Chapter 11

Producing Enough Food for the World

Crops

Rangeland:

Provides food for grazing and browsing animals without plowing and planting

Pasture:

Plowed, planted and harvested to provide forage for animals

Aquaculture

• Aquaculture– The farming of food in aquatic habitats

• Mariculture– The farming of ocean fish

Six Ways Agroecosystems Differ from Natural Ecosystems

1. Try to stop ecological succession and keep the agroecosystem in an early successional state

2. Monoculture: Large areas planted with a single species

3. Crops are planted in neat rows

4. Farming greatly simplifies biological diversity

5. Plowing is unlike any natural soil disturbance

6. Genetic modification of crops.

Limiting Factors• Limiting Factor: The single requirement for

growth available in the least supply in comparison to the need of an organism

2 Types of Life-Important Chemicals1. Macronutirents2. Micronutirents

Synergistic Effects: a change in availability of one resource affects the response of an organism to some other resource

Permaculture• Permaculture is a branch of ecological design, ecological engineering,

environmental design, construction and integrated water resources management that develops sustainable architecture, regenerative and self-maintained habitat and agricultural systems modeled from natural ecosystems

Increasing the Yield per Acre

1. The Green Revolution

- Programs that have led to the development of new strains of crops with higher yields, better resistance to disease or better ability to grow under poor conditions

2. Improved Irrigation

Organic Farming

3 Qualities1. It is more like natural ecosystems than

monocultures

2. It minimizes negative environmental impacts

3. The food that results from it does not contain artificial compounds

Genetically Modified Food• Genetically Modified Crops are modified

by genetic engineers to produce higher crop yields and increase resistance to drought, cold, heat, toxins, plant pests and disease.

Chapter 12

Effects of Agriculture on the Environment

Many environmental problems result from agriculture:

• Soil erosion • Sediment transport

and deposition downstream

• On-site pollution from fertilizers and pesticides

• Deforestation

• Desertification• Degradation of water

aquifers• Salinization• Accumulation of toxic

metals and organic compounds

• Loss of biodiversity

Where Eroded Soil Goes: Sediments Also Cause Environmental Problems

Ways to slow erosion:

• Making Soil Sustainable

• Contour Plowing

• No-Till Agriculture– Combination of farming practices that include

not plowing the land and using herbicides to keep down weeds.

Integrated Pest Management

– Control of agricultural pests using several methods together, including biological and chemical agents

– Goals:• To minimize the use of artificial chemicals

• To prevent or slow the buildup of resistance by pests to chemical pesticides

The Terminator Gene

• A genetically modified crop which has a gene to cause the plant to become sterile after the first year

• Is it really available? It is debateable.– Monsanto denies– Farmers suspect

Farming Crisis in India/ Vandana Shiva

• https://www.youtube.com/watch?v=Av6dx9yNiCA

• https://www.youtube.com/watch?v=vi1FTCzDSck

• https://www.youtube.com/watch?v=yGA7HDTkivI

• http://www.nytimes.com/2014/02/23/world/asia/after-farmers-commit-suicide-debts-fall-on-families-in-india.html?_r=0

Grazing on Rangelands

• Overgrazing occurs when the carrying capacity is exceeded. It can cause severe damage to lands

• It is important to properly manage livestock, including using appropriate lands for gazing and keeping livestock at a sustainable density

Desertification

• Desertification is the deterioration of land in arid, semi- arid and dry sub humid areas due to changes in climate and human activities

• Can be caused by– Poor farming practices– Conversion of marginal grazing lands to

croplands

Carrying capacity of pasture and rangeland in the United StatesAverage # of cows per square kilometer