Soils for Plant Growth A Unit of the Michigan State University Extension Master Gardener Curriculum

Soils for Plant Growth Objectives Define soil Understand its composition Understand its physical properties Understand its chemical properties Identify essential plant nutrients and their management

Objectives Understand management practices related to changing soil properties Understand environmental implications of soil management practices Use knowledge gained to analyze and assess concerns related to soil properties Soils for Plant Growth

What Is Soil? Soils for Plant Growth

What Is Soil? Soils for Plant Growth

What Is Soil? Soils for Plant Growth

What Is Soil? Soils for Plant Growth

What Is Soil? Not DIRT!!! Precious resource Loose, unconsolidated material on the earth’s surface Soil scientist’s definition Soils for Plant Growth

What Is Soil? “A natural body of the earth’s surface having characteristics resulting from climate and living organisms acting upon parent material as conditioned by slope over periods of time” Soils for Plant Growth

What Is Soil? Parent material Organisms

Soils for Plant Growth What Is Soil? Parent material Organisms Climate Topography Time

Soil Provides Anchorage Water Air Nutrients Growth-producing chemical environment Soils for Plant Growth

Soil Is Composed of Mineral solids Organic solids Pore spaces Soils for Plant Growth

Ideal Soil Composition Water Air Mineral Organic 45% 5% 25% Soils for Plant Growth

Physical Properties of Soil Texture Structure Pore space Density Temperature Color Soil organisms Organic matter Groundwater Soils for Plant Growth

Soil Texture Sand Silt Clay Soils for Plant Growth

Finer Coarser Sand Loamy Sand Sandy Loam Silt Loam Clay Loam Clay Soils for Plant Growth

Percent Clay Percent Silt Percent Sand clay sand silt silt loam loam sandy loam sandy clay loam sandy clay clay loam silty clay loam silty clay loamy sand

Soil Structure LooseAggregated Soils for Plant Growth

Influence of Soil Structure Soils for Plant Growth

Texture Vs Structure Texture is unchangeable Structure can be improved or destroyed Soils for Plant Growth

Compaction Compressed StructureGood Structure Soils for Plant Growth

Excessive Tillage Too Much Tillage Soils for Plant Growth

Porosity Porosity Water holding capacity Porosity Drainage Porosity Aeration Porosity Density Soils for Plant Growth

Macro- and Micropores Water-filled microprore Air-filled macropore Soils for Plant Growth

Water Movement SandLoamClay Soils for Plant Growth

Soil Density Sand Clay Soils for Plant Growth

Soil Temperature Soils for Plant Growth

Soil Color Affects soil temperature Indicates how much organic matter is present Predicts natural drainage conditions Soils for Plant Growth

Topsoil Color Dark High organic matter Formed under cool, wet conditions Light Low organic matter Formed under warmer, drier conditions

Soil Organisms Bacteria Fungi Mycorrhizae Lichens Protozoa Invertebrates Vertebrates Soils for Plant Growth

Organic Matter Vs Humus Leaves Manure Grass clippings Decomposes rapidly Highly decomposed Stable Rich in nitrogen Slowly degradable decomposes to form Organic matter humus Soils for Plant Growth

Groundwater Stored in aquifers, water-saturated zones beneath the earth’s surface Part of the soil environment if close to the surface - high water table Easily contaminated Soils for Plant Growth

Points to Remember Know the physical characteristics of your soil Adding organic matter is usually beneficial Don’t over till Don’t compact Maintain groundcover on slopes Avoid bringing in soil of drastically different texture Soils for Plant Growth

Chemical Properties of Soil Intensity - Electroconductivity Capacity - Cation Exchange Capacity Availability Balance - Nutrient ratios EC CEC pH Ca:Mg Soils for Plant Growth

Chemistry 101 Atom The smallest unit of a substance that has all the properties of that substance No net electrical charge Model behaves a bit like our solar system - + Electron (-) Proton (+) Neutron Soils for Plant Growth

Chemistry 101 Molecule A group of atoms connected by chemical bonds No net electrical charge Example: H 2 O - water H H O Soils for Plant Growth

Chemistry 101 Ion - An atom or molecule that has an electrical charge due to the loss or gain of electrons H 2 O H + + OH - Soils for Plant Growth

Chemistry 101 Ion Cation - an ion with a positive charge Ca ++ Mg ++ H + K + NH 4 + Anion - an ion with a negative charge OH - NO 3 - SO 4 -- Cl - Soils for Plant Growth

Chemistry 101 Unlike charges attract Like charges repel ++ + _ Soils for Plant Growth

Soil particle – ++Ca – +K – ++Mg Chemical Properties of Soil Capacity - Cation Exchange Capacity CEC Soils for Plant Growth

Cation Exchange Capacity Humus Clay Soils for Plant Growth ++Ca +K Mg++ ++Mg +H NH 4 + +NH 4

Cation Exchange Capacity Very low with not much clay or humus Intermediate loamy texture or sandy with more humus Progressively more clay and/or humus Probably an organic soil CEC Soils for Plant Growth

Chemical Properties of Soil Availability CEC pH Soils for Plant Growth

What Is pH and Why Is It Important? H 2 O H + + OH - Remember: Everything is dissolved in water Soils for Plant Growth

AcidAlkaline Neutral Battery acid Vinegar Orange juice Pure water Baking soda AmmoniaBleachLye

Soils for Plant Growth AcidAlkaline Neutral Most plants AlfalfaBlueberries

Factors Influencing Soil pH Components of the soil Lime Water quality Type of nitrogen applied Amount of fertilizer Crop species Soils for Plant Growth

What Does This Plant Tell You about the pH of the Soil? Soils for Plant Growth

What Does This Plant Tell You about the pH of the Soil? Soils for Plant Growth

K+K+ NO 3 - Cl - Ca ++ Chemical Properties of Soil Intensity - Electroconductivity EC Soils for Plant Growth

Ca:Mg Fe:Mn K:Ca:Mg N:K Chemical Properties of Soil Balance - Nutrient ratios EC CEC pH Ca:Mg Soils for Plant Growth

Essential Elements Soils for Plant Growth HOPKNS Ca Fe C B Mg Cl Mn Mo Cu Zn!

Soils for Plant Growth HOPKNS Ca Fe C B Mg Cl Mn Mo Cu Zn! Essential Elements

Soils for Plant Growth HOPKNS Ca Fe C B Mg Cl Mn Mo Cu Zn! Essential Elements

Macronutrients Nitrogen (N as NO 3 and NH 4 ) Soils for Plant Growth

Macronutrients Nitrogen (N as NO 3 and NH 4 ) Phosphorous (P) –Associated with root growth and flower development –Potential pollutant –Deficiency results in purpling of leaves Soils for Plant Growth

Macronutrients Nitrogen (N as NO 3 and NH 4 ) Phosphorous (P) Potassium (K) –Reduced growth / vigor –Marginal necrosis on older leaves –Wilt Soils for Plant Growth

Macronutrients Nitrogen (N as NO 3 and NH 4 ) Phosphorous (P) Potassium (K) Magnesium (Mg) Calcium (Ca) Sulfur (S) Soils for Plant Growth

HOPKNS Ca Fe C B Mg Cl Mn Mo Cu Zn! Essential Elements

Changing Soil Properties Changing physical properties –Bringing in sand / clay / topsoil –Adding compost Changing chemical properties –Fertilizing –Adjusting the pH Soils for Plant Growth

Changing Physical Properties Changing soil texture –Bringing in sand / clay / topsoil Changing soil structure –Adding compost Soils for Plant Growth

What about Gypsum? Is it a quick fix for clay soils? Gypsu m

Urea Tri-Superphosphate Muriate of Potash Inert Material Fertilizer Composition N P K NPK Soils for Plant Growth

Pounds of Actual Nitrogen 1 pound of actual nitrogen per 1,000 square feet of lawn 3 pounds of actual nitrogen per 1,000 square feet for trees or shrubs 2 pounds of actual nitrogen prior to planting vegetables then side dress with 1 pound of actual nitrogen

Soils for Plant Growth How Much Fertilizer? divided by 20 = 5

Soils for Plant Growth How Much Fertilizer? ? divided by ? = ?

Raising Soil pH Lime –Dolomitic lime (calcium and magnesium) –Calcitic lime (calcium only) –Hydrated lime (calcium only with faster reaction) Wood ashes Soils for Plant Growth

Lowering Soil pH Ammonical nitrogen (ammonium sulfate) Iron sulfate Acids Elemental sulfur Soils for Plant Growth

Why Test Soil? Basis for using lime and fertilizer Diagnosing problems Evaluating nutrient balances Protecting the environment Soils for Plant Growth

Taking a Soil Sample When Where How Amount Preparing and packaging Fill out the form completely Soils for Plant Growth

Interpreting Soil Test Results Lawns Soils for Plant Growth

Interpreting Soil Test Results Gardens Soils for Plant Growth

What Is Soil? “A natural body of the earth’s surface having characteristics resulting from climate and living organisms acting upon parent material as conditioned by slope over periods of time” Soils for Plant Growth

Horizons “A” horizon - topsoil “E” horizon - transition “B” horizon - subsoil “C” horizon - parent material “R” horizon - bedrock Soils for Plant Growth

What’s the Soil Like Where You Live? Soils for Plant Growth

What Would You Do? New home on farmland Soil compacted during construction Owner wants to establish a lawn Soils for Plant Growth

What Would You Do? Vegetable garden in full sun Sandy soil Plants lack vigor Plants turn yellow by mid-summer Soils for Plant Growth

What Would You Do? Three-year-old flower beds Annuals and perennials Unsatisfactory results Clay soil Soils for Plant Growth

What Would You Do? Trees and shrubs won’t grow Dead rhododendrons Yellowing pin oak Plants slowly dying Heavy clay soil Soils for Plant Growth

Questions and Comments