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Soils

Soils. Functions of Soil. Anchor roots Aeration of roots Supply mineral nutrients Supply moisture Maintain pH suitable for plant growth. Functions of Soil. Do all plants require soil to grow?. Functions of Soil. Do all plants require soil to grow? No… Called “ Hydroponics ”.

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Soils

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  1. Soils

  2. Functions of Soil • Anchor roots • Aeration of roots • Supply mineral nutrients • Supply moisture • Maintain pH suitable for plant growth

  3. Functions of Soil • Do all plants require soil to grow?

  4. Functions of Soil • Do all plants require soil to grow? • No… Called “Hydroponics”

  5. Soil Classification • Organic -decayed plant and animal materials (O.M.) • Unstable and breaks down over time • 20% O.M. = an organic soil • Peat, bark , compost or manure added added to improve the O.M. content in soils • Good water holding capacity • Good aeration • Permeable to water • Good fertility • Reduces erosion • Easy to cultivate

  6. Soil Classification • Earthworms (Lumbricus terrestris) • “Intestines of the earth”! • 50,000 - 1,000,000/acre • Eat tons of leaves, stems & dead roots/acre and produce “castings” • Consume their body weight in plant material every 24 hours! • Turn over 40 tons of soil/acre/year

  7. Soil Classification • Earthworms • Brought to North America by European settlers in the 17th & 18th centuries • Charles Darwin (1881) said "It may be doubted whether there are many other creatures which have played so important a part in the history of the world.” • Inorganic fertilizers reduce the #’s of earthworms

  8. Soil Classification • Inorganic - comes from mineral rocks • Varies by location

  9. Soil Texture Sand • Range is: • Sand (largest) 2.0 - 0.02 mm • Silt (medium) 0.02 - 0.002 mm • Clay (smallest) <0.002 mm • A combination of all three = loam Silt Clay

  10. Soil Triangle

  11. Soil Structure • Aggregates - soil particles that group into clumps • Freezing & thawing • Wetting and drying • Root growth • Earthworms • OM + clay = “glue” that holds soil particles together

  12. Rototill only when the soil is not too wet. If too wet and you rototill, you will destroy soil aggregates!

  13. infiltration runoff a) aggregated soil b) soil crusts after aggregates break down

  14. Soil Structure • Legumes (peas, beans, clover) • N2-fixing (Rhizobium bacteria) • Makes atmospheric N available to the plant • Some are deep-rooted perennials • Opens up soil to water and aeration

  15. Soil Structure • Structure affects pore space • Large particles (sand) • large pores • little structure • good aeration • good infiltration • poor water holding capacity • low fertility • Warms quickly in spring

  16. Soil Structure • Structure affects pore space • Small particles (clay and silt) • small pores • low aeration • slow infiltration • high water holding capacity • high fertility • Warms slowly in spring • If you have a clay soil, DO NOT plow/turn when wet. This will destroy the structure!

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