Soil and
Water Management
From rocks come soils.
All soils were once part of rock, but with time and various physical and
chemical processes of weathering, rock becomes unconsolidated into loose rock
particles. It is from these particles
that a soil may develop; it is called
parent material.
The
transformation of rock into soil is called soil formation and can be shown as
follows:
Rock-->weathering-->parent
material-->soil formation-->soil
The
process of soil formation releases nutrients for plant growth that have been
tied up in the minerals of the rocks.
The properties of individual soils are closely related to the properties
of the parent material from which they have been derived. Knowing the parent material can tell much
about the soil, since the parent material will determine the amount and kind of
nutrients present, the texture and various other physical and chemical
properties.
Parent
material has various effects on the rates of soil formation. For example, in a sandy-textured soil, lime
(CaCO3) will leach more rapidly than from a fine-textured soil,
causing the soil to acidify. Frequently a fine-textured soil has a greater
nutrient capacity and more nutrients than a coarse-textured one. Organic matter in the soil is also increased,
due to the greater plant growth resulting from more plant nutrients. Fine texture is usually reflected in a
greater water holding capacity of the soil, as well.
The
chemical composition of the parent material has a substantial effect on the
nature of the soil. For example, young
soils derived from limestone often have a much higher level of plant nutrients
than a young soil from a granitic origin.
This higher level of nutrients is going to result in greater plant
growth which in turn will affect the rate of soil formation.
The
weathering or soil-forming process is a result of climate (rain and
temperature), organisms (microbes, plants, animals), relief (topography),
parent material, and time. The
interaction of these processes has been titled the "CLORPT Equation"
by the late Hans Jenny of U.C. Berkeley.
In some environments one of the factors may be more important than
others. For example, on a steep slope,
soil may be thin because it is constantly eroding, but at the base of the slope
soil, the soil may be quite deep because rain has had time to act on the
material in place.
When
speaking of the age of a soil, it is not time necessarily that "ages"
a soil.. The age of a soil is
relative. Age is how transformed from
the original a soil is. As soil becomes
older, it develops distinct layers or horizons.
The horizons are labeled with letters to distinguish them. The top horizon, commonly called topsoil, is
given the letter "A." This
letter indicates a layer of mineral soil which has been enriched by the
accumulation of organic matter derived from plants growing in this layer. This is the zone of greatest biological
activity.
Below
the "A" horizon, frequently exists a soil layer where clay has
accumulated by migration from the "A" horizon. This horizon of clay accumulation is called
the "B" horizon. In young
soils where there has been insufficient time for clay to accumulate, there is
no "B" horizon present. As
soils age, increasing amounts of clay accumulate until a "B' horizon
forms. If the soil remains stable for
tens of thousands of years, enough clay can accumulate to result in dense,
growth-restricting layer called a claypan.
The
layer of loose soil beneath the "A" or "B" horizons, which
is largely unaffected by organic matter or clay accumulation, is called the
"C" horizon. The "C"
horizon is often called the parent material of the overlying horizons.
Soils
which form in hilly or mountainous terrain usually have a consolidated rock
below the soil horizons. The rock layer
is termed the "R" horizon, or regolith. If the depth to consolidated rock is deeper
than 6 or 7 feet, the soil is usually considered to lack an "R"
horizon.
In
principle, as soon as a surface is available for plant growth, it becomes a
soil, but the soil formation process will continue indefinitely until it is
covered by more sediment or is eroded.
The soil around houses has often been disturbed by development, and may
not show a neat profile of soil formation.
What is at the surface may not even be from the site. The best places to see soil horizons are at
road cuts or where excavation is being done.
Figure 1. Each horizon has different chemical, physical and
biological features which distinguish
one from another.
Countering the forces of soil
formation are the forces of erosion - wind, water, gravity and in certain areas
of the country, snow and ice. As soon as
erosive forces abate, soil formation
commences.
Soil Physical Properties
The
physical properties of soils affect many properties of plant growth and soil
management. These properties are
texture, structure, density, porosity, consistency, soil organic matter and
color. Having an understanding of these
properties can help in soil fertility management.
Texture
Soil
texture is the relative proportions of sand, silt and clay in a soil. In some cases, larger mineral fractions
predominate and a gravely or sandy soil results. In other cases, the finer or colloidal (small
enough to stay in suspension) fraction predominates and the soil has clayey
characteristics. A sandy soil is often
called a "light" soil, while a clayey soil is referred to as a
"heavy " soil. These terms are
only a reflection of the relative ease of working the two soils. While organic matter may have a tremendous
affect on a soil's physical properties, it is not normally considered in a
soil's texture because its can vary so greatly.
Soil
is a collection of solid material (including organic matter), water and
air. The percentages of solids, water
and air differ according to the soil's texture.
The percentages for a moist, loam soil are:
The
reason for assessing soil texture is that physical properties will change
according to the proportions of each size fraction (or soil separate)
present. Properties change largely due
to the surface area of the particles. A
soil of clay particles has about 10,000 times the surface area of a soil of
sand grains of the same weight.
As
surface area increases due to more clay particles, the soil becomes more sticky
and plastic (able to be molded).
Additionally it shrinks and swells, holds more water, has slower gas and
water movement and generally holds more nutrients.
Soil
scientists give names to different textures of soils based on the proportions
of sand, silt and clay in the soil.
There are 13 textures which can be used to describe soils, and often these
are grouped into larger categories (Table 1).
By using the "Feel method" (Fig.2), one can easily arrive at a
soil's texture.
Table 1.
Soil textural classes.
|
General |
Terms |
Texture |
|
sandy (light) |
coarse |
sand |
|
|
|
loamy sand |
|
loamy |
moderately coarse |
sandy loam |
|
|
|
fine sandy loam |
|
|
medium |
loam |
|
|
|
silt loam |
|
|
|
silt |
|
|
moderately fine |
clay loam |
|
|
|
sandy clay loam |
|
|
|
silty clay loam |
|
clayey (heavy) |
fine |
clay |
|
|
|
sandy clay |
|
|
|
silty clay |
Figure
2. Determining soil texture by the "feel" method.
Bulk
Density
What
is heavier, a pound of cement or a pound of feathers? They're the same, but what is different? The volume of each material needed to obtain
a pound. This is the basis of bulk
density. Generally, rocks have a density
of 2.65 grams per cubic centimeter (g/cm3 or weight/volume). There is some variation depending on the
minerals present, but for most purposes a solid piece of rock has a bulk
density 2.65 g for every cubic centimeter of volume. If this solid rock is crushed, some of the
volume will now be air along with the rock, and the bulk density
decreases.
The
more finely the rock is crushed, the lower becomes the bulk density because
there is more and more air occupying a given volume. The voids between the particles are called
pores, so that, as the material is crushed more and more finely, the total
porosity increases. This is analogous to
filling a coffee grinder to the brim with beans, grinding the beans and then
finding the ground coffee spilling out of the grinder because the coffee's
volume has been expanded.
As
the porosity increases, the amount of surface area increases. As soil particles become smaller and smaller,
the soil has more surfaces. This is an
important concept to remember when water and soil fertility are discussed.
If
porosity increases with decreasing particle size, why does a sandy soil (higher
bulk density, lower porosity) drain better than a clayey soil? The clay soil may have more total pores, but
they are much smaller than the large pores of sand and are less able to
transmit both water and gasses.
Compaction
confounds the native bulk density of a soil.
When pressure (foot, truck, fallen tree, etc.) is placed on soil
(especially wet soil), the pore space is compressed and the volume reduced,
increasing the density. Undisturbed
sandy soils generally have a higher bulk density than a clayey soil, e.g.,1.6
vs. 1.2 g/cm3. However,
sandy soils are more resistant to compaction than a finer textured soil. A compacted, sandy soil of the same moisture
as a clay soil may only increase its bulk density to 1.8, but the clay may
increase to 2.0. A surface soil will
often have a higher bulk density than the subsurface because it has been
compacted. Especially in hilly lands, a
compacted surface leads to lower water holding capacity and infiltration rate,
which can lead to more rainfall runoff and erosion. One reason for cultivating, is to reduce the
bulk density of soil to make it easier for plant roots and water infiltration. After turning the soil, walking on it should
be avoided. If necessary put down a
board and walk on it.
The
presence of organic matter can have a tremendous effect on bulk density. Organic matter has a low bulk density and
will decrease the bulk density of a soil, as well as changing other physical
and chemical soil properties as it is added.
Soil
structure
Knowing
the proportions of sand, silt and clay present tells us soil texture. Soil structure tells how these particles are
arranged. The grouping of particles in
different arrangements plays a very important part in such physical properties
as water movement, aeration, bulk density and porosity, just as texture
does. A soil of "good"
structure will have good drainage, infiltration, aeration and overall good
tilth.
Different
cementing agents, such as clays, humus,
plant and microbial exudates, silica and carbonates bind different soil
particles into aggregates or peds.
Aggregates are naturally occurring structures that take on
characteristic shapes reflective of individual soils. These shapes can be flat (platy), columnar,
cubical (blocky), or crumby. The shapes
can be large or small, well-defined or poorly-defined. They can be nonexistent (structureless or
massive). The degree of development of
structure is enhanced with the amount of clay and organic matter present. If a form is artificially created (by tillage
or digging) it is called a clod.
The
formation of aggregates is due to the various forces in the soil which push
particles together: earthworm activity, root growth, shrink/swell on wetting
and drying, freezing/thawing. Climate is
very important as it affects rainfall, temperature, types of plants growing
and, therefore, the amount of organic matter present in the soil.
The presence of different salts of calcium in the soil contributes to
aggregation, as well. Sodium tends to
disperse soils (deflocculate aggregates), destroying structure.
Soil
structure takes years to form, and can be instantly lost through
mismanagement. Working or walking on
soil when it is wet leads to compaction and loss of structure. Soil needs to be somewhat moist to work it,
but wetting s soil and immediately working it will ruin it. A soil should be allowed to drain for one to
two days after watering it before working it.
The length of time depends on the soil texture, the more clay, the
longer the time.
A
soil profile may have a single type of aggregation, but more commonly there is
a characteristic structural pattern with each horizon. This will be determined in large part by the
degree of weathering of the soil, which in turn is a function of the soil
forming factors: climate, parent material, time, relief and organisms present.
Soil
color
Soil
color is a helpful guide to the condition of the soil. For example, the darkness or lightness of the
soil will influence the temperature of the soil, light soil being cooler, dark,
warmer. Color is a function of the
amount of organic matter present, the color of the original parent material,
the degree and kind of weathering of the soil, the amount and type of surface salts present and the aeration of the
soil. Organic matter imparts a darkness
to the soil and, in part, indicates the fertility of the soil. The soil's darkness can also be due to the
parent material (PM); a light soil may be
from a siliceous (silica containing) PM which would have a lower inherent
fertility than a darker mafic (high in magnesium and iron) PM. As a soil ages, its color gradually turns red
or yellow, which indicates that it is losing nutrients. In arid or poorly drained environments, salts
can accumulate at the surface, usually calcium carbonate, calcium sulfate or
sodium carbonate. These salts are
normally white, but if there is any
organic matter in the soil, the sodium salt will cause oxidation (slow combustion)
of the material, turning it black, as well as causing aggregates to
disperse. Within the soil, if there are
periods of poor aeration due to poor drainage, mottles will appear, usually
rust colored. If there is prolonged
water logging, gleying (blue, green or gray colors) will appear . Just looking at soil color can tell many
potential problems with that soil.
Soil
organic matter
The
organic fraction of soil includes living and dead organic matter. The dead organic matter is in various stages
of decomposition, and when the material becomes resistant to further
decomposition it is called humus. Soil
humus is very important to soil fertility.
It has the ability to retain plant nutrients (like clay), and can aid in
the formation of aggregate structure.
The living portion of organic matter is also important in soil
fertility. Earthworms help to maintain
good soil physical properties. Bacteria,
fungi and other microorganisms are required for humus formation, and they often
aid plants in obtaining essential nutrients.
Some of the soil microorganisms are very detrimental to plant growth,
but careful irrigation management can control many of these pathogens.
Since
organic matter is important to soil fertility, it is often added to garden
soils in large amounts. An important
consideration in the addition of organic matter to soils is the relationship
between the amounts of carbon and nitrogen in the organic matter. Some plant material, such as straw or bark
has a high carbon to nitrogen ratio. This
high C:N ratio will slow the decomposition of the straw and if there is any
available nitrogen in the soil, the nitrogen will be absorbed by the microbes
decomposing the straw. Since microbes
can absorb nitrogen faster than plants, there may be an induced nitrogen
deficiency if high C:N materials are incorporated just prior to planting or
during plant growth. If high C:N
materials are merely applied to the surface as a mulch, nitrogen deficiency is
not a problem, and can be a real benefit in reducing weeds and retaining soil
moisture.
Composting
is an excellent method of obtaining organic matter to add to soil. There are some important aspects of
composting that must be considered if the use of compost is contemplated. The most important factor is time.
Depending of the level of management, fresh organic matter can become
compost in as little as 2 or 3 weeks.
With little management, it can take
An
important factor in the use of composts is the potential spread of weed seeds
and plant diseases. Spread of weed seeds
is controlled by excluding seed bearing weeds from the compost pile.
The disease problem can be controlled by insuring that the organic
matter is well decomposed before it is added to the garden. If adequate (>102-140° F) temperatures are
sustained in the pile, most weed seeds and diseases are controlled. For further information on composting, see
the reference list at the end of this paper.
Management
of soil physical properties
Depending
on the intensity of management and the resources available, there are many ways
of influencing soil physical characteristics.
Addition of organic matter to both heavy and light soils can improve
aeration and moisture conditions principally by improving aggregation, porosity
and bulk density. This may be
impractical on large areas or for low profit operations, simply due to the
expense, volume and unavailability of material.
In this case, conservation of soil organic matter can be practiced by
reducing erosion (most organic matter is in the surface horizon of mineral
soils) and ensuring that the soil is covered with growing vegetation as much of the year as
possible. The detrimental effects of
compaction and loss of structure can be averted by reducing traffic,
designating traffic areas and by not working the soil when it is wet. The detrimental effects of salts and poor
drainage/aeration can be addressed by various reclamation and engineering
solutions, expense being the major criterion of which method to use.
Soil Chemistry
It
may be hard to imagine, but the soil is one giant, complex biochemical
reaction. As organic matter decomposes
and soil particles dissolve, materials are released. These can be valuable plant nutrients (Table
2) or, if in high enough concentration, can be toxic materials, such as salts,
sodium, chloride and boron. These ions
are invariably charged, meaning they have a positive(+) or negative (-) charges
on them. These are called ions. Just as clay soils hold more water than sandy
ones, a clay will hold more positively charged ions because a clay soil has
more surface area to attract ions. Soils
in most cases are negatively charged, so that negatively charged ions, such as
chloride and sulfate are repelled by soils.
This means they are easily leached from soils with adequate irrigation
or rain. Soil organic matter is also
negatively charged; therefore, it can act to hold nutrients, as well.
Soil
pH is another element of soil chemistry that needs to be considered in addition
to the presence of nutrients in the soil.
The more hydrogen ion (H+) present in the soil system, the
more acid it is. The less hydrogen, the
more alkaline the soil. The pH range is
from 1 to 14, with 14 being the most alkaline.
A value of 7 is neutral, neither too acid nor alkaline. The closer to pH 1, the more acid. Most soils in
Acidity
and alkalinity are important because plants usually thrive in a given pH
range. The more acid a soil, the more
micronutrients are available in the soil (such as iron, zinc and manganese),
and the less calcium and phosphorus are available. Increasing alkalinity much above pH 7 can
have the reverse effect of decreasing micronutrients and increasing calcium and
phosphorus. A near-neutral or just
slightly acid (pH 6.5) soil is considered ideal for most plants, since most
nutrients are available around pH
7. There are some plants that prefer a
more acid soil, such as azalea or blueberry, but instead of trying to amend the
soil to lower the pH, the best solution is to plant something that is adapted
to that soil's pH.
Adjusting
soil pH can be done with lime (calcium carbonate) or wood ashes when the pH is
low, and with sulfur when the pH is high.
The materials need to be incorporated in the rooting area of the
soil. Soil pH can change soon after
watering the soil for lime, but may take several months for sulfur to lower
pH. This is because sulfur conversion to
acid is mediated by microbes which take their time and is temperature and
moisture dependent. Long-term use of
ammonium fertilizers also has a tendency to lower pH. And because one of the breakdown products of
organic matter is ammonium and carbon dioxide (carbonic acid when it is
dissolved in water), additions of
various organic materials tend to lower pH's of high pH soils.
A
common misconception is that gypsum lowers soil pH. The major effect of gypsum is that of
improving water infiltration. If a
sodium salt problem is present (which can cause high pH), by increasing
infiltration and leaching of the sodium, soil pH will decrease. If a sodium condition is not present, gypsum
will not lower soil pH. If the soil is
strongly resistant to pH change after additions of soil amendments, specific
fertilizers can be applied to plants, such as iron sulfate or chelate to
correct plant iron deficiency symptoms.
Table 2. Essential
Mineral Elements for Plants.
|
Element |
Symbol |
Form Available to Plants |
Source |
|
|
|
Hydrogen |
H |
H2O |
Water |
|
|
|
Carbon |
C |
CO2 |
Air |
|
|
|
Oxygen |
O |
O2, H2O |
Air, Water |
|
|
|
Nitrogen |
N |
NO3-, NH4+ |
Soil/Air |
|
|
|
Phosphorus |
P |
H2PO4- |
Soil |
|
|
|
Potassium |
K |
K+ |
Soil |
|
|
|
Calcium |
Ca |
Ca+2 |
Soil |
|
|
|
Magnesium |
Mg |
Mg+2 |
Soil |
|
|
|
Sulfur |
S |
SO4-2 |
Soil |
|
|
|
Iron |
Fe |
Fe+3 |
Soil |
|
|
|
Boron |
B |
H3BO3 |
Soil |
|
|
|
Zinc |
Zn |
Zn+2 |
Soil |
|
|
|
Manganese |
Mn |
Mn+2 |
Soil |
|
|
|
Chlorine |
Cl |
Cl- |
Soil |
|
|
|
Copper |
Cu |
Cu+2 |
Soil |
|
|
|
Molybdenum |
Mo |
MoO4-2 |
Soil |
|
|
|
Nickel |
Ni |
Ni+2 |
Soil |
|
|
|
|
|
|
|
||
Hunger Signs in Plants
Since Greek and Roman times, the appearance of a plant has
been used to help identify plant health.
The plant speaks through distress signals. The message may be that there is simply too
little or too much water. Or the sign
may tell us of a disease caused by
a microorganism, such as a fungus, virus
or bacteria. The plant may show symptoms
of attack by nematodes, insects or rodents or from injuries from frost or
lightning. According to the plant
species, these signals may differ slightly, but frequently they can be
generalized.
It is also possible to generalize about the signals linked
to the nutritional status of a plant. Learning these symptoms can alert us to
appropriate steps to correct the toxicity, deficiency or imbalance of
nutrients.
There are 17 elements essential for plant growth (Table
2). Hydrogen, oxygen, and carbon come
either from the air or water. The others
come from the soil. Depending on the
quantity needed by the plant, these are called either primary or trace
(micronutrients) nutrients. The
micronutrient nickel is required in such small amounts (50-100 parts per
billion) by plants that it was identified only in 1990 as being an essential
nutrient. Other micronutrients are iron,
manganese, boron, chlorine, zinc, copper and molybdenum. Some other nutrients have been identified as
being essential for only certain plants, such as silicon for sugar cane.
The primary nutrients are measured on a percent (parts per
100) dry weight tissue basis. These are
nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. The trace elements are measured on a part per
million dry weight basis. For example, a
typical analysis of a dried leaf from a healthy tomato plant might show 3%
nitrogen, 1% potassium, 100 ppm (parts per million) iron and 50 ppm boron.
Although plants require more primary than trace nutrients,
all the essential elements need to be present for a healthy plant. An excess, deficiency or even an imbalance of
these elements will lead to individual symptoms which are characteristic to
most plants. The following list is a
description of the more common nutritional problems in
Excess or toxicity
*Boron - chlorosis
(yellowing), leading to tissue death (necrosis) along the margins of older
leaves.
*Sodium , Chloride -
necrosis of the leaf tips and margins on older leaves.
Deficiency
*Phosphorus - smaller
plants; occasionally, older leaves darker than normal or have a reddish or
purplish cast, a common symptom in sweet corn.
*Potassium -
scorching (firing or necrosis) along leaf margins of older leaves; plant growth slow, with poorly developed root
system; stalks weak and fall over.
*Nitrogen - older
leaves chlorotic, venation not prominent as in iron deficiency.
*Zinc - depending on
the plant species, occasionally interveinal (between the leaf veins) chlorosis
on younger leaves, but frequently the leaves small and in a rosette (leaves clustered in a circular
pattern near branch tips).
*Iron - younger
leaves will show interveinal chlorosis.
These and other problems can be corrected with appropriate
fertilizers, amendments and manures and also by soil and water management. Not enough can be said about appropriate
water management, especially if it is of a poor quality (high in salts,
chloride , sodium of boron). When a
plant transpires water through its leaves, any salts that were in the water are
left behind. These can gradually
accumulate and cause toxicities if there is inadequate rainfall or enough water
is not applied to leach these salts below the root zone. In well-managed plants, you may never see the
symptoms discussed here, but learning the signals can help direct your
activities if you do.
There are some excellent publications with photographs that
can be obtained at nurseries and libraries that will aid in identifying the
hunger signs of plants. If it is vital
that a nutrient problem be diagnosed, a commercial laboratory can perform a
tissue test for around $50. If a cheaper
diagnosis is desired, sweet corn can be planted as a bioindicator. This plant expresses the deficiency symptoms
very clearly and unambiguously if there is something lacking.
Correcting nutrient deficiencies
Having
identified a nutrient problem, consider first whether there is some management
problem that can be corrected first. For
example, yellow leaves can be a symptom of both over and under-watering, as
well as nitrogen or sulfur deficiency.
Iron chlorosis is associated with water-logged conditions, and until
irrigation is corrected, iron chlorosis will persist no matter how much iron
chelate is applied. Also, subtropicals,
such as lemon and avocado will often have yellowish leaves in cooler parts of
the year, and will naturally green up when the weather turns warmer. The long term correction may not be additions
of fertilizers, but selection of the appropriate plant for the conditions or
the correction of the soil pH.
A
fertilizer by law must have a guaranteed analysis. Synthetic fertilizers, such as urea or
ammonium nitrate can easily fulfill this requirement. On the fertilizer container are the nitrogen
(N): phosphorus (P): potassium (K) ratio.
The numbers on the container, like
Synthetic
fertilizers are characteristically fast acting, generally low in cost per pound
of actual nutrient and some acidify the soil.
Their disadvantages are that being salts, if they are mismanaged, they
have a burn potential and if a nitrogen fertilizer, the potential for leaching
of nitrogen is high. Slow-release
nitrogen fertilizers are available at much higher cost and their release rates
are governed by such environmental factors as soil moisture content and
temperature.
A
fertilizer is termed "complete" if it contains N,P and K; and "incomplete," if it is missing
one or more of these. The term
"complete" should not be interpreted as meaning that these are the
only nutrients a plant needs. In fact
the container may have other constituents than those listed on the label, but
since their proportions cannot be consistently guaranteed, they are not
listed. This is the case with manures
like cow and chicken. Since their
analysis varies from season to season and for the length of time they have been
exposed to decomposition, it is difficult to guarantee the analysis. For this reason manures are not even legally
fertilizers, although they are more complete than most fertilizers since they
contain most nutrients required to grow plants.
Organic concentrates, such as bonemeal, cottonseed and fish emulsion,
also contain a variety of nutrients, but their cost per pound of nutrients is
high relative to synthetic fertilizers.
The principal limitations to organic amendments is their bulk, availability, odor, potential salt and weed seed hazards, and expense per pound of actual nutrient. However, the value of manures and amendments does not lie solely in their nutritional additions, but also on the physical and biological effects they have on soil and plants. Organic amendments decrease soil bulk density, improve infiltration and water and nutrient holding capacities, and often increase disease resistance in plants.
Suggested Fertilizer Rates for
Table
3 shows the approximate nutrient content of manures, the analysis of a few representative
fertilizers, and suggested yearly rates of application per 1,000 square feet
of garden area. (The rates given are for
materials used singly. If combinations
of two or more materials are used , reduce the rates accordingly.) Table 4 gives suggested amounts of a few
commercial fertilizers per 100 feet of row when rows are spaced 1, 2, 3
feet apart. (The number of measuring
cups given is approximate, based on the density of the fertilizer.) The amount of material applied by a combination
of broadcast and sidedress should not exceed the total amount for the material
shown in Table 3.
Table
3.
|
Type of Manure or Fertilizer |
Nitrogen (N) |
Phosphorus (P2O5) |
Potassium (K2O) |
Suggested Amounts of Material (pounds) |
|
chicken manure, dry |
2 - 4.5 |
4.6 - 6.0 |
1.2 - 2.4 |
125 |
|
steer manure, dry |
1 - 2.5 |
0.9 - 1.6 |
2.4 - 3.6 |
450 |
|
dairy manure, dry |
0.6 - 2.1 |
0.-1.1 |
2.4 - 3.6 |
600 |
|
calcium nitrate |
15.5 |
0 |
0 |
16 - 25 |
|
ammonium nitrate |
33.5 |
0 |
0 |
7 - 12 |
|
ammonium sulfate |
21 |
0 |
0 |
12 - 19 |
|
urea |
46 |
0 |
0 |
5 - 9 |
|
|
19 |
9 |
0 |
13 - 21 |
|
16-20-0 |
16 |
20 |
0 |
16 - 25 |
|
|
12 |
12 |
12 |
20 - 35 |
Table
4.
|
Type of Fertilizer |
|
|
Row Spacings1 |
|
|
|
|
|
1 foot |
|
2 feet |
|
3 feet |
|