Скачать презентацию Feeding the world Is there enough to nourish Скачать презентацию Feeding the world Is there enough to nourish

ae828ea2eb149c3c789bd7a27f43fc38.ppt

  • Количество слайдов: 39

Feeding the world Is there enough to nourish everyone? Feeding the world Is there enough to nourish everyone?

Overview § World food production is adequate in quantity and quality (nutritional value) to Overview § World food production is adequate in quantity and quality (nutritional value) to feed the current human population. § Modern food problem is largely due to • Distribution Issues • Poverty in large part of the world

§ Some farmland is lost for food production • Suburban development (e. g. , § Some farmland is lost for food production • Suburban development (e. g. , CT where farming has been decreasing for years)

Overview § Increases in food production have been accomplished: • Increasing area in production Overview § Increases in food production have been accomplished: • Increasing area in production • Increasing production per unit area

Soils § Definition: • Rock modified by biological, chemical and physical processes such that Soils § Definition: • Rock modified by biological, chemical and physical processes such that the material will support rooted plants § How long does it take to make soils? § 1 mm per 10 - 40 yrs

Soils § To grow crops we need soils. What is soil? ~Weathered rock? • Soils § To grow crops we need soils. What is soil? ~Weathered rock? • Chemical elements, including organics, required for plant growth • Air and water pass freely through the soil • Should retain water well • Fine clays help retain moisture, chemicals • Sands and coarse particles help with drainage

Soils § Soils are damaged due to: • Removal of natural ground cover § Soils § Soils are damaged due to: • Removal of natural ground cover § Farming, Deforestation, Overgrazing • Erosion: wind and water • Acidification, excess leaching • Pollution

Soils Soils

Soils Soils

Soils § Agriculture in the 20 th century has damaged more than 109 ha Soils § Agriculture in the 20 th century has damaged more than 109 ha of land through erosion and soil loss

Soils § In US • One third of topsoil lost, 80 x 106 ha Soils § In US • One third of topsoil lost, 80 x 106 ha of land ruined or marginalized for agriculture • Rates of soil erosion are controversial but it seems that since the 1930’s rates have decreased from 17 to 13 tonnes/ha/yr

Soils • Rivers carry 4 x 109 tons/yr of sediment, 75% from agricultural lands; Soils • Rivers carry 4 x 109 tons/yr of sediment, 75% from agricultural lands; sedimentation rates in coastal waters have increased by factors of 25 over the last 150 years (e. g. LIS) § Excess sedimentation wordwide is a problem § In US $500 million/yr dredging expenses

Soils & Agriculture Advances have been made in tilling practices • Contour Plowing: plow Soils & Agriculture Advances have been made in tilling practices • Contour Plowing: plow perpendicular to the slope. Tests show reduction in erosion from 14. 4 tons/ acre to 0. 1 ton / acre • No-Till agriculture: currently ca. 100 million acres in US • Terracing

‘No Till’ Agriculture reduces nutrient losses ‘No Till’ Agriculture reduces nutrient losses

Soil Erosion Soil Erosion

Terraces § used in traditional cultures § Reduce erosion § Maintain fertility Bali rice Terraces § used in traditional cultures § Reduce erosion § Maintain fertility Bali rice paddies

Percentage of Land in Agriculture 9% Africa, 11% N. America, 11% Asia, 20% Europe, Percentage of Land in Agriculture 9% Africa, 11% N. America, 11% Asia, 20% Europe, 11% World

Land & Agriculture Land & Agriculture

Land & Agriculture Land & Agriculture

Land & Agriculture World Grain Production has leveled off Per person production declining? Land & Agriculture World Grain Production has leveled off Per person production declining?

Land & Agriculture World Grain Production has leveled due to: • in production from Land & Agriculture World Grain Production has leveled due to: • in production from former USSR? • limits fertilizer effects? • erosion, salinization, lack of irrigation water?

World Food Supply Shrinking? Year # Days in supply of grain 1987 104 1995 World Food Supply Shrinking? Year # Days in supply of grain 1987 104 1995 62 1996 49

Food Security, India § § In 1950, 51 x 106 tons food grain In Food Security, India § § In 1950, 51 x 106 tons food grain In 1995, 200 x 106 tons food grain In 1995, 30 x 106 tons food grain in surplus In 1995, 40% of population (>350 million people) were starving § People are too poor to buy the available food!

Food Security § Problem: distribution • Solution: increase local production § Problem: poverty – Food Security § Problem: distribution • Solution: increase local production § Problem: poverty – people too poor to buy available food • Solution: employment, social welfare

Food Security: Can we meet the future demands? § By 2025, we will have Food Security: Can we meet the future demands? § By 2025, we will have to triple irrigated lands • Volume of water will equal the Nile or 10 Colorado Rivers § Water diversion will have competition from providing local drinking water and for local crops § In 2025, use of runoff to increase from 54% to 70% • Destruction of rivers, fisheries and aquatic species

Genetically Modified (GM) Crops § Placement of foreign genes into crops (or other organism) Genetically Modified (GM) Crops § Placement of foreign genes into crops (or other organism) § Enhance production and growth under usually deleterious climates or conditions § Disease and insect resistance

Genetically Modified (GM) Crops § Panacea or Plague? ? ? • NAS panel (2002) Genetically Modified (GM) Crops § Panacea or Plague? ? ? • NAS panel (2002) says no strong evidence of environmental damage • Evidence for gene spreading (e. g. , GM genes in taco products) • Evidence for allergic responses in humans § Growth genes in cereal – shrimp – human allergy and immune response § Who owns the resources? ? ?

Food production depends on soil, water and energy supplies - all are stressed! Food production depends on soil, water and energy supplies - all are stressed!