Lecture 18 - Agriculture pt.2

8.2

What is agriculture and what are the past and current trends in agricultural practices?

The practice of cultivating soil, producing crops, and raising livestock for food, fiber, and other products to sustain and enhance human life

• monoculture

What are the consequences of agricultural practices in terms of environmental sustainability?

• soil degradation

• water pollution

• biodiversity loss

• soil salinization

What are some agricultural methods we can use to minimize soil degradation and environmental damage caused by industrial agriculture?

• polyculture

• crop rotation

• organic fertilizers

• Integrated Pest Management (IPM)

• conservation tillage

Unintended consequences of industrial farming

• Loss of soil fertility

• Depleted water supplies

• Salinization of soil

• Water pollution

• Evolution of pesticide resistance in insects

• Toxic chemical exposure

• Increased dependence on fossil fuels

• Reduction in small-scale farming

what is organic farming?

does sustainable farming have to be organic

no

what is biomimicry?

Agroecology

• Mimicking natural ecosystems on your farm

• Minimizes the use of pesticides and fertilizers – saves $$

• Enhances biodiversity

• Creates a self-regulating system

• Leads to financial gain through polyculture

integrated farming

solutions to overconsumption of water

Plants take up less than half of the water we apply in irrigation

• Drip irrigation ensures only as much water as is needed is applied

• Computerized moisture sensors can help control water application

Alternatives to Inorganic fertilizers: Organic Fertilizers

• Provide nutrients including micronutrients

• Improve soil structure

• Improve nutrient retention

• Improve water-holding capacity

Organic fertilizers feed the soil while inorganic fertilizers feed just the plants

Integrated pest managment

combines a variety of techniques for controlling pests

decreases but not eliminate pests

reduces but does not necessarily eliminate pesticide use

• Biocontrol

• Mechanical pest removal

• Close monitoring of populations

• Habitat complexity

• Crop rotation

• Intercropping

• Transgenic crops

• Use of chemicals

non-traditional farming practices

• contour farming

• reduced tillage

• terrace farming

• crop rotation

• strip cropping

• cover crops

contour farming

when farming on hilly land, rows are planted along slope, following the lay of the land, rather than oriented downhill to reduce the loss of water and soil after a rainfall

reduced tillage

planting crops into soil that is minimally tilled reduces soil erosion and water needs (reduces water reduces evaporation). it also requires less fuel because of less tractor use

terrace farming

on steep slopes, the land can be leveled into steps. this reduces soil erosion and allows a crop like rice to stay flooded when needed

crop rotation

planting different crops on a given plot of land every few years helps maintain soil fertility and reduces pest outbreaks since pests (or their offspring) from the year before will not find a suitable food when they emerge in the new season

strip cropping

alternating different crops in strips that are several rows wide keeps pest populations low; it is less likely the pest will travel beyond the edge of a strip and they may not find another row of this crop

cover crops

during the off-season, rather than letting a field stand bare, a crop can be planted that will hold the soil in place. nitrogen-fixing crops like alfalfa that improve the soil are often chosen

plant ______ instead of ______ for grain crops

plant perennials instead of annuals for grain crops

why are perennials better than annuals for grain crops?

• can be harvested year after year without replanting

• reduces heavy machinery and soil compaction

• roots sequester carbon

• roots reach deeper into soil and access more water

• deep roots hold soil and prevent erosion

which farming practices help reduce soil erosion?

contour & terrace farming

which farming practices help improve soil fertility?

crop rotation & cover crops

which farming practices help reduce pest outbreaks?

strip cropping & crop rotation

food miles

the distance a food travels from its site of production to the consumer

carbon footprint

the amount of carbon released to the atmosphere by a person, company, nation, or an activity