Agriculture and Food Resources

Transcription

1 Visualizing Environmental Science Agriculture and Food Resources Chapter Chapter 14 7 [chapter opener image] Copyright

2 Maintaining Grain Stocks for Food Security Food security having access at all times to adequate amounts and kinds of food needed for healthy, active lives World grain stocks provide a measure of food security Grain stocks are remains of grains from previous harvests which provide a cushion against poor harvests and rising costs Have been decreasing since 1980s 90s highs Stockpile in 2010 would have fed the world for only 72 days UN says it should not be below 70 days supply

3 World Food Problems At least 1 billion people in the world lack food for healthy, productive lives 2009 World Summit on Food Security Most live in rural areas of poorest developing countries 182 million children under age 5 suffer from undernutrition World Health Organization (WHO) A type of malnutrition in which there is underconsumption of calories or nutrients that leaves the body weakened and susceptible to disease Even if receiving enough calories, undernutrition happens if not enough essential nutrients: protein, vitamins, minerals 2 billion people worldwide suffer from micronutrient deficiencies

4 World Food Problems Millions of children suffer from kwashiorkor, caused by severe protein deficiency. Note the characteristic swollen belly, which results from fluid retention. Photographed in Haiti. Globally, millions of adult men and women are hungry. This homeless man is suffering from severe malnutrition and starvation. Photographed in New Delhi, India. Marasmus is progressive emaciation caused by a diet low in both total calories and protein. Symptoms include a pronounced slowing of growth and extreme wasting of muscles. Photographed in Somalia.

5 World Food Problems Overnutrition A type of malnutrition in which there is overconsumption of calories that leaves the body susceptible to disease Usually diets high in saturated fats, sugar, and salt Results in high blood pressure, obesity, and increased rates of diabetes, heart disease, etc. Mostly a problem in highly developed nations and in urban areas of developing nations As income increases, people can afford more meats and sugars, so paradoxically, their diet can become less healthy even though they are better off financially OR poor people in developed countries suffer more from unhealthy diets than the wealthy Slow Food Movement

6 The Principal Types of Agriculture

7 The Principal Types of Agriculture Subsistence agriculture Utilized by most farmers in most developing countries Traditional agricultural methods that depend on labor and a large amount of land Just enough food to feed farmer and family Cultivation methods vary depending on area Shifting cultivation Slash-and-burn agriculture Nomadic herding Intercropping Polyculture

8 Challenges of Agriculture Victim of urbanization, suburban sprawl Parking lots, housing developments, shopping malls Farm Bill 1996 Farmland Protection Program Voluntary sale of conservation easements to prevent farmland from being converted to non-agricultural uses (30 yrs forever) Farmers retain full rights to use their property for farming

9 Challenges of Agriculture Global decline in domesticated plant and animal varieties Replacement of many local varieties with just a few kinds of modern varieties bred for uniformity and maximum production Loss of genetic diversity of nutritional value, size, color, flavor, resistance to disease, adaptability to climates and soil types Germplasm conservation Plant or animal material that may be used in breeding Seeds, plants, plant tissues of traditional crop varieties Sperm and eggs of traditional livestock breeds

10 Challenges of Agriculture Increasing crop yields Scientific advances since 1940s have increased food production dramatically in highly developed countries Fertilizers, pesticides, higher yield plant varieties Average U.S. wheat yields,

11 Challenges of Agriculture Green revolution 1960s high yield varieties of rice and wheat developed Traditional rice plant on left taller, lower grain yield Hybrid in center (1960s) higher yield, disease resistant Rice plant on right (1990s) high yield, disease resistant; shorter and stronger stalk to support heavier grain production without collapsing

12 The Foods We Eat Of the thousands of edible plants and animals in the world, only 14 plant species make up most of the world s food supply

13 Challenges of Agriculture Green revolution Criticisms Has made developing countries dependent on imported technologies at the expense of traditional agriculture High energy costs Environmental problems from excessive pesticide and fertilizer use

14 Challenges of Agriculture Post-green revolution era World s demand for rice, wheat, corn will continue to increase into the future Increasing amounts of grain needed for humans, livestock, and biofuel production Cannot be met without increasing amount of farmland Modern agricultural methods must be introduced to developing countries to increase their crop yields

15 Confined Animal Feeding Operation (CAFO)

16 Environmental InSight Impacts of industrial agriculture Increasing antibiotic resistance

17 Solutions to Agricultural Problems Moving to sustainable agriculture Agricultural methods that maintain soil productivity and a healthy ecological balance while having minimal long-term impacts Combines modern with traditional techniques Diversification of crops and livestock Breeding of resistant varieties, to reduce use of chemicals Water and energy conservation Crop rotation, conservation tillage to preserve soil quality Animal manure and leguminous crops to decrease the need for chemical fertilizers Not a single program; adapted to local needs/conditions

18 Solutions to Agricultural Problems Second green revolution Away from high yield, towards long term-sustainability Options and approaches Organic agriculture Integrated pest management Reduction in intensive agricultural techniques Increasing focus on long-term sustainability of the soil Organic farming - In 2008, 2 million hectares farmed organically in the U.S. Rapid growth in organic agriculture in U.S. today

19 Solutions??? to Agricultural Problems Genetic engineering Manipulation of genes to produce a particular effect E.g., taking a specific gene from one species and placing it into an unrelated species Goals to develop desirable characteristics in crops and livestock (= as traditional breeding) Has the potential to produce More nutritious food plants that contain all essential amino acids or that would be rich in vitamins Resistant to viral diseases, drought, heat, herbicides, salinity, insect pests, cold, etc.

20 Solutions to Agricultural Problems Here, a plasmid, a small circular molecule of DNA, introduces desirable genes from another organism into a plant cell

21 Most GMOs are Engineered for Pesticide Production or Pesticide Tolerance Bacillus thuringiensis (Bt), a bacterium, makes toxins lethal to butterfly and beetle pests. Biotechnologists have created plants with genes for natural insecticides. So far this is effective, but experts worry that Bt plants churn out toxin constantly, and may create the perfect conditions for creating Bt resistance in pests.

22 BT toxin, the Start of Biotechnology Issues The toxin is produced year round creating: Perfect conditions for resistance development Threats to nontarget species Also present in pollen, potentially threatening nontarget insects such as Monarch butterflies

23 Solutions to Agricultural Problems First GM crops were approved in the U.S. in early 1990s Since 2000, GM production in developing countries has increased faster than in developed countries GM production More productive farm animals, fast growing hogs and fish Utilized in the development and production of vaccines against disease organisms Plants can be modified with genes that protect against insect pests and provide resistance to herbicides

24 Solutions to Agricultural Problems Concerns about GM foods In 1999 EU placed moratorium (since lifted) on approvals for all GM foods EU refused to buy U.S. corn since 80+ percent of U.S. corn is GM Patenting of seeds/food Farmers are scared of bioengineering corporations Spreading of GM genes to wild relatives of crop plants may harm natural ecosystems Worry that consumers may develop allergies to new GM foods (even though routinely tested) Scientific consensus is that health risks associated with consuming GM varieties is the same as those of consuming traditionally bred varieties There are still unanswered questions about effects on environment

25 Controlling Agricultural Pests Pest Any organism that interferes in some way with human welfare or activity Some pests compete with us for food, others spread disease Pesticide The agent used to reduce pest populations Can be grouped by target organisms Insecticides Herbicides Rodenticides Fungicides

26 Controlling Agricultural Pests Benefits of pesticides Effectively control organisms that spread disease Malaria, typhus Monocultures (single species grown in large areas) amplify effect of pests Monoculture crops generate very simple ecosystems, pests thrive, lots of food

27 Controlling Agricultural Pests Problems with pesticides Ideal pesticides Narrow-spectrum kills only the intended pest Readily breaks down into safe materials Does not move around in the environment Most pesticides Broad-spectrum kills a variety of organisms, including beneficial ones Do not degrade readily, or break down into other dangerous materials Move around in the environment enter water, air

28 Pesticides and Health Risks Children may suffer neurologically from pesticides and show increased levels of anger, aggression, autism, and attention deficit disorder.

29 Controlling Agricultural Pests Problems with pesticides Genetic resistance In the 50 years of wide pesticide use, at least 520 species of insects and mites and at least 84 weed species have evolved genetic resistance to certain pesticides

30 Controlling Agricultural Pests Problems with pesticides Bioaccumulation Biological magnification Natural enemies (beneficial organisms) also die off from pesticide exposure The resulting fewer natural controls for pests leads to increased pest populations and need for even larger pesticide use for their control Movement of herbicides into water supplies increases human exposure and slightly elevates cancer risk

31 Controlling Agricultural Pests Alternatives to pesticides Biological controls Uses naturally occurring disease organisms, parasites, or predators to control pests Pheromones/hormones Natural substance produced by animals to stimulate a response in other members of the species Reproductive controls Genetic controls Quarantine Irradiation

32 Controlling Agricultural Pests Alternatives to pesticides Integrated pest management (IPM) Combination of pest control methods that if used in the right order and at the proper times, keeps the pest population small enough to prevent substantial economic loss