Human geography - Population and the environment

Population density

The amount of people per km squared (densely or sparsely)

Population distribution

The way a population is a over an area (evenly or unevenly)

Factors impacting food production (environmental)

- Climate (temperature/growing season/water availability)

- Soils (Type/composition/nutrient level)

Global patterns in food production and consumption over time

- in 1960s food production was evenly distributed

- Consumption was uneven with LICs averaging below 2000 kcals a day and HICs averaging over 2,300

- Modern day production is majorly occuring in asia and africa

- Population has increased by 250%, there is enough food for 2,500 kcals each but uneven wealth and unsuitable storage solutions dont allow for that

Reasons for increase in food production - Technology and the green revolution

- New crop varieties modified to produce higher yields and withstand climatic constraints

- Advancements in the technology to monitor, sow, harvest, irrigate, fertilise and protect crops

Reasons for increase in food production - Increase in global trading

- Refrigeration, containerisation and the internet lead to more global trade of food.

-LICs have ability to trade and import foods

- Policy drives for better distribution of food

Food security

Having enough nutritious and affordable food to sustain a whole country/region

Green revolution features...

- Increase in productivity of agriculture

- Decrease in fear of mass starvation in developing world

- Started in USA taken to India and enhanced to suit the climate there

- Crop modification relevant to the climate

- Chemical fertilisers (cheaper,quicker, mass produced)

- pesticides stopping the crops getting eaten

- 35% increase in production

Pesticides limitations

- Negative impact on human health

- Pollution of soil and water

- soft top soil hardened by chemical residue, prohibiting further agriculture

- Nitrates enter the water table, and lakes which drown aquatic life

Double burden of malnutrition

Coexistence of undernutrition and overweight/obesity both causing malnutrition

Open systems (farms)

- Transfers energy and matter from one system to another

Closed systems

- Energy can be transferred across system boundaries, not matter

Commercial agriculture

- Majority of the produce is sold for a profit

- Farms make a livelihood from this and most of the money is reinvested into the farm

Subsistence agriculture

- The majority of the produce is consumed by the farmers

- Little is reinvested or sold for profit

Intensive farming

- Capital or labour intensive

- Lots of money or people invested into the farm

- Output is usually high due to this

Extensive farming

- Framing is carried out over a large area

- No real pattern to amount of relative capital or labour invested in relation to the outputs

Organic farming

- Use of natural substances rather than chemical fertilisers

- Way to distinguish farming styles

Agricultural Productivity

The ratio of agricultural outputs to agricultural inputs (measured in TFP)

total factor productivity

ratio of inputs to outputs in an agricultural system

McCarty and Lindberg's optima and limits model

- States that crops have an optimum condition for growth

- As it moves away from the circle of optima, more money is invested and yield decreases

- Limit of production lies between the plant growing and the adverse terrain, climatic and soil conditions

- Doesnt consider climate change which could positively enhance yield in some areas.

- Doesnt consider where humans can remove the limita of production (hydroponics and aeroponics)

5 reasons soil is key to the planets sustainable future?

1. responsible for the quality and quantity of food

2. Is a finite resource where nutrients are depleted faster than they are replenished

3. Helps mitigate climate change as it acts as a carbon sink

4. Soil has high biodiversity

5. Managing soil sustainably makes economic and environmental sense as it is cheaper than rehabilitating or restoring its functions

Zonal soils

mature soils reflecting climatic conditions and associated vegetation

Food security depends on...

- Food availability - sufficient quantities of food, available on a consistent basis

- Food access - having sufficient resources to obtain appropriate foods for a nutritious diet

- Food use - Appropriate use based on knowledge of basic nutrients and care, as well as adequate water and sanitation

- Food stability - availability, access, and utilisation components remain sustainable for future generations.

Food security management; Production

- Focus on increasing production to meet demands of a growing population

Food security management; Demand

- Uneven distribution is caused by overconsumption in wealthier countries that can afford to purchase it

- especially high calorie food such as meat

- focus on reducing demand for certain types of food to support more even distribution strategies

Food security management; Distribution

- Sufficient food is produced its just distributed wrong

- Focus on reducing post production losses including wastage and consumption and production ends of the chain

- Ensuring better mobility of food produced through free trade or aid.

Soil O-horizon

- Top soil

- Composed of organic matter containing fresh and partly decomposed matter

- Can be thick or thin depending on the location

Soil A-Horizon

- topsoil rich in decomposed organic matter

- Nutrients are leached to lower levels

- biological activity is high here (earthworms)

Soil E-horizon

- A layer in soil under the O or A layer that has lost minerals due to leaching from rainwater.

Soil B-horizon

- Subsoil

- Nutrients from the A horizon accumulate

Soil C-Horizon

-Unconsolidated and weathered parent material, resting on the bedrock

- Likely to have large chunks of rock material

Soil R-Horizon

- Bedrock

- Consolidated parent material

- Formed Millions of years ago

Soils functions; Cycling nutrients

- Carbon, Nitrogen, Phosphorus and many other nutrients are transformed and cycled in the soil

- Can be done artificially (Fertilisers) but can go wrong (New green revolution)

Soils functions: Regulating water

- Helps to control where rain, snowfall and irrigation water goes.

- water and dissolved solutes flow over land or into and through the soil

- If soil is compacted too much, surface runoff increases and flood risk is elevated

Soil functions: Sustaining plant and animal life

- Provides habitats for some

- soil organisms such as worms directly alter the structure, which enables other species to access nutrients

- Plant root systems bind the soil together through released compounds, preventing soil erosion and encouraging a diverse vegetation mix

Soil functions: Filtering and buffering potential pollutants

- Soil is largest terrestrial store of Co2 (2x the atmosphere)

- Soil sequestration refers to long term build up of carbon in the soul

- Minerals and microbes are responsible for filtering, buffering, degrading, immobilising and detoxifying organic and inorganic materials

Soil functions: Physical stability and support

- Provides stability for roots - where soil is eroded, desertification takes over and growth is challenging

- The network that enables plant root systems to flourish can only take place where soil structure is good and storing nutrients within it.

Chernozem structure

- Black soils rich in organic matter

- Mineral content coming from wind blown (loess) sediments

- High percentage of phosphorus and ammonia

- Clay like structure, good for retaining water

Chernozem locations

- Found in continental climates

- Cover an estimated 230 million Ha

- Mainly in Eurasia and North America

Chernozem Agricultural practices

- Previously dominated by nomadic herdsmen and hunter-gatherers.

- High fertility attracts modern agriculture including arable cropping and cattle ranching

- Crops include cereals, oilseed plants and potatoes

Red/yellow latosols of the tropical rainforest structure

- 40 meters deep

- Hot wet conditions weathers the bedrock, providing minerals to the soil

- Ferrallitisation (where bedrock is broken down into clay minerals and sesquioxides) occurs

- Red colour is due to iron and aluminium

- Downward movement of water through the soils

- Silica minerals are washed out of the A horizon, in a process known as eluviation or leaching

- Most organic nutrients are stored in the vegetation, not in the soil

Red/Yellow latosols of the tropical rainforest locations

- Located in tropical rainforests

- Mainly in South america

Red/yellow latosols of the tropical rainforest agricultural practices

- Shifting cultivation, where small areas are cleared and burnt, providing nutrients to the soil.

- This land is then farmed for 2-3 years before the people move on

- This only supports small numbers of people and therefore population density is very low in these areas

- Ranchers have began to clear larger areas of rainforest for cattle ranching in more recent years

Wind soil erosion: Creep

- Wind rolls particles along the surface

- Or they are moved by being hit by other particles

Wind soil erosion: Saltation

- Suspended particles are lifted by winds and then dropped

- Bounce across the surface

- Most common type

Wind soil erosion: Abrasion and attrition

- Suspended particles cause abrasion of soil when they fall

- Also they break other particles down (attrition)

Wind soil erosion: suspension

- Small particles are suspended in the air and transported around

- Majority are released within 100km of erosion site

- Sediment is known as as loess

Wind soil erosion management

- Increasing the soil cohesion - Applying organic matter to the soil which improves its structure

- Increasing plant cover - Surface wind speeds are cut, and roots act as a binding agent

- Increasing roughness - Leaving crop residue and ploughing into the soil

- Planting lines of trees or hedgerows - Cuts wind whcih reduces both evaporation and wind erosion

Soil water erosion: River bank erosion

- Soil is washed away by unmanaged rivers as they meander around flood plains

Soil water erosion: Gully erosion

- If rills are not repaired they can grow into 'Gullies'

- Land cannot be used to grow crops

- Large ditches are a hazard for farm machinery

Soil water erosion: Sheet erosion

- Raindrops loosen the soil

- Overland flow transports topsoil in a sheet

Soil water erosion: River erosion

- Short lived, well defined streams

- rainfall gathers on surface and runs downhill forming channels called 'Rills'

How does soil erosion lead to infertility

- Removes nutrient rich topsoil

- Reduces depth available for rooting and water storage for crop growth

- Reducing infiltration of water into the soil, increasing runoff and therefore erosion

Soil water erosion management

- Judicious use of manure and stabiliser topsoils

- Protecting soil in winter by early sowing or use of cover crops

- Work across slopes whenever possible, reduces overland flow and creation of rills and gullies

- Installing and maintaining field drains

What is waterlogging of soil?

Soil is considered to be waterlogged when there are anaerobic conditions for plants

Effects of waterlogged soil

- Root tissue decomposition

- Growth and repair is stalled

- If it is not dealt with crop will die

- If it is ended, plants continue respiration - older surface roots allow the plants to survive

Groundwater fed waterlogging

- Rate of rising groundwater is not matched by Evapotranspiration

- Can be a natural rise in groundwater or be caused by flooding from irrigation canals

Surface fed waterlogging

- Precipitation, irrigation water or river floodwater exceeds percolation and evapotranspiration

- Water stays in or on the soil

Causes of salinisation - High groundwater

- 3m or closer to the surface

- water rises to the surface through capillary action, rather than percolating down, it then evaporates

Causes of salinisation - Excessive water application

- All irrigation water contains dissolved salts, derived as it passes over and through the land

Causes of salinisation - Excessive rainfall

-Contains dissolved salts that are evaporated and left behind

Distribution of salinisation

- 10-20% of farmland worldwide impacted

- Found in Chinas Northern plain, central asia, san Joaquin valley in California, and Indus plain of Pakistan

Salinisation

- Build up of salts in soils eventually to toxic levels for plants (3,000-6,000 ppm)

- Biggest impact is that it decreases the osmotic potential of the soil, so plants struggle to get water from soil

- Extreme cases land is abandoned for being too salty to justify the farms profitability

Treatment of salinisation

- Treated by 'flushing' the land with water which leads to salinisation of other areas, where this water goes

- In extreme cases the salt crust is too thick and water just runs off

Platy soil structures

- aggregated into plates or sheets

- Water circulation is impacted due to the sheets overlapping

- Found in forest and high altitude soils

Prismatic and columnar soil structures

- Found in lower clay rich layers

- Formed into vertical columns separated by cracks

- Water circulated with great difficulty and drainage is poor

Blocky structures

- Clung together in angular blocks

- Found in the B-horizon where clay has accumulated

- Larger blocks shows resistance to water penetration

Granular and crumb structures

- Particles of sand, silt, and clay grouped into spherical grains

- Water circulates easily

-Found in the topsoil (Horizon A)

Mortality

Relates to death - measured by death rate and infant mortality rate

Morbidity

Refers to being ill - with disease or symptoms of disease. Can also describe the incidence of disease within a population

well-being

State of being comfortable, healthy and happy

Health

Defined by WHO as a state of complete physical, social and mental well-being and not just the presence or absence of disease

DALYs (disability-adjusted life years)

Measure of morbidity within a population, measuring the number of years of healthy life lost by being in a state of poor health or disability

Non-Communicable disease

a disease not capable of being spread from one person to another

HALE

Healthy life expectancy

Limitations of the DTM

- Western centric

- Doesn't account for development after stage 5

- Idealistic (Other factors like war are unaccounted for)

- Not a complete summary

- Phase 3 is very wide, making comparisons difficult

ETM facts

- Coined by Abdel Omran in 1970s

- Focused on changes in patterns of health and disease and the impacts of these patterns on the demographic economic and sociological state of an area

- Stage 1 - Age of pestilence and famine

- Stage 2 - Age of receding pandemics

- Stage 3 - Age of degenerative and man made diseases

- Stage 4 - Age of delayed degenerative diseases and emerging infections (Added in 1980s)

ETM - Age of pestilence and famine

- Mortality is high and fluctuates which prevents sustained population growth

- Low and variable life expectancy (20-40)

- Death is associated with cyclical patterns of outbreaks and famine

ETM - Age of Receding Pandemics

- Rate of mortality declines as disease epidemics occur less frequently

- Life expectancy and therefore population increases

- Due to advancement of healthcare and medicinal systems

ETM - Age of degenerative and manmade diseases

- Mortality continues to decline

- Infectious diseases are replaced with NCDs

- Life expectancy increases to over 50

- Fertility becomes more important factor in population growth

ETM - Age of delayed degenerative disease and emerging infections

- declining death rates, which are concentrated at late ages

- life expectancy increases to 70-80

-Causes remain the same as stage 3 (NCDs) but begin to concentrate at later and later ages due to medical advancements

Blue zone communities' Power 9 principles - Activity

- Move naturally

- No specific amounts of exercise set

- Natural movement for around 20 minutes a day

Blue zone communities' Power 9 principles - Downshift

- Stress is natural

- Rituals built into their daily routines for example meditation or prayer to destress

Blue zone communities' Power 9 principles - Purpose

- Specific vocabulary for purpose

- Studies have shown correlation between articulation of purpose and living longer

Blue zone communities' Power 9 principles - Wine at 5

- Not all blue zone communities practice this

- Consume moderate daily consumption of alcohol (2-4 Glasses of wine a day)

Blue zone communities' Power 9 principles - Plant-based

- 95% live on plant based diets, specifically beans and legumes

- Mostly carbohydrate heavy diets, but mainly beans

Blue zone communities' Power 9 principles - 80% rule

-Stop eating when feeling 80% full

- Eat slowly so brain can catch up with the stomach

- Breakfast is the largest meal, dinner is the smallest

Blue zone communities' Power 9 principles - Loved ones first

- Close family relationships

- Children are likely to keep ageing parents with them, not viewed as a burden

Blue zone communities' Power 9 principles - Belonging

- Many are faith based communities

- Sense of belonging with community and with God

Blue zone communities' Power 9 principles - Right tribe

- Surrounded by people with similar health habits

- Peer-pressure is next to non-existent