TERRESTRIAL ECOSYSTEMS Agriculture TERRESTRIAL ECOSYSTEMS

What do you think of when you hear the word… agriculture???

TRADITIONAL AGRICULTURE

Traditional Agriculture Agriculture is the practice of growing and raising plants or livestock for food and other human needs Mechanized agriculture refers to the use of machines that use fossil fuels in order to work Monoculture is the growth of a single crop on a large area of land MONOCULTURE ADVANTAGES DISADVANTAGES Ploughing, fertilizing, applying pesticides and seeding is simpler Less expensive Low genetic and biological diversity Removes soil nutrients Requires use of synthetic fertilizers Vulnerable to pests and disease Require more pesticides and herbicides

Synthetic fertilizers When crops are harvested, the nutrients that have been absorbed by the mature plants are removed from the field with the crop. These nutrients must be replaced. The nutrients most often depleted are nitrogen, phosphorus, and potassium. Farmers who use monoculture replace these nutrients with fertilizers. Scientists estimate that 25% of the world’s food crops are developed because of fertilizers. As the population continues to grow, so will the use of synthetic fertilizers.

Effects of synthetic fertilizers Synthetic fertilizers have a large effect on aquatic ecosystems. Rainwater dissolves and carry fertilizers to lakes, rivers, and other bodies of water. Excess nutrients cause algae to grow rapidly causing an algal bloom. Eventually the algae die and begin to decompose using large amounts of oxygen. Now there is less oxygen available for other aquatic organisms, such as fish.

Synthetic pesticides PESTICIDE PROBLEMS Pesticides are targeted for one species, but often others are harmed as well (fish, birds, other plants, etc.) Overtime some pests have become resistant to pesticides Some pesticides breakdown, but others do not and remain highly toxic Pesticide drift. A pesticide is any chemical used to kill or control populations of unwanted organisms (weeds, insects, or fungi). Synthetic pesticides are man- made. The goal is to prevent the loss of crops and food supplies to pests or infection. Pesticides can have a negative effect on the environment.

Common Pests in Saskatchewan Gophers Grasshoppers Blackleg (canola) Smudge (wheat) Clubroot (canola) Sclerotinia Fusarium

irrigation Inefficient Inefficient Irrigation – adding water to an agricultural field to allow certain crops to grow where the lack of water would normally prevent their cultivation. Canada – 8% of water is used for crops India – 90% of water is used for crops Kuwait – 4% of water is used for crops There are 3 types of irrigation: 1. Surface (flood) Irrigation 2. Spray Irrigation 3. Drip Irrigation Inefficient Evaporation Surface run off Inefficient Sprinkler system Evaporation Uses pipes with strategically placed openings Conserves water

Genetically modified crops Genetic engineering involves taking a small section of DNA called a gene from one organism and inserting it into another organism. An organism with a genetic make-up (DNA) that has been altered by scientists is called a genetically modified organism (GMO) There are two agricultural methods: Inserting genes from a bacterium Kill insects Called Bt crops Inserting a gene for herbicide resistance Crops can be sprayed to kill weeds without damaging the crop

SUSTAINABLE AGRICULTURE

Sustainable agriculture Sustainable agriculture is the practice of producing food to meet the needs of the present without compromising the ability of future generations to meet their needs. Sustainable agriculture addresses environmental, economic, and social needs throughout the process of food production.

Polyculture Polyculture is an agricultural practice in which diverse species are raised in the same area. This is unlike monoculture, in which only one species is grown in a large area. Benefits of Polyculture: Increase biodiversity Conserve topsoil Reduced need for water Less fertilizer and pesticides Companion planting – planting two or more plant species close to each other so that some benefit occurs Example: Aboriginal people used the “Three Sisters” (Corn, Beans, and Squash) The corn provided structure for the beans to grow up; the beans return nitrogen to the soil; and the squash provides dense leaf coverage, which reduces weed growth.

Soil conservation Soil conservation involves reducing soil erosion and maintaining soil fertility Soil Fertility Retaining topsoil is the best way to maintain soil fertility Farmers want nutrient rich soil Crop rotation is the practice of growing different crops at different times on the same land Example Year 1 – grow wheat (removes nutrients) Year 2 – grow legumes (replaces nutrients)

Organic Fertilizers Compost – produced when microorganisms in soil break down organic matter in the presence of oxygen Mulch – general term for protective ground cover (manure, wood chips, straw) Green Manure – produced by growing grasses or legumes on a field and then ploughing it into the topsoil at a later time (this increases the nutrients in the soil for the crop that will be grown next)

Integrated pest management Integrated Pest Management (IPM) is a system that uses biological organisms, chemical substances, and crop rotation to help keep pest populations under control. This parasitic wasp is invading the eggs of a European corn borer. The wasp is an example of biological pest control.

Sustainable irrigation Drip Irrigation delivers water directly to the roots of plants. 90% efficiency rate is designed properly. Reduces fungal diseases because there is less water sitting on the plant leaves. Drawback – initial cost is greater than other methods. Recycled water is used in some parts of the world

Renewable energy Another aim of sustainable agriculture is to reduce the use of fossil fuels and replace them with renewable energy sources Solar power Wind power hydropower Consumers can participate by buying locally grown foods (reduces the amount of fossil fuels used to transport food over large distances)

Organic farming An organic product is one that has been produced without the use of synthetic fertilizers or pesticides, hormones, antibiotics, synthetic additives, genetically modified ingredients, or irradiation. In Canada, organic products must meet strict standards defined by the government. 2% of Canadian farms are certified organic. It takes 3-5 years for a farmer in Canada to make the change from conventional to organic farming profitable. Organic foods are becoming increasingly accepted.

LIVESTOCK PRODUCTION

Methods of Raising Livestock About 50% of livestock are raised by grazing on rangelands and enclosed pastures Livestock roam and feed Grasses, alfalfa, clover, etc. The other 50% are raised in Confined Animal Feeding Operations (CAFO’s) and feedlots Industrialized for rapid growth 10,000 hogs, 1 million chickens, 100,000 cattle

Advantages and disadvantages of CAFO’s Increase meat and dairy production CAFO’s reduce risk of overgrazing CAFO’s have lower costs CAFO’s provide employment at the local level Spread of disease CAFO’s – animals do not eat their natural foods CAFO’s – unhealthy living conditions CAFO’s – require use of antibiotics

Raising livestock sustainably Rotational Grazing – confining animals to a small area of pasture for a short time, before shifting them to a new location. Mimics the effects of wild herds. Livestock will feed and fertilize the ground equally. Smart Pasture Operations (SPO’s) are an alternative to CAFO’s Animals eat grass, rather than corn and soybean Less crowded Less use of antibiotics Organically raised livestock Polyculture livestock (rotating between livestock and crops)