Great Soil-Great Gardens I Basic Soil Science Brad Park, Rutgers University Materials developed by: Karen A. Plumley, Ph.D. Research Director, Alliance for Low Input Sustainable Turf Soils Instructor, Rutgers Golf Turf Management School
Great Gardens Great Soil I I. What is Soil? Basic Soil Science II. Physical Properties of Soil III. Soil Organic Matter IV. Soil Water V. Chemical Properties VI. What are the properties of YOUR soil? VII. Web Resources
What is Soil? A natural body covering the earth s surface in which plants grown Comprised of mineral and organic materials Formed naturally by the combined effects of climate, living organisms, parent material, topography and time.
What is Soil?
THE FUNCTIONS OF SOIL 1. Medium for Plant Growth - Provides ventilation of gases i.e. CO 2 and O 2 - Stores water & supplies nutrients - Modifies temperature - Provides support - Seed germination bed 2. Water Supplies - Storage / Filtration 3. Habitat for Soil Organisms who recycle organic waste
How much soil feeds the world? 75 % of earth s surface is water which leaves 25% 50% of that 25% is desert, polar or mountainous which leaves 12.5% 40% of that 12.5% is too steep, too infertile, too rainy or too rocky which leaves 7.5%
How do soils form? Soil formation is simultaneously: Breakdown of old Synthesis of new Losses Additions Translocations Each soil is a unique individual that develops as a result of the climate, living organisms, parent material, topography and time.
A Natural, Forest Soil Profile Horizons = layers O A E B Parent Material
II. SOIL PHYSICAL PROPERTIES - Texture Texture = % sand + % silt + % clay Clay Silt Very Fine Fine Sand Medium Coarse Very Coarse Gravel 0.002 mm 0.05 mm 2.0 mm
II. SOIL PHYSICAL PROPERTIES - Texture Sand Broken down rock frags Silt Chemically inert compared with clay and OM Promote air movement and drainage
II. SOIL PHYSICAL PROPERTIES - Texture Clay Broken rock fragments or synthesized in soil Chemically Reactive Increase soil s water and nutrient hold capacity
12 Textural Classes
II. SOIL PHYSICAL PROPERTIES - Structure Aggregate = secondary soil particles create porosity of soil www.emc.maricopa.edu/.../biobookplanthorm.html
II. SOIL PHYSICAL PROPERTIES - Structure Aggregate Shape Granular Prismatic Blocky Platey Promote air movement / drainage Resist compaction Inhibit air movement / drainage Easily compacted http://ltpwww.gsfc.nasa.gov
II. SOIL PHYSICAL PROPERTIES - Structure Importance of Aggregates Aggregates are destroyed by: Cultivation (too wet) Compaction Aggregation is promoted by: Root growth Addition of organic material
II. SOIL PHYSICAL PROPERTIES - Structure Porosity Total volume of pores Filled with water and air in constantly changing proportions
II. SOIL PHYSICAL PROPERTIES - Porosity Compaction
II. SOIL PHYSICAL PROPERTIES - Color
III. SOIL ORGANIC MATTER Gives soils their dark color.
III. SOIL ORGANIC MATTER Biological origin Source: Live biomass Non-living (various stages of decomposition) Humus: relatively stable end product of decomposition
Constantly changing form as soil critters and microbes consume it
In one teaspoon of healthy soil there should be: 600 million bacteria three miles of fungal hyphae 10,000 protozoa 20 to 30 beneficial nematodes in a teaspoon of soil Dr. Elaine R. Ingham, Soil Food Web
Selman Waksman Waksman coined the term antibiotics It was at Rutgers that Waksman's team discovered streptomycin and eomycin Streptomycin = first antibiotic to cure tuberculosis Received the Nobel Prize for the discovery of streptomycin
III. SOIL ORGANIC MATTER Benefits of Organic Matter Enhances biological activity Improves cation exchange (nutrient holding and release) Increases water holding capacity Increases porosity and infiltration Improves soil structure and tilth Reduces crusting and erosion
IV. SOIL WATER Function of Water in Plants Without water life isn't possible Solvent for every chemical reaction that makes up life Evaporation on the leaf cools the plant Required in photosynthesis Needed for cell expansion and growth Plants use water to maintain their shape
II. Qualitative Plant-centric PROPERTIES Description Description OF WATER of of Soil Soil Wetness Wetness PLANT AVAILABLE WATER Plant Unavailable Water Water between saturation and FC Plant Available Water Water between FC and PWP Plant Unavailable Water Water in soil beyond PWP Drought tolerant plants cannot extract water beyond -15 bars
IV. SOIL WATER - Storage Water Holding Capacity Amount of water a soil can retain is influenced by: Texture Structure Organic Matter Can be increased by raising organic matter levels sand < silt < clay
II. PROPERTIES OF WATER IV. SOIL WATER - Movement 1. Texture and Pore Size Size and total pore space Rate of movement through soil Adsorptive forces vs. gravitational forces
II. IV. PROPERTIES SOIL WATER OF - Movement WATER 2. Soil Structure: Allows gravitational water to drain more quickly Granular Prismatic Blocky Platey
V. SOIL CHEMICAL PROPERTIES - Fertility
V. SOIL CHEMICAL PROPERTIES- ph ph Degree of Acidity or Alkalinity Alkaline ph above 7.0 Neutral ph 7.0 Acid (example) ph below 7 Soil ph an important plantgrowth factor that can be managed Alkaline ph above 7.0 Neutral ph 6.0-6.5 Acid (example) ph below 6.0 Brady & Weil, 1999
Effects of Soil ph Affects nutrient availability (solubility) Aluminum toxicity damages roots at low ph Direct damage also possible at high ph Brady & Weil, 1999
V. SOIL CHEMICAL PROPERTIES - CEC Cation Exchange Capacity A measure of soil fertility and nutrient retention Higher CEC = higher fertility Cation- a positively charged ion NH 4 + K + Ca 2+ Fe 2+
V. SOIL CHEMICAL PROPERTIES - CEC Cation Exchange Capacity Clay and humus have negative charges on their surface Cations are attracted and held clay and humus Once attracted, cations are protected from leaching Provide nutrient reserve for plants when they are exchanged into soil solution Dependent on texture and OM
Cation Exchange Capacity protects nutrient from leaching Sandy Soil Clay Soil
VI. What are the properties of YOUR soil? Soil TEST!
VI. What are the properties of YOUR soil? Soil TEST Evaluate nutrient levels Determine soil ph Receive most appropriate recommendation for fertilizer & lime Soil Testing kits available at county offices of Rutgers Cooperative Extension: njaes.rutgers.edu/soiltestinglab
VI. What are the properties of YOUR soil? Web-based copies may be found at: http://websoilsurvey.nrcs.usda.gov/app/
VII. WEB RESOURCES Glossary of Soil Science Terms Soil Science Society of America https://www.soils.org/publications/soils-glossary/ Soil Formation USDA http://soils.usda.gov/education/facts/formation.html/ Lessons - Soil Genesis and Development Plant & Soil Sciences elibrary PRO http://passel.unl.edu/pages/index2col.php?alllessons=1&tag=soil+genes +and+development Soil Surveys on the Web USDA http://websoilsurvey.nrcs.usda.gov/app/
How can I stand on the ground every day and not feel its power? How can I live my life stepping on this stuff and not wonder at it? - William Bryant Logan