[C5] Chapter 5: Farming and Famine

Sahel

Physical Constraints

Climate
Problem	Explanation	Impact	Adapation
High annual mean temperature	Low latitude	- Low carrying capacity - Low water input - Shifting with rainfall - Unsuitable for arable farming	Nomadic herding → livestock rearing → transhumance → search for water and pasture
Large annual range of temperature
Low annual rainfall	- Interior location - Less maritime influence	Drought / water shortage throughout the year	- Extensive // subsistence farming - Cultivation of drought-resistant species (goat, camel) → low water consumption
Uneven distribution of rainfall	- Onshore wind brings summer rainfall - Offshore wind brings little rainfall in winter → summer rain
High potential evapotranspiration rate	Drought	Limited scale of farming
Annual potential evapotranspiration rate exceeds annual rainfall		Limited choices of crops // livestock	Limiting number of livestock

Soil
Problem	Explanation	Impact	Adapation
Poor soil	Mainly sandy soils → thin and infertile	Topsoil blown away	Limiting number of livestock → reduce overgrazing
Poor soil	Easily eroded	Land desertification	Limiting number of livestock → reduce overgrazing

Vegetation
Problem	Explanation	Impact	Adapation
Sparse vegetation	- Scattered grasses - Thorny shrubs	Poor crop yield	Dig pits in soil → collect rainwater in pits → reduce loss of rainwater through surface runoff → crops absorb rainwater more efficiently
	Little organic matter
	Not enough to sustain livestock rearing in one place throughout the year	Low carrying capacity	Add organic matter → improve infiltration

Drainage
Problem	Explanation	Impact	Adapation
Water shortage	No major river running through Sahel	Hinder sedentary crop growing	Cover pits with thin soil → increase water-holding capacity
	Only River Niger and River Nile cover a small area	Difficult to develop efficient irrigation system	Cover pits with thin soil → increase water-holding capacity
	Lake Chad is the largest lake in the region → shrunk by 90% since the 1960s	Drought / water shortage throughout the year	Plant crops → grow drought-resistant crops → provide shading effect → reduce moisture evaporation

Cultural Constraints

Population
Problem	Explanation	Impact
Population increase continuously	Increase in demand on food	- Population growth rate higher than increase in number of livestock - Number of livestock per capita declines - Increasing number of livestock may exceed carrying capacity of land

	Overgrazing	Trampling of soil
	Over-cultivation	Land desertification → further lowering productivity → misuse of water resources

Educational and technological level
Problem	Explanation	Impact
Low educational and technological level	Low farming technology	People are poorly educated → unable to overcome physical constraints
Low educational and technological level	Low literacy rate	Lack knowledge to apply modern farming technology → adopt primitive farming

Capital
Problem	Explanation	Impact
Low capital input	Poverty	Low farming income → less able to afford modern farming technology → lack money to buy imported food

Political
Problem	Explanation	Impact
Unstable political environment	- Civil war - Conflicts - Corruption	- Farmers are forced to leave their farms - Farmland is destroyed by armed people - Farmers lose seeding and growing season → further lowering land productivity

Southern California (SC)

Physical Constraints

Climate Along west coast: Mediterranean climate Inland regions: semi-arid to arid climate
Problem	Explanation	Impact
Low annual rainfall	- Central Valley is in rain shadow → moist air cannot reach inland - Southern tip of SC affected by offshore winds for most of the years → high evaporation rate	Drought / water shortage throughout the year

Extreme climate → climatic hazards	- Occasional frosts - Wildfires - Drought	Short growing season

Relief
Problem	Explanation	Impact
Rugged (>400m)	- Coast ranges - Sierra Nevada	Lack of arable land

Desert → central and southeastern SC	- Mojave Desert - Colorado Desert

Soil
Problem	Explanation	Impact
Infertile	- Little organic matter	Must rely on chemical fertilizers to improve fertility
	- High temperature with low rainfall → difficult for rocks to decompose into soil + release nutrients	Low yield

Alkaline	High evaporation rate → salts beneath soils to surface (salinization)	Not suitable for growing crops

Pest
Problem	Explanation	Impact
Exotic crops	Brought to areas that lack natural predators of pests → 25 major pest species	- Farmers have to apply heavy doses of pesticides → harmful for human health - Each species causes econ loss reaching over USD $1 million

Physical Favorable Factors

Climate
Factor	Impact
Monthly temperature above 0 degrees	- Long frost-free period - Long growing season

Relief
Factor	Impact
Presence of lowland → southern tip of Central Valley → Imperial Valley → coastal lowland	More flatland for growing → increase area of arable land

Water supply
Factor	Impact
Presence of river channels	More water supply → provision of stable irrigation water

Snow melt water from mountains	- Increase area of arable land - Extend growing period into dry season → more intensive farming

Cultural Constraints

Population
Problem	Explanation	Impact
Population increase	Increase demand for water	Competition for water supply

Inadequate farm labor	Agricultural salaries are traditionally lower than salaries in other industries	- Young people unwilling to work as farmers → difficult to find enough farm labor → farmers have to hire contract labor from Mexico

Cultural Favorable Factors

Capital
Factor	Impact
- High investment - Machinery is used - Water schemes - Input of pesticides and fertilizers	High output of cash crops

Educational and technological level
Factor	Impact
Have the knowledge to and skills to apply cultural inputs	Higher yield

Research and development
Factor	Impact
Develop new species of crops	High yield

Government policies
Factor	Impact
Provision of loans and subsidies to support farmers	Sell in local and overseas market for cash

Transport
Factor	Impact
More developed railway and road transport	Sell in local and overseas market for cash

Political stability
Factor	Impact
Stable political environment	Sell in local and overseas market for cash

Farming Adaptations

Soil and water conservation
Adaptation	Effective	Ineffective	Notes
Fallowing	Nutrients can recover	Cannot change climatic conditions → cannot overcome climatic constraints	Water conservation
Cover cropping	- Leguminous crops can help fix nitrogen in soil - Replenish soil nutrients → protect soil from wind and water erosion - Improve water-holding capacity of soil → reduce evaporation		Water conservation
Mulching	Keep soil moisture → reduce evaporation → suppress weed growth		- Water conservation - Soil conservation
Planting windbreaks	- Slow down soil erosion - Reduce evaporation		Soil conservation
Agroforestry	- Control soil erosion → enrich the soil - Provide space and shelter for wildlife → increase biodiversity → timber and fruits from trees become other sources of income		Soil conservation
Terracing	Prevent soil erosion	Insufficient water for irrigation	Ensure sustainable agricultural development (man-made)
Terracing	Conserve water Increase infiltration		Ensure sustainable agricultural development (man-made)
Conservation tillage	Conserve water Increase infiltration		Ensure sustainable agricultural development (natural)
Crop rotation	Leguminous crops help maintain soil fertility		- Less disturbance to the fragile environment - Avoid depletion of certain soil nutrients
Multiple cropping	- Reduce soil erosion - Control pests // diseases // weeds
Mixed farming	Increase soil fertility (manure from livestock provide soil nutrients)

Irrigation system
Adaptation	Effective	Ineffective	Consequence
A large-scale mechanized irrigation scheme	- More stable water supply throughout the year - More arable land - More choices of agricultural produce	Only increase short-term water supply	Over-irrigation
Gravity flow irrigation		Less developed countries lack capital to afford such farming technique	Accelerate capillary action → salinization
Sprinkler irrigation	- More crops can be grown in the field - Higher yield → higher income and profit	Misuse of technique may reduce the long-term agricultural productivity	Water table drops
Drip irrigation		Irrigation scheme might not function well because of inadequate annual rainfall	- Accelerate capillary action → salinization - Depletion of groundwater

Chemicals
Adaptation	Effective	Consequence
Chemical fertilizers	- Provide nutrients - Increase yield - Increase crop quality	- Upset ecological system - Eutrophication - Excess growth of algae
Pesticides	- Control pests - Increase yield - Increase crop quality	- Reduce biodiversity - Contamination of soil and food - Pest species resistant to pesticides (superbugs)
Herbicides	Kill weeds which use up soil nutrients	- Block out sunlight → prevent photosynthesis of aquatic plants → remove oxygen in water

Biotechnology

Adaptation

Effective

Consequence

GM crops (genetically modified)

- Development of drought-resistant crops

- Require less water and chemicals for growing

- Modified to suit climatic conditions

- Improve farm productivity

- Increase food security of growing population

- Secure income

- Increase yield

- Increase crop quality

- Cannot change climatic conditions

→ unable to increase water supply

- Increase in food production depresses food price

→ reduce farmers' income

→ farmers in debt

- Unknown effects on human health

- Over-cultivation

- More vulnerable to natural hazards

Mechanization
Adaptation	Effective	Consequence
Greenhouse	- Protect temperature-sensitive crops in winter - Protect crops from wind and frosts // climatic hazards - Can grow more crops in winter	- Disadvantage of small-scale production - Cost of buying machines
Machines	- Improve farm productivity - Increase income from selling farm produce - Stimulate farm-related industries - Improve quality of life - Alleviate famine problem	- Cost of buying machines - Farmers in debts - Unemployment

Precision farming
Adaptation	Effective	Consequence
GIS (geographical information system)	Scientific data collected for analysis	- Does not change climatic conditions - Climatic hazards related to temperature still exist (hill fire // frost)
GPS (global positioning system)	Accurate data for precise inputs
Remote sensing	Reduce wastage of resources
Telecommunication	Raise productivity
Mobile computing	Not exceeding carrying capacity of land
Advanced information processing	Maintain sustainable agricultural development
Computers	Low water consumption

Organic farming
Adaptation	Effective	Consequence
Use naturally decomposed fertilizers (compost) and manure	Enrich soil	- Local farmers lack knowledge to apply technique - LDC lack capital to afford such farming technique
Yellow sticky trap	Control pests and weeds
Recycle materials and resources	Cause less harm to environment
Rely on renewable resources
Careful use of water resources

Comparison between Nomadic Herding and Arable Farming

	Arable	NH
Arable is better	Sedentary —> people can invest in farming tech infrastructure for the area	NH non-sedentary —> farming infrastructure such as irrigation system is not easy to move around as it is too heavy
Arable is better	Can grow leguminous crops —> improve soil fertility	NH cannot grow plants as people move around and do not stay long for growing plants
NH is better	Sedentary farming may lead to over-cultivation —> soil and water are depleted	Allow land to recover and regenerate the pasture by transhumance
NH is better	Nomad have no skills and know-how to grow crops	Nomads get used to the operation