* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download CSS 200 notes wk1
Survey
Document related concepts
Human impact on the nitrogen cycle wikipedia , lookup
Arbuscular mycorrhiza wikipedia , lookup
Soil respiration wikipedia , lookup
Soil horizon wikipedia , lookup
Soil erosion wikipedia , lookup
Crop rotation wikipedia , lookup
Surface runoff wikipedia , lookup
Plant nutrition wikipedia , lookup
Soil compaction (agriculture) wikipedia , lookup
Soil food web wikipedia , lookup
Terra preta wikipedia , lookup
No-till farming wikipedia , lookup
Soil salinity control wikipedia , lookup
Sustainable agriculture wikipedia , lookup
Soil microbiology wikipedia , lookup
Soil contamination wikipedia , lookup
Transcript
CSS 200 – SOILS and PLANT NUTRITION - NOTES WEEK #1 THE IMPORTANCE OF SOILS SOILS ORIGIN AND DEVELOPMENT INTRODUCTION and OVERVIEW Introduction (me and students) Syllabus (posted online and will go over in class) Handouts (posted online and will go over in class) THE BIG PICTURE – THE EARTH (Show Ball) FINITE ECOSYSYTEM - BIOSPHERE CAUSE and EFFECT are all INTERCONNECTED EVERYTHING comes from the EARTH! EXCEPT for the SUN & ENERGY, MOON & STARS We tend to take this FOR GRANTED because we are so REMOVED from BASIC PROCESSES of our own EXISTENCE HOW MANY OF YOU... GROW some or all of your own FOOD? Have BUILT your own SHELTER? MADE or manufactured anything from RAW MATERIALS? If EVERYTHING comes from the EARTH the SIGNIFICANCE of CONSUMPTION and RECYCLING becomes VERY IMPORTANT Can be looked at in TWO WAYS: REDUCE, REUSE, RECYCLE (Show overhead) PRECYCLING (Show overhead) Giving THOUGHT to what you NEED Making choices for the LEAST IMPACT on the EARTH If buying new is the best option, consider the PACKAGING and its IMPACT OLD SAYING: “USE it up, WEAR it out , MAKE it do, or do WITHOUT” WHY REDUCE our IMPACT on the EARTH? US is 5% of WORLD POPULATION US PRODUCES 25% of WORLD’S WASTE!!! IMPERATIVE that we think how we can REDUCE our IMPACT, because all that WASTE has got to go SOMEWHERE (and more often than, not its back into the ground) This is the BASIS for SUSTAINABILITY Our NATURAL SYSTEMS already do this MAN has created a problem through DISRUPTION of NATURAL PROCESSES and needs to be RECTIFIED THE IMPORTANCE of SOILS SO... what does this have to do with SOILS??? “SOIL is the most COMPLEX ECOLOGICAL SYSTEM on the PLANET” MERITS our ATTENTION and PROTECTION for a number of reasons: Important to CIVILIZATIONS (Show computer clip) SOILS can MAKE or BREAK CIVILIZATIONS Example: Nile River – yearly flooding brought silt and other rich deposits over the valley floor – AGRICULTURE flourished and SUPPORTED a large POPULATION Example: Dust Bowl of the 1930’s – natural DROUGHT and WIND, combined with MISUSE of soil brought WIND EROSION and tremendous loss of soil and destruction of the land and people on it GROWING POPULATIONS but LIMITED LANDS World population growing and doubling every 40 years Only 7% of EARTH is ARABLE (tillable) and SUITABLE for AGRICULTURAL USE Of that ...some is LOST to DEGRADATION (poor management practices) and/or URBANIZATION (population pressures) Example: Amazon River Basin – cleared for agricultural use, without the ecosystem of the rain forest, soils degrade rapidly and are unrecoverable SOIL - INTERFACE between ATMOSPHERE and CRUST, important to MANY CYCLES on the earth (Show overheads) CORE, MANTLE, CRUST (3-19 mi.), and THIN LAYER of SOILS ( Show overheads) Example: A GIGANTIC APPLE 200’ in diameter but with the same layer of SKIN as a regular apple, SKIN REPRESENTS the ratio of SOIL : EARTH SOIL LAYER is an INTERFACE that acts with CRUST and ATMOSPHERE to CYCLE and STORE various ELEMENTS rather than lose them TEMPERATURE – soils modulate temps Roots grow > 40 degrees Optimal 55 – 85 degrees All growth stops > 122 degrees CARBON CYCLE PHOTOSYNTHESIS – takes CO2 RESPIRATION – takes O2 plants incorporate in to tissues NITROGEN CYCLE ATMOSPHERIC N2 transformed into N for plants to use by MICROBES in soils plants incorporate in to tissues OTHER MINERAL (NUTRIENT) CYCLES Nutrients come from ROCKS and MINERALS that soils contain plants incorporate in to tissues GAS EXCHANGE Exchange of O2 and CO2 from ATMOSPHERE to SOIL and back through SOIL PORES WATER CYCLE Rainfall, Run-off, infiltration and percolation of water through SOIL PORES Evaporation and transpiration of water Evapotranspiration All CYCLES IMPORTANT for LIFE, and our EXISTENCE on this PLANET would end if not for SOILS MEDIUM for PLANT GROWTH PLANTS DEPEND on SOILS for: ANCHORAGE Roots grow in the PATH of LEAST RESISTANCE GOOD ANCHORAGE depends on FAVORABLE SOILS WATER SOIL supplies nearly all WATER a plant uses Without moisture ROOTS DIE or DO NOT GROW Water is AVAILABLE in SOIL PORES OXYGEN All life needs O2 to RESPIRE to release ENERGY and GROW AIR provides O2 and is AVAILABLE in the SOIL PORES we call this AERATION (0 – 21% O2 in air) SOILS are usually LOWER in O2 than the atmosphere - O2 in CRITICAL supply as ROOTS take in O2 and RESPIRE CO2 AIR and WATER COMPETE for PORE SPACE in SOILS Example: Waterlogged soil = 0 % O2 Aerated soil = 21 % O2 NUTRIENTS – 17 ESSENTIAL C, H, O – come from WATER and AIR 14 OTHERS come from the SOIL, from ROCKS and MINERALS ROOTS absorb these as IONS in the SOIL SOLUTION (water that ions dissolved in) SOIL MATRIX 3 – PHASE SYSTEM (Draw on board) ARRANGEMENT of SOLID particles and PORE SPACES or RELATIONSHIP of SOLID, LIQUID, GAS in SOILS IDEAL for PLANT GROWTH ROOTS grow in the PORE SPACES of soils and ABSORB WATER, NUTRIENTS and O2 from ROOT HAIRS ROOT HAIRS are at the tips of roots and absorb the most water ROOTS grow best where there is OPTIMAL CONDITIONS of adequate WATER, O2, NUTRIENTS Draw tree canopy and root growth Example: Tree roots in good conditions are 60-100% greater than canopy Top 12” of soil – for O2, H2O, nutrients (primarily AERATION) Example: Black plastic and effect on roots and lack of O2 USES OF SOIL AGRICULTURAL USES CROPLAND Soil worked and crops planted, managed and harvested ANNUAL CROPS – require yearly soil preparation Concerns are weeds, fertilization and organic matter ISSUE: Soil EROSION due to uncovered soil PERENNIAL CROPS – planted every 3-20 years Soil held in place by cover crops or Horticultural crops ISSUES: control weeds, reduce erosion, compaction, OM stability GRAZING LAND Loosely managed land Planted in native and non-native grasses, shrubs FOREST LAND Disturbs soil the least, planted with tree species ISSUES: Logging practices – less vegetation, compacted soil, erosion, compromises new tree planting ORNAMENTAL PLANTS Landscaping plantings in heavily disturbed soils ISSUES: compaction, disturbed soil layers, NON-AGRICULTURAL USES RECREATIONAL Playgrounds, golf courses, parks, campgrounds, sports fields, etc. ISSUES: compaction, shear resistance, grading, drainage, hardness, maintenance FOUNDATIONS for BUILDINGS SHRINK - SWELL POTENTIAL – swell when wet and shrink when dry - UNSTABLE for FOUNDATIONS LOAD BEARING CAPACITY – soils high in clay or organic matter have LOW load bearing capacity because may shift and crack WASTE DISPOSAL Human sanitary waste uses soil to filter and break down harmful substances Example: Septic systems and drain fields Example: Sewage Sludge used on crops, highly regulated by government Hazardous waste – leaching is prime concern BUILDING MATERIALS Historically used: Sod (Dakotas – grass, soil and roots) Adobe (in the SW – sun dried blocks) Rammed earth and Cob house building Example: Cob house by Building 3 Engineered soils – to support a load or stress Example: Under sidewalks surrounding trees LAND USE in the US Although MOST of our land (non-federal) is still in AGRICULTURAL USE, it is rapidly being lost to URBAN DEVELOPMENT and DEGRADATION URBAN DEVELOPMENT Urban Development - 7% and growing Example: Urban growth boundary – one way to curb growth and allow better decisions for urban planning than using prime farm land Cropland – 25% Rangeland – 27% Pasture – 8% Forest land - 27% Conservation land – 2% SOIL QUALITY and DEGRADATION SOIL is basically NON-RENEWABLE in our LIFETIMES SOIL QUALITY or HEALTH is important over the long term SOIL DEGRADATION is the LOSS of QUALITY due to: Erosion Pollution Desertification – Changes in soil chemistry Salination – saltiness of soil Loss of OM BMP – BEST MANAGEMENT PRACTICES are MAINTENANCE of SOIL QUALITY important to understand and implement SOIL ORIGIN & DEVELOPMENT Soil is a SLOWLY RENEWABLE RESOURCE MANY YEARS to DEVELOP (100’s to 1000’s of years) NON-RENEWABLE in our LIFETIMES Still can GROW, CHANGE and DEVELOP over TIME ROCKS, MINERALS, and NUTRIENTS ROCK (solid bedrock of earth’s crust) is broken down to PARENT MATERIAL (smaller rocks) and through the process of WEATHERING is further broken down to SOIL DIFFERENCES between ROCK, MINERALS & NUTRIENTS ROCK – Solid bedrock which is a mixture of MINERALS of DIFFERENT KINDS and PROPORTIONS MINERALS – PURE INORGANIC ELEMENTS or COMPOUNDS of a DEFINITE CHEMICAL COMPOSITION usually CRYSTALLINE in form NUTRIENTS – Dissolved IONS in water called the SOIL SOLUTION ROCKS are CLASSIFIED by: How they’re FORMED MINERAL COMPOSITION TEXTURE 3 MAJOR CLASSIFICATIONS of ROCKS based on how they’re FORMED IGNEOUS ROCK – created by the COOLING and SOLIDIFICATION of MOLTEN ROCK – LAVA (extrusive) & MAGMA (intrusive) Covers ¼ surface of CRUST, but makes up ¾ of total Examples: GRANITE – coarse texture, E. US BASALT – fine texture, Cascades OBSIDIAN – cooled rapidly, glassy, sharp, Newberry Crater, Archeologist? PUMICE – N. Crater Lake area @ Lemolo Lake shores covered SEDIMENTARY ROCK – deposits of MUD and SAND (through wind and water erosion) that are CEMENTED together by CHEMICALS or PRESSURE Most formed in PREHISTORIC SEAS Covers ¾ surface of CRUST (over igneous) Examples: LIMESTONE – finer, gives us ground lime SANDSTONE - coarser METAMORPHIC ROCK - formed when either IGNEOUS or SEDIMENTARY ROCK is subjected to GREAT HEAT & PRESSURE Examples: LIMESTONE >>>>> MARBLE SANDSTONE >>>>> QUARTZITE SHALE >>>>> SLATE SOIL is FORMED from the WEATHERING of ROCK ROCK (solid bedrock of earth’s crust) is broken down to PARENT MATERIAL (smaller rocks) and through the process of WEATHERING is further broken down to SOIL 2 TYPES of WEATHERING PHYSICAL WEATHERING FRACTURING ROCK – physically breaking apart rock Freezing and thawing water in rock (frost wedging) Heating and cooling EROSION of ROCK – physically wearing rock away Rain and running water Wind CHEMICAL WEATHERING – changing rock chemically WATER (mildly acidic) DISSOLVES minerals in rock into SOLUTION HYDROLYSIS – WATER reacts with minerals to create NEW, SOFTER COMPOUNDS Example: Limestone and vinegar or HCl Acid fizzes OXIDATION - O2 reacts with minerals to form NEW COMPOUNDS Example: Oxidation of Iron with O2 = rust PLANTS aid in PHYSICAL and CHEMICAL WEATHERING too ROOT WEDGING - pries apart and fractures rock LICHENS – form mild acids that dissolve rock FACTORS AFFECTING SOIL FORMATION PARENT MATERIAL CLIMATE LIFE TOPOGRAPHY TIME (HUMANS?) PARENT MATERIAL PARENT MATERIALS (broken up rocks) are derived from ROCKS which are composed of MINERALS, all of which directly influence the SOIL that develops 3 TYPES of SOILS are formed (2 Mineral, 1 Organic) RESIDUAL SOILS – are soils FORMED IN PLACE on top of existing BEDROCK Less common Form slowly from weathering TRANSPORTED SOILS – are soils that have been TRANSPORTED and DEPOSITED from their ORIGIN to a NEW AREA More common Form relatively quickly GLACIAL ICE - action of glacier moves soil Examples: GLACIAL TILL – pebbles, rocks and boulders moved and dropped in place GLACIAL OUTWASH – sandy soils along rivers and streams LACUSTRINE DEPOSITS – finer sediments in lakes WIND – wind moves FINE SAND or SILT Examples: EOLIAN - sandy soil of Midwest LOESS - silty soil of the Palouse (SE WA and NE OR) WATER – water in rivers and streams moving deposits called ALLUVIUM Examples: FLOODPLAINS – like Nile river DELTAS – river deposits when reach ocean, very fertile GRAVITY – hilly, mountainous areas where deposits move downhill by gravity are called COLLUVIUM Example: TALUS – deposits of rock and soil at the bottom of hill, often seen hiking VOLCANIC SOILS – ash and pumice expelled from active volcano and sometimes also carried away by wind Example: ASH & PUMICE – common in PNW, Hawaii, Alaska CUMULOSE SOILS – soils that accumulate in one spot ORGANIC DEPOSITS – plant debris breaks down slowly to form deposits Organic soils contain > 20 % OM Formed under WATERLOGGED conditions in lake or bog Decreased O2 > decreased decomposition of OM > increased OM accumulation from plants CLIMATE (Show handout) TEMPERATURE Incr. T >>> Incr. WEATHERING Incr. T >>> Incr. PLANTS >>> Incr. DECOMPOSITION >>> decreases OM overall RAINFALL Incr. RAINFALL >>> Incr. LEACHING Lime, clay and nutrients move further down in soil Incr. RAINFALL >>> Incr. PLANTS >>> Incr. OM LIFE - PLANTS & ANIMALS PLANTS – VEGETATION affects soil formation Grasslands high in OM because of root dieback every year Forests low in OM because most of it above ground in leaves SOIL BIOLOGY – all sorts of ORGANISMS in soils aid in mixing, OM decomposition, holding and releasing of nutrients TOPOGRAPHY SLOPE – steepness ASPECT – where slope facing, N, S, E OR W Affects T and moisture Contrast bottom of hill to top TIME The LONGER the TIME, the MORE DEVELOPED the SOIL PROFILE Developing 1’ of soil can take 100 – 100,000 YEARS 0 YEAR – first EXPOSED to ATMOSPHERE (HUMANS?) some consider HUMANS as another FACTOR as we manipulate the landscape we TURN BACK TIME to ZERO DESTROY horizons by plowing or grading, create pans, deplete OM, create conditions for erosion BMP is crucial THE SOIL PROFILE (Show overhead) To STUDY SOILS we DIG a PIT called a PEDON Usually 3’ x 3’ x 5’ DEEP SOILS CHANGE over TIME in response to 4 PROCESSES ADDITIONS OM, transported soils, pollution LOSSES (out of the profile) Deep leaching, erosion TRANSLOCATIONS – movement within the profile Leaching down Evaporation or Flooding up TRANSFORMATIONS – chemical alterations OM decay Weathering to smaller particles Chemical alterations Because of these processes, SOILS FORM LAYERS called HORIZONS YOUNG soils have FEWER HORIZONS and SHALLOWER PROFILES OLDER soils have more DISTINCT HORIZONS and DEEPER PROFILES tend to acidic, leached, less productive soils SOIL PROFILE shows all HORIZONS from TOP to UNWEATHERED PARENT MATERIAL (Show overhead) O – LITTERLAYER - OM, usually undisturbed soil A – TOPSOIL OM accumulates Darker color Best layer for plant growth E – ELUVIATION Leached (or washes out) layer within the A layer Light color Example: Sandy forest soils with high rainfall B – SUBSOIL Low OM More clay Illuviation - Leachates accumulate (or washes in) C – PARENT MATERIAL Broken up rock Little weathering Roots can penetrate cracks R – BEDROCK Solid rock with some cracks LAYERS named by CODES identifies POSITION in PROFILE and provides some INFORMATION about it SUBDIVISIONS of HORIZONS– transition layers between soil horizons AB - between A & B with A DOMINANT LOWERCASE LETTERS (see Appendix #4) Denote a trait within a horizon Example: p – plow layer, t - clay layer NUMBERS (see Appendix #4) Denote extra layers within horizons Example: Bt1 & Bt2 LAB Work on WS1 – MINERALS, ROCKS, AND PARENT MATERIALS Draw profile for WS2 – SOIL ORIGIN and DEVELOPMENT Due next week