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Soils, Fertilizers and Composting

Bill Hlubik Professor, Agricultural and Resource

Management Agent RCE, Middlesex County

EARTH Center

Fertile, properly managed soils are the foundation for healthy plants.

Proper management of soils can help reduce plant stress and disease problems while protecting the local environment.

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Improper management of soils can lead to:

• Poor Yields

• Decreased Profits -$$$$$$

• Increase in Diseases and Pests

• Soil Erosion

• Environmental Problems

What is soil ?

– a natural body on the surface of the earth in which plants grow; comprised of mineral and organic materials and living organisms

– Minerals - Sand, Silt, Clay in varying proportions

– Soil Micro and Macro Organisms

Physical Characteristics

• Soils are comprised of: – Solids

• Mineral component

• Organic component

– Liquids • water

– Gases • ex. O2, CO2

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12 Textural Classes of Soil

• Based on percentage of sand, silt and clay

Physical Characteristics – Water Movement in Soil

• Infiltration

– Movement of water into the soil surface

Physical Characteristics - Tilth • Tilth or structure is affected by several factors, including:

– Organic matter, limestone, biological activity

• All increase aggregation or flocculation of particles

– Sodium

• Decreases aggregation or dispersion of particles

• Tilth is primarily a ‘by-product’ of biological activity

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Topsoil

Subsoil

Parent Material

Soil Profile • Layers in the soil are called

‘horizons’

• The upper layer is called ‘topsoil’

• The middle layer is called the ‘subsoil’

• The parent material or bedrock is found below these layers

Soils Map of New Jersey

• This map shows the major soil series of NJ

• Note the strong association between the bedrock geology and the soil formed

• Soils differ across geographical regions due to many other factors, not just geology

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Local Soils Maps

• Soils types can vary within a small area due to many factors

• Natural differences, erosion, replacement, building

• Web-based copies may be found at: http://websoilsurvey.nrcs.usd

a.gov/app/

Soil Biological Indicators

• Soil microorganisms (fungi and bacteria) and other fauna (e.g., earthworms, insects, arthropods) influence the availability of nutrients for crop growth by decomposing soil organic matter and releasing or immobilizing plant nutrients.

Soil Testing

Take multiple, randomly

selected sub-samples from

the area to be tested

6-8”

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Soil Testing

• Best results are obtained from properly

collected sample

– Remove any stones, roots and other materials

– Air dry the sample before sending it to the

laboratory

Soil Testing

• Complete the soil testing questionnaire

– Indicate current and intended use of the site

Soil Testing

– Indicate whether a new seeding/planting or

established planting

• Send the soil sample and questionnaire to

the laboratory

• Results are usually returned in 1-2 weeks

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SAMPLE

Evaluate and Implement

• Review and interpret the soil test results

– Existing pH level

• Numerical value

• Verbal description

– Existing nutrient levels and corresponding fertility category

• Very low, low or medium = Below optimum

• High = Optimum

• Very high = Above optimum

Determines

amount of

lime Selection of

liming

materials

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Need for

phosphorus

and

potassium

fertilizer

Need for

micronutrient

fertilizer

Soil Sample

• Results will provide information on:

– soil texture

– soil pH

– soil nutrient levels

– fertilizer and limestone/sulfur recommendations

• Use it, don’t lose it!

Fertilizers and Nutrients

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Fertilizer What do the numbers mean ?

10-6-4

N – P - K • Nitrogen

• Phosphorus

• Potassium

Fertilizers

• Quick release – water soluble

• Slow release

• Organic or Natural

Chemical Characteristics

• Nutrients

– Essential chemical elements required for plants to grow

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Chemical Characteristics

• Macronutrients:

– Nitrogen (N)

– Phosphorus (P)

– Potassium (K)

– Calcium (Ca)

– Magnesium (Mg)

– Sulfur (S)

• Micronutrients

– Iron (Fe)

– Copper (Cu)

– Boron (B)

– Chlorine (Cl)

– Manganese (Mn)

– Zinc (Zn)

– Molybdenum (Mo)

Chemical Characteristics – Plant Nutrients

Chemical Characteristics – Plant Nutrients

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Nutrient Sources

• Nitrogen often comes from fertilizer application and from the air (legumes N from atmosphere)

• Phosphorus often comes from fertilizer, bone meal, and superphosphate.

• Potassium is supplied to plants by soil minerals, organic materials, and fertilizer.

Nutrient Sources

• Sources of calcium are calcitic and dolomitic limestone, gypsum, and superphosphate.

• Magnesian and dolomitic limestones, soil minerals, organic material, and fertilizers are sources of magnesium for plants.

• Sulfur may be supplied to the soil from rainwater. It is also added in some fertilizers as an impurity, especially the lower grade fertilizers. The use of gypsum also increases soil sulfur levels.

Compaction

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Physical Characteristics - Drainage

• Drainage affects

– Soil drying or moisture holding

– Air flow or gas exchange

– Selection of turf grass species

Physical Characteristics - Drainage

• Do a mini ‘perc test’ or percolation test to determine the internal drainage

1. Dig a 12 inch deep hole

2. Fill hole with water

3. Let all of water drain out of hole

4. Fill hole again and measure time for

water to drain out

Physical Characteristics - Drainage

• Evaluate the results. If all of the water drains out of the hole in:

– 15-30 minutes or less = well drained soil

– 30-45 minutes = moderately drained soil

– Greater than 45 minutes = poorly drained soil

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Physical Characteristics - Drainage

• Based on internal and surface drainage, do the following:

– Choose plant materials appropriate for the site

– Improve water drainage and percolation

– Irrigate when necessary

– Use mulches to conserve moisture

Physical Characteristics – Compaction

• Compaction

– Physical pressure due to weight on soil squeezes out the air space, making the soil more dense

• Bulk Density

– The weight of dry soil per unit volume including air space

Physical Characteristics – Compaction

• Reducing Compaction

– Mechanical aeration

– Tillage

– Organic matter

– Chemically

– Prevention

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Physical Characteristics – Compaction

Images from Turf North, Nov 2005

Physical Characteristics – Compaction

Organic Matter

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Organic Matter

• Leaf Compost

– Add 3 to 4 inches on bare ground

– Economical

– Some weeds and other contaminants

– Mix in top 6 to 12 inches of soil

Physical Characteristics - Tilth

• Tilth or structure is affected by several factors, including:

– Organic matter, limestone, biological activity

• All increase aggregation or flocculation of particles

– Sodium

• Decreases aggregation or dispersion of particles

• Tilth is primarily a ‘by-product’ of biological activity

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Physical Characteristics - Tilth

Physical Characteristics - Tilth

Composting

• Leaves

• Vegetable and Fruit scraps

• Paper products

• Meat scraps

• Bones

• Oils and Soaps

YES NO

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Composting

• Size of bin

• Carbon to Nitrogen ratios

• Watering

• Aerating

• Adding Soil

Resources

• www.ifplantscouldtalk.rutgers.edu

• Educational demonstrations at the EARTH center at Davidsons Mill Pond Park in South Brunswick, NJ

• Master Gardener Program