Ways to increase crop yield Cambridge IGCSE Environmental Management revision
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In plain words
The world has more mouths every year and no more land. So the extra food has to come from getting more out of each field. This unit covers the ways to do it, apart from fertilisers and pest control, which have a unit of their own.
10 things to know
- Yield is the amount of crop produced from each unit of land.
- Mixed cropping is growing two or more crops in the same field at the same time. Intercropping does this in alternate rows. The crops use different nutrients and root depths, pests spread less easily, and if one crop fails the other may survive.
- Crop rotation is growing a different crop in a field each year, in a planned order. Pests and diseases of one crop die out, and each crop takes different nutrients. Peas and beans add nitrates to the soil.
- Improved irrigation. Trickle, or drip, irrigation delivers water slowly through pipes straight to the roots, so little is lost by evaporation. Rainwater harvesting collects and stores rain for dry periods. Automated watering systems use sensors to water only when the soil is dry.
- Mechanisation is the use of machines such as tractors and harvesters. Work is done faster and at the right time, and more land can be farmed.
- Genetically modified organisms have had their genetic material changed, by removing, changing or inserting individual genes, to give favourable characteristics, such as resistance to pests or drought.
- Controlled environments. In a greenhouse, temperature, light and water are controlled, so crops grow all year. In hydroponics, plants grow without soil, with their roots in water containing nutrients. In aeroponics, the roots hang in the air and are sprayed with a nutrient mist.
- Managed grazing, or livestock rotation, moves animals from field to field so the grass can recover.
- Urban farming grows food in towns and cities, on roofs, in gardens and indoors. Agroforestry grows trees among crops or livestock: the trees give shade and shelter, their roots hold the soil, and they supply fruit, timber and firewood.
- Limitations. Machines, greenhouses, hydroponics and modified seed are expensive, and need fuel, energy or skill. Machines compact the soil and replace workers.
Worked example
A farmer in a dry region floods the fields to irrigate them. Explain why changing to drip irrigation would raise the yield for the same amount of water.
- With flooding, much of the water evaporates or runs off before the crop can use it.
- Drip irrigation delivers water slowly, directly to the roots.
- Very little is lost, so the same water can supply a larger area of crop.
Tips and tricks
- Intercropping and crop rotation are often confused. Intercropping is different crops at the same time. Rotation is different crops in different years.
- For genetic modification, name the characteristic and say how it raises yield: "resistant to insects, so less of the crop is eaten".
It lands in your notebook with its questions as flashcards.
Ways to increase crop yield: 6 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What is yield?
More crop from the same land means a higher yield.
In which method do roots hang in the air and get sprayed with nutrient mist?
In hydroponics the roots sit in water.
Why does drip irrigation save water?
Little is lost to evaporation or run-off.
What is agroforestry?
The trees protect the soil and give extra products.
Which is a benefit of crop rotation?
A pest that eats wheat starves in a year of beans.
Why does managed grazing protect the land?Stretch
Moving the animals on prevents overgrazing.
Quiz
6 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 7 marks. Write your answers on paper, then check them.
Ways to increase crop yield
Cambridge IGCSE Environmental Management 0680 · 7 marks · papermunch.org
Name ______________________________ Date ______________
Describe what is meant by crop rotation.[2]
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A different crop is grown in the same field each year, in a planned order.
Explain how growing crops in a greenhouse increases yield.[3]
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Temperature, light and water can be kept at the best levels for growth. Crops can be grown all year round. The crop is protected from pests and from bad weather.
Describe how a crop can be genetically modified, and give one favourable characteristic.[2]
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Its genetic material is changed by removing, changing or inserting individual genes. One characteristic: resistance to a pest (or to drought, disease or herbicide; or a higher yield).
Answers: Ways to increase crop yield
- 1. A different crop is grown in the same field each year, in a planned order.
- 2. Temperature, light and water can be kept at the best levels for growth. Crops can be grown all year round. The crop is protected from pests and from bad weather.
- 3. Its genetic material is changed by removing, changing or inserting individual genes. One characteristic: resistance to a pest (or to drought, disease or herbicide; or a higher yield).