AQA GCSE Geography (8035) — Challenges in the human environment
Irrigation is the artificial application of water to land to assist in the growing of crops when natural rainfall is insufficient. By providing a reliable water supply, irrigation can increase crop yields and allow farmers to harvest multiple times a year, improving food security in arid regions or during dry seasons.
There are several strategies to implement irrigation, ranging from colossal infrastructure to small-scale interventions:
Every time you eat a perfectly round, out-of-season tomato in winter, there is a high chance it was grown without a single grain of soil. Modern agriculture uses high-tech environments to maximise crop production.
Both hydroponics and aeroponics recycle water in a closed-loop system, using up to 95% less water than traditional soil farming. They offer sterile conditions that do NOT require heavy pesticide use and allow for precise nutrient control. However, they have high initial setup costs, require immense electrical energy, and are highly vulnerable to system failures where a power cut can kill crops in hours.
Examples include Thanet Earth in the UK and Almeria in Spain, which uses these technologies to produce over 2.7 million tonnes of fruit and vegetables annually.
In the 1960s, a new type of wheat and rice prevented millions from starving, increasing yields by 40% almost overnight. This was the start of the Green Revolution, heavily reliant on biotechnology.
GM can significantly improve food security. For example, Golden Rice is genetically modified to contain high levels of Vitamin A, providing 50% of a child's daily requirement in LICs (Low-Income Countries). In commercial usage, GM maize in the Philippines increased yields by 24%. In Europe, specific DNA removal in pigs can make them resistant to diseases like Porcine Reproductive and Respiratory Syndrome (PRRS), potentially saving £1.5 billion annually.
However, disadvantages include the high cost of infertile "terminator seeds" (which force farmers to buy new seeds annually). There is also the risk of creating "super-weeds" through cross-breeding, alongside unknown long-term biodiversity impacts.
To measure the success of GM crops, geographers and agricultural scientists calculate the percentage yield increase.
Worked Example:
A farm switches from traditional rice to GM rice. Traditional rice yielded , and the GM rice yields . What is the percentage increase?
Step 1: Identify the values. Original Yield = , New Yield = .
Step 2: Substitute into the equation.
You might picture farming as green fields, but from space, this region of southeast Spain looks like a giant white "Sea of Plastic". The Almeria greenhouse scheme covers 26,000 to 31,000 hectares in the arid Campo de Dalías.
Despite receiving only 200mm of rainfall annually, the area enjoys 3,000 hours of sunshine. This allows it to produce over 50% of Europe's out-of-season fruit and vegetables, generating US$1.5 billion annually (13% of the province's GDP). This massive agribusiness creates a powerful multiplier effect, providing jobs in packing, plastic factories, and research.
Unlike Northern European greenhouses, they do NOT require artificial heating or lighting due to the natural warmth, keeping their energy footprint lower. It also uses advanced drip irrigation and hydroponics to minimise water waste, alongside the Bajo Almanzora desalination plant to reduce groundwater reliance.
However, the development has severe social and environmental costs. It relies heavily on cheap, often illegal, migrant labour from North Africa living in poor shanty town conditions. Environmentally, aquifers are being depleted, and massive amounts of plastic waste are dumped into rivers and the sea. Uniquely, the white plastic roofs reflect so much sunlight that they cause a localised cooling of 0.3°C per decade, known as the albedo effect.
Concluding Judgement: Overall, the Almeria greenhouse scheme is highly successful economically, generating vast revenue and widespread employment through the multiplier effect. However, its long-term sustainability is deeply flawed. The severe environmental degradation—such as aquifer depletion and plastic pollution—alongside the social exploitation of migrant labour, means its economic success comes at an unsustainable cost to both local ecosystems and human welfare.
Understanding water management explains why countries are willing to sign treaties over rivers even when they are politically opposed. The Indus Water Treaty (1960) between India and Pakistan helps manage the world's largest continuous irrigation system.
The Indus Basin Irrigation System (IBIS) features three major dams (including the Tarbela Dam with a reservoir capacity of 11 billion m³), 12 major link canals, 64,000 km of minor canals, and 1.6 million km of ditches. This colossal infrastructure has increased cultivable land by 40%, irrigating 14 million hectares.
Yields have surged: wheat by 36-38%, rice by 39%, and fruit by 150%. Furthermore, the reservoirs support flood control, fish farming for dietary protein, and Hydroelectric Power (HEP) for NEE (Newly Emerging Economy) development.
However, the system faces significant challenges. High evaporation in the arid climate causes salinization, which now affects 20-25% of Pakistan's irrigated land. Poor drainage also leads to waterlogging, where saturated soils prevent plant roots from receiving oxygen.
Additionally, there are high maintenance costs and ongoing social conflicts between upstream and downstream users. Dam construction also led to the forced displacement of local people.
Concluding Judgement: The IBIS has achieved remarkable economic and agricultural success by increasing cultivable land and crop yields to support a growing population and NEE development. Nevertheless, its environmental sustainability is severely compromised by widespread salinization and waterlogging, which threaten future soil fertility. High maintenance costs and geopolitical conflicts further indicate that while it successfully boosts short-term food supply, major interventions are necessary to ensure it remains a sustainable resource for future generations.
Why does a US$100 foot-pump sometimes save more lives than a multi-million-dollar dam? In many LICs, large-scale agribusiness is too expensive and complex to maintain.
Appropriate Technology involves small-scale, low-cost, and sustainable solutions suited to local skills and wealth. It frequently empowers communities with the help of an NGO (Non-Governmental Organisation) without creating dependency on expensive imports.
Examples include:
Students often confuse 'appropriate technology' with 'cheap technology'; it must also be sustainable and suited to local skills, not just low-cost.
In 9-mark 'Evaluate' questions on large-scale developments like Almeria, examiners expect a balanced conclusion that explicitly weighs economic successes (e.g., the multiplier effect) against environmental costs (e.g., aquifer depletion).
Use specific data, such as Almeria generating US$1.5 billion annually or IBIS having 1.6 million km of ditches, to move your answer into the Level 3 mark band.
When calculating percentage yield increase, remember to subtract the original yield from the new yield first, otherwise your final percentage will be incorrect.
Irrigation
The artificial application of water to land to assist in the growing of crops when natural rainfall is insufficient.
Large-scale canal networks
Massive schemes involving dams and vast networks of canals to distribute water across large areas, such as the Indus Basin Irrigation System.
Drip irrigation
Advanced systems that deliver water slowly and directly to the plant's roots to minimise water waste.
Micro-irrigation
Small-scale, low-cost irrigation solutions, such as treadle pumps or porous clay pots, often used as appropriate technology in LICs.
Hydroponics
A method of growing plants using mineral nutrient solutions in water, without soil.
Aeroponics
Growing plants in an air or mist environment without soil, where roots are sprayed with nutrients.
Vertical Farming
Stacking crops in layers to maximise the crop yield per square metre of land.
Green Revolution
A significant increase in agricultural production resulting from the introduction of high-yield varieties of grains, improved irrigation, and biotechnology.
Biotechnology
The use of biological processes or genetic modification of organisms to improve crop yields or products.
Genetic Modification (GM)
Altering the genetic material of an organism by inserting genes from another to create specific traits.
High-Yielding Varieties (HYVs)
Seeds specifically developed to be more productive than traditional varieties.
LICs (Low-Income Countries)
Countries with lower levels of economic development and lower average incomes, often relying on primary industries like farming.
Agribusiness
Large-scale commercial farming and the businesses associated with it, such as packing and research.
Multiplier effect
When an initial economic investment creates additional jobs and wealth in a region, leading to further economic growth.
Albedo effect
The extent to which a surface reflects light from the sun; highly reflective surfaces like white plastic roofs cause a localised cooling effect by reflecting solar radiation.
Indus Water Treaty (1960)
An agreement between India and Pakistan to manage transboundary water rights of the Indus river system.
NEE (Newly Emerging Economy)
Countries that have begun to experience higher rates of economic development and rapid industrialisation.
Salinization
The accumulation of salts in soil due to high evaporation in arid areas, which degrades land quality.
Waterlogging
Soil saturation with water that prevents plant roots from receiving enough oxygen.
Appropriate Technology
Small-scale, low-cost, and sustainable technology suited to local skills and wealth.
NGO (Non-Governmental Organisation)
A non-profit organisation that operates independently of any government, often providing aid or development support.
Sand dams
Low-cost concrete walls built across seasonal rivers that trap sand, allowing water to be stored safely in the sand's air spaces.
Put your knowledge into practice — try past paper questions for Geography
Irrigation
The artificial application of water to land to assist in the growing of crops when natural rainfall is insufficient.
Large-scale canal networks
Massive schemes involving dams and vast networks of canals to distribute water across large areas, such as the Indus Basin Irrigation System.
Drip irrigation
Advanced systems that deliver water slowly and directly to the plant's roots to minimise water waste.
Micro-irrigation
Small-scale, low-cost irrigation solutions, such as treadle pumps or porous clay pots, often used as appropriate technology in LICs.
Hydroponics
A method of growing plants using mineral nutrient solutions in water, without soil.
Aeroponics
Growing plants in an air or mist environment without soil, where roots are sprayed with nutrients.
Vertical Farming
Stacking crops in layers to maximise the crop yield per square metre of land.
Green Revolution
A significant increase in agricultural production resulting from the introduction of high-yield varieties of grains, improved irrigation, and biotechnology.
Biotechnology
The use of biological processes or genetic modification of organisms to improve crop yields or products.
Genetic Modification (GM)
Altering the genetic material of an organism by inserting genes from another to create specific traits.
High-Yielding Varieties (HYVs)
Seeds specifically developed to be more productive than traditional varieties.
LICs (Low-Income Countries)
Countries with lower levels of economic development and lower average incomes, often relying on primary industries like farming.
Agribusiness
Large-scale commercial farming and the businesses associated with it, such as packing and research.
Multiplier effect
When an initial economic investment creates additional jobs and wealth in a region, leading to further economic growth.
Albedo effect
The extent to which a surface reflects light from the sun; highly reflective surfaces like white plastic roofs cause a localised cooling effect by reflecting solar radiation.
Indus Water Treaty (1960)
An agreement between India and Pakistan to manage transboundary water rights of the Indus river system.
NEE (Newly Emerging Economy)
Countries that have begun to experience higher rates of economic development and rapid industrialisation.
Salinization
The accumulation of salts in soil due to high evaporation in arid areas, which degrades land quality.
Waterlogging
Soil saturation with water that prevents plant roots from receiving enough oxygen.
Appropriate Technology
Small-scale, low-cost, and sustainable technology suited to local skills and wealth.
NGO (Non-Governmental Organisation)
A non-profit organisation that operates independently of any government, often providing aid or development support.
Sand dams
Low-cost concrete walls built across seasonal rivers that trap sand, allowing water to be stored safely in the sand's air spaces.
