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Soils and the Environment > Chapter Seven - Soil Micro Organisms > Flashcards

Chapter Seven - Soil Micro Organisms Flashcards

1
Q

Identify TWO different soil organisms that affect soil formation?

A

Many living organisms are present in soil including archaea, bacteria, fungi, algae, protozoa

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2
Q

What is Humus and Give TWO advantages of humus in soil?

A

Humus is the dark organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.

Advantages:
(1)Retains moisture in the soil
(2)Loosens the soil – better aeration and drainage
(3)Encourages the increase of soil organisms
(4)Makes nutrients available to plants
(5) It adds body to light soil and loosens heavy, sticky soils

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3
Q

What affects soil formation?

A

Plants, animals and micro- organisms (fungi and bacteria) all affect soil formation by producing or contributing to humus production.

The amount of humus in soil is a direct result of how much plant material has been incorporated into it.

If vegetation is sparse soil will be
low in humus and less fertile.

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4
Q

What is the most important in soil for humus production?
A) Worms
B) Algae
C) Bacteria
D) Vegetation

A

D) Vegetation.

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5
Q

Saprophytes are bacteria that live on living material?
True or False?

A

False.

Saprophytic bacteria live on dead material, such as dead leaves, plants and animal remains.
Important in releasing Carbon, Nitrogen and other essential nutrients.
Examples include cheese mould and yeast.

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6
Q

What are Bacteria?

A

Bacteria are very small, single-celled organisms
that can only be seen under a microscope.
Bacteria are classified according to their shape.
Although part of the plant kingdom they differ greatly from the common green plant in that they do not have roots, leaves, or flowers.
Both beneficial and harmful bacteria.
Farmers can change the conditions necessary for the growth of both types of bacteria.

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7
Q

What are the three bacterial shapes?

A
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8
Q

What illness does Spherical or Cocci bacteria cause?

A

Pneumonia. Sore Throat. Boils.

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9
Q

What illness does Rod Shaped (bacilli) bacteria cause?

A

T.B.
Lock Jaw.
Typhoid.

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10
Q

What illness does Spiral Shaped (Spirochetes)

A

Cholera.
Syphillis.

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11
Q

How do Bacteria reproduce?

A

Bacteria mainly reproduce by cell division.

The cell grows until a certain size is reached after which the cell divides into 2 parts giving rise to 2 daughter cells.

The rate of division varies but under favorable conditions it can happen once every 20 minutes.

So after 7 hours under favorable conditions over 1 million bacteria could have been produced from one.

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12
Q

What is the difference between saprophytic bacteria and parasitic bacteria?

A

Depending on their food source Bacteria are classified as saprophytes or parasites.

Saprophytic bacteria live on dead material, such as dead leaves, plants and animal remains.

Important in releasing Carbon, Nitrogen and other essential nutrients.
Examples include cheese mould and yeast.

Parasites
Parasitic bacteria live on living material and in doing so can cause much damage to crops e.g. rotting of turnips, swedes, potatoes, and salmonella.

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13
Q

How are bacteria classified? Give one example?

A

Bacteria are classified according to their shape.
Eg Bacillus, Coccus, Spirillus.

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14
Q

Which one of the following is NOT caused by rod shaped bacteria?
A) Pneumonia
B) Lockjaw
C) Typhoid
D) T.B.

A

A) Pneumonia

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15
Q

. Which of these is NOT a bacteria shape?

A) Circles
B) Spirals
C) Rods
D) Spherical

A

A) Circles

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16
Q

Which one of the following is the ONLY example of a parasitic fungus?

A) Mushrooms
B) Potato Blight
C) Yeast
D) Bread Mould

A

B) Potato Blight

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17
Q

What conditions are necessary for growth of Bacteria?

A

Presence of suitable food (living or dead material depending on if parasitic or saprophytic bacteria).

Presence of moisture(ideally damp moist conditions)

Suitable pH - (Different bacteria require different ranges of pH.
If the pH goes above or below this range their growth
ceases.
Lactic acid bacteria in silage grow at pH 3.8 to 4.2.
Therefore, it is very important in silage-making to get
the pH in this range.
At this pH level respiration stops and the silage preserves well.)

Moderate temperature - All the bacteria of importance in agriculture and horticulture require moderate temperatures.
If the temperature goes to either extremes of heat or cold the bacteria either die or their activity slows down.

Oxygen -Some bacteria require air while others survive without it.

Aerobic – Require oxygen to grow
Anaerobic – Don’t require oxygen to grow

The lactic acid bacteria in silage require no air to survive.
Most pathogenic bacteria are anaerobic E.g. Clostridium
Blackleg
Tetanus
Botulism

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18
Q

What pH is needed for silage making bacteria to survive?

A

In silage making the lactic acid bacteria grow best at pH 3.8 to 4.2.

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19
Q

What is the difference between Aerobic Bacteria and Anaerobic bacteria?

A

Aerobic – Require oxygen to grow
Anaerobic – Don’t require oxygen to grow

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20
Q

Most Anaerobic Bacteria are

A

Most pathogenic bacteria are anaerobic E.g. Clostridium
Blackleg
Tetanus
Botulism

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21
Q

What bacteria are important in fermentation of good quality silage?
A) Aerobic Bacteria
B) Citric Bacteria
C) Lactic Acid Bacteria
D) Parasitic Bacteria

A

C) Lactic Acid Bacteria.

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22
Q

List 3 effects of Harmful Bacteria?

A

1.Cause disease in humans and animals e.g. whooping cough, T.B.,b rucellosis and scour.
2. Cause rotting of many vegetables and fruits
e.g. rotting of potatoes,
swedes, and turnips.
3. Cause spoilage of food e.g. souring of milk

23
Q

Name 4 uses of Beneficial Bacteria?

A
  1. Play an important role in the supply of nitrogen for plant growth.

2.Improve soil fertility by aiding the decay of dead plant and animal remains.

3.Enhance silage preservation.

4.Useful in the manufacture of antibiotics

24
Q

Which of the following is NOT a potential cause of moss growth in a field?

A) Poor soil fertility
B) Compaction
C) Nitrogen application
D) Poor drainage

A

C) Nitrogen Application

25
Q

What are the four stages of the Nitrogen cycle?

A
26
Q

Give TWO examples of beneficial fungi?

A

Yeast -alcohol manufacturing-sugars break down into Co2 and alcohol.

Penicillin - Antibiotics.

Mushrooms- Saprophytic Fungi grow naturally in meadows and decaying trees.

27
Q

Whys study Fungi?

A

Controlling fungi is very important for good farm
management.
Fungi can cause disease in both animals and plants if not controlled properly.
It can have a significant effect on productivity.
Some fungi are beneficial e.g. mushrooms

Do not make their own food.

They get their food from other sources

Depending on which way they get their food, fungi are classified as either saprophytes or parasites.

28
Q

Structure of a Fungus

A

Fungi are different to plants.
Instead of a cell, a fungus has a hypha.
These hyphae are tiny needle link structures, a group known as mycelium.
Think of a loaf of bread in damp conditions.
The blue mould that forms are the mycelium spreading over and onto the surface of the bread

29
Q

What conditions to Fungi need to grow?

A
30
Q

Name ONE harmful fungi in relation to cereal crops?

A

Rusts and smuts in cereal crops
Rhychosporium in cereal crops
Septaria in cereal crops
Mildew in cereal and many other crops
Take All in cereal crops
Eye Spot in cereal crops
Potato Blight fungus in potatoes

31
Q

What weather conditions favour potato blight?
A) Frost
B) Wet and windy
C) Very mild and Sunny
D) Damp and muggy

A

Damp and muggy.

32
Q

Describe lifecycle of
Saprophytic Fungus

A

It starts its life cycle as a spore.

Can only be seen under a microscope

Spores are blown and spread through the air

When it lands on a ready source of food, such as damp bread it
absorbs the food and moisture, it grows

The hyphae grow across the surface giving a mouldy appearance

When the spores in the mould build up they burst and spread through the air and contaminate other food.

33
Q

Life Cycle of Fungus: Parasitic Fungi

A

When a parasitic spore (potato blight fungus) lands on a potato leaf
it sends out hyphae into the cells of the leaf and feeds on the plant juices.

Parasitic fungi use live material as a source of food.

The cells on the leaf of the potato plant are killed and the disease spreads further into the plant.

The dead cells turn brown giving the symptoms of potato blight.

The fungus then sends out hyphae which develop swellings at the tips and release spores into the air.

This causes more infection to other plants.

The spores can be washed into the soil where they can affect the tuber.

34
Q

Types of Fungi: Beneficial Fungi

A

Yeast
Alcohol manufacturing- sugars break down into CO2 and alcohol
Penicillin
Antibiotics
Mushrooms
Saprophytic fungi grow naturally in meadows and decaying trees.
Commercial crops are grown on compost.

35
Q

Describe Viruses?

A

Viruses are not cells
Very small
Many can only live within a cell.
This means that it must be transferred between plants and animals within another organism - A vector transmits viruses to different plants, e.g. sucking insects e.g. aphids
Foot and mouth was the first virus disease to be discovered of cattle.

All Viruses are parasitic and cause damage to many commercial crops:
Leaf roll, mosaic barley, dwarf virus disease of sugar beet, peas, beans and tomatoes.
Shades of green and yellow on the leaves.
Curling of leaves.
It may cause little damage, or it can destroy the whole plant.
In plants some viruses are known to be spread by insects such as aphids.

36
Q

Why buy certified seed? How do you cure viruses in plants?

A

There is no method of curing a virus-infected plant
If it is practical the diseased plant should be removed and destroyed in the hope of avoiding disease spread of the virus to the rest of the crop.

Buying certified seed is the most preventative measure available to farmers and growers eg potatoes and strawberry runners.

37
Q

In the decomposition of organic matter, which of these are the first organic compounds to be broken down?
A) Carbohydrates
B) Fats
C) Slurry fertiliser
D) Amino acids and sugars

A

(D) The first organic compounds to be broken down are those that are easy to break down, including
amino acids and sugars.

38
Q

A fungus starts its life as a spore, grows hyphae, which then branch out to absorb nutrients? True/False?

A

True.

39
Q

What causes an increase in the growth rate of algae on water?

A

Algae growth can be increased by the pollution of water by
nitrate or phosphate

40
Q

Eutrophication is an increase of growth of algae as a result of over-enrichment of water.
What TWO nutrients are usually responsible for this?
A) Nitrate and Phosphate
B) Sulphate and Potash
C) Nitrate and Sulphate
D) Sulphate and Phosphate

A

A) Nitrate and Phosphate

41
Q

What is the Carbon Cycle?

A
42
Q

Describe ONE difference between fungi and algae?

A

Alga are photosynthetic plants. They can manufacture their own food and are found mainly in water on land in very moist environments. Fungi does not make it’s own food.

43
Q

After 7 hours, how many bacteria can be formed from one bacteria under favourable conditions?
Select one:
A) 1 million
B) 100,000
C) 1,000
D) 10,000

A

A) 1 million

44
Q

Describe Decomposition of Organic Matter?

A
45
Q

What is the difference between green wastes and organic manures?

A

Green waste is biodegradable waste composed of materials such as grass or flower cutting and hedge trimmings as well as domestic and commercial food waste. High in Nitrogen.

Organic manures - cattle and pig slurries, poultry manures and farmyard manure (FYM). Wide variation in nutrient content.

46
Q

Why is the presence of Bracken (common fern) within a sward dangerous for grazing cattle?

A

Poisonous to cattle.

47
Q

What is the minimum interval (days) that must be observed between spreading cattle slurry and grazing?

A

30 days minimum interval between spreading and grazing.

48
Q
  1. Select the correct statement from the following options?
    A) Nitrogen availability is highest in spring and farmers should aim to have 70% of slurry applied by the end of April.
    B) Nitrogen availability is highest in the summer and farmers should aim to have 60% of the slurry applied by the end of April.
    C) Nitrogen availability is highest in autumn and farmers should aim to have 50% of slurry applied by the end of April.
    D) Nitrogen availability is highest in spring and farmers should aim to have 50% of slurry applied by the end of April.
A

Nitrogen availability is highest in spring and farmers should aim to have 70% of slurry applied by the end of April.

49
Q

Give TWO negative implications of applying organic matter mid-season rather than in spring?

A
50
Q

Benefits of buying Certified Seed?

A
51
Q

If cattle slurry is to be used on grass for grazing you should adhere to four basic recommendations that minimise the risk of un-palatability in the sward and disease spread. List two of these recommendations?

A
52
Q

When is hydrogen sulphide from slurry at its greatest? List any TWO times?

A
53
Q

List TWO ways in which carbon can be released into the atmosphere in agriculture – (Use the Carbon Cycle)

A

Plants take carbon dioxide from the air and use it to make food.

Animals then eat the food, and the carbon is stored in their bodies or released as CO2 through respiration.

54
Q

Bacterial growth is dependent on FIVE Conditions which must be present for bacteria to grow and thrive.
Describe in detail these FIVE conditions with appropriate examples

A

Bacteria require constant supply of food. Living or dead depending on if parasitic or saprophytic bacteria.

Require damp moist conditions.
Different bacteria require different ranges of pH.

Moderate temperatures.

Soils and the Environment (7 decks)

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