3.4 Increasing agricultural yields

Question 1

Techniques to improve agricultural yields.

Answer 1

• crop rotation
• fertilisers
• improved irrigation
• insect control (insecticide and biological
  control), weed control (herbicide), fungi control (fungicide)
• mechanisation
• selective breeding of animals and plants
• genetically modified organisms GMOs
• controlled environments: greenhouses and hydroponics

Question 2

crop rotation

Answer 2

growing different types of plants in different plots each year.

Question 3

Advantages of crop rotation

Answer 3

• Diseases in the soil affecting the plant are left behind;
• Pests need to find a new site ؞ their population is reduced;
• The soil in the new plot is likely to have the essential nutrients;
• Crops ready to harvest at different times ؞ less potential waste, less labour and machinery needed.

Question 4

Fetilisers

Answer 4

• Adds nutrients into the soil
• Contain minerals such as nitrogen, potassium and phosphorus essential for plant growth

Question 5

Types of fertilizers

Answer 5

Organic
Inorganic

Question 6

What is used to control weed, insect and fungi

weed- A plant that is growing in an inappropriate place which then compete with the main crop

Answer 6

• Insect control (insecticide and biological control),
• weed control (herbicide),
• fungi control (fungicide)

Question 7

What is Irrigation

Answer 7

supplying water to the cropss

Question 8

Common water application methods:

4

Answer 8

• Overhead Sprinklers
• Clay Pot Irrigation System
• Trickle Drip System
• Flood irrigation

Question 9

Overhead Sprinklers ad and dis

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Answer 9

Advantages-
* Easy to set up
* Can cover a large area from one sprinkler
* No need to attach pipes to each plant

Disadvantages
* Large droplets may cap the soil
* Small droplets may be blown away by wind
* Water lands on leaves and soil, which evaporates quickly

Question 10

Clay Pot Irrigation System ad and dis

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Answer 10

• Porous clay pots that are buried in the soil next to the root of the plant
• Each pot is filled with water, which gradually seeps into the soil around the roots

Advantages
* Simple technology;
* Easy to check the amount of water;
* High efficiency.

Disadvantages
* Only suitable for permanent plants;
* Large labour cost

Question 11

how does Trickle Drip System work?

Answer 11

1. main feeder pipe brings water, controlled by valve;
2. (smaller) pipes carry water to plants;
3. water drips from holes close to plants;

Question 12

ad and dis of Trickle drip system

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Answer 12

benefits
* prevents, overirrigation / waterlogging
* water provided close to roots or plants
* less water used / water, is conserved / not wasted
* constant / slow / steady flow of water
* reduces run-off / soil erosion
* reduces amount of weed growth;
only crop plant receives water;

Disadvantages-
* Expensive to install; complex to maintain.
* Grit can block tubes; (needs a filter installed)

Question 13

Flood irrigation

Answer 13

water delivered to the field by a soil channel or pipe to flow freely over the ground throughout the crop
Advantages-
* Inexpensive;
* Can cover large areas quickly.

Disadvantages-
* Damages soil structure.
* Inefficient use of water;

Question 14

Mechanisation

advantages

Answer 14

• Larger area can be cultivated;
• Reduces labour cost;
• Ploughing can be done even when soil is heavy
• Additional attachments can be done to apply fertilisers and pesticides.

Question 15

Selective breeding Process

Answer 15

1. Identify which characteristics of the species are important
2. Select parents that exhibit these characters.
3. Breed the parents and raise the offspring from these parents
4. Select the best offspring that show desired characteristics
5. Repeat the process.

Drawbacks: slow process; less success rate.

Question 16

genetically modified organisms

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Answer 16

the DNA of one organism is inserted into another.
Advantages-
* higher yields from lower inputs;
* growth of plant in inhospitable areas
* less use of insecticides which impact the environment;
* crops can be made resistant to, drought / pests / insect damage / salinity / look more appealing /
* have longer shelf-life;

Disadvantges-
* risk of GM characteristics (such as herbicide resistance) getting into other plants;
* reduction in crop genetic diversity;
* unproven technology may have long-term (unknown) environmental effects/heath impacts;
* impacts on non-target species;
* increase in herbicide use (on resistant crops) may have toxic effect in local ecosystem;

Question 17

Examples of controlled environments

Answer 17

controlled environments:
1. greenhouses and
1. hydroponics

Question 18

Green houses

Used to manage the environment for plant growth.

Answer 18

They are structure with walls and roof made chiefly of transparent material, such as glass or poly carbonate
material .

Question 19

hydroponics

Answer 19

Its a method of growing plants in a water based, nutrient rich solution.
Hydroponics does not use soil, instead the root system is supported using an inert medium such
as, rockwool, clay pellets or peat.

Question 20

ad an dis of hydroponics

Answer 20

Advantages:
* Soil-free farming: No need for soil.
* Adaptable to various environments: Can be used in diverse locations.
* High crop yields: Produces large quantities of plants.
* Efficient harvesting: Easy to collect the produce.
* Precise nutrient delivery: Provides plants with exact nutrients.
* Water conservation: Uses water efficiently.

Disadvantages:
* High initial investment: Requires a significant upfront cost.
* Suitable for smaller-scale production: Best for limited growing areas.
* Technical expertise required: Needs specialized knowledge to operate.
* Vulnerable to diseases: Prone to disease outbreaks.
* Sensitive to environmental factors: Requires careful maintenance of conditions.**