food-resources1.ppt

Food Resources

Food in the World

• 15 plants and 8 animals supply 90% of our food

• 66% of people eat mainly rice, wheat, and corn (grains)

• The top third of the economic chain eats primarily meat.

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World Food Problems

• Reasons for problems:– Population growth– Degradation and loss

of cropland– Little growth in

irrigation– Decline in global

fertilizer

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Undernutrition

• Undernutrition-Consuming insufficient food to meet one’s minimum daily energy requirement for a long enough time to cause harmful effects

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Malnutrition

• Malnutrition-Faulty nutrition. Caused by a diet that does not supply a persons with enough protein, essential fats, vitamins, minerals, and other nutrients.

Overnutrition

• Overnutrition-an excessive intake of food, especially fats

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Impacts of OvergrazingLand Degradation• Overgrazing removes the vegetal cover over the

soil • Roots cannot go deep into the soil• Adequate soil moisture is not available• Thus overgrazing leads to multiple actions

resulting in loss of soil structure, hydraulic conductivity and soil fertility

Loss of useful species• Overgrazing adversely affects the composition

of plant population and their regeneration capacity

• The original grassland consists of good quality grasses with high nutritive value

• Replacement by secondary species

Types of Food Production

• Industrialized agriculture• Traditional agriculture

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Industrialized Agriculture

• Industrialized agriculture-Use large amounts of fossil fuel energy, water, commercial fertilizers and pesticides to produce huge quantities of single crops

• www.alaskajournal.com/.../ foc_20030804021.

www.alaskajournal.com/.../ foc_20030804021.

Traditional Agriculture

• Traditional agriculture-practiced by 2.7 people on earth– Traditonal subsistence agriculture-produce

enough food to stay alive– Traditional Intensive agriculture-farmers increase

inputs of human and draft labor, fertilizer and water to get a higher yield per area of cultivated land to produce enough food for families, and their income

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Green Revolution

• Involves 3 steps• 1. Developing and planting monocultures

of selectively bred or genetically engingeered high yeid varieties of key crops

• 2. Lavishing fertilizer, pesticides, and water on crops to produce high yeilds

• 3. Often increasing the intensity and frequency of cropping

• Traditional Agriculture and its Impacts• It usually involves a small plot, simple tools,

naturally available water, organic fertilizers and a mix of crops

• Low production• Deforestation• Soil Erosion• Depletion of Nutrients

• Modern Agriculture and its Impacts• It makes use of hybrid seeds of selected single crop

variety, high-tech equipments and lots of energy subsidies in the form of fertilizers, pesticides and irrigation water

• The Impacts• Fertilizer related problems• Pesticide related problems• Water logging• Salinity problems

FERTILIZER RELATED PROBLEMSMicronutrient Imbalance• Most of the chemical fertilizers used in modern

agriculture have nitrogen, phosphorus and potassium which are essential macronutrients

• Farmers use these indiscriminately to boost up crop growth.

• Nitrate Pollution• contaminate the ground water• Eutrophication

Pesticide related problemsCreating resistance in pests and producing new pests• Some individuals of the pest species usually survive even after pesticide

spray• The survivors give rise to highly resistant generations

Death of non-target organisms• Many insecticides are broad spectrum poisons

• Many of the pesticides are not biodegradable and keep on accumulating in the food chain, this process is called as biomagnification

Water logging• Over irrigation of croplands• Preventing excessive irrigation, sub-surface drainage

technology and bio-drainage with trees like Eucalyptus are some of the remedial measures to prevent water logging.

Salinity Problems• Saline soils are characterized by the accumulation of soluble

salts like sodium chloride, sodium sulphate, calcium chloride, magnesium chloride

• The most common method for getting rid of salts is to flush them out by applying more good quality water to such soils.

In India per capita land availability for agriculture land has declined from 0.48 ha in 1951 to 0.14 ha in 2001

More than 40% of the farmers in India were found to be reporting poor yields not due to sub-standard seeds, irrigation problems etc. but due to degrading land quality

It is estimated that 5 million tonnes of topsoil is eroded every year and 20 % of such land is so damaged that it is categorized as wasteland

Land Resources

Status of our land 23% of usable land

degraded

Causes Deforestation Agricultural mismanagement Urbanization Soil erosion Pollution Disturbed natural cycles

Land Resources

Other problems Water logging Soil salinity Desertification In Egypt – 90%farms affected by

waterlogging In Pakistan – 66% irrigated land salinized In India – 12-25%

Land Resources