OHIO STATE UNIVERSITY EXTENSION. Soil and Nutrients. OSUE Master Gardeners Mahoning County Class of Bill Snyder March 21, 2017

Transcription

1 OHIO STATE UNIVERSITY EXTENSION Soil and Nutrients OSUE Master Gardeners Mahoning County Class of 2017 Bill Snyder March 21, 2017

2 Soil vs DIRT

3 Ecological Roles of Soil 1. Medium for plant growth 2. Recycling system for nutrients and organic wastes 3. Habitat for soil organisms 4. System for water supply and purification 5. Engineering medium

4 Soil (as a medium for plant growth) provides: Physical Support - matrix Air - respiration and ventilation Water - solvent, chemical, heat capacity Nutrients at least 18 essential elements Moderation of Temperature - insulation Protection from Toxins - phytotoxins Vent gases Decompose or adsorb toxic organics Suppress toxic organisms

5 Soil Investigation Gross Examination In Situ Investigation

6 Soil Investigation In Situ Investigation In Situ Ø in place or position Ø undisturbed

7

8 Bryce Canyon

9

10

11 O Soil Horizons

12 Master Soil Horizons O O Horizons Leaf litter - organic matter is the dominant material

13 Master Soil Horizons O A Horizons Mineral horizon at the surface showing organic matter enrichment - minerals are the dominant material. Often coarser in texture due to loss of finer materials to lower horizons and through erosion.

14 Master Soil Horizons O E Horizons Subsurface horizon showing depletion of organic matter, clay, iron and aluminum compounds due to leaching.

15 Master Soil Horizons O B Horizons Subsoil horizon showing enrichment of clay material, iron, aluminum and organic compounds (material washing in from horizons above).

16 Master Soil Horizons O C Horizons Horizons of loosened or unconsolidated parent material.

17 Master Soil Horizons O R Layers Consolidated bedrock with little evidence of weathering.

18 Soil Classification Based on the Soil Profile (Horizons) Pedon: the smallest sampling unit that displays the full range of properties characteristic of a particular soil. Pedons occupy from about 1 to 10 m 2 of land area.

19 Polypedon Many similar soil pedons joined together is termed a polypedon. The landscape as a whole can be viewed as being composed of many different polypedons. A polypedon of sufficient size is termed a soil individual.

20

21

22 All soil individuals in the world with similar profile properties and horizons are said to belong to the same Soil Series Approximately 10,500 in the United States More than 400 in Ohio Roughly 117 in Mahoning County

23 Examples of Soil Series Walla Walla Molokai Canfield Ravenna Mahoning Ellsworth

24

25

26 soils.usda.gov

27

28

29

30

31

32

33

34

35

36

37

38 Soil Investigation Gross Examination In Situ Investigation

39 Soil Investigation Gross Examination

40 Soil Composition According to Dr. Sally Miller Department of Plant Pathology The Ohio State University Soil Has Three Major Components: 1. the living 2. the dead and 3. the very dead.

41 Ideal Soil Composition 20-30% Air 45% Inorganic Material 50% Pore Space 50% Solids 20-30% Water 5% Organic Material

42 Soil Composition Inorganic Material

43 The Inorganic Material in Soil Results in Soil Characteristics Soil Texture Soil Structure

44 Soil Texture Sand Silt Clay

45 Particle Size Electron Microscope Light Microscope Visible CLAY SILT SAND

46 Particle Size (cont.) (Flour) (Table Sugar or Salt) (Modeling Clay). Relative Sizes

47 Particle Size Electron Microscope Light Microscope Visible.

48 Some properties of sand, silt and clay Property Sand Silt Clay Water-holding Capacity Low* Medium to high High* Aeration Good Medium Poor Drainage rate Fast Slow to medium Very Slow Decomposition of Organic Matter Rapid Medium Slow *Clay will hold 50 times the water as sand.

49 The relative amounts of sand, silt and clay result in the textual quality of the soil.

50

51 Using a Textural Diagram

52 Example 1: 15% sand: 70% silt: 15% clay Silt Loam

53 Example 2: 30% sand: 25% silt: 45% clay X Clay X X X

54 Example 3: 15% sand: 50% silt: 35% clay Silty Clay Loam X X X X