There are hundreds of these in any ecosystem.

They may occur between plants, animals, soil, and humans.

When water leaches or runs off from an agroecosystem, bringing fertilizers with it. This is expensive for the farmer and it can be harmful to the natural ecosystems. It may cause eutrophication in local ponds and streams.

It can cause health issues if the water is used as a water source for humans.

A decrease in soil organic manic matter and erosion are symptoms of this. It can result in dust storms and poor soil quality for growing crops.

This is found commonly in agroecosystems. One way to protect from this is cover crops.

The phenomenon of increasing global temperatures due to human activities. It has been known for a decade now, but it is only becoming a public concern recently, due to a general apathy towards the subject.

We are seeing more weather extremes: hurricanes, cold snaps, heat waves. Increased risk of management in agriculture.

A species that invades an area it does not normally live in. They may dominate an ecosystem, choking out native species. They can cause a change in pests, making pest control difficult for farmers.

For weeds simply pulling them from the ground does little good since the forest seed bank already has their seeds.

Each species in an ecosystem performs a number functions, such as producer (plants), population control (predator), nitrogen fixation, the list goes on and on. 

This is what those functions are called.

It is difficult to put a price on this.

The death of an entire species. Species have died out since the begining of life: it is one of the pillars of evolution. 

It is not the number of species lost that is concerning, it is the ecologcial services lost.

The planting of a single crop on a plot of land year after year with little to no rotation. Common crops for this are corn and wheat.

Overall this reduces yields.

A crop that was domesticated in the Balsas River Valley in Mexico up to 8000 years ago from its ancestor teosinte. It is used mainly for animal feed. It has high water, light, temperature, and growing season needs. Not efficient to grow on marginal lands. The optimum temperature to grow it at is 24 to 30C. It can grow at higher temperatures but then its water needs are increased. High temperatures can reduce pollen viability. Cold soil temperatures delay early season growth. Low night temperatures can damage it. If there is a drought during the flowering stage, the whole crop may be lost.

50% of the carbon in this plant goes to the grain portion.

They are breeding it to be short season, drought resistant, and light efficient among other things.

A mode of thought about ecology in which the ripple effect is taken into consideration. Focuses on the large number of interactions between elements in an ecosystem.

Works best for complex problems, recurring problems where past attempts made it worse, and issues where a solution is not obvious.

A form of ecolocial management used to make food for humans. It is rooted in maximizing production, economic return, and production efficiency. It is part of the larger ecosystem.

It was invented/discovered by ancient people to create a permanent source of food. They wanted a secure food source in a time of climate change and population growth. It has less work, more production, and a broader diet. It originated in multiple areas of the world around the same time period. Some species were domesticated in multiple centers. These areas do not necessarily co-incide with the world's most fertile lands.

When a plant is domesticated it shows traits more useful to humans such as:

-Larger fruits or edible parts

-No seed dispersal

-Seeds have a dormancy period

-Main stem is tillered

-Size of plant is increased

-Reduced in toxic compounds.

Animals are grazed on the land; sometimes this is the only type of agriculture this land can handle.

For plant systems, unwanted vegetation is controlled, fallow periods are used, but never cover crops. Less fertilizers are used because the plants are already growing slowly and there would be no point. Less pesticides for economic reasons.

A companion crop triplet planted by the Native Americans. It is maize, beans, and squash. The beans and maize provide stalks for the squash to grow on. The squash acts as a ground cover, reducing weeds. The beans fix nitrogen in the soil. The three crops together complete a human's protein needs. When intercropped, these three produce higher yields than they would planted separately.

There is a little-known 4th sister: the Rocky Mountain bee plant. It attracts pollinators to the squash and bean flowers.

The fourth agricultural revolution (1940-late 1970s). Lead mainly by Norman Borlaug, a plant breeder. Plants now

-respond better to fertilizer

-have more stress tolerance

-insensitive to photoperiod

-reduced in size so that there is less lodging and more growth in grains rather than in height

-shorter growing season

-pesticide resistance.

-higher yields.

It also caused:

-decrease in biodiversity

-shorter crop rotation

-increase in pests an weeds

-less ecological resistance to stresses

-widescape monoculture

-deteriorating soil structure and fertility

This revolution was not prominent in poorer countries, only those with high-input systems.

Norman Borlaug

Agricultural practices within or on the fringe of a city or metropolis. It is an interaction between agricultural, natural, and urban ecosystems. A diversity of food and non-food products are raised or grown, procesed, and distributed. It makes use of unused human and material resources in the area. It is experiencing a resurgence not since Victory Gardens of WWII, however it is not just about gardens! 

It creates food security, reduces hunger, increases urban outputs. It is complementary to rural agriculture. 

On an urban planet, cities need to adopt systems to assure their own sustainability in the long-term. Urban outputs should be crucial outputs.

Urban areas mostly export machinery, money, and wastes. They import food and materials. Toronto imports 6000 tonnes of food daily and none out. It feeds over 10 million people.

Developing countries have little infastructure for this. They have to spend 40% to 60% of their income on food.

Urban agriculture is a way to increase urban outputs.

More than half the world lives in an urban area. Nearly all population growth is in urban areas. City population growing 2 to 3 times faster than the country; the equivalent of 5 new cities the size of Beijing every year. The fastest growing cities low-income cities in Asia and Africa. The number of urban-dwellers in Saharan Africa is projected to rise by 45%. The growth is accompanied by poverty, unemployment, and lack of food security. The populations are generally young.

It is driven by high birth rates and rural hunger, poverty, and insecurity, not economic opportunity.

This is a nightmare for politicans. Hunger is historically proven to be very bad for politics.

-Less transportation (less pollution)

-Lessens atmospheric pollutioin. Fixes carbon from air.

-Rooftop agriculture decreases temperatures inside the building in the summer; less need for air conditioning (electricity, pollution).

-Raises environmental awareness

-Food is fresher. Less risk of perishability

-Short marketing channels

-Reuse city wastes and wastewater

-Conserves urban soils

-Protects environmentally fragile lands

-Makes use of contaminated lands (be careful of heavy metals and other toxins. Keep pH high for safety).

-Saves money

-Huge market in the city for livestock products, horticultural products, and ornamental plants/flowers.

-Creates jobs, improves urban livelihood, generates income. Especially good for impoverished families.

-Improves quality of life

-Creates food security

-Improves nutrition

-Improves the urban environment

-Imroves the microclimate

-Improves biodiversity. Gives a habitat for urban wildlife. Brings in pollinators.

-Contaminated soil and water

-Growing near roadsides, food can absorb toxins from cars. Leafy greens especially effected, tubers not as much.

-Land is expensive. Interferes with more productive use of urban lands

-Little time between productio and consumption: pesticide residues.

-Poor management by inexprienced and unknowledgable agriculturalists: misuse of agricultural chemicals.

-Sketchy, unsafe, inefficient improvisations.

-Not simple to co-ordinate. Alliances between growers, community, and regulations.

-Diversion from investments in rural agriculture

An agricultural method used mainly in urban agriculture. There is a soil or hydroponic system in a greenhouse or in the open air (hydroponics never in open air) on a building's rooftop. Water and heat come from the building.

The world's biggest soil rooftop green house is in New York City. It grows over 40,000 lbs of organic produce a year.

In Montreal there is a 31000 square foot greenhouse producing over 40 crops year-round.

In Asia rice, eggplant, and soybeans are produced on rooftops, although rice requires some innovative techniques.

The ability of a city to supply itself with its own food needs.

La Havana is 50%.

Mexico City is over 50%

Beijing is fully self-sustainable.

Soil having a non-agricultural, manmade surface layer more than 50 cm thick that has been produced by mixing, filling, or by contamination of land surface in urban and suburban areas. Undistributed soil effected by the urban environment. "Anthropogenic" soil. It is:

-little organic matter (although there is soil life)

-highly compacter

-highly eroded

-highly saline

-sometimes infertile

-contaminated

-biological changes associated with chemicals

-increased potentil of invasion of exotic or invasive species

A highly underused resource. From urban areas it comes in the form of kitchen wastes and wastewater. 

It may be composted. Vermiculture (worms) can degrade it. 

The fluctuating state of the atmosphere in a small region over a short-term period. Temperature, wind speed, moisture, precipitation, clouds, fog. It is caused by rapidly developing and decaying air movements, which are caused by pressure differences in the atmosphere.

It effects crop growth.

The average weather over a large region over 30 years.

The major ones are tropical, desert, warm temperate, cool temperate, and polar. Climate is determined by latitude (angular intensity of the sun), air currents, latitude, elevation, precipitation, clouds, and seasons.

It determines the kinds of wildlife an area has. It determines what crops can be grown in an area.

It is possible to farm in a dessert if you use irrigation. Desserts have better sunlight (few clouds), less weeds and other pests, and less ecological diversity. Pollinators are shipped in. It uses up huge amounts of water. It is an unsustainable food system.

Asparagus needs a vernalization period. Because there is no winter, a period of water stress acts as vernalization.

Light from the sun ultimately powers all life and everything on Earth.

Light availability depends on daylength and cloud cover. A plant's ability to recieve light is a factor in light usage.

There are different changable factors farmers can implement.

Fertilizer type, amount, and application

Planting/harvesting date

Tillage and cover crops

Pest and disease management

Crop rotations

The ecosystem has factors that effect crop growth

The nitrogen and carbon cycles

Soil water holding capacity

Soil fertility

Early plant emergence

Canopy is filled on the longest days

Better use of stored water at pollination

Earlier canopy closure

Earlier silking at a lower temperature

Warmer nighttime temperatures during grain filling

Earlier maturity, reducing in drying costs

More time in fall for fall operations

A form of soil fertilization where nitrogen fixing plants are grown alongside or in rotation with crops. Nitrogen fixing trees may be intercropped with corn. Red clover may be intercropped with winter wheat. Hairy vetch.

You get the same yield for 40 to 70 kg less fertilizer. This is a sustainable nitrogen input. Crops can still be recovering the nitrogen even years later.

Losses depend on management practices, environment, residue quality, C/N ratio, and time of death of legumes. Killing in the fall casuses less nitrogen in the spring and can lead to leaching. 

The proportion of all N inputs that are removed in harvest crop biomass or stays in the cropping system.

N inputs are 46% N fertilizer 20% biological N fixation, 12% atmospheric deposition, 11% animal manures, 7% crop residues. A good value for this comes with efficient fertilizer, a high PE_N value, synchronization between crop N demand and N supply, sound management factors, and biophysical ddeterminants being taken into account.

The percentage of nitrogen fertilizer recovered in above-ground plant biomass in a growing season. There are two methods of measuring it:

1. Using "labelled" nitrogen isotopes to keep track of nitrogen. Very expensive; a lot of paperwork.

2. Count the difference in the amount of N harvested and the amount of N aplied and compare it to a plot which did not recieve fertilizer.

The value for this for preplant fertilizer is 47.8%. Actual farm measure of this is generally lower. The average values for nitrogen fertilizer have gone up sine 1980 due to improved management practices (reduced use in the fall, split applications, and using alternatives to N fertilizer).

The process by which plants harness sunlight, CO2, and water to make biomass and energy. Water is slplit and the hydrogen is used to fixate carbon into sugars.

CO2 + H2O --> C6H12O6 + O2

It takes place in the thylakoid of a chloroplast. C3 plants will lose some to photorespiration, when C4 plants will not.

How much radiation is available. Depends on clouds and weather. Depends on the wavelength of light; plants can only take light between 400 nm and 700 nm. Depends on latitude and season.

Changes in PAR help plants detect when there is competition around them and grow accordingly.

Leaves that are angled upwards shade the leaves below them less and the whole plant is better off. 

They have bred corn to have erect leaves.

Carbon sinks bring carbon out of the air and carbon sources release it back into the air.

In agricultural systems carbon losses are harvests and grazing and inputs are manures and crop residues.

It depends on the soil type, location and use.

A marsh has 70%, forest has 21%, sod 7% and corn fields 4%. 90% of its mass is water. It acts as an aggregate; promotes soil structure. Forms a bank of nutrients; holds nutrients. Decreases erosion, runoff, soil compaction, crusting. Better water infiltration and capacity. Reducess stresses; temperature, wind, heavy rainfall, drought. Increases long term soil productivity; it turns into soil eventually. Consists of the living (active), the dead (active organic matter), and the very dead (stable humus). 

In Canada it has been improving lately.

SOM which stays in the soil for 15 to 1000 years. It turns into active or passive SOM.

The ratio of carbon atoms to nitrogen atoms. The lower this ratio is (more nitrogen), the faster things decompose. Microbes need 8 carbons for every 1 nitrogen. Residues with ratios bigger than 24:1 cause them to have to scavenge for nitrogen.

Saw dust has a very high ratio. Sewage has a very low ratio.

As decomposition progresses the ratio decreases (carbon is released into the atmosphere) and soluble nitrogen goes up. When the ratio is high to begin with there is a soluble nitrate depression period.

Temperature increases to the south

Moisture increases to the east

Soil carbon increases north and east

An element essential for plants. It has many forms including atmospheric nitrogen, nitrite, nitrate, ammonium, and nitrous oxide. It is in chlorophyll, hormones, enymes, proteins, DNA, roots; everywhere in the plant. Too little or too much can harm plants. It can be harmful to the environment.

You can detect the nitrogen levels in a plant based on how green the leaves are using reflectants or by testing for chlorophyll levels.

Right source

Right rate

Right time

Right place

Precipitation brings water to the soil, where it evaporates or is transpirated through plants, or runs off into surface water where it evaporates and becomes precipitation again. Soil is a reservoir for water.

This cycle effects plant residues, soil organic mater, and the mineralizationo rate of ammonia to nitrates.

Occurs when the available soil moisture is less than the crop's water requirements. The plant deals with this by:

1. Escaping drought period: crop duration, increase time to flowering.

2. Recovering from drought: new productive tillers.

3. Avoid low water status: extract more water from soil, constrict stomata.

4. Tolerate drought: plant mechanisms, increase WUE, osmotic adjustment, cell protection.

The underground part of a plant which takes up water and nutrients. The less roots, the less water uptake, but roots are a carbon sink, lessening photosynthesis.

Restricted root growth may be due to physical reasons (soil compaction), chemicals (acidity, boron, aluminium), biological (diseases, insects, nematodes), or poor rotations.

To increase root growth, improve soil structure (tillage), soil organic matter, root channels, and microbial activity.

Strives to meet environmental as well as productive goals in agriculture. Applies ecological concepts to design and manage sustainable agroecosystems. Ensure adequate plant nutrition, water supply, and protection from diseases and pests.

Use crop rotations, cover crops, intercropping, legumes, green manure, reduced tillage, mulches, residue return, manure, composts, biosolids, natural enemies, wildlife refuges, soil and water conservation, resiliance to stresses, reduced erosion, maintained fertility, and decreased chemical inputs.

1. Enhance diversity

2. Promote biological interactions and synergisms

3. Sustain soil organic matter levels and soil biotic activity

4. Maintain soil cover. 30% of land covered 100% of the time.

An organism whose genes have been altered. GMO crops have traits beneficial to agriculture. They have nothing to do with organic agriculture and may be used in organic systems.

Bt corn, Bt cotton, Golden Rice, Roundup Ready.

It can mean something different depending on your background. Industrial agriculture may be sustainable, and local foods are not necessarily sustainable. Some deffinitions:

- A rejection of the industrial approach to food production from the 20th century.

-Embracing organic, free-range, low-input, holistic, biodynami systems.

-Local foods

-Animal welfare

-Using natural resources, knowledge, and science to produce safe, nutritious products while being economically, environmentally, and socially responsible.

-Doing what you have always done, pretending it is a new idea.

-Efficient production of high quality products while improving the environment, social, and economic conditions for farmers, employees, and communities, while safeguarding health and welfare of farmed species.

1. Environment: protect the natural resources

2. Social: social relations between farmers and rural communities, ensuring and creating employment and animal welfare.

3. Economic: ensure economic viability of farming systems at a local level.

1. Food Safety

2. Animal Health and Welfare

3. Environment

4. Economics and Food Affordability

5. Health and Safety

There are no certification programs for holistically grown foods. They are usually voluntary, with a logo on the product. Farmer Unions may be against certification. They can be customer developed (Tesco's Nurture), farm developed (GlobalGAP), attribute specific (Certified Humane), country specific (UK's Red Tractor), or commodity specific (Certified Greenhouse).

Most are a questionnaire with yes/no questions, or rating extent of various actions.

Problems with them are that they are expensive, few auditors, constanly changing requests, market access barriers, and some farms can't get them due to not enough man power to deal with the bureaucracy.

-Grain Farmers of Ontario

-Pulse Canada

-Grains Roundtable

-Dairy Farmers of Canada

-Canola Council of Canada

-Local Food Plus

-Environmental Farm Plan

This livestock can effectively weed an area by eating all the weeds.

They can graze alongside cattle. The cattle protect them and provide shade. They emit less greenhouse gases than steers. They can be produced in NZ and shipped to UK emiting less GHG than if it were local UK.

Their gestation period is 5 months. Energy requirements of a pregnant ewe can be matched to the growth curve of forages. Flushing (3 weeks) and pregnancy periods cannot be changed, but lactation and maintenance can be controlled to time feed requirements.

Biomass fibre is used to make plywood, concrete fibres, and paper.

If there is excess fibre in a cattle's diet, it produces greenhouse gasses. There are feed additives to try and minimize this methane roduction, and maximize instead VHA production.

A management system for grazing with multiple paddocks which are grazed and then allowed to recover. Growth has an S-shaped curve. Depending on the size of the herd, about 20 paddocks will be needed, an acre each. Movable electric (solar powered) fences can be used. Water must be provided for the grazers.

Despite what you might think, intensive management takes up less time for the farmer than a tie-stall barn. There is high production per acre, low biodiversity and resiliance.

A management system for grazing where the livestock are allowed to graze on the same very large field for the entire season. More tractor traffic, so denser soil. There is low production per acre, and high biodiversity and resiliance.

Its ok to let cattle out a few days before the forage is fully ready. They won't eat it, they will be playing.

1. If there is no rule against it, it is allowed.

2. If nobody follows the rule, it is not a rule, and cannot be enforced.

This is why a Social Licnce to Operate becomes important.

A ranking of importance of nutrients based on how long an animal can survive without them.

1. Oxygen

2. Water

3. Carbohydrates

4. Protein

5. Vitamins

6. Minerals

7. Fat

The 4th most populated country. Almost entirely cities. No welfare or retirement plans. Meat consumption popular with richer people. 

Mixed aquaculture and rice or duck production requires expertise, land, and resources. Not everyone can do it. 

Catfish are produced in a hole in the ground. 

Only a half of the animal is turned into meat. The other half, the offal, is rendered into other products, including animal feeds. Need to be careful of pathogens. 

In the olden days, all of the animal was used.

Must be fine tuned, using testing, calibration, and planning. The 4 Rs must be considered. Testing must be done regularily, after aggitation to be accurate. If the farmer doesn't know the nutrient availability, they will over-apply it.

Manure affects not only crops, but soil biota as well. It can be applied by surface banding, shallow inection, or deep injection. Deep injection can cause N loss through leaching. Manure needs breakdown time before N release, but fall application can cause leaching over the winter. The more spread out, the better manure breakdown.

Dependent on

1. Resistance to stress

2. Resiliance to stress

3. Strength of links

Sucession that occurs if disturbance removes biomass, but not soil or organic matter; tillage, fire, hurricane. 

The seedbank is still present. Tillage only moves the seeds around. There is still some carbon and N cycling. Increased run-off (vegetation gone). High surface temperatures.