Soil ManagementSite Selection, Soil Fertility

Warren RobertsGeorge Kuepper

Where We’re Going• Soil Texture and Drainage• Site Selection• Soil Fertility & pH

• Fertilizers & Nutrients

Later Sessions• Soil Biology & Micro-Organisms

• Compost, Cover Crops and Green Manures

• Organic Farming

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Commonly Known Soil Types• Sandy, Sandy Loam, Loam

• Light Soil (Not Really)

• Clay• Heavy Soil (Not Really)

• Sandy Soils are Actually Heavy• Clay Soils are Actually Light

An Acre of Soil Weighs What?

• Acre furrow slice• Top plow layer over one acre• Usually 6-7 inches deep• Averages about 2 million lbs

Definitions

• Clay (0.001 – 0.002 mm)• Silt (0.002 - 0.050 mm)• Sand (0.050 - 2.00 mm)• Gravel (>2.00 mm)

Pore Space• The portion of the soil volume occupied by

air and water

• Ideally half air and half water

• Very Important for Plant Growth

Loose Soil

Compacted Soil

Pore Space• Macro Pore (Large Spaces)

• Sands• Micro Pore (Small Spaces)

• Clay

Loose Loam Soil

Compacted Loam Soil

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Water Movement in Soil

• Gravity• Primary force in sandy soils

• (large pores)

• Capillary Forces, Osmotic (Suction)• Primary force in clay soils

• (small pores)

Aerobic vs Anaerobic

Soil Moisture

• Saturation• All pores filled

• Can become Anaerobic

• Field Capacity• Drainage has ceased• Capillary action holds remaining water• Micro-pores may be full

Soil Moisture at 24 inches

http://www.mesonet.org/

Ideal Soil• Most Desirable

• Loam• Sandy Loam• Loamy Sand• Sandy Clay Loam

• Least Desirable• Sand

• Won’t hold water• Clay

• Difficult to work

Ideal Soil• Well Drained Area

• Not in a flood plain• Not in a low-lying area where water can accumulate

• Good air drainage• Not subject to late spring frosts or early fall frosts

• Deep Soil• Not overlying a rocky base• Not overlying a clay base

Ideal Organic Soil• Not Contaminated from Previous Years • Not Contaminated by Neighbors• Not Contaminated by Highways, Power Line

Right-of-Ways

Ideal Soil• Easy to Access• Easy to Irrigate• Easy to Control Predators

• Deer, Raccoons, Feral Hogs, Coyotes, Humans

Ideal Soil

•Organic Matter

Ideal Soil – Noble Foundation

Ideal Soil– Noble Foundation

Organic Matter

Organic Matter – For Whatever the Reason

• Holds Water• Prevents Excess

Drying

• Improves Drainage• Prevents Saturation• Keeps Soil Aerobic

• Prevents Runoff

• Like a Sponge

Organic Matter – For Whatever the Reason

• Holds Nutrients• Prevents Nutrient

Loss• Prevents

Environmental Contamination

Organic Matter – For Whatever the Reason

• Improves Tilth• Provides Larger

Pore Spaces for Root Growth

• Allows for Air-Water Movement

Organic Matter – For Whatever the Reason

• Wonderful

Ideal Soil

• 50% Solid Matter• 45% Mineral• 5% Organic

• 50% Pore Space• 25% Water• 25% Air

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OM (%)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8 Before After

Soil Fertility

• Supplies Nutrients to the Plant for Growth and Development

Soil Fertility• Essential Plant Nutrients

• 16 (18) required for plant growth, development, and reproduction

• Macronutrients: (large quantities used by the plant)

• Micronutrients: (small quantities used by the plant )

Soil Fertility – Macro Nutrients

• Primary

• Secondary

• Carbon ( C )• Hydrogen ( H ) • Oxygen ( O )

• Nitrogen ( N )• Phosphorus ( P )• Potassium ( K ) Kalium

• Calcium (Ca)• Magnesium ( Mg)• Sulfur (S )

Soil Fertility

Micro Iron ( Fe )Boron ( B )Copper ( Cu)Chlorine ( Cl )Manganese ( Mn )Molybdenum ( Mo)Zinc ( Zn )Cobalt ( Co )Nickel ( Ni )

Soil Fertility

• See Hopkins Cafe. • Managed by My Cousin, Colonel Mo Cleaver

Soil Fertility• See Hopkins Cafe. Managed by My Cousin,

Colonel Mo Cleaver.

• C H O P K N S • Ca Fe

• Mg Bo Mn Cu Zn• Co Mo Cl• Ni

pH

• Definition: Inverse Concentration of Hydrogen Ion Concentration, Expressed in Moles per Liter

• Practical Definition: Amount of Acid in the Soil• pH goes up as H+ concentration goes down

• VERY Important, but Often Overlooked

Soil pH

pH and Nutrient Availability

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Lane Agricultural Center - OSU

Typical Fertilizer• 5-10-15• 13-13-13• 34-0-0• 18-46-0• 0-0-62• 0-46-0

Typical Fertilizer

• N-P-K (Not Really)• Actually N-P2O5-K2O

Next Session• Soil Sampling and Soil Testing