HEALTHY SOILS
HEALTHY SOILS
• ELBERT WELLS, CONSERVATION PLANNER
• NATURAL RESOURCES CONSERVATION SERVICE
• 525 HIGHLAND ROAD, SUITE 106
• COATESVILLE, PENNSYLVANIA 19320
• PHNOE NUMBER: 610 466-7502, EXTENSION 105
• FAX: 855-847-3607
• EMAIL: [email protected]
WHY SOILS ARE IMPORTANT
• Food (directly or indirectly).
• Support our buildings –foundations.
• It give us a place to play.
• Fiber (Trees, cotton, etc.).
• Fuel (Wood, ethanol, corn and
pellets).
• Recycles and detoxifies waste
WHAT MAKE SOILS IMPORTANT?
Soils are the Foundation Resource
HEALTH SOILS
• Is defined as the continued capacity of soil to function as a vital living ecosystem that
sustains plants, animals, and humans.
• The definition speaks to the importance of managing soils so they are sustainable for
future generation.
• To do this, we need to remember that soils contains living organisms that when
provided the basic necessities of life – food, shelter, and water –perform functions
required to produce food and fiber.
• Only “living” things can have health, so viewing soils as a living ecosystem reflects a
fundamental shift in the way we care for our soils.
• Soils aren’t an inert growing medium, but rather is teaming with billions of bacteria,
fungi, and other microbes that can be managed to provide nutrients for plants
growth, absorb and hold rainwater for use during dryer periods, filter and buffer
potential pollutants from leaving our fields, serve as a firm foundation for
agriculture activities, and provide habitat for soil microbes to flourish and diversify
to keep the ecosystem running smoothly.
WHAT SOILS DO!
• Healthy soils give us clean air and water, bountiful crops and forests, productive
grazing lands, diverse wildlife, and beautiful landscapes. Soils do all this by
performing five essential functions:
• 1.
Regulating water – Soils helps control where rain, snowmelt, and
irrigation water goes. Water and dissolved solutes flow over the land or
into and through the soil.
• 2.
Sustaining plants and animal life – The diversity and productivity of living
things depends on soils.
• 3.
Filtering and buffering potential pollutants – The minerals and microbes
in soil are responsible for filtering, buffering, degrading, immobilizing, and
detoxifying organic and inorganic materials, including industrial and
municipal by-products and atmospheric deposits.
WHAT SOILS DO!
• 4.
Cycling nutrients – Carbon, nitrogen, phosphorus, and other nutrients are
stored, transformed, and cycled in the soils.
• 5.
Physical stability and support – Soil structure provides a medium for plant
roots. Soils also provide support for human structures and protection for
archeological treasures.
HEALTHY SOILS
• SOIL HEALTH, ALSO REFERRED AS SOIL QUALITY.
• HEALTHY SOIL IS DEFINED AS THE CONTINUED
CAPACITY OF SOIL TO FUCTION AS A VITAL LIVING
ECOSYSTEM.
• Healthy soils are managed so they are sustainable
for future generations
• Health soils contains living organisms that when
provided the basic necessities of life – food,
shelter, and water – they will perform functions
required to produce food and fiber.
Benefits of soil health
• Less Erosion
• High Water Infiltration
• Lower Evaporation
• More Organic Matter Conservation
• Improved Soil Structure
• Higher biological Activity
• More Earthworms
• Reduced total Phosphorus Losses
• Lower Labor Needs Per Acre
• High Efficiency Of Farm
Operations
SOILS HEALTH INDICATORS
• Surface Cover – Year-round cover from living crops or dead mulch; cover 50-100 after
planting.
• Soil Structure (0-3 inches) – Soil aggregates crumb, don’t disintegrate in water, soil tilth
excellent; good weight-bearing capacity and no crusting and sealing.
• Organic Matter (0-3 inches) Soil dark color; visible organic matter at surface; organic
matter content high (>4% in top 2 inches) approaching level under native vegetation.
• Soil Erosion – No visual evidence of rills or soil movement and deposition in the field; few
to no rock fragments visible at surface.
• Soil Compaction – Soil not very resistant to penetration with soil compaction tester; no
evidence of plow pan; low penetration resistance in subsoil.
• Water Infiltration – Water drains well after heavy rain; ponding largely absent; low runoff.
• Soil Biodiversity - Much evidence of earthworm activity; many night crawler mounds;
spiders and ground beetles visible under residue.
• Plant and root growth – Seedling emerge somewhat even and fast; plants growth vigorous
and even; plants resist drought stress; root growth vigorous; roots fibrous roots explore
soil profile.
WATER RUNOFF IS A LEADING CAUSE
FOR SOIL EROSION IN PENNSYLVANIA
• Chester County receives on an average of 45
inches of precipitation annually (rain and snow).
Factors influencing infiltration
• Soil Texture – The type of soil (sandy, silty, clayey) can control the rate of infiltration.
• Soil Crust – A crust on the soil surface can seal the pores and restrict the entry of
water into the soil.
• Soil compaction – A compacted (plowpan) or an impervious layer close to the surface
restricts the entry of water into the soil and tends to result in ponding on the surface.
• Soil Aggregation and Structure – Soils that have stable strong aggregates as granular
or blocky soil structure have a higher infiltration rate than soils that have weak,
massive, or platelike structure.
• Water Content – The content or amount of water in the soil affects the infiltration rate
of the soil. Infiltration rate is generally higher when soil is initially dry and decrease
as soil become s wet.
• Frozen surface – Frozen soil greatly slows or completely prevents water entry.
• Organic Matter – An increase amount of plant material, dead or alive, generally
assists the process of infiltration.
• Pores – continuous pores that are connected to the surface are excellent conduits for
WHAT SOIL DOES
• Regulate water – Soil helps control where rain, snowmelt, and
irrigation water goes. Water and dissolved solutes flow over the
land or into and through the soil.
• Sustaining plant and animal life – The diversity and productivity
of living things depends on soil.
• Filtering and buffering potential pollutants – The minerals and
microbes in soil are responsible for filtering, buffering,
degrading, immobilizing and detoxifying organic materials,
including industrial and municipal by-products and atmospheric
deposits.
• Cycling nutrients – Carbon, nitrogen, phosphorus, and many
other nutrients are stored, transformed, and cycled in the soil.
• Physical Stability and support – Soil Structure provides a
medium for plants roots. Soils also provide support for human
structures and protection for archeological treasures
Principal Threats to Soil HEALTH:
Erosion
Organic matter decline
Salinization
Soil biodiversity loss
Compaction
Landslides
Contamination
Sealing
A Rain Drop hitting the ground
SOIL PROFILE
What is a disturbance? What is a disturbance?
Examples for agricultural systems include:
What is a disturbance:
• Heavy traffic load
• Pollutants
• Tillage
• Saline irrigation water
• Fertilizers
• Grazing pressure
• Pesticides
• Weeds
• Monoculture
• Climate
Manage for Increased Diversity
(biological disturbance)
Some Types of Diversity &
Complexity
Management Examples
• Species & Genetic
• Cover crops, varieties
• Habitat
• Intercrop, trap crops
• Temporal
• Use of Rotations
• Food Web ‘Health’
• Organic amendments
• Targeted solutions
• Limit-specific crops
INHERENT AND DYNAMIC
PROPERTIES OF SOILS
• Dynamic properties or qualities is a soil’s natural ability
to function. (Example, sandy soil drains faster than
clayey soil. Deep soil has more room for roots than soils
with bedrock near the surface. These characteristics do
not change easily.
• Dynamic Soil Quality is how soil changes depending on
how it is managed. Management choices affect the
amount of soil organic matter, soil structure, soil depth,
and water and nutrient holding capacity.
Conservation Tillage
Cover Crops (PMC SH Study
intermediate disturbance
Rotational Grazing is intermediate disturbance
Some Factors Affecting
Resistance and Resilience
These factors are difficult to manage
These factors can be managed!
• Soil Texture
• Disturbance
• Soil Depth
• Diversity & Complexity
• Soil Horizon Sequence
• Water, Nutrients & Energy
Soil ph
• Soil pH thus affects the availability of several plant
nutrients.
• A pH range of 6 to 7 is generally most favorable for plant
growth
• sources. This is considered neutral to slightly acidic.
• Great diversity of pH difference in Pennsylvania, although
soils are more likely to be acidic than alkaline.
• Low pH soils can be adjusted by adding lime. High pH
soils can be adjusted by adding sulfur or sulfuric acid.
Soil survey
• Designed to:
•
Delineate different soils across the landscape
•
Predict soil behavior for different uses
•
Highlight limitations and hazards inherent in the soil
• Includes:
•
Text
General description
•
Map units descriptions
•
Use and Management
•
Interpretive tables
•
Maps
• Over 70,000 different kinds of soil have been delineated in the United States
• In a soil survey, soils are classified into map units which consist of one or more soil
• series within a slope class.
• A soil series (or soil type) has a combination of traits unique to it such as parent material, texture,
drainage, and landscape position.
HYDROLOGIC SOIL GROUP
CHARACTERISTICS
• SOIL GROUP
• A – Soils having high infiltration rates, even when thoroughly wetted and
consisting chiefly of deep, well to excessively-drained sands or gravels.
These soils have a high rate of water transmission.
• B - Soils having moderate infiltration rates, when thoroughly wetted and
consisting chiefly of moderately deep to deep, moderately fine to moderately
coarse textures. These soils have a moderate rate of water transmission.
• C - Soils having a slow infiltration rates when thoroughly wetted and
consisting chiefly of soils with a layer that impedes downward movement of
water, or soils with moderately fine to fine texture. These soils have slow
rate of water transmission.
• D - Soils having very slow infiltration rates when thoroughly wetted and
consisting chiefly of clay soils with a high swelling potential, soils with a
permanent high water table, soils with a clay pan or clay layer at or near the
surface, and shallow soils over nearly impervious material. These soils have
a very slow rate of water transmission
GENERAL SOILS
• The solid portion of a typical soil sample is made
up of the following:
• Sand
• Silt
• Clay
• Humus
PENNSYLVANIA’s SOILS ARE
GENERALLY DERIVED FROM
THREE BASIC ROCK:
• Igneous
• Sedimentary
• Metamorphic
DEFINITION OF SOIL
This definition is from Soil Taxonomy, second edition.
soil - Soil is a natural body comprised of solids (minerals and organic matter), liquid, and
gases that occurs on the land surface, occupies space, and is characterized by one or both
of the following: horizons, or layers, that are distinguishable from the initial material as a
result of additions, losses, transfers, and transformations of energy and matter or the
ability to support rooted plants in a natural environment.
The upper limit of soil is the boundary between soil and air, shallow water, live plants, or
plant materials that have not begun to decompose. Areas are not considered to have soil if
the surface is permanently covered by water too deep (typically more than 2.5 meters) for
the growth of rooted plants.
The lower boundary that separates soil from the nonsoil underneath is most difficult to
define. Soil consists of horizons near the Earth's surface that, in contrast to the underlying
parent material, have been altered by the interactions of climate, relief, and living
organisms over time. Commonly, soil grades at its lower boundary to hard rock or to earthy
materials virtually devoid of animals, roots, or other marks of biological activity. For
purposes of classification, the lower boundary of soil is arbitrarily set at 200 cm (6.5 FEET).
PENNSYLVANIA SOILS
• •The horizons are common in Pennsylvania. Most
soils do not contain every horizon.
• •How do we differentiate horizons? (changes in color,
texture, structure, roots, redoximorphic features (mottling)
or other.
• Soil Texture – sand, silt, clay
•
Sand - feels gritty
•
Silt - feels floury
• Clay - sticky when wet
• Loams – mixture of materials, high silt soils and loams
are most conducive to plant growth
• • How does texture affect water in soils?
• The soil textural triangle is important in identifying soil
texture.
SOIL PROFILE
Soil color
• Determined by air and water drainage, organic
matter, parent material
• Topsoil – dark organic matter – vegetation, soil
critters,
• Subsoil – less OM
• Red soils – often high iron, well-drained
(example of a rusty pipe)
• Wet Soil - Lack of oxygen (air) – leads to grey
colors and redoximorphic
• concentrations and depletions (mottling)
Soil structure
Soil Structure
The naturally occurring arrangement of soil particles. Each
individual unit is called a ped. Near surface soil structure is often
influenced by land use and management.
Soil formation and classification
• The National Cooperative Soil Survey – identifies and maps over 20,000 different kinds of soils
in the United States. Most soils are given a name which come from the location where the soil
was first mapped. Named soils are referred to as soil series.
• Soil Survey Report- Include the soil survey maps and the names and descriptions of the soils in
a report area. The soil survey reports are published by the National Cooperative Soil Survey
and are available to everyone.
• Soil – Soils are named and classified on the basis of physical and chemical properties in their
horizons (layers). “ Soil Taxonomy” uses color texture, structure, and other properties of the
surface two meters deep to key the soil into a classification system to help use soil information.
The system provides a common language for scientists.
• Soil and their Horizons – Horizons different from one another, depending on how and when
they were formed.
FACTORS INFLUENCE SOIL FORMATION
• Parent Material – Few soils weather directly from the underlying rock. These “residual “ soils have the
same general chemistry as the original rocks. +More commonly, soils form in materials that have moved
in from elsewhere. Materials may have moved many miles or a few feet. The material in which soils form
is called “parent material”. In the lower part of the soils, these materials may be relatively unchanged
from when they were deposited by moving water, ice, or wind.
• Climate – Soils vary, depending on the climate. Temperature and moisture amounts cause different
patterns of weathering and leaching. Wind redistributes sand and other particles especially in arid
regions. The amount Intensity, timing, and kind of precipitation influence soil formation. Seasonal and
daily changes in temperature affect moisture effectiveness, biological activity, rates of chemical reactions,
and kinds of vegetation.
• Topography – slope and aspect affect the moisture and temperature of soil. Steep slopes facing the sun
are warmer, just like the south-facing of a house. Steep Slopes may be eroded and lose their topsoil as
they form. Thus, they may be thinner than the more nearly level soils that receive deposits from areas
upslope. Deeper, darker colored soils may be expected on the bottom land.
HEALTHY SOILS
• ELBERTR WELLS, CONSERVATION PLANNER
• NATURAL RESOURCES CONSERVATION SERVICE
• 525 HIGHLAND ROAD, SUITE 106
• COATESVILLE, PENNSYLVANIA 19320
• PHNOE NUMBER: 610 466-7502, EXTENSION 105
• FAX: 855-847-3607
• EMAIL: [email protected]