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CHEMICAL FERTILISERS
WHAT ARE CHEMICAL FERTILISERS?A chemical fertilizer is a substance applied to soils or directly onto plants to
provide nutrients optimal for their growth and development. The essential
nutrients contained in these fertilizers are nitrogen, phosphorous, and potassium
(NPK), as well as other nutritional substances in
smaller amountsall presented in a form that
can easily be absorbed and metabolized by
plants. Chemical fertilizers have become a staple
in many yards and gardens, and can be a key
component of a healthy lawn care routine. Read
on for some basic information on chemical
fertilizer and how you can use it most effectively
in your yard. Fertilizer is any organic or
inorganic material of natural or synthetic origin (other than liming materials)that is added to a soil to supply one or more plant nutrients essential to the
growth of plants. Conservative estimates report 30 to 50% of crop yields are
attributed to natural or synthetic commercial fertilizer. European fertilizer
market is expected to grow to 15.3 billion by 2018.
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WHY DO PLANTS NEED FERTILISRS?In order for a plant to grow and thrive, it needs
a number of different chemical elements. Themost important are:
Carbon, hydrogen and oxygen - Availablefrom air and water and therefore in
plentiful supply
Nitrogen, phosphorus, potassium (a.k.a. potash) - The three macronutrientsand the three elements you find in most packaged fertilizers
Sulfur, calcium, and magnesium - Secondary nutrients Boron, cobalt, copper, iron, manganese, molybdenum and zinc -
Micronutrients
The most important of these (the ones that are needed in the largest quantity by a
plant) are nitrogen, phosphorus and potassium. If you have read the articlesHowCells WorkandHow Food Works, you have heard about things like amino acids,
cell membranes and ATP. Nitrogen, phosphorus and potassium are importantbecause they are necessary for these basic building blocks. For example:
Every amino acid contains nitrogen. Every molecule making up every cell's
membrane contains phosphorous (the
membrane molecules are called
phospholipids), and so does every molecule ofATP (the main energy source of all cells).
Potassium makes up 1 percent to 2 percent ofthe weight of any plant and, as an ion in cells,
is essential to metabolism.
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Without nitrogen, phosphorus and potassium, the plant simply cannot grow
because it cannot make the pieces it needs. It's like
a car factory running out ofsteelor a road crew
running out of asphalt.
If any of the macronutrients are missing or hard to
obtain from the soil, this will limit the growth rate
for the plant. In nature, the nitrogen, phosphorous
and potassium often come from the decay of plants that have died. In the case of
nitrogen, the recycling of nitrogen from dead to living plants is often the onlysource of nitrogen in the soil.
To make plants grow faster, what you need to do is supply the elements that the
plants need in readily available forms. That is the goal of fertilizer. Most fertilizerssupply just nitrogen, phosphorus and potassium because the other chemicals are
needed in much lower quantities and are generally available in most soils.
Nitrogen, phosphorus and potassium availability is the big limit to growth.
How Does Fertilizer Work? There is an old saying that you are what you eat.
This is as true of plants as it is of humans. Without
the proper nutrients, plants will not grow and
produce as expected. For plants, proper nutrition
comes from the nutrients in the soil or fromcommercial fertilizer.
Water soluble fertilizers are designed to mix with water and applieddirectly to the plant with a hose or sprayer. This type of fertilizer is ideal for
http://science.howstuffworks.com/iron2.htmhttp://science.howstuffworks.com/iron2.htmhttp://science.howstuffworks.com/iron2.htmhttp://science.howstuffworks.com/iron2.htm7/29/2019 Chemical Fertilisers
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foliar feeding but may also be applied to
roots. By applying the mixed fertilizer to
the leaves, plants are able to utilize the
nutrients right away. Nutrients areabsorbed through the leaves and go
directly to plant growth. Run off
penetrates the soil and provides
nutrients that are absorbed by the roots.
Granular fertilizer is applied to the soil and must be mixed into the existingsoil to prevent burning the young roots of growing plants. This formula
breakdowns over a period of time when exposed to rainfall or regular
watering. It may be applied prior to planting and during the growing
season. Contact with leaves will cause plant damage.
Each of these fertilizer types comes in a premixed formula that consists ofthree main elements: nitrogen, phosphorus and potassium, sometimes
referred to as potash. The numbers indicated on the bag, such as 10-10-
10, represent the percentage of each element in the formula. To determinewhich formula is right for you, you need a basic understanding of the
effect each element has on plant growth.
Nitrogen works to promote lush green leavesand rapid growth. When applied at the right
time, nitrogen will give your plants a boost in
growth, but it is best applied early in the
growing season, well before the onset of
blooming and fruit. If too much nitrogen is
applied close to blooming time, you may
sacrifice blooms and end up with lush
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vegetation that fails to set fruit. A lack of nitrogen will result in yellowing
or curling of older leaves and stunted growth.
Phosphorus promotes vigorous blooms and healthy plant cells. Apply afertilizer high in phosphorus just prior to blooming to encourage profuse
blooms that are brimming with color. Plants suffering from a phosphorus
deficiency may show signs of purpling along the veins.
Potassium is needed to build a strong root system to support the plant'sgrowth and to maintain health. This is especially important for large plants
that require vigorous root systems for support. A lack of potassium will
result in stunted growth and general poor health.
ADVANTAGES OF CHEMICAL FERTILISERS1. Chemical fertilizers have smaller bulk and hence
are easy to store, transport and apply.2. Chemical fertilizers are nutrient specific. Thus for
supplying a particular nutrient we can select somespecific chemical fertilizer. For example, super
phosphate is used in case the soil is deficient in
phosphorus.
3. Chemical fertilizers are soluble in water and hence are easily absorbed by
plants.
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NEGATIVE EFFECTS OF CHEMICALS FERTILISERSThe biggest issue facing the use of chemical
fertilizers is groundwater contamination. Nitrogenfertilizers break down into nitrates and travel easily
through the soil. Because it is water-soluble and can
remain in groundwater for decades, the addition of
more nitrogen over the years has an accumulative
effect.
At the University of Wisconsin, Madison, they discovered the effects of chemical
fertilizers are compounded when mixed with a single pesticide. They discovered
altered immune, endocrine and nervous system functions in mice, as well as
influence on children's and fetus's developing neurological, endocrine and
immune systems. These influences "portend change in ability to learn and in
patterns of aggression."
One popular fertilizer, urea, produces ammonia emanation, contributes to acid
rain, groundwater contamination and ozone depletion due to release of nitrousoxide by gentrification process. With it's increased use and projections of future
use, this problem may increase several fold in the coming decades.
Groundwater contamination has been linked to gastric cancer, goiter, birth
malformations, and hypertension; testicular
cancer and stomach cancer.
Excessive air- and water-borne nitrogen fromfertilizers may cause respiratory ailments,
cardiac disease, and several cancers, as well as
can "inhibit crop growth, increase allergenic
pollen production, and potentially affect the
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dynamics of several vector-borne diseases, including West Nile virus, malaria,
and cholera."
Perhaps one of the scariest effects of chemical
fertilizers is something called
methemoglobinemia. In infants it is
alternatively known as Blue Baby Syndrome.
The risk most often occurs when infants are
given formula reconstituted with nitrate
contaminated water. The condition causes a decrease in oxygen in the blood and
results in a blue-grey skin color, causes lethargy and/or irritability and can lead
to coma or death.111 I've been unable to find whether the same risk exists for
breastfeeding babies whose mothers drank contaminated water.
Nitrogen groundwater contamination also contributes to marine "dead zones".
The increase in the water-soluble nitrates creates an influx of plant-life, which
eats up oxygen and starves out fish and crustaceans. This has an impact not only
on the aquatic ecosystem, but on local societies who depend on food sourced from
those areas.
And then there is the highly questionable use of raw sewer sludge as a fertilizer.
Yes, you heard me right. In some countries, raw, uncomforted and untreated
human waste is applied directly to crops and soil, a practice known as "night soil"
since it's typically applied at night. The risk of disease is obvious and highand this
practice should never be confused with "humanure", a long, highly involved
process of decomposing human waste into a safe resource.
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What is organic fertilizer?
There are natural, organic fertilizers that aren't made bymixing chemicals together. Organic fertilizers are made bymixing natural ingredients, ingredients that are naturally
high in N or P or K or all of them, and that also contain
trace elements.
Chicken poor blood and bone meal or fish extract and things like that. They
contain the NPK in varying ratios, and some trace elements, and maybe other
gobbledygook like growth factors, auxins , macromolecules, enzymes.
However, it's still easily possible to get the balance wrong, especially if you don't
know what exactly is in that bag and what exactly your plants need.
Maybe it's theoretically possible to grow reasonably healthy kids on a diet like
that, if you do add enough different herb, fruit and vegetable extracts, in a high
quality form where most of the goodness in them is actually preserved. And if you
really understand what you are doing there, what EXACTLY the kids need!
Harmful Effects of Fertilizers
According to the Environmental Protection
Agency, most fertilizers contain about the
same basic materials: nitrogen, potassium,
phosphorus and sometimes other nutrients,like zinc, needed for healthy plant growth.
Many people use fertilizers to give extra life
to their lawn and garden, but few people
consider the potential drawbacks of these
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fertilizers. In an effort to be as environmentally conscious as possible, it is
important to consider the potentially harmful effects of fertilizers as well as the
benefits.
Human CarcinogensThe most significant harmful effects come from fertilizer that is designed to kill
or prevent weeds. According to the EPA's Office of Pesticide Programs, 12 of the
most popular pesticides in the United States have ingredients known to cause
cancer. Organic fertilizers are guaranteed to be safe for the
environment, the body and free of pesticides.
Water PollutionWhile fertilizers may be beneficial to the plants,
they are not always as healthy for the rest of the
environment. Many of the "quick-release"
fertilizers have been known to lead to oxygen
loss in waterways due to runoff into the street
and, as a result, into the water. High amounts of
nitrogen can find their way into waterways in
this way, causing an excess of algae and a resulting loss of oxygen in the water.
This can have a negative effect on fish and other wildlife in the water.
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Toxic Waste PotentialMany people do not realize that some fertilizers are made from the residuals of
waste water treatment facilities or recycled from other areas that cause them totest positive for toxic waste. According to the federation of Public Interest
Research Groups (PIRG), 29 popular fertilizers tested positive for 22 toxic heavy
metals, including silver, nickel, selenium, thallium and vanadium. All of the
metals found are linked directly to human
health hazards.
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