often strongly influenced by deep roots.
time to track production from the various sections of
Any soil health concern should be addressed prior
your fields that seem different. Compare your observa-
to transplanting. Depending on the results of tests and
tions with the results of your soil tests, so you can be
field analyses, it is often worthwhile to perform one-
sure that the various areas within a field are receiving
time investments like drainage installation, in-row deep
optimum management. Each of the farming systems
ripping, and deep lime and compost incorporations, as
discussed above has its limitations and opportunities
these are difficult to perform after the establishment of
for building better soils, although the approaches and
trees, vines, or canes.
details may differ. Whatever crops you grow, when you
Post-establishment, the emphasis should be on man-
creatively combine a reasonable number of practices
aging the surface layer. Avoiding compaction is impor-
that promote high-quality soils, most of your farm’s soil
tant, and maintaining good surface mulches is generally
health problems should be solved along the way, and
also beneficial, depending on the crop type.
the yield of your crops should improve. The soil will
have more available nutrients, more water for plants to
SOME FINAl THOUgHTS
use, and better tilth. There should be fewer problems
The old folk saying “The farmer’s footprint is the best
with diseases, nematodes, and insects, all resulting in
fertilizer” could be modified to “The farmer’s footprint
reduced use of expensive inputs. By concentrating on
is the best path to improved soil health.” If you don’t
the practices that build high-quality soils, you also will
already do so, begin to regularly observe and record
leave a legacy of land stewardship for your children and
the variability in crop yield across your fields. Take the
their children to inherit and follow.
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glossary
Acid. A solution containing free hydrogen ions (H+) or a
Beds. Small hilled-up, or raised, zones where crops
chemical that will give off hydrogen ions into solution.
(usually vegetables) are planted. They provide better-
Acidic soil. A soil with a pH below 7. The lower the pH,
drained and warmer soil conditions. They are similar
to ridges but generally broader, and they are usually
the more acidic the soil.
shaped after conventional tillage has occurred.
Aggregates. The structures, crumbs, or clumps formed
Buffering. Slowing or inhibiting changes. For example,
when soil minerals and organic matter are bound
buffering can slow pH changes by neutralizing acids
together with the help of organic molecules, plant roots,
or bases. A substance that can buffer a solution is also
fungi, and clays.
called a buffer.
Alkaline soil. A soil with a pH above 7, containing
Bulk density. The mass of dry soil per unit volume; an
more base than acid.
indicator of the density and compactness of the soil.
Allelopathic effect. Suppression of the germination or
Calcareous soil. A soil in which finely divided lime is
growth of one plant by another. The chemicals respon-
naturally distributed; it usually has a pH between 7 and
sible for this effect are produced during the growth of a
slightly more than 8.
plant or during its decomposition.
Cation. A positively charged ion such as calcium (Ca++)
Ammonium. A form of nitrogen (NH +
4 ) that is avail-
or ammonium (NH +
4 ).
able to plants and is produced in the early stage of
organic matter decomposition.
Cation exchange capacity (CEC). The amount of
negative charge that exists on humus and clays, allow-
Anion. A negatively charged element or molecule such
ing them to hold on to positively charged chemicals
as chloride (Cl–) or nitrate (NO –
3 ).
(cations).
Aquifer. A source of groundwater below the land
Chelate. A molecule that uses more than one bond to
surface.
attach strongly to certain elements such as iron (Fe++)
Available nutrient. The form of a nutrient that a plant
and zinc (Zn++). These elements may later be released
is able to use. Nutrients are commonly found in the soil
from the chelate and used by plants.
in forms that the plant can’t use (such as organic forms
C:N ratio. The amount of carbon divided by the
of nitrogen) and must be converted into forms that the
amount of nitrogen in a residue or soil. A high ratio
plant is able to take into its roots and use (such as the
results in low rates of decomposition and can also result
nitrate form of nitrogen).
in a temporary decrease in nitrogen nutrition for plants,
Ball test. A simple field test to determine soil readiness
as microorganisms use much of the available nitrogen.
for tillage. A handful of soil is squeezed into a ball. If the
Coarse-textured soil. Soil dominated by large
soil holds together, it is in the plastic state and too wet
mineral particles (the size of grains of sand); may also
for tillage or field traffic. If it crumbles, it is in the friable
include gravels. Used to be called “light soil.”
state.
Colloid. A very small particle with a high surface area
Base. Something that will neutralize an acid, such as
that can stay in a water suspension for a very long time.
hydroxide or limestone.
The colloids in soils—the clay and humus molecules—are
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glossary
usually found in larger aggregates and not as individual
mix fertilizers and manures with the soil, and smooth
particles. These colloids are responsible for many of
the soil surface.
the chemical and physical properties of soils, including
Drainage. The loss of soil water by percolation down
cation exchange capacity, chelation of micronutrients,
through the soil as a result of the gravitational force.
and development of aggregates.
Also: Removal of excess soil water through the use of
Compost. Organic material that has been well decom-
channels, ditches, soil shaping, or subsurface drain
posed by organisms under conditions of good aeration
pipes.
and high temperature, often used as a soil amendment.
Elements. Components of all matter. Seventeen ele-
Controlled traffic. The restriction of field equipment
ments are essential for plant growth; elements such as
to limited travel or access lanes in order to reduce com-
carbon, oxygen, and nitrogen combine to form larger
paction on the rest of the field.
molecules.
Conventional tillage. Preparation of soil for planting
Erosion. The wearing away of soil by runoff water
by using a moldboard plow followed by disking or har-
(water erosion), wind shear (wind erosion), or tillage
rowing. It usually breaks down aggregates, buries most
( tillage erosion).
crop residues and manures, and leaves the soil smooth.
Evaporation. The loss of water from the soil surface as
Coulter. A fluted or rippled disk mounted on the front
vapor.
of a planter to cut surface crop residues and perform
Evapotranspiration. The combined processes of
minimal soil loosening prior to seed placement. Multiple
evaporation and transpiration.
coulters are used on zone-till planters to provide a wider
band of loosened soil.
Fertigation. The application of soluble fertilizers
through an irrigation system, which allows for nutrient
Cover crop. A crop grown to protect the soil from ero-
spoonfeeding of plants.
sion during the time of the year when it would otherwise
be bare. Sometimes called a green manure crop.
Field capacity. The water content of a soil following
drainage by gravity.
Crumb. A soft, porous, more or less round soil aggre-
gate. Generally indicative of good soil tilth.
Fine-textured soil. Soil dominated by small mineral
particles (silt and clay). Sometimes called “heavy soil.”
Crust. A thin, dense layer at the soil surface that
becomes hard upon drying.
Friable soil. Soil that crumbles when force is applied.
A soil generally goes from the plastic to the friable state
Deep tillage. Tillage that loosens the soil at a greater
when it dries.
depth (usually more than 8 inches) than regular tillage.
Frost tillage. Tillage performed when a shallow (2–4-
Denitrification. The process by which soil organisms
inch) frozen layer exists at the soil surface.
convert dissolved nitrate to gaseous nitrogen under
anaerobic (low-oxygen) conditions. This occurs when
Full-field (full-width) tillage. Tillage that results in
soils become saturated and results in losses of nitrous
loosening soil over the entire width of the tillage pass—
oxide (a potent greenhouse gas) and dinitrogen (N2, an
for example, moldboard plowing, chisel tillage, and
inert gas).
disking.
Disk. An implement for harrowing, or breaking up, the
Green manure. A crop grown for the main purpose of
soil. It is commonly used following a moldboard plow
building up or maintaining soil organic matter; some-
but is also used by itself to break down aggregates, help
times called a cover crop.
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Groundwater. Water contained below the ground
Lignin. A substance found in woody tissue and in the
surface, typically in the pore spaces of underground
stems of plants that is difficult for soil organisms to
geologic deposits.
decompose.
Heavy soil. Nowadays usually called “fine-textured
Lime or limestone. A mineral consisting of calcium
soil,” it contains a lot of clay and is usually more difficult
carbonate (CaCO3) that can neutralize acids and is com-
to work than coarse-textured soil. It normally drains
monly applied to acid soils.
slowly following rain.
Loess soil. Soil formed from windblown deposits of
Humus. The well-decomposed part of the soil organic
silty and fine-sand-size minerals; they are easily eroded
matter. It has a high cation exchange capacity.
by wind and water.
Infiltration. The process of water entering the soil at
Micronutrient. An element, such as zinc, iron, copper,
the surface.
boron, or manganese, that is needed by plants in only
Inorganic chemicals. Chemicals that are not made
small amounts.
from chains or rings of carbon atoms—for example, soil
Microorganisms. Very small and simple organisms
clay minerals, nitrate, and calcium.
such as bacteria and fungi.
Irrigation. The application of water to soil to provide
Mineralization. The process by which soil organisms
better moisture conditions for crop growth. Flood and
change organic elements into the “mineral” or inorganic
furrow irrigation practices pond the soil with water for
form as they decompose organic matter; for example,
a limited time and allow it to infiltrate. Micro-irrigation,
organic forms of nitrogen are converted to nitrate.
including drip, trickle, and microsprinkler irrigation,
Moldboard plow. A commonly used plow that com-
refers to a set of practices that apply localized irrigation
pletely turns over the soil and incorporates any surface
water at low rates through small tubes and emitters and
residues, manures, or fertilizers deeper into the soil.
are generally water conserving. Supplemental irriga-
tion refers to a practice used in humid regions where
Mole drainage. A practice used on heavy clay soils
rainfall provides most crop water needs and irrigation is
whereby water is removed through subsurface chan-
primarily used to maintain adequate soil moisture levels
nels 2–3 feet deep. This practice does not involve pipes;
during limited drought periods. Deficit irrigation refers
the channels are generated with the use of a bullet-type
to a water-conserving practice whereby water supply is
plow. Channels generally need to be rebuilt every four to
reduced below maximum levels and mild crop stress is
six years.
allowed, with minimal effects on yield.
Monoculture. Production of the same crop in the
Landslide. The instantaneous downward fall of large
same field year after year.
soil volumes as a result of gravity. Landslides may occur
Mulch. Organic materials like straw and wood chips
on steep slopes when they become supersaturated with
that are applied to soil as a surface cover; generally also
water.
includes cover crop material left on the surface and
Least-limiting water range. See Optimum water
heavy amounts of crop residues left at the soil surface
range.
after harvest.
Legume. Plants—including beans, peas, clovers, and
Mycorrhizal relationship. The mutually beneficial
alfalfa—that form a symbiotic relationship with nitrogen-
relationship that develops between plant roots of most
fixing bacteria living in their roots. These bacteria help to
crops and fungi. The fungi help plants obtain water
supply the plants with an available source of nitrogen.
and phosphorus by acting like an extension of the root
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glossary
system and in return receive energy-containing chemical
which 7 is neutral, less than 7 is acidic, and greater than
nutrients from the plant.
7 is basic.
Nitrate (NO –
3 ). The form of nitrogen that is most
Photosynthesis. The process by which green plants
readily available to plants and is normally found in the
capture the energy of sunlight and use carbon dioxide
greatest abundance in agricultural soils.
from the atmosphere to make molecules needed for
Nitrification. The process by which soil microorgan-
growth and development.
isms convert ammonium into nitrate.
Plastic. The state of a soil that molds easily when force
Nitrogen fixation. The conversion of atmospheric
is applied. Compare to Friable.
nitrogen by bacteria to a form that plants can use. A
Plastic limit. The water content of soil at the transi-
small number of bacteria, including the rhizobia living
tion from the plastic to the friable state; the upper limit
in the roots of legumes, are able to make this conversion.
of soil moisture at which tillage and field traffic do not
Nitrogen immobilization. The transformation of
result in excessive compaction damage.
available forms of nitrogen, such as nitrate and ammo-
Polyculture. The growth of more than one crop in a
nium, into organic forms that are not readily available
field at the same time.
to plants.
PSNT. The pre-sidedress nitrate test is a soil test for
No-till. A system of planting crops without tilling the
nitrogen availability in which the soil is sampled to a
soil with a plow, disk, chisel, or other tillage implement.
depth of 1 foot during the early crop growth.
Optimum water range. The range of soil water
Raised beds. Crops grown in rows that are raised
content in which plants do not experience stress from
from the inter-row areas to provide better drainage and
drought, high soil strength, or lack of aeration.
aeration and deeper topsoil. Raised beds are wider than
Organic chemicals. Chemicals that contain chains or
ridges but aim to achieve the same benefits.
rings of carbon connected to one another. Most of the
Recycled wastewater. Water derived from the
chemicals in plants, animals, microorganisms, and soil
treatment of municipal wastewater and used for crop
organic matter are organic.
irrigation.
Oxidation. The combining of a chemical such as
Respiration. The biological process that allows living
carbon with oxygen, usually resulting in the release of
things to use the energy stored in organic chemicals.
energy.
In this process, carbon dioxide is released as energy is
Penetrometer. A device that measures soil resis-
made available to do all sorts of work.
tance to penetration, which indicates the degree of
Restricted tillage. Tillage that includes only limited
compaction; it has a cone-tipped metal shaft that is
and localized soil disturbance in bands where plant rows
slowly pushed into the soil while the resistance force is
are to be established—for example, no-till, zone-till,
measured.
strip-till, and ridge-till systems. Compare with Full-
Perennial forage crops. Crops such as grasses,
field tillage.
legumes, and grass-legume mixtures that form a com-
Rhizobia bacteria. Bacteria that live in the roots of
plete soil cover (sod) and are grown for pasture or to
legumes and have a mutually beneficial relationship
make hay and haylage for animal feed.
with the plant. These bacteria fix nitrogen, providing it
pH. A way of expressing the acid status, or hydrogen ion
to the plant in an available form, and in return receive
(H+) concentration, of a soil or a solution on a scale on
energy-rich molecules that the plant produces.
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glossary
Ridge tillage. Planting crops on top of small ridges
Texture. A soil’s sand, silt, and clay content. “Coarse-
(usually 2–4 inches in height), which are generally
textured” means that a soil has a high sand content, while
re-formed annually with a special cultivator.
“fine-textured” means that a soil has a high clay content.
Rotation effect. The crop-yield benefit from rotations,
Thermophilic bacteria. Bacteria that live and work
which includes better nutrient availability, fewer pest
best under high temperatures, around 110°–140°F. They
problems, and better soil structure.
are responsible for the most intense stage of decomposi-
Runoff. Water lost by flow over the soil surface.
tion that occurs during composting.
Saline soil. Soil that contains excess free salts, usually
Tile drainage. Removal of excess soil water through
sodium and calcium chlorides.
pipes buried in the soil, typically 3–4 feet deep.
Traditionally, the pipes were made of clay tile, but they
Saturated soil. Soil whose pores are filled with water,
are now corrugated flexible PVC pipes with perforations.
resulting in a virtual absence of soil air.
Tillage. The mechanical manipulation of soil, generally
Silage. A feed produced when chopped-up corn plants
for the purpose of loosening the soil, creating a seed-
or wilted hay is put into airtight storage facilities (silos)
bed, controlling weeds, or incorporating amendments.
and partially fermented by bacteria. The acidity pro-
Primary tillage (moldboard plowing, chiseling) is a
duced by the fermentation and the lack of oxygen help
more rigorous practice, primarily for loosening soil and
preserve the quality of the feed during storage.
incorporating amendments. Secondary tillage (disking,
Slurry (manure). Manure that is between solid and
harrowing) is a less rigorous practice, following primary
liquid; it flows slowly and has the consistency of a very
tillage, that creates a seedbed containing fine aggregates.
thick soup.
Tillage erosion. The downslope movement of soil
Sod crops. Grasses or legumes such as timothy and
caused by the action of tillage implements.
white clover that tend to grow very close together and
Tilth. The physical condition, or structure, of the soil as
form a dense cover over the entire soil surface.
it influences plant growth. A soil with good tilth is very
Sodic soil. Soil containing excess amounts of sodium.
porous and allows rainfall to infiltrate easily, permits
If it is not also saline, clay particles disperse, and the soil
roots to grow without obstruction, and is easy to work.
structure may be poor.
Transpiration. The loss of water from the soil through
Soil structure. The physical condition of the soil,
plant uptake and evaporation from leaf surfaces.
which depen