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1. Describe how crop yield is measured.
Crop yield is a measurement of the amount of crop that’s harvested per unit area of land, this is often expressed in tonnes per hectare (can also be measured in kilograms per hectare). It is a measurement often used for cereal, grain or legume.

2. Outline the basic resources that crops need to grow.
Crops need a variety of resources in order to grow. Solar radiation is needed as the energy from the sun provides light to plants. It also determines temperature regimes which are most favourable for their growth.
Crops also need carbon dioxide, which they get from the atmosphere. Plants use carbon dioxide for photosynthesis (where the plant converts energy into a carbohydrate molecule), which helps them grow.
Soil water, which is contained in the pore spaces between soil particles is also crucial for the plant. Mineral nutrients can be found dissolved in the soil water that improves their growth.
Oxygen is needed for plants to respire, they don’t only take in carbon dioxide for photosynthesis.
Lastly they need nitrogen. Nitrogen is used by plants to make amino acids, proteins and DNA.

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3. Explain how new technologies have raised crop yields.
Technology plays a big part when it comes to crop yields as it has raised it in many ways. By using machines, the speed and efficiency of cultivating large areas of land has increased. Crops are now harvested more quickly.
Plant breeding provides new high-yielding varieties of plants which grow vigorously. They are also more resistant to diseases and can adapt to a wider range of conditions.
Agrochemicals protect plants, improving growth rates. Herbicides, insecticides, fungicides, pesticides, growth hormones and fertilisers are some examples.
Irrigation has now become more sophisticated. Piezometers are used to measure soil moisture by using soil probes. This way irrigation water is applied to plants if needed.

4. Demonstrate why the world is vulnerable to food shortages.
The world is vulnerable to food shortages due to a few things. Most suitable land is already under cultivation. This means that the challenge in the future would be to expand food production without taking up a significant amount of land.
Poverty, lack of investment in agriculture, natural disasters, rising food prices as well as conflict can lead to food shortages as well.

5. Study Figure 4.3 then answer the following questions:
a. What crop had the greatest increase in yield?
Corn has had the greatest increase in yield
b. What was the yield in 1980 for:
i. Corn: 3.2 tonnes per hectare
ii. Rice: 2.8 tonnes per hectare
iii. Wheat: 1.8 tonnes per hectare

6. Outline the constraints that the biophysical environment places on crop production.
There are multiple constraints that the environment places on crop production. Crops have to rely on many things, in the different environments.
In the Aerial environment, stalks are extended and leaves are up in the atmosphere. Crops then take in oxygen and carbon dioxide, as well as trap solar energy. Temperature and precipitation are crucial as it decides if a crop can be grown in that region.
In the soil environment, roots of plants help anchor them to the soil. Roots enable plants to absorb water, mineral nutrients and oxygen. The productivity of crops depend on the condition of soils. Soils can have differing natural variables such as nutrient levels, water-holding capabilities and structures. Fertile soils are able to give crops what they need, while infertile soils give limitation on development and growth.
Topography, refers to the shape of the land surface. This can reduce land use, and can be related to the type of soil. Flat valley bottoms or plains have the most arable land for unrestricted agricultural use due to their deep, fertile soils. These areas are usually used to produce high-yielding crops. Ridge tops and steep slopes have thin, stony soils and are an erosion hazard if the land becomes disturbed, making them unsuitable for cultivation. However, people have been able to make steep sloping land crop supporting instead, this is done by terracing.

7. Assess the importance of technology in raising crop yields.

Technology has played a big role in raising crop yields. New breeding techniques have come out, and this has led to genetic engineering. Due to this high-yielding crops have been created. There has been an expansion of land due to irrigation. Agrochemicals (such as fertilizers, liming, acidifying agents, soil conditions, pesticides and etc.) have been important in increasing the yield of crops.