Chemistry Holiday Assignment

7/29/2019 Chemistry Holiday Assignment

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Chemistry and Gardening

Name: Curtly Frank

School:Queens College

Date: Wednesday 11, 2013

Teacher: Ms. Jordan
http://2.bp.blogspot.com/-DU69g8nWtK0/T8wICx54alI/AAAAAAAAEl0/TCqTJmMEvBA/s1600/fertalizer.jpg


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Chapter 1: Essential Elements for Plant

Growth and Their Sources (S.O.

6.1:6.2)

Plants require sixteen various elements for their proper growth and

development. These nutrients are categorized according to the quantity in which

they are needed. Nutrients that plants require in large amounts (e.g. nitrogen) are

called macronutrients, while those needed in much smaller amounts (e.g. zinc) arecalled micronutrients or traces.

Macronutrients are divided into two groups:

Primary Nutrients: these are the three most important nutrients to a plant.They are nitrogen, phosphorus and potassium.

Secondary elements: these are the three other macronutrients; calcium,magnesium and sulphur. Though they are essential to plants, they are not

needed in as large amounts as the primary macronutrients, but are needed

in larger quantities than micronutrients.

Nitrogen: this element is absorbed as either ammonium ions (NH+

4) or as nitrate

ions (NO-3). Nitrogen is important to plants because it promotes vegetative growth.

Nitrogen is one of the most easily leached elements. Nitrogenous fertilisers include

ammonium sulphate ((NH4)2 SO4) which contains 20% nitrogen, ammonium nitrate(NH4NO3) which contains 35% nitrogen, and urea (CO(NH2)2) which contains 46%

nitrogen.

Phosphorus: absorbed as phosphate ions (PO3-

4), phosphorus stimulates root

growth and is also used to alter the maturity rate of plants. Fertilisers rich in


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phosphorus include super-phosphate (P2O5) which has 19-21% phosphorus

availability, triple super phosphate (P2O5) which has 47% phosphorus availability,

and ammonium phosphate ((NH4)3PO3) which has 12-21% phosphorus availability.

Potassium: plants take up potassium as K+ ions. Potassium is needed in plants

because it is essential for the formation and transfer of carbohydrates. Potassium

rich fertilisers are Muriate of Potash (KCl) which has 60% potassium oxide, and

Sulphate of Potash (K2SO4) WHICH HAS 48-50% potassium oxide.

*Some fertilisers combine nitrogen, phosphorus and potassium in a fertiliser called

NPK. NPK is available in various ratios of each of the three, (e.g. 10N:10

P:10

K,

15N

:10P

:10K

)

Some micronutrients required by plants are:

Sulphur: one of the constituents of proteins, sulphur is important to plants with

high protein levels (e.g. legumes).

Calcium: this element is essential to the development of root tips.

Magnesium: this is one of the fundamental parts of the chlorophyll molecule and is

therefore needed for all green plants.

*Some micronutrients are found in fertilisers rich in macronutrients (e.g. sulphur

can be found in sulphate of potash).


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Chapter 2: Effects When Elements are

Deficient (S.O. 6.3)

Deficiency of any one of the major elements required by plants results in

visible side-effects.

Nitrogen: deficiency of this nutrient results in stunted growth, yellowing of leaves

and leaves dropping off.

Phosphorus: phosphorus deficiency results in purple pigmentation of leaves,

stunted growth in green parts of the plants and poor root development.

Potassium: deficiency of potassium results in drying of leaves from the tips

backwards, irregular molting of leaves and pre-mature falling of buds.
http://www.google.gy/url?sa=i&rct=j&q=deficiency+of+nitrogen+in+plants&source=images&cd=&cad=rja&docid=mUYipYaNiga2aM&tbnid=aY_CIpgEILoSEM:&ved=0CAUQjRw&url=http://www.bio.miami.edu/dana/226/226F09_12.html&ei=baYHUpykJYG4yQGakoGgAQ&bvm=bv.50500085,d.aWc&psig=AFQjCNFYsMG1P6-BVr_4hkTGOZ3vQyXJ9g&ust=1376319418340986


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Chapter 3: Nitrogen Compounds in

Home Gardening- Organic Manure vs.

Fertilisers; the Nitrogen Cycle (S.O. 6.4)

Nitrogen is one of the macronutrients needed by plants. It is also one of the

most easily leached nutrients. As such, nitrogenous fertilisers are needed

constantly to replenish nitrogen supplies. The nitrogen cycle is the continuous

circulation and conversion of nitrogen through its various forms through the

environment. This constant cycling of nitrogen is very essential for nitrogen to

remain in the soil.

The amount of nitrogen returned to the soil by the nitrogen cycle in home

gardens is not enough, and therefore nitrogenous fertilisers are needed to provide

the additional nitrogen needed.

Organic vs. Inorganic Fertilisers

Organic fertilisers are any fertilisers derived from animal or vegetative

matter. Inorganic fertilisers are fertilisers derived from chemical substances and

are generally in the form of soluble powders, granules, or crystals.

Organic Fertilisers Inorganic Fertilisers

Nutrients are released at a slow and

consistent rate, thus resulting in steady

growth.

When inorganic fertilisers are dissolved

in water and reach a body of water (e.g.

lake/river) it results in pollution.

Improves soil structure. After a period of time, plants and

farmers become dependent on

inorganic fertilisers.

Helps to prevent topsoil erosion. Are easier to uses and apply than

organic fertilisers.

Help to retain soil moisture. Nutrients are instantly available toplants.

Cheaper than inorganic fertilisers. Are more expensive than inorganic

fertilisers, but are added less frequently.

Must be applied at more regular

intervals to supply essential quantities

of nutrients.

Regular use contributes to a decrease in

pH, and is therefore a cause of soil

acidification.


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Chapter 4: Humus, Why We Need It!

(S.O. 6.5)

Humus is any organic matter which is added to the soil to influence the

texture and nutrient & water retention. Humus is sometimes used to describe

manure or natural compost. Humus serves as a host and source of food for micro-

organisms in the soil.

When humus is added to the soil, it helps to promote the activities of soil

organisms. Humus adds very important nutrients to the soil while helping to

improve the structure of the soil. Humus conserves soil moisture, prevents erosion

and has a buffering effect on the soil. The addition of humus to soils also helps to

reduce quick soil temperature fluctuations.
http://www.google.gy/url?sa=i&rct=j&q=humus%20soil&source=images&cd=&cad=rja&docid=5rooOWGgWrv0mM&tbnid=Bf1lN-S7O7S-xM:&ved=0CAUQjRw&url=http://www.swac.umn.edu/classes/soil2125/doc/s10chap1.htm&ei=FsgHUrXOIYGK9QTj8YCgCA&bvm=bv.50500085,d.aWc&psig=AFQjCNFltXzxGiJ9R58qnnR6UBXR-8Txrw&ust=1376328059944406


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Chapter 5: Lime and Soil (S.O. 6.6; 6.7)

pH is the measure of the acidity or alkalinity of a substance. Soil pH refers to

the pH of the soil. The majority of agricultural crops thrive within a pH of 6.5-8.6. If

the soil is too acidic, lime can be added to soil. The addition of lime to the soil, on a

chemical level, increases the pH of the soil, thus removing soil acidity. Also, lime

hastens the decomposition of organic matter and helps to develop nitrogen-fixing

bacteria. Lime can be added as limestone (CaCO3), quicklime (CaO) or slaked lime

(Ca(OH)2).

Lime, physically, compliments soil structure helps to reduce weeds.

When ammonium is added to the soil it reduces the soil pH, thus making the

soil more acidic (NH4+

+ H2O NH3(aq) + H3O+). Since lime does the opposite, when

the two are added together, each counteracts the activity of the other (2NH 4+

+

CaO NH3 + Ca2+

OH).

Adding lime to Soil
http://www.google.gy/url?sa=i&rct=j&q=adding%20lime%20to%20soil&source=images&cd=&cad=rja&docid=moKNDqsowER94M&tbnid=lo1TVJ_xW-UAzM:&ved=0CAUQjRw&url=http://www.diynetwork.com/outdoors/knowing-and-improving-your-soil/page-6.html&ei=ne0HUofFLIbe9AS1rYGYCA&bvm=bv.50500085,d.aWc&psig=AFQjCNFHteS03yOW0TAPWnQvFMuDsdxCYw&ust=1376337675525039


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Chapter 6: Chemical and Biological

Control of Pests (S.O. 6.8)

A is any substance used for the prevention and/or removal of any unwanted

pests. Pesticides can be either biological or chemical. Both classes of pesticides are

found to have harmful effects on the effects on the environment in the long run.

Some such effects are:

Water Pollution: when pesticide run-off gets into contact with large bodiesof water they pollute the water.

Nitrogen Fixation: pesticides reduce the efficiency of nitrogen fixation, thusresulting in a higher need for nitrogenous fertilisers.

Pesticide Drift: when pesticides are sprayed in the air, they are carried bythe wind and can be scattered for miles, resulting in wide scale air pollution.

Biological Pesticides (Biopesticides):

Biopesticides are pesticides used for biological control of pests and are

organic in nature. Advantages of biopesticides are that they:

Do not have traces of harmful residues. Are cheaper than chemical pesticides. Are better for the environment due to them being biodegradable.

Disadvantages of biopesticides are that they:

Work slower than other pesticides. Allow for living organisms adapt and increase their resistance to any other

form of control.

Are very specific.Chemical Pesticides:

Chemical pesticides are pesticides that are inorganic in nature. Some

advantages of chemical pesticides are that they:

Are fast acting. Are more effective than biopesticides.


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Are less specific and therefore can target a wider range of pests.Disadvantages of chemical pesticides are that they:

Remain on the surface of the fruit for days after being picked, so there is riskof ingestion of pesticide residue.

Are more expensive than biopesticides.


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Chapter 7: Herbicides (S.O. 6.9)

Herbicides are also known as weed-killers because they get rid of unwanted plants.

Herbicides are categorized as either selective or non-selective. Non-selective

herbicides kill all plants they are sprayed on; while selective herbicides target only

a select variety of plants and the rest are immune to their effects (e.g. selective

herbicides can target broad leafed plants while fine leafed crops are unaffected).

Herbicides have advantages and disadvantages. Some are:

Advantages Disadvantages

Herbicides are highly effective and can

kill many harmful crops.

Herbicides are toxic and can be fatal if

ingested.

Herbicides have no harmful effects on

the soil.

Herbicides are damaging to the

environment.Over time, herbicides increase plant

resistance, therefore making the plants

harder to destroy.


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Chapter 8: Hydroponics (S.O. 6.10)

Hydroponics, from the Greek words hydro (water) and ponos (labour), is

an adopted method of cultivation in which roots of the plants are immersed in

nutrient-enriched water. Hydroponics can be done with our without the use of

sand or gravel for mechanical support, but is generally done without it.

Hydroponics is sometimes referred to as planting without soil. The first published

work on planting without soil was in the Sylva Sylvarum, a book published in 1627.

In the 18th

century, scientists discovered that plants absorb all their mineral

requirements as inorganic ions. Soil is a reservoir for these minerals, but only when

the minerals are dissolved in water can the plants absorb them. Therefore, when

these minerals were introduced into a plants water supply by artificial means, soil

would no longer be required for plant growth. This led to the development of

hydroponics.

There are many benefits of hydroponics. The most notable are:

Increased Production: hydroponics allows for plants to grow faster andhave a stable and larger yield of crops. This allows a much higher profit.

Healthier Plants: hydroponics promotes healthier plants because there isprecise control over the plants environment (e.g. pH and nutrition can be

easily changed). Also plants grown through hydroponics eliminate the risk of

soil-borne diseases, and fewer pesticides are used.

Water Efficiency: hydroponic systems use less water than traditionalfarming systems. This is a result of water in the system being recycled and

recirculated. For this reason, hydroponics is used in areas where water is

not always readily available.

Wide Crop Production Range: hydroponics allows the production of plantsthat are out of season or even plants that need a specific climate to grow,


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provided the plants are in a greenhouse where conditions can be precisely

recreated. Also, most terrestrial plants can be grown using hydroponics.

Though hydroponics is very effective, it comes at disadvantages. If there is a failure

of the hydroponic system, the plants would quickly die without soil as a buffer.

Setting up hydroponic systems is expensive, and many hydroponic plants need

varying fertilisers.
http://www.google.gy/url?sa=i&rct=j&q=hydroponics%20how%20it%20works&source=images&cd=&cad=rja&docid=81UUjj5tp2N_1M&tbnid=6gwDaRTCDmfywM:&ved=0CAUQjRw&url=http://www.growingmarijuana.com/hydroponic/grow-hydroponic.php&ei=FH8DUqSJBsKbygGNtYHIAg&psig=AFQjCNGzQCHi5d35q8FJPrcjhq6UXZe6VA&ust=1376046761810283http://www.google.gy/url?sa=i&rct=j&q=hydroponics%20how%20it%20works&source=images&cd=&cad=rja&docid=7xYeI--XcD9vnM&tbnid=HiwgPUzPNlRFiM:&ved=0CAUQjRw&url=http://www.smallfish-bigpond.com/category/hydroponics/&ei=5X0DUpqlCsOoyAHomYGYAg&psig=AFQjCNGzQCHi5d35q8FJPrcjhq6UXZe6VA&ust=1376046761810283http://www.google.gy/url?sa=i&rct=j&q=hydroponics%20how%20it%20works&source=images&cd=&cad=rja&docid=81UUjj5tp2N_1M&tbnid=6gwDaRTCDmfywM:&ved=0CAUQjRw&url=http://www.growingmarijuana.com/hydroponic/grow-hydroponic.php&ei=FH8DUqSJBsKbygGNtYHIAg&psig=AFQjCNGzQCHi5d35q8FJPrcjhq6UXZe6VA&ust=1376046761810283http://www.google.gy/url?sa=i&rct=j&q=hydroponics%20how%20it%20works&source=images&cd=&cad=rja&docid=7xYeI--XcD9vnM&tbnid=HiwgPUzPNlRFiM:&ved=0CAUQjRw&url=http://www.smallfish-bigpond.com/category/hydroponics/&ei=5X0DUpqlCsOoyAHomYGYAg&psig=AFQjCNGzQCHi5d35q8FJPrcjhq6UXZe6VA&ust=1376046761810283


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Bibliography

CXC Agriculture Third Edition, Sahadeo Ragoonanan (Caribbean EducationPublishers), pp. 77-78, 82, 86-87.

Biology for CXC, M.V.B. Roberts & June Mitchelmore (Thomas Nelson andSons Ltd.) p. 28

http://www.britannica.com/EBchecked/topic/279000/hydroponics http://www.ehow.com/info_8127318_uses-hydroponics.html http://home.howstuffworks.com/chemical-elements-needed-for-plant-

growth.htm

http://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardening

http://en.wikipedia.org/wiki/Organic_fertilizer http://en.wikipedia.org/wiki/Humus http://www.ehow.com/list_6157122_advantages-disadvantages-

herbicides.html

http://en.wikipedia.org/wiki/Biological_pesticides http://en.wikipedia.org/wiki/Pesticide
http://www.britannica.com/EBchecked/topic/279000/hydroponicshttp://www.britannica.com/EBchecked/topic/279000/hydroponicshttp://www.ehow.com/info_8127318_uses-hydroponics.htmlhttp://www.ehow.com/info_8127318_uses-hydroponics.htmlhttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://en.wikipedia.org/wiki/Organic_fertilizerhttp://en.wikipedia.org/wiki/Humushttp://www.ehow.com/list_6157122_advantages-disadvantages-herbicides.htmlhttp://www.ehow.com/list_6157122_advantages-disadvantages-herbicides.htmlhttp://www.ehow.com/list_6157122_advantages-disadvantages-herbicides.htmlhttp://www.ehow.com/list_6157122_advantages-disadvantages-herbicides.htmlhttp://en.wikipedia.org/wiki/Biological_pesticides#Advantageshttp://en.wikipedia.org/wiki/Biological_pesticides#Advantageshttp://en.wikipedia.org/wiki/Pesticidehttp://en.wikipedia.org/wiki/Pesticidehttp://en.wikipedia.org/wiki/Pesticidehttp://en.wikipedia.org/wiki/Biological_pesticides#Advantageshttp://www.ehow.com/list_6157122_advantages-disadvantages-herbicides.htmlhttp://www.ehow.com/list_6157122_advantages-disadvantages-herbicides.htmlhttp://en.wikipedia.org/wiki/Humushttp://en.wikipedia.org/wiki/Organic_fertilizerhttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://wiki.answers.com/Q/Why_are_nitrogen_compounds_important_to_home_gardeninghttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://home.howstuffworks.com/chemical-elements-needed-for-plant-growth.htmhttp://www.ehow.com/info_8127318_uses-hydroponics.htmlhttp://www.britannica.com/EBchecked/topic/279000/hydroponics

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