AgriculturePart 1

Human Nutritional Requirements Healthy diet

Male = 2500 calories Female = 2000 calories

Balance of nutrition Protein = 30% of all calories Carbohydrates = 60% of all calories Fat = 10% of all calories

Should also include micronutrients (i.e. vitamins, minerals, etc.)

Plants and nutrition About 100 species of 350,000 known plant

species are grown for human food

Wheat and rice supply over half of the human intake

Nearly all cultures have some version of the “rice and beans” meal Rice and beans provide all 8 essential amino

acids and together are a “complete” protein source

Meat and nutrition 8 species of animals supply over 90% of the

worlds needs

20% of the world’s richest countries consume 80% of the world’s meat production

Consequences of increased meat consumption More greenhouse gasses Need more resources (growing space, water,

etc.)

MeatConsequences

It takes 16 lbs. of grain to produce 1 lb. of meat

90% of the grain produce in the US goes to animal feed

Consuming grain directly would provide a 20x increase in the available calories and 8x increase in the amount of protein

Benefit

Concentrated sources of proteins

Malnutrition 11 million children die each year from starvation 850 million people (~13% of the world

population are malnourished) Chronic undernourishment leads to vitamin and

mineral deficiencies Stunted growth Weakness Increased susceptibility to illness

Diseases caused by protein deficiency Marasmus Kwashiorkor Victims are less than 80% of their normal weight

for their height

Types of Agriculture Subsistence:

agriculture is carried out for survival, few to no crops available for sale

Types of Agriculture Agroforestry:

system of land use in which harvestable trees or shrubs are grown among or around crops or on pasture land to preserve or enhance the productivity of the land.

Types of Agriculture Monoculture:

growing only a single crop species

Types of Agriculture High-input agriculture: includes use of mechanized equipment, chemical fertilizers, and pesticides

Types of Agriculture Industrial agriculture

or corporate farming:Characterized by

Mechanization Monocultures use of synthetic

inputs: Chemical fertilizers Pesticides Emphasis on

maximizing productivity and profits

Types of Agriculture Plantation: a

commercial tropical agriculture systems devoted to exports Governments and

companies exploit the tropical rainforest for economic gain

Agricultural practices remove natural habitat, disturb the land, and use synthetics

Types of Agriculture Tillage: surface is

plowed, breaking up the soil, followed by smoothing of soil and planting Exposes land to

wind and water erosion

Types of Agriculture Low-till, no-till, or

conservation-till agriculture: soil is disturbed little or not at all to reduce soil erosion Lower labor costs Reduces need for

fertilizer Saves energy

Types of Agriculture Polyculture: uses

different crops in the same place to imitate natural diversity Includes:

Crop rotation Multicropping Intercropping Alley cropping

Requires more manual labor

Avoids some plant diseases

Types of Agriculture Alley Cropping: plant

crops in strips with rows of trees or shrubs on each side. Increases biodiversity Reduces surface runoff

and erosion Reduces wind erosion Improves use of nutrients Modifies microclimate for

improved crop production Improves wildlife habitat

Types of Agriculture Crop rotation:

planting a field with different crops form year to year to reduce nutrient depletion

Example: rotation corn or cotton (depletes nitrogen) with soybeans (adds nitrogen to soil)

Types of Agriculture Intercropping: to grow more than one crop in

the same field, in alternating rows or sections

Types of Agriculture Interplanting:

growing two different crops in an area at the same time Plants should have

similar nutrient and moisture requirements

Types of Agriculture Low input: depends

on hand tools and natural fertilizers, lacks large-scale irrigation

Types of Agriculture Organic farming: a

form of agriculture that relies on crop rotation, green manure, compost, biological pest control, and mechanical cultivation to maintain soil productivity and control pests Limits the use of

synthetic additives

Green RevolutionFirst started in1950

Involved: Planting monoculture High applications of

inorganic fertilizers and pesticides

Widespread use of artificial irrigation systems

Before: Increased crop production was due to increased acreage farmed

After: crop acreage increased 25% but crop yield increased 200%

Second started in 1970

Continues to today Involves growing

genetically engineered crops

Before: farmers grew locally adapted strains

Now: farmers grow crops engineered to produce more yield E.g. 50% of wheat in

US comes from 9 genotypes

Criticisms of the Green Revolution

GR is unsustainable Increasing food production ≠ increasing food

security Not all famines are caused by decreases in food

supply GR agriculture produces monocultures while

traditional includes poly culture There has been a drop in productivity of

intensely farmed land in the past 30 years Desertification Land degradation

Criticisms of the Green Revolution

Necessary to purchase inputs rural credit institutions, causing farmers to go into debt and sometimes lose land

GR agriculture increases pesticide use Salinization, water logging, and lowering

water levels in certain areas increased due to increased irrigation

GR reduce agricultural biodiversity – relied on only a few high yield varieties of each crop susceptibility of food supply to pathogens and permanent loss of many valuable genetic traits

Genetic Engineering and Crop Production EVERYTHING YOU EAT IS A GMO

Selective breeding which lead to domesticated species is a form of genetic engineering

Genetic engineering = moving genes from one species to another or designing gene sequences with desirable characteristics.

Transgenic = an organism with the genes of another species in it (usually one not closely related)

Genetic engineering and crop production Transgenic genes

Pest, drought, mold, and saline resistance Higher protein yields Higher vitamin content

~75% of all crops grown derive from modern genetically engineered or transgenic crop species

Genetic engineering and crop production

In 2006, 10 million farmers in 22 countries planted 252 million acres of transgenic crops

Most transgenic crops are herbicide and pesticide resistant Soybeans Corn Cotton Canola alfalfa

Others: Sweet potatoes

resistant to a virus Rice with increased

iron and vitamins Plants able to

withstand weather extremes

Golden Rice – has genes from daffodil and a bacterium Supplies vitamin A to

populations suffering from deficiency

Assignment What type(s) of agriculture are we using

in the ECA garden?

Irrigation ¾ of the fresh water on earth is used for

agriculture World wide 40% of crops come from 16% of

irrigated farmland Inefficiencies:

Seepage Leakage evaporation

Up to 70% of water is lost Drip irrigation – reduces water usage and waste

but more expensive to install

Sustainable agriculture Main goals:

Environmental health Economic profitability Social and economic equity

Four parts: Efficient use of inputs Selection of site, species, and variety Soil management Species diversity

Efficient use of inputs Maximize reliance on natural, renewable farm

inputs Goal: develop efficient biological systems that

do not require high levels of inputs Use least toxic and least energy intensive

options Use preventative strategies before chemical

inputs E.g. Integrated pest management

Selection of site, species, and variety Understanding location to select appropriate

plants for the site Soil type and depth Previous crop history Climate topography

Pest resistant crops (when possible)

Soil management Proper soil water and

nutrient management help prevent crop stress

Soil is viewed as a fragile living media that must be protected to increase aggregate stability soil tilth diversity of

microbial life

Methods to protect soil: Cover crops Compost Manures Reducing tillage Maintaining soil

cover with plants Mulch

Species diversity Farmers grow a lot of crops to

Limit economic risk Increase health of soil and environment

Optimum diversity reached by integrating crops and livestock in the same farm Grow crops on level ground and pasture or forage

crops on steeper slopes Reduces soil erosion Manure is a fertilizer Feeding and production is more flexible in animal

production systems Animals can eat “failed” crops

Types of Pesticides Biological – living organisms to control pests

Bt, ladybugs, parasitic wasps, etc.

Carbmates – affect the nervous system of pests Can be used in lower doses that chlorinated

hydrocarbons (100 grams vs. 2000 grams) More water stable can contaminate water

sources

Types of Pesticides Chlorinated hydrocarbons and other persistent

organic pollutants (POPs) Example: DDT Synthetic organic compounds that do not break

down easily in the environment Capable of bioaccumulation Affect the nervous system Low water solubility, high lipid solubility, semi-

volatility, high molecular mass Volatize in hot regions, accumulate in cold regions

Fumigates Used to sterilize the soil and prevent pest

infestation Grain storage

Types of Pesticides Inorganic

Broad based toxin Accumulate in the environment Examples: arsenic, copper, lead, mercury

Organic and natural - natural toxins derived from plants Examples: tobacco or chrysanthemum

Organophosphates Extremely toxic but degrade quickly Used to control mosquitoes

Pros and Cons of pesticide usePros Kill unwanted pests that

carry disease More food means food is

less expensive Newer pesticides are

safer and more specific Reduces labor costs Agriculture is more

profitable

Cons Accumulate in food chain Pests develop resistance and

create a pesticide treadmill $5 - $10 in environmental

damage done for every $1 of pesticide used

Pesticide runoff effects aquatic systems through biomagnifications

Inefficiency only 5% of pesticide reaches the pest

Threatens endangered species, pollinators, and human health

Integrated Pest Management Does not eradicate pests but controls their numbers Methods:

Polyculture Intercropping Planting pest-repellent crops Using mulch to control weeds Using natural methods to control pests (Bt) Natural insect predators Rotating crops to interrupt insect life cycles Releasing sterilized insects Developing genetically modified crops that are insect

resistant Constructing mechanical controls (insect barriers,

traps, etc.)

Relevant Laws Federal Insecticide, Fungicide and Rodenticide

Control Act (FIFRA)(1947) Regulate manufacture and use of pesticides Pesticides must be registered and approved Label must contain direction for use and disposal

Federal Environmental Pesticide Control Act (1972) Requires registration of all pesticides in U.S.

commerce Food Quality and Protection Act (FQPA) (1996)

Emphasizes protection of infants and children in reference to pesticide residue in food