EnvironmentalFactors - Environmental factors that can...

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Environmental factors that can impact food resources as part of the worldwide ecosystem: water resources, pollution and scarcity, climate change
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The impact of food production on the environment. Biodiversity, bioinvasion, pollution and habitat destruction.
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Is it the earth or humanity that produces food? If earth, some limits already approaching If humanity, experience is ground for optimism: When asked for more food, world's farmers and agricultural scientists have come through Both human and natural resources are essential to agriculture But balance between the two is shifting: every year world gains 76 million people, while farmland loses about 25 billion metric tons of topsoil
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Bad news for food security Land scarcity + water scarcity = Food scarcity
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Land scarcity Since 1980s: arable land constant, but total agricultural land has continued to grow d/t more land as pasture, as more meat and dairy products added to average diet Can land under cultivation continue to grow? Some estimates: there is about 30% more land available worldwide for cultivation But can only increase land by 30% if none of currently available land is lost to agriculture
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Land Scarcity Reasons for concern: As urban areas expand, farmland paved over: United States: 3.2 million acres per year California: 100,000 acres per year, one of highest conversion rates in the US But: urban areas worldwide take only 3% of land mass, so this may not be a big factor
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Land Scarcity Land currently under production may be degraded through soil loss or contamination so that it can no longer be used for crops - may be biggest factor Global warming may result in expansion of ocean areas and flooding of coastal areas FAO says that new technologies will help increase production Pessimists: the 30% more land available includes much marginal land that will not produce good yields
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Land degradation Soil can disappear through erosion Soil can become chemically unsuitable for agriculture: Nutrient depletion (ex: same crop year after year) Salinization (ex: irrigation with water that contains low levels of salt, or when groundwater is depleted by irrigation and sea water seeps in, called salt water inversion ). Acidification of soil d/t too much use of certain fertilizers, or drainage problems
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Land degradation Since 1972, loss of 200 million hectares of trees, 480 million hectares of topsoil; increase of 120 million hectares of desert
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Water Scarcity demand --beyond sustainable yield of aquifers Farming, human activities siphon off water from underground aquifers-hold most of world’s fresh water Amount of land under irrigation has grown Irrigation especially important in growing rice: provides 80% of food-Bangladesh, 70%-China, and over 50%-India and Indonesia Yields on irrigated land 30-200% higher than non- irrigated land Irrigation contributes to land degradation through erosion, waterlogging, salinization, and acidification
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This note was uploaded on 09/08/2010 for the course NUFS 139 at San Jose State University .

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EnvironmentalFactors - Environmental factors that can...

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