Section 2 of Topic 3 Agriculture

1. UNIT 3 –
AGRICULTURE
AND THE
ENVIRONMENT
Section 3: Increasing Agricultural
Yield

2. Recap from last lesson
Activity:
Place the letter for each of the following farms/ production types into the table below:

3. LEARNING OBJECTIVES
 Describe techniques to increase agricultural
yields

4. CONTENTS
Section 3 - Increasing agricultural yields
 3.1 What is agricultural yield?
 3.2 Why is it important to increase yield?
 3.3 Intensive Farming Techniques – 4 methods
 3.4 Other Modern Methods – 4 methods

5. Agricultural Yield?

6. 3.1 What is agricultural yield?
In agriculture, the yield is a measurement of the amount of a
crop grown, per unit area of land.
Unit: kg/hactare
Agricultural yields have increased steadily throughout the course of
human history both by bringing new land under cultivation and also
by applying greater levels of science and technology to existing
farms so that more can be produced from the same area of land

7. INCREASING AGRICULTURAL YIELD
•Commercial farmers seek to improve profits by increasing yield
•Arable farmers- increase amount of grain or fruit produced
-e.g. normal yield (8 tonnes per sq metre) goes up to 8.5 tonnes per 1000 sq
metres (6.25% increase)
•Livestock farmers e.g. increase milk production over the year
•Agricultural yields have increased over the course of history
•Increased developments in science and technology
•Intensive vs. extensive farming
•Intensive farming techniques- used to increase yield (rotation, fertilizers, irrigation,
controlling pests and diseases)

8. Since 1961, the global production of cereal crops have more than doubled (2.3%
per year)

9. Graph questions:
1. What type of crop holds the highest yield from 1961- 2020?
2. Approximately how much of rice has been produced in 1961?
3. Approximately how much of rice has been produced in 2020?
4. Calculate the approximate difference in production between 1961 and 2020.

10. Graph questions: Ans.
1. What type of crop holds the highest yield from 1961- 2020?
Potaoes/ bannanas
2. Approximately how much of rice has been produced in 1961?
2,4 t
3. Approximately how much of rice has been produced in 2020?
4,9 t
4. Calculate the approximate difference in production between 1961 and 2020.
2,5 t more produced in 2020 in comparison with 1961

11. 3.2 Why is it important to
increase agricultural
yield?
1. To tackle world hunger
2. To increase profitability
3. To encourage sustainable farming
https://www.youtube.com/watch?v=iloAQmro
RK0

12. 01 ROTATION
02 FERTILISERS
03 IRRIGATION
04 CONTROLLING PESTS AND FERTILISERS
Used to increase agricultural yields….
3.3 Intensive Farming Techniques

13. 3.3.1 ROTATION
• This practice involves regularly changing the
crop that grows in a particular place
•not a modern practice (there is evidence of
this being done in the Middle East 8000 years
ago.)
•E.g. year one potatoes are planted, the next
year peas are planted and the following year
maize
•Growing the same type of crop every year in
that area can deplete the soil
•Different crops draw on different nutrients in
the soil, so with rotation some nutrients are
returned back to the soil

14. 3.3.1 ROTATION

16. 3.3.2 FERTILISERS

17. FERTILISERS
 natural or synthetic substance added to soils to
supply one or more nutrients removed by crops
When plants are removed the nutrient cycle is
broken
Natural ecosystems- plants die and decompose and
nutrients are returned to the soil
Heavy ploughing
Intervention by farmer
Synthetic- chemical based fertilizers
Organic fertilizers
Overuse of fertilizers Eutrophication

18. 3.3.2 FERTILISERS (Cntd)
Fertilisers replace lost nutrients (N, P and K) and maintain the
productivity of the land for optimum plant growth
Problem with overuse of fertilisers:
Eutrophication – fertilisers are washed off the land by rain water
into lakes and rivers, this cause an increase in nitrate and
phosphate in water causing rapid algae growth.
Such algal blooms are dangerous for aquatic life as they cover the
water surface and prevent light and oxygen to reach other water
plants, fish and insects.

19. 3.3.3 Irrigation
01
02
03
04
Surface Irrigation
Sprinkler Irrigation
Localised irrigation
Sub or seepage
irrigation
05
Inground Irrigation

20. IRRIGATION
 artificial supply of water (why?)
NB to increase yield
Subsistence and commercial
Older forms- dug canals
New- mechanised
Advantage- control of water
Main types: surface, localised, sprinkler, sub/seepage and in-
ground

21. Surface Irrigation
Most common
Controlled by mud dikes (barrier used to
regulate or hold back water)
Known as flood irrigation
Terraced rice fields use this technique (flows
from one field to another)
Water loss occurs through evaporation

22. Localised irrigation
More precise, targeted approach
Drip irrigation- small drops of water delivered
through roots through narrow rubber pipes located
above or just below surface)
Highly efficient (evaporation is minimised)

23. Sprinkler irrigation
Imitates rainfall
Water piped through hose and distributed over
fields as a fine spray from above
they rotate slowly- avoids water logging of areas
Some are on wheels for easy movement to other
fields

24. Sub or seepage irrigation

25. Sub or seepage irrigation
This system provides plant roots with water from under
the soil
It is effective where the water table is close to the surface
Combination of pumping stations, canals and weirs used
to raise water level
Less wasteful compared to surface and sprinkler irrigation
systems (why?)
Needs careful management (why?)
Also needs to be careful of salination

26. In-ground irrigation

27. In-ground irrigation
Entire irrigation system (pipes, sprinklers,
drippers and valves) is buried underground
Mainly to service individual properties/ plots
Not suitable for farms (financially and spatially)

28. Activity:
Copy and complete the following table:
Types of irrigation
Type How it works? Advantage/Disadvantage
Surface irrigation
Localized irrigation
Sprinkler irrigation
Sub or seepage irrigation
In- ground irrigation

29. 3.3.4 CONTROLLING PESTS AND
DISEASES
 Fungicides
 Herbicides – used against weeds (for cereal crops)
 Pesticides
 Insecticides
Problems
1. Bioaccumulation – Gradual build up of toxins in the food chain
affecting top predators such as animals and birds
2. Overuse leads to insects and weeds becoming resistant to
toxins over time

30. CONTROLLING PESTS AND DISEASES
If pests or diseases attack agricultural crops the yield
will decrease
Intensive commercial farmers- spray crops with a range
of synthetic chemicals (pesticides)
Pesticides kill or control insects
There are three main types of pesticides namely;
 Fungicides (chemicals used to kill fungi)
 Herbicides (chemicals used to kill weeds)
 Insecticides (chemicals used to kill insects)
The used of pesticides have proven to increase
agricultural yields

31. Use of pesticides have however had serious
ecological impacts (*how? And why?)
Bioaccumulation: increase in the concentration
of a chemical in a biological organism over time
(more compared to the chemical’s concentration
in the environment)
Systemic pesticides: pesticides that are absorbed
or transported gradually through the food chain
(e.g. from plants to insects to reptiles etc.)
DDT: type of insecticide that was banned
CONTROLLING PESTS AND DISEASES

32. Activity:
Write a paragraph to explain how pesticides can
harm people, their food supply and their
socioeconomic circumstance.

33. 01
MECHANISATION
SELECTIVE BREEDING
GENETIC
MODIFICATION
CONTROLLED GROWING
ENVIRONMENT
3.4 Other Modern Methods

34. Other methods of
increasing agricultural yields
Mechanisation (use of machinery/ technology e.g. remote sensing
and GIS use)
Selective breeding (breeding from certain individual plants/ animals)
Genetic modification or engineering (scientific process- genetic
structure is changed)
Controlling growing environments (remove plants or animals from
natural environment and cultivate or look after them in artificial
conditions)

35. Group Activity – Comparative Analysis
Problem Statement - You have been
approached by a farmer who wants to
increase his agricultural yield
You are to advise him on the best way in
which he can adopt to increase the yield…..
Constraint – He has budget to apply only
one method to his crops

36. Group Activity – Comparative Analysis
Group A:
Rotation OR
Selective Breeding
Group D:
Irrigation – surface, localized,
sprinkler, sub-seepage or
inground OR Mechanisation
Group B:
Fertilizers OR
Controlling pests and Diseases
Group C:
Genetic Modification
OR Controlled
Environment

37. Case Study - Identify 7 Methods adopted by
Israel to increase agricultural yield
 https://www.youtube.com/watch?v=v1DT4yvxpMw
 For each method, write 3-4 lines in your copybook of why
you think it was a good option to adopt for Israel to
increase its agricultural yield
 Note: You may use your device to conduct additional research