Soil used for land foundations1800s: Most people (80%) worked on farms; now, most in citiesThe PedospherePedon = soilInteraction between atmo/bio/litho/hydro-spheres rxn with soilUnder the vegetation“Pioneer” species - Lichen, moss, fungiDirt: Mineral based, comprised only of pebbles and ground rockSoil: Mineral based, but includes plants, fungi, animals, water, air, organicsGeologic Defn: Loose surface of Earth distinguished from solid bedrock (support of life not required)Pedosheric Defn: Loose, altered surface material that nourishes/supports organisms (includes rocks, water, snow, air)Four main parts of soilSOLID (50%)1. Minerals(45%)Allows plants to anchor2. OrganicsPlant/animal debrisStructural support to the soilGives soil more volume to hold waterSPACE (50%)3. Air (25%)Mainly carbon dioxide due to respiration4. Solution (water)Important for drainage, holding space between particlesLife in the soilArthropods, nematodes (flat worms), bacteriaFunctions of soilCarst topography – lots of limestone sedimentary rock that water runs through well, but limestone dissolves under acidic conditionsCommon in Florida,  sinkholesBE sure foundation of a house, if on a hill, is connected to the bedrock beneath the soil so that in an earth quake, its fineEngineering and structural support – increases amplitude of earthquakesRecycles nutrients and organic wasteMedium for plant growthHabitat for soil organismsWater supply and purificationCheaper to conserve land of a water shed than to collect/treatSoil ManagementUSA spends 150 billion $ on soilNutrition Assistance (74%)Conservation and forestry (7%)Farm/Commodity Programs (13%)Other (19%)Rural, poor communities have the worst farm landGive money to them to increase the quality of the landParent materials cause soil formationIgneous rock – “molten” below ground, lava aboveSometimes molten cools underground – graniteCools quickly  smaller, finer crystalsMetamorphic Rock – subduction zones, “altered”Brings water with it (oceanic submerge under terrestrial plate)MarbleWeather very quickly – crumble and turn to claysSedimentary Rock – “deposited”from shells of calcium carbonate organismsLimestone, sandstoneDeposited from rivers/windWhat can break nitrogen triple bonds?Bacteria, nitrogen fixers make it biologically availableNew study showed that nitrogen could come from “meta-sedimentary rock” vs strictly airMight be part of the missing carbon sink and missing nitrogen sourceWhat Influences soil formation?Parent material95% of world’s soils have been transported (water/wind)Alluvium – sediment that has been transported by waterClimateDetermines degree/level of environmental changeWarm, wet, cold determines how quickly parent material is broken down, and what biology is in the soilMore plants = physically break down more bed rockPhysical processesGlaciers, volcanoes, windDust storms – important source of iron to the ocean increases productivity in the areaBlocks out radiation/sunWarming in the ocean due to decrease in dust storms in the middle east intensify Atlantic hurricanesSulfates – net cooling effectDust bowl1930s: poor farming practices led to collapse of wheat industry across the Great PlainsWidespread, deep plowing reduced soil moisture, led to excessive dust/erosionLittle rain, few rivers, high winds, extreme weatherNo electricity + not enough wind  cant pump water from Ogallala for any more than just the kitchen gardensInfluences on production of soil formationLiving organisms: Recycle/restore nutrients and prevent erosionInvasive species to soilAlien wormsLitter decomposes faster  soils exposed, decrease in biodiversityPeople transport the worms (vehicle tires)Good in compost heaps, but not forests ….Landscape position: localize changes in temperature/moistureTime: Required to form layered soil horizonsYoung soils are not layered, older soils are notFood webs and soil formationThreats to soil biodiversityPrecipitation and temperature affect soil biodiv.Polar deserts – most threatened (dry and cold)Much of Earth covered with degraded soilARTICLE POSTED ON BLACKBOARDNitrogen enrichment/climate change suppresses soil biodiv.Soil properties determine useSoil classified by color, texture, structure, consistency, rootsMaster Soil HorizonsO Horizon – organicsA - topsoilB – subsoilC – substratumR – bedrock – cannot always find this horizonWill not find every horizon in ever area of soilProcesses contribute to soil formationAdditions – natural and anthropogenic; added/depositedLosses – natural and anthropogenic; eroded, leached, lostTranslocations – abiotic/biotic movement of materials within soilTransformation – abiotic/biotic transformations within soilSoil StructureDetermined by % of sand, silt, claySand – >500 microns; Silt – >50 microns; Clay – <2 micronsDepends on what you’re growing to see what is idealTo determine soil quality …1. Bulk Density (BD)BD= Mass of soil/Volume of total2. Soil Porosity (SP)SP = Volume of void spaces/volume totalSoil classificationBased on properties at various levels and/or categories“Soil Order” = general, “Soil Series” = Most detailedCA State soil – San Joaquin SoilSandy and loam soilsCommon in SoCalClays also presentSoil Science and Applications 03/05/2013Soil used for land foundations 1800s: Most people (80%) worked on farms; now, most in citiesThe Pedosphere-Pedon = soil-Interaction between atmo/bio/litho/hydro-spheres rxn with soil-Under the vegetation-“Pioneer” species - Lichen, moss, fungiDirt: Mineral based, comprised only of pebbles and ground rockSoil: Mineral based, but includes plants, fungi, animals, water, air, organics-Geologic Defn: Loose surface of Earth distinguished from solid bedrock (support of life not required)-Pedosheric Defn: Loose, altered surface material that nourishes/supports organisms (includes rocks, water, snow, air)Four main parts of soil-SOLID (50%) 1. Minerals(45%)Allows plants to anchor 2. OrganicsPlant/animal debris Structural support to the soilGives soil more volume to hold water-SPACE (50%)3. Air (25%)Mainly carbon dioxide due to respiration4. Solution (water) Important for drainage, holding space between particlesLife in the soil -Arthropods, nematodes (flat worms), bacteria Functions of soil-Carst topography – lots of limestone sedimentary rock that water runs through well, but limestone dissolves