B4 - Intensive and Organic Farming

Question 1

What is the point of intensive farming?

Answer 1

Intensive farms try to produce the maximum amount of food per hectare of land. Highest yield.

Question 2

What are some advantages of intensive farming and why?

Answer 2

1. High yield - Maximum production is achieved per unit of land.
   The use of pesticides means that less food is lost to pests.
2. Low cost of production - The maximum output is achieved from the land available, such as by using fertilisers to increase plant growth.
3. Less labour intensive - The use of artificial chemicals and machines means fewer people are needed to do the work.

Question 3

What are some disadvantages of intensive farming and why?

Answer 3

1. Pesticides - If not used carefully these may damage the environment.
2. Fertilisers - If too much soluble fertiliser is used, it can wash into streams and lead to pollution. ( eutrophication )
3. Battery rearing of animals in small enclosures - This tends to be less humane, and it can cause disease to spread quickly through the animal population.

Question 4

Explain the three main types of pesticides

Answer 4

1. Insecticides kill insects, which might be a pest because
   they eat the crop the farmer is growing, or because they spread
   disease among animals.
2. Fungicides kill fungi, which can lead to the decay of plants. Some fungi can cause illness in animals, such as ringworm in sheep.
3. Herbicides kill weeds, which might compete with the crop for resources such as light, water, and soil minerals

Question 5

How do pesticides work and reduce energy loss?

Answer 5

• The use of pesticides reduces damage to the crop or herd. The pests are stopped from competing with the crop or herd for resources. There are no weeds competing with the crop for sunlight energy, so the crop has the maximum rate of photosynthesis. More plant material is available to be passed to the next link in the food chain.
• At every link in the food chain less energy is lost to pests. This increases the yield for the farmer, and also increases profits.

Question 6

What are the disadvantages of pesticides?

Answer 6

they are artificial chemicals that can enter and build up or accumulate in the food chain. Some pesticides can directly affect human health.

Question 7

Give some examples of harmful pesticides

Answer 7

• Dioxins were washed into lakes. Here they were absorbed in small amounts by phytoplankton. The phytoplankton were eaten by zooplankton. Dioxins do not break down in their bodies, so as they eat a large number of phytoplankton, the concentration of the poison builds up in their body. This effect continues, causing toxic levels which poison animals further up the food chain such as water birds.

Question 8

Describe what battery farming is. Advantages and disadvantages? ( look in book for good notes)

Answer 8

• Battery farming is a technique in which large numbers of animals are reared indoors.
• The advantage to the farmer is that the animals cannot move around as much and are kept warmer, which stops them wasting energy.
• The disadvantage is that it is less humane, the animals cannot roam freely, and their behaviour changes as a result.

Question 9

What is fish farming? Advantages and disadvantages?

Answer 9

Fish is a healthy food option. Many fish such as salmon and trout have become popular in recent years. However, we cannot keep harvesting the wild fish population because they cannot sustain increased levels of fishing.
To meet the increased demand in a sustainable way, fish farms have been developed. Fish are bred and reared in large cages in rivers or the sea. Fish farming techniques are on the increase in many places.

Question 10

Advantages of glasshouses?

Answer 10

• Farmers can manipulate the environment and grow tender crops all year round.
• Diseases can be treated and controlled inside the glasshouse more easily than in fields.
• Pesticides and fertilisers are contained inside, so they do not escape into the natural environment.
• Glasshouses can be placed all around the UK, so we do not have to import so many crops from abroad.

Question 11

How do hydroponics work? Advantages and disadvantages?

Answer 11

Inside glasshouses, plants are grown without soil. They are suspended with their roots exposed, and sprayed with or bathed in a solution containing the correct concentration of minerals dissolved in the water. The glasshouse may have several rows of the plant stacked above one another. This means that several sets of plants can be grown in the same space. Any mineral solution that is not absorbed by the plant is collected and recycled, reducing waste.

Question 12

What is the aim of organic farming?

Answer 12

they try to produce smaller amounts of healthy, good quality food. Their approach does not make great use of artificial chemicals.

Question 13

How do organic farmers promote plant growth ? ( disadvantages in brackets )

Answer 13

• animal manure and compost adds the minerals and improves fibre content of the soil, so that it retains water better. The mineral release is slow, but it is maintained over a longer period of time as the wastes are slowly decayed. (It can sometimes be difficult in practice to obtain and spread enough manure).
• Weeding removes competition from other plants. (This is labour intensive.)
• vary seed planting times, planting in batches. They harvest a small number of plants regularly, and do not have to preserve them.

Question 14

How does biological control work? Advtnages and disadvantages?

Answer 14

They introduce a natural predator for the pest, which will kill and eat the pest.
Pros:
• no need for artificial chemicals
• no chemicals to escape into the environment and damage or kill other animals.
Cons:
• The predator may not eat the pest, but other useful species.
• The predator may increase in number and become out of
control.
• The predator may not stay in the area where it is needed.
• Adding organisms to or removing them from any food
web may have an impact on that web. It will change the numbers of other organisms in the web.