less material to change the pH in sandy soil Higher buffering capacity = more exchange sites = clay/organic matter Alkaline soils: Usually contain calcium and magnesium carbonates Carbonates must be dissolved if you want to make soil neutral Soils will become alkaline if: They are over-limed They are irrigated with alkaline water Parent material is calcium-rich CaCO3 and MgCO3 develop (in arid conditions) Acid soils: Add sulfur (cheap also) microorganisms and time is required to acidify soils with sulfur Become acidic if: Rainfall and leaching of base cations Organic matter decay resulting in organic acids Harvest of crops Acidic parent material Factors that lower pH: Formation of carbonic acid from dissolved carbon dioxide in soil water Decomposition of sulfur compounds through “acid rain” Altering pH lower: Sulfur Organic matter Acidifying materials: Peat Fertilizers Iron Sulfate (will reduce the availability of phosphorous *where calcium increases phosphorous is limited* Altering pH to raise: Add lime (because it contains calcium and magnesium carbonates) - rate of application depends on a soil’s CEC, the texture and the initial pH - the more fine it is, the faster the pH will change Soil Salts Salt: a combination of a negative ion (anion) acid with a positive ion (cation) base All soils contain salts Many salts are plant nutrients Salt measurement: Soil salts are expressed in terms of electrical conductivity EC: measures soil capacity to conduct an electrical current (expressed in decisiemens/meter (dS/m) or milisiemens/cm (mS/cm) Soluble salts: are those that dissolve easily in water (relative to gypsum CaSO4) Have the greatest effect on plant growth Salt terms: Saline - high in salts (EC > 4 mS/cm) Sodic - high sodium (pH > 8.5, SAR > 12) If EC is above 1 there is a concern Salt contributors to the soil: Saline bedrock Saline groundwater De-icing salts in winter: when temps increase, plants try to absorb water but are limited by salt concentrations Irrigation practises Bio-solids composted from sewage sludge can contain high levels of salt Fertilizers: can contain a lot of salt Index: ≤ 25 is low > 50 in sandy loam soils and >75 in silty clay loam soil is high Excess salts: May break down aggregates Creates surface crusting and decreases infiltration Destroys microbial life Causes decline and death, particularly in trees Soil salt - signs; Arid regions where evaporation exceeds rainfall: Salts build up on the surface Salts can accumulate to toxic levels - flush soil with high-quality water to drain other salts If absorbed by the plant, may cause leaf scorch or bud deformity Reduce the plant's ability to take in water causing drought conditions Salt tolerance in plants: Factors: Type of plant/soil Time of year Weather cycles when salt is applied How quickly it is leached away The health of the plant before the salt application Stressed tree Confined compacted soils May die from a small dose of salt Healthy tree Growing in generous volumes of well-drained soil Might not be affected by large dosages of salt Managing salt: Choose salt-tolerant plants Develop well-drained soils with drainage systems a meter below the root zone or install a deep well-draining soil. Use fertilizers with low salt indexes and reduce fertilizer use Apply mulch to the soil to reduce evaporation rates Maintain irrigation to keep soil evenly moist Don’t plant at the very top of berms, ridge where salts may accumulate Design low curbs along edges of planting beds, lawns, and tree openings in sidewalks to divert water from soil Increase soil volumes of planting areas to increase the health of trees Managing sodium salts: Mix gypsum into the surface of sodium-salted soils before flushing with water Salinization: the process where salts accumulate over time Sodium causes deflocculation This reduces aeration and promotes soil compaction. Microorganisms are sensitive to salt concentrations. Tree age; older trees are less likely to suffer damage compared to younger trees probably because of extensive root systems Heavy metals: Excess salinity means sodium can mobilize heavy metal ions in the soil releasing them into the soil solution with the risk of leaching into streams and groundwater Soil biological properties Soil Biota: microorganisms, soil animals, and plants living all or part of their lives in or on the soil pedosphere Organisms grow and reproduce They feed on by-products from roots (exudates) and plant and animal residue and feed on each other Needs: oxygen, water, food (carbon/nitrogen), pH, non-toxic environment, warm temperatures Rhizobium: bacteria that form on the roots of legumes and cause bumps on the roots. Converts atmospheric nitrogen and turns it into ammonium. Organic matter: is a source of energy for soil organisms Supplies most of the natural soil nitrogen, half of the phosphorous, a major portion of sulfur, and many organic compounds Contributes to the CEC (reservoir for plant-available nutrient storage) Enhances soil structure needed for gaseous diffusion, water movement and storage, root penetration and extension. Additions: Fresh residue: dead roots ad leaves and other plant parts, and bodies of animals (both micro and macro) Transformations: Active organic matter: soil organisms continually change organic compounds from one form to another They consume plant residue and other organic matter and then create by-products, wastes, and cell tissue Microbes feed plants: some of the wastes released by soil organisms are nutrients that can be used by plants. Stabilization of organic matter: eventually soil organic compounds become stabilized and resistant to further changes (Humus) Includes: dead plant material, animal, and other organic substances Organic compounds: what is used as food by microorganisms Includes: root exudates: soluble sugars, amino acids, and other root secretions (easily digested by bacteria) Lignin: hard to degrade, some fungi can be used as food Humus: not readily decomposed, physically protected within aggregates, too complex to be used by microorganisms Wood products: chipped wood, shredded leaves, and sawdust, if properly composted and screened can be very good. Plant residues: many are coarse for a mixed component, mulches: do not want fast decomposition. Sawdust is very raw and high C: N ratio (decomposes slowly) Food waste: a wide variety of materials (worm castings, sea kelp) Manures: require composting to reduce C: N ratio, odour, and pathogens, desirable when finely screened, ones with bedding from cows and horses are preferred. Poultry is considered hot. CCME guidelines: Wanted to ensure people were comfortable using compost so they could keep it out of the landfill Consistency in compost Helps protect public health and the environment Why there are 2 categories: A: small concentration of trace elements and sharp foreign matter (use for anything) B: A little bit higher concentration of trace elements and sharp foreign matter (specific use) C: N ratio Standards: When compost is added: 33:1 *must know Plant tissue and farm manure: 20:1 Stems or cereal crops (straw): 100:1 Sawdust: 400:1 Soil organisms: 4:1 to 9:1 Stability: stage of compost decomposition where CO2, Heat, and water vapour are produced To test, measure the heat evolution from a moist sample Maturity: Test using bioassay (germination rate) and root elongation tests Tests detect the presence of volatile fatty acids, alcohols, soluble salts, heavy metals, or ammonia (all produced under anaerobic conditions Properties of humus: Odour: produces no unpleasant odour Organic content: 30-70% Mineral content: 0-1.5% Coarseness: 25mm-13mm screen (depends on use) CEC: increases as material decomposes Nutrient content: low compared to commercial fertilizer, more valuable contributions to the soil's physical properties Soil sampling: Used to determine nutrient labels in the soil (can do everything except bulk density) A small amount of soil is used to determine properties throughout a much larger area Take separate samples from areas different from the rest of the field (from areas with less traffic) Timing: Before establishing a long-term crop (fall is best) Minimum: every 3-5 years Before fertilizers are applied Problem soils anytime Number of samples: for lawns, sample at least 10 sites Depth: consider the crop and how deep its roots go, AND what you want to know Equipment: use a soil probe or soil auger (can use a trowel or garden spade, but a soil probe is best) Clean bucket to collect and mix the samples Keep samples from different depths separate **After the sample is taken air dry it or put it in a cooler to limit microbial reproduction and remove thatch and any live plant material** Record keeping: keep a map of your layout Show sampling sites, unusual features Keep records of soil test results plus any applications and results in performance Plant nutrient levels: Critical level: minimum concentration of nutrients required to produce a healthy specimen Sufficiency range: healthy plant nutrient levels that range between critical value and toxic level Luxury consumption: plant uptake of nutrients above a level required for optimum growth. Not harmful for plant growth Toxic level: concentration of nutrients high enough to cause reduced growth or impaired plant development Nitrogen cycle: *know additions, transformations, and losses* Microbial relationships: Nitrogen fixation - symbiotic, microbes that live in aerobic environments can fix atmospheric nitrogen (bacteria: rhizobium) N2 from the atmosphere is converted to ammonia and then to ammonium NH4 Nitrification: addition: soil bacteria collaborate to oxidize ammonia to eventually produce nitrate NO3- Know that ammonium converts to nitrate Denitrification: losses: microbial reduction of nitrate NO3- to produce nitrogen gas, usually in waterlogged soils high in organic matter Immobilization & demineralization: Immobilization: when residues with high C: N are being decomposed, all readily available within the soil may be tied up by the microbes, unavailable to plants but not lost in the soil, plants show nitrogen deficiencies Mineralization: the process of converting organic N to plant available forms by a succession of soil microorganisms Non-symbiotic: fix atmospheric nitrogen without a relationship with plants Contains nitrogenase enzyme Ex. azobacter, cyanobacteria Phosphorous: Additions: Fertilizers, rock phosphate, organic matter, and manures may contain high amounts of phosphorus Losses: removal or organic matter, soil erosion, ties up with calcium in alkaline soils, ties up iron, manganese, and aluminum in acidic soils Potassium: Additions: Organic matter, soil minerals, fertilizer Losses: Removing organic matter Plant uptake * in clay soil* **Plant-available form of sulfur is converted by microorganisms (bacteria)** Sulfur is prone to leaching because of its negative charge Container mixes: Media: a combination of components designed to give optimum ratio of AIR, WATER, MINERALS, and SUPPORT Components: sphagnum peat, coir fiber, vermiculite, perlite, rice hulls, sand, pine bark, Rockwool Physical Properties: Support: keeps plants upright, anchors roots Total porosity: percentage of media composed of pore spaces (optimum greenhouse pore spaces: 75-85%) light bulk density is desired for low pot weight Aeration porosity: MACROPORES: water drains through media with large pores quickly 15-20% = large containers 20-25% = rapid growth Capillary porosity: MICROPORES: Symptoms of poor aeration and water-logging: Wilting Roots with brown tips Lack of root hairs Soul smell Stunted growth Chlorosis in older leaves Necrotic margins Roots forming on stems and media surface Stable organic matter: provides aeration, drainage, and water-holding capacity B. Chemical properties: media components can affect mineral content and availability Cation Exchange Capacity (CEC): the sum of the exchangeable cations that media can retain per unit weight Acceptable pH: determination of acidity or alkalinity (greenhouse mixes: pH = 5.5-6.5) Low soluble salts/ initial low fertility: dissolved mineral salts found in media, can be a source of mineral supply - can also be toxic Buffering capacity: media's ability to resist change in pH (components with a high CEC also have a high buffering capacity C. Biological properties: consider the presence or absence of harmful pathogens and beneficial microorganisms Pest-free: components are considered sterile from the bag (mineral soils/sands must be pasturized=low temp for a long time and killing bad organisms) Beneficial microorganisms: compost brings biological life to a mix (mycorrhizae) D. other desirable characteristics of media: Biologically, physically, chemically stable Standardized and uniform from batch to batch Media components should be: economical, readily available, easily mixed, lightweight Media components: Field soil: **no longer used in container mixes Because of the potential for pathogens it needs to be pasturized High bulk density is also an issue - in container it limits aeration porosity Not consistent Pasteurization: eliminates harmful organisms - no beneficials are harmed Soil should allow uniform penetration of steam fumigant (60 C for 30 minutes for most harmful organisms Oversteaming at too high temp will sterilize Pasteurization methods: Steam: fast, effective, economical Aerated steam: steam from boiler is combined with air to create 70C mix to push through media Peat moss: Acidic: 3.5-5 Non-renewable (kind of) Low carbon footprint High CEC, low salts, H2O holding capacity Adds OM with stability Difficult to re-wet Coir: coconut husk All benefits of peat but better Easier to re-wet Renewable Expands by 5-9x (good for shipping) Better drainage - but holds water in micropores Porous materials: Vermiculite: Crushes easily Only one use Ties up phosphates Will not decompose High porosity, low bulk density Sterile Perlite: Very good or high drainage and aeration Low bulk density Inert Dangerous to breath Floats Contains fluoride Rice hulls: Substitute for perlite Safer, easily renewable Good porosity Stable within 1 year Sterile Sawdust/ wood products; Extreme variability and potential for toxins All wood products MUST be composted before use Sand: Stable and inert Must be washed Heavy (increases bulk density) Good drainage and aeration when used alone Rockwool: Low CEC Sterile Additives/ amendments: Wetting agents - gels or floral balls Fritted (slow)/ chelated (fast) trace elements Superphosphate (root establishment) Osmocote (long-term nursery crops only) Lime: Calcium carbonate/ calcitic lime Daily quick impact For pH change of 1 = 4,600 lbs / acre Sources: limestone, burned or hydrated lime Dolomitic Lime Slow release Adds magnesium Bio Char: Lightweight and porous Carbon sink Variable Expensive to produce - greenhouse grades are not priority production Hydroponics: Require some form of media for their roots Rockwool bags are an option as Leca Special mixes: Rooftop planters: 3 parts compost ¼ peat handful of perlite Environmental Stewardship Principles: Water management: #1 topic rainwater/greywater harvesting Raingardens Bioswales Permeable pavers Drip/water efficient irrigation Rain gardens: Depression or low planted area planted with deep-rooted perennials and grasses Collects rainwater, prevents runoff, recharges groundwater Bioswales: swale planted with grasses and deep-rooted perennials Used to infiltrate and treat stormwater runoff Drip irrigation: from of irrigation that distributes water right to the plant through emitters or small holes in tubing. Prevents water loss through evaporation and wind Puts water right at plant roots #2 Low maintenance landscapes: Native plants/adapted drought tolerant plants Reduce lawn area Smart yard #3 recycled materials: pavers/pave-edge Gravel from concrete] Mulch Reusable gardening containers #4 Urban agriculture BioPhilia: Green roofs Living walls Heat Island Effect: Non permeable and reflective surfaces (concrete/glass) not absorbing heat and instead projecting it into the atmosphere Effects of Urban Heat Island: Increase in storm water temperature Reduced water, food and shelter for wildlife Heat related human illness Higher cost of energy due to air conditioning Higher pollution How to reduce the effects: More, dense vegetation (green roofs) Painting streets and roofs white Low Impact Development: Source control: controlling quantity, enhancing quality Controlling quantity of surface runoff and enhancing quality of water back into nature Problem: increase in impermeable surfaces in urban areas leads to: Increased flooding Decreased groundwater Recharge Decreased evaporation Decreased transpiration Increased urban island heat Key Principles of LID: Preserving natural site features Small-scale stormwater management on site Controlling stormwater as close to the source as possible Minimizing and disconnecting impervious areas Prolonging stormwater runoff flow paths and times Creating multifunctional landscapes Methods of source control: Constructed wetlands Stormwater ponds Rain gardens and bioswales Green roofs and living walls Permeable pavers Permaculture Natural environment, food and resources utilizing ecosystem patterns Sustainable living: using nature how it was intended Self-sustaining ecosystems Ethics: 3 foundational principles Care of the earth Care of the people Share the surplus Earth care: Natural systems and biodiversity Work towards regeneration (restore soil, create habitats, protect water) Create conditions in which life can flourish People care: Work with nature, not against it Provide for human needs (food, water, medicine, building materials, beauty, community) Fair share: Avoid hoarding (don’t deny other people of species their needs through our own over-consumption) Good designs will eventually create a surplus (food, water, income, biomass) How permaculture works: Systems designed to be interactive Based on the concept of sustainability Besides climate, the permaculture philosophy focuses on building soil, no till, composting, rotational cropping, green manure. Permaculture principles: Observe and interact (with nature) Catch and store energy Obtain a yield Apply self-regulation and accept feedback Use and value renewable resources and services (reduce consumption of non-renewables) Produce no waste (make use of all resources) Design from patterns to details Integrate rather than segregate (systems interact with each other) Use small and slow solutions (local solutions) Use value and diversity Use edges and value the margins Creatively use and respond to change *** KNOW THE BULK DENSITY FORMULA FOR FINAL* Know what SAR stands for (Sodium Adsorption Ratio Ratio between sodium compared to calcium and magnesium What do microorganisms need How sulphur is converted to sulfate - bacteria Primary minerals (sand and silt): | Secondary Minerals (clays): Unchanged in composition since it was formed in cooling lava Coarse particle size Contribute to air and water movement Iron oxides, gypsum, quartz, feldspars, dolomite, and apatite Sand: small total surface area per volume | Results from the decomposition of a primary mineral Forms sheets or layers that hold most minerals for plant growth Fine particle size <0.002mm Good water holding capacity and fertility It has very high surface area Well-aggregated: | Compressed soil: Large macropores - air-filled Medium to small micropores - water-filled | Reduced volume - loss of macropore space Some macropores become micropores Additions: Fertilizers, rock phosphate, organic matter, and manures may contain high amounts of phosphorus | Losses: removal or organic matter, soil erosion, ties up with calcium in alkaline soils, ties up iron, manganese, and aluminum in acidic soils Additions: Organic matter, soil minerals, fertilizer | Losses: Removing organic matter Plant uptake