12. Intensifying food production - Technology

The Green Revolution: Waging A War Against Hunger http://www.youtube.com/watch?v=HucSCNQ01X4

http://www.indiastudychannel.com/resources/16174-Impact-Green-Revolution.aspx

http://en.wikipedia.org/wiki/Green_Revolution

Effects of use of irrigation and chemicals on water and soil quality (Salinisation, waterlogging, eutrophication)

Waterlogging and salinisation in the Murray-Darling Basin in Victoria, Australia

Use of chemical fertilizer resulting in eutrophication.

Is high-tech farm the solution to food production?

Watch the video and find out how vertical farming is carried out in San Francisco.

Aerofarms (Aeroponics) reducing 90% water need, save on space and allow for temperature control etc.

Rooftop farming with vertical farm in Singapore:

Aquaponics in Singapore

Fish farm in Singapore

What are the effects of continuing intensification of food production?

Waterlogging

• Extensive irrigation can cause the ground to be waterlogged

• Waterlogging occurs when too much water seeps into the soil and causes the soil to be oversaturated with water

• This causes the roots to be deprived of air and nutrients that the crops need, eventually causing them to die

• This could lead a reduction in food production

Salinization

• Salinization occurs when water added to the soil during irrigation evaporates, causing salt to be left behind on the soil after evaporation

• Excessive irrigation combined with inadequate drainage system, could also raise the level of the groundwater and bring salt particles closer to the surface

• The groundwater may reach the upper soil layers, bringing up dissolved salts from the ground (capillary effect, or the upward movement of saline (salty) moisture through the fine spaces between the soil particles)

• Saline soils could reduce the ability of crops to absorb water through their roots

• The salt also inhibits (discourages) the ability of crops to transpire causing them to die, thus reducing food production

• Effects of salinisation and waterlogging in Murray-Darling Basin in Victoria, Australia

  • Murray-Darling Basin became salt concentrated due to human activities such as irrigation development and land clearing

  • Characterised by low terrain, low rainfall and high evaporation rate, the low-lying rocks beneath the Murray-Darling River Basin have high salt content

  • This salt dissolves in the groundwater and finds its way to the surface

  • In addition, widespread tree clearance has also allowed more rainwater to seep into the ground and caused the groundwater levels to rise, bringing dissolved salts with it

  • Thus even non-irrigated land is affected by salinisation

Eutrophication

• Overuse of chemical fertilizers and pesticides causes chemicals to become concentrated in the soil and water, contaminating the groundwater

• Chemicals will seep into the soil and find their way to streams and rivers

• They become nutrients for the algae to grow, leading to eutrophication

• When the algae cover the water surface, they block sunlight from reaching the aquatic plants, causing them to die

• As a result, fishes feeding on aquatic plants will also die

• The decomposition of the aquatic plants and animals depletes the oxygen in the water

• Pollution from sewers in villages, towns and cities can contribute to the increase of nutrients in rivers and lakes, causing eutrophication

• Effects of eutrophication in the Potomac River, Washington D.C, the USA

  • Pesticides from farmland are found to be contaminating the groundwater, making it unsuitable for drinking

  • About 50% of the population in the USA obtains water from groundwater

· Some species of plants and animal life which depended on pre-eutrophic conditions may be adversely affected and cannot survive the eutrophic conditions, more competitive species may invade and compete with the remaining species.

· As freshwater algae blooms, dies or eaten, toxins are released which can kill livestock and humans consuming the poisoned meat and the contaminated shellfish can cause paralysis in humans and drinking water contaminated with nitrogen can be toxic to people and fatal to very young children.

· Eutrophication is reducing the supply and quality of water for domestic use as well as for farming purposes and fish harvesting.

What are the possible measures for dealing with problems as a results of salinization, water logging and eutrophication?

• One method of dealing with the salt problem is to flush the salt out of the soil using more water

• However, this only adds pressure on limited water supplies and also means that saline water is drained to another location, affecting other farmers

• The building of an extensive drainage system is expensive and cannot be completed rapidly

• In some affected areas, excessively saline water is being pumped into evaporation ponds

• Some saline water is also being pumped into rivers so that it mixes with freshwater and becomes less saline

• Another method is to plant new salt-tolerant crops and deep-rooted salt-tolerant trees such as eucalyptus to help lower water table and saline level

· Possible measures for dealing with eutrophication

• One method is to implement control measures aimed at preventing nutrients from reaching water bodies because it is less effective to treat the water bodies once the problem has occurred

• Another method is to raise awareness of eutrophication through public campaigns, school environmental education programmes and targeted outreach within the communities to help prevent and control environmental degradation

• This continuous effort to monitor the pollution level in the environment requires the cooperation between the government, organisations and the community