Population and the environment - Environment and population Flashcards

1
Q

what systems are farms considered to be

A

open systems

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2
Q

what are the inputs of a farm

A

physical human and economic factors that determine they type of farming in an area

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3
Q

what are the outputs of a farm

A

products from the farm e.g. crops cultivated and animals reared

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3
Q

what are the processes of a farm

A

farming methods - the activities carried out to turn inputs into outputs, vary depending on inputs and also by level of technology available

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4
Q

what is agricultural prouctivity

A

key measure of the economic performance of agriculture and an important driver of farm income
measured in terms of yeild or by total factor productivity

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5
Q

what is total factor productivity

A

takes all inputs employed in farms production and compared with total outputs
if TFP in growing/improving - total output growing faster than total input, producer is using inputs more efficiently and precisely or adopt alternative cultivation and livestock raising practices
TFP differs as it takes into account a broader set of inputs used in production
encompasses the average productivity of all inputs employed in production of all crop and livestock commodities

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6
Q

what does TFP improve with

A

crops
raising livestock

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7
Q

how does TFP improve with crops

A

higher yielding, disease resistant and drought or flood tolerant crops
more efficient and timely cultivation and harvesting practices
using technologies that indicate precisely when and how much water and fertilizers to apply

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8
Q

how does TFP improve with raising livestock

A

breeding animals for favorable genetic qualities and behavior
using better animal care and disease management practices
adoption of high quality feeds contribute to greater productivity

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9
Q

what is commercial farming

A

farmers and agribusinesses maximizing profits
high investment of capital into land, contractors, machinery, agrochemicals, animal welfare
specializing in signal crop (monoculture)
raising one type of animal

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10
Q

what is subsistance farming

A

direct production of sufficient food to feed family or community involved
any excess product sold or bartered
tribes in Guiana highlands of Venezuela - clear small area of rainforest, burn vegetation to provide fertile ash, cultivate plot for 3-5 years, continual weeding before plot loses its fertility, clear another plot, return to original plot when vegetation has regenerated naturally

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10
Q

what are the different types of farming

A

commercial
subsistance
intensive
extensive
arable (growing of crops
livestock (animals)
mixed
CAN HAVE MORE THAN ONE TYPE OF FARMING AT ONCE

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11
Q

what in intensive farming

A

high investment into labor, land and capital
produces high yields per hectare from small areas of land

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12
Q

what is arable farming

A

growing of crops
subsistance (slash and burn shifting cultivation - south america) or commercial (potato cultivation UK)
flatter land
soil of higher quality

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12
Q

what is livestock farming

A

raising animals
subsistance or commercial

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12
Q

what is extensive farming

A

low inputs into labor machinery, capital but large into area of land
low yield per hectare
hill sheep farming in upland areas uk

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13
Q

what are the characteristics of a polar climate

A

long and cold winter
temp falling below -40
glacial ice and a surface layer of snow permanently covering the land
long hours of sunshine in the summer
average temp rising above 0 in summer
permently frozen ground - permafrost

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14
Q

what is the distribution of polar climates

A

66.5 degrees north and south of equator
northern hemisphere - greenland, northern canada
southern hemisphere - antarctica

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15
Q

how many people live in polar climates

A

around 13.1 million
spread between 8 countries
population density of less than 4 per square kilometer
as healthcare improved and discovery of vast natural resources number of arctic people started to grow - influx of immigrants
population growth slowed or declined recently
2/3 arctic population live in large settlements
indigenous communities are small and widely scattered

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16
Q

how does farming occur in polar climates

A

only form of arable farming can occur when farmer makes an artificial environment - Tim Myers farms seven hectares of land in Alaska, nutrient rich soil is frozen so to get to it have to thaw ground by clearing vegetation and spread manure, composted tundra and a slurry of salmon, lake water added and dry molasses to increase biological life
Raised beds and high polytunnels help mitigate the low temperatures and short growing seasons
vast underground root cellar stores expand lifespan of harvest
In north america innuit groups hunt caribou as well as seals in winter and fish in summer
Caribou can be tamed for milking to provide milk as well as meat, skin for clothes and tents, antlers and marrow of the bones

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17
Q

what are the characteristics of a tropical monsoon climate

A

low pressure summer - winds blow on shore bringing rain
cloudy sky in summer and clear sky in winter
rainy seasons with very high rainfall in summer
hot and wet summer - Mumbai has annual rainfall of 1,811mm with 120mm falling in 4 months
cool and dry winter
high annual temp - 26
temp - 30 in summer, 19 in winter

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18
Q

how is climate change affecting agriculture in polar climates

A

significant warming of up to 1 degrees Celsius per decade
continuation would result in a warmer wetter climate resulting in thawing of permafrost and glacial retreat, shorter snow season and reduced sea ice
cause change in migration patterns of wildlife
have effect of indigenous population threatening sustainability of existing settlements, infrastructure and lifestyles
sea transport tourism and mineral exploitation could benefit
fishing forestry and agriculture will change

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19
Q

what is the distribution of tropical monsoon climates

A

between tropics and subtropics that surround the equator
Central and South America, Central Africa, South and Southeast Asia

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20
Q

How is climate change affecting agriculture in tropical monsoon climates

A

adapt to the monsoon climate and the risks of abnormality in the seasons (e.g. prolonged dry seasons and shorter wet seasons or vice versa) can be detrimental to crops
Rainfall varies - wheat, rice, tea, vegetables and farm animals can suffer from droughts and floods, impacting the farmers’ livelihoods and the region’s food supply
Agriculture adds up to over 15% of India’s GDP
when crops fail because of a lack of rain, the economy suffers.
less predictable weather - jeopardize traditional subsistence rice cultivation
lead to research in less water intensive cultivation

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21
Q

how does the tropical monsoon climate impact human activities

A

more that 60% of population lives in areas affected by monsoon climate mainly due to urbanisation
during monsoon seasons spread of waterborne diseases carried by mosquitoes increases
warmer temps and shifting weather patterns can worsen air quality - lead to asthma attacks and other respiratory and cardiovascular health affects
Agriculture based around monsoon season - beneficial for crops e.g. rice
Waterlogged land is perfect for growing semiaquatic rice
commercial rice fields that use irrigation have been developed
people move to these areas for better opportunities in farming, better food security - leads to overpopulation, causes poor life quality.
Floods and droughts caused by the monsoon directly affect the population, e.g. the 2014 monsoon caused nearly 300 people to die in Pakistan and India, mainly due to flooding causing landslides

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22
Q

how has climate change affected agriculture

A

agriculture likely to be the most venerable economic sector due to dependance on climate and weather

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22
Q

why is the Asia pacific region likely to be the hardest hit by climate change

A

people mainly agrarian
60% of population living in rural areas
around 1 billion people face direct impact due to climate change
consequences to livelihood and way of life
regions population expected to increase by another 850 million by 2050

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23
Q

What is climate smart agriculture

A

made in 2012 global conference on agriculture food security and climate change held by FDA
approach to address the interlinked challenges related to food security and climate change
economic - sustainably increasing agricultural productivity to support equitable increase in farms incomes food security and development
social - adapting and building the resilience of agricultural and food security systems to climate change at multiple levels
environmental - reducing and/or removing greenhouse gas emissions from agriculture
not take roots in the asia pacific region

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23
Q

what are the impacts of climate change on the asia pacific region

A

become warmer
rising sea levels - affects growing conditions, affects ability to live on low lying islands
changing rainfall, temp, sea levels - severe water shortages or floods, changing to crop growing seasons or reduced yields

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24
Q

What is a case study for adaption of agriculture to climate change

A

Mewat, Haryana
low rainfall drought prone area
mean min temp increase at rate of 0.18 every 10 years during monsoon season and by 0.47 during dry season
from 2020 - 2050 min temp increase by 1.87 during monsoon season and 2.72 during dry season
IARI developed custom set of interventions to conserve resources, adapt to climate change and improve livelihoods
superior seed varities tested and made available at village seed banks
heat stress tolerant wheat introduced - increase yields by 12-18%
farmland levelled using lasers - improves water efficiency by 5-15%
underground pipelines laid in fields - delivers drip integration - 40% savings, irrigated area increase by 45%, labor hours required for irrigation reduced by 28%
crop diversification - high yielding varieties of chili tomato and onion accompanied by improving produtction technology (starting seedlings in a nursery, raised bed planting) increases household profits by £320 per hectare 44-86% higher than those who maintain conventional cropping
access to info and communications technology platform mkRISHI - connects farmers to weather forecasting and agricultural production advisery services

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25
Q

why is soil important

A

in a gram of soil there are as many as 50,000 species of microorganisms
soil hosts over 1/4 of planets biodiversity
microorganisms make antibiotics which used in medicine
takes more than 100 years to build 5mm of soil
stores 3x as much carbon as all plant
loosing soil 10-15x faster than it can be rebuilt
sustain 95% of food prodution

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26
Q

what are the three types of soil

A

zonal
intrazonal
azonal

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26
Q

what are zonal soils

A

mature soils reflecting climatic conditions and associated vegetation

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26
Q

what are intrazonal soils

A

reflecting the dominance of other factors e.g. characteristics of the parent rocks

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27
Q

what are azonal soils

A

generally immature and skeletal with poorly developed profiles

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28
Q

what is the structure of podsol

A

thin litter of pine needles
thick black layer of mor (acid) humus
dark staining from down washed humus few soil organisms in acidic conditions
bleached horizon becoming sands as finer materials are washed downwards
increasing acidity as goes further down
waterlogging may occur
organic matter redeposited
hard pan of iron
layer of aluminum
accumulation of clays stained by iron oxides
weathered bedrock - throughflow of soil water loss leads to a loss of nutrients
parent material

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28
Q

what are the conditions where podsol occurs

A

areas of boreal forest do not receive particularly heavy rainfall
podsoilation process requires a genral downward movement of water through soil
precipitation exceeds evapotranspiration due to low temps
coniferious trees shelter ground from drying winds - moderate precipitation can provide a surplus so allows downward infiltration and percolation
very poor nutrient cycle - coniferous evergreen trees do not take up elements such as calcium magnesium and potassium - these are not returned to soil when leaves fall hence a poor mor (acid) humus

29
Q

what are the characteristics of podsols

A

accumulation of a hard pan of iron beneath the zone of leaching and marking the highest point of the water table
clear differentiation of horizons indicating that there may be fewer mixing agents

30
Q

what is podsol and where is it found

A

soil of taiga - vast continous belt of subtropic climate across North america and eurasia between tundra north and temperate grassland south
found in coniferous forests due to harsh withers and cool summers
found in heathland and moors of UK due to cool climate

31
Q

What are podsols used for in UK

A

associated with upland sheep farming and heather moorland
controlled burning of heather in 10-15 years rotation for the breeding of grouse for shooting
grouse shooting employs 2500 people and generates £150 million annually - important to UK rural economy

32
Q

Why are podsols in danger

A

tagia is slowly disappearing due to logging

33
Q

what is the structure of tropical red latsols

A

tropical equatorial rainforest
thick litter layer
thin humus layer created as litter is quickly broken down giving soil a red grey colour
many active biota
build up of iron and aluminium oxides gives the soil a dark red colour
rapid leaching of silica and dissolved salts
some silica is redeposited giving the soil a yellowish colour
clays produced as a result of chemical weathering
weathered bedrock
parent material

34
Q

where are tropical red soils found

A

5 degrees either side of equator
hot wet humid climate without seasons

35
Q

what is organic farming

A

way of producing food which recognises the essential connections between the soil, plants, animals and people
great diversity of farming operations on organic farm e.g. crops and livestock
smaller feilds, boundries e.g. hedges kept - proved homes for insects and animals - can help control pests
Synthetic fertilisers and pesticides are avoided
keep pollution to a minimum

35
Q

what are the characteristics of tropical red latsols

A

infertile soil
deciduous tropical rainforest trees shed leaves at any time of year - constant supply of leaf litter which decomposes with other biota rapidly into humus supplying nutrient to support sustainable new growth very quickly
rapid nutrient cycling - if tropical rainforest is cleared the ready supply of new humus is haltered and soil becomes quickly exhausted of stored nutrients then become exposed of excessive leaching of nutrients and to erosion by gullying during the heavy daily rainstorms

35
Q

why are tropic red latsols in danger

A

deforestation - felling, bulldozing and burning
population and economic growth and development - lad for settlements and infrastructure, land for ranching plantations, hardwood timers, access for mineral exploitation

35
Q

what is the soil like in an organic farm

A

well looked after
farmers trying to build up healthy and fertile soil which is rich in fungi and microbes
help rot and decompose dead plants and animals, recycling organic material back into the soil.
add composted manure and other farm waste to soil in order to increase humus content providing more nutrients for plant growth
help increase the amount of soil and maintain the fertility farmers use crop rotations where they grow a variety of crops in different places at different times
Crops such as clover and grass help improve soil fertility
wheat and potatoes take a lot of nutrients out of the soil
The rotation of these crops helps “rest” the soil, build up nutrients, help break the lifecycle of weeds and pests that may thrive if only one crop was grown over a large area of land
Clover has special “nodules” on the roots which contain bacteria that are able to change nitrogen gas into nitrate animals - sheep or pigs also used in rotations - graze on the resting land which would be sown with grass or clover
They feed on roots of crops and their manure will feed the soil and enrich it.

35
Q

how do organic farms control pests

A

Chemical pesticides that may damage crops are not used to control flora and fauna
farmers rely on natural predator and prey relationships such as hoverfly larvae feeding on aphids
make sure predators are present farmers provide food, habitats - example keeping trees and hedgerows for bats and birds

35
Q

how do organic farms treat animals

A

high standards of animal welfare
Animals provided with shelters and plenty of space making them less stressed, more content and the ability to behave instinctively
With the animals being outside as much as possible and moving around regularly there is no build up of parasites in the soil which reduces likelihood of animals picking up diseases
Additionally animals are fed organically grown food of plant origin that comply with regulation set - 90% of cows daily dry food has to be grown organically with the remaining 10% coming for specifically sourced places where the food cannot contain any animal protein or genetically engineered products. Herbal and homoeopathic medicines used to treat diseases, vaccines and antibiotics being used when must.

36
Q

what are the benifits for organic farms

A

Healthier animals and healthier meat - Livestock is free to roam and only eat grass and certified organic feed
No additives - unknown long term effects on health of regularly consuming additives/preservatives are avoided
No GMOs (genetically modified organisms) - Unknown health effects and possibilities of contamination are avoided
No chemical pesticides - Toxic residue left on food from pesticides not present so not transferred into bodies - also dangerous to insects.
Better for the environment - No chemicals used - cannot contaminate water sources, surrounding habitats and the soil. Machinery used release reduced CO2 emissions, use sustainable methods to protect animals and promote biodiversity maintaining soil fertility

37
Q

what is a case study for organic farming

A

John Alpe
1000 acre farm in Lancashire
focus on managing the land organically alongside sheep and cattle farming. bought the farm in 1994 milk prices - 22p/litre, lamb - £40/head
1998 prices dropped - 16p/litre £22/head
After drop in price farm not profitable - consider selling the farm or increase output significantly to make his assets work harder or switch to organic
John already involved in several countryside stewardship schemes to help make the most of the landscape and wildlife already on the farm move to organic would help him increase what he was already working on. Now nearly 200 acres of heather regeneration, lots of land in ground nesting habitat, 300 acres of species rich botanically imported grassland, 15 acres of wildflower hay meadows and 25 acres of woodland
manages the environment to give birds opportunities to feed, nest and breed. still has dairy cattle and sheep with 40 milk cows which conventionally would not be enough to flourish but with the milk prices they receive they are able to flourish.

38
Q

what are the four components of food security

A

food availability
food access
food use
food stability

39
Q

what are the regions where food security is more at risk

A

along equator
central africa - Chad
landlocked countries
low risk - europe north america

40
Q

what are the reasons for countries at risk of food security

A

unstable governments
conflicts
landlocked - harder to trade and more expensive to trade
LIC - no infrastructure and technology
lass at risk HIC - have technology and money

41
Q

what are strategies to improve food security

A

green revolution
economic growth and expansion of social protection
different types of farming
hydroponics
urban farming
reducing food waste

42
Q

what is the green revolution

A

use of high yielding varities of seeds, agrochemicals, machanisation and irrigation in drylands, drainage of swamp and bog lands, land clearance. Most been in LICs and NEEs
1960-1980 in EU farmers offered grants by the common agricultural policy if they increased food production. resulted in surplus of food (wine lakes and butter mountains)
emphasis on creating a balance between food production and environment

43
Q

how can different types of farming improve food security

A

help increase food supply
aquaculture - farming of aquatic plants and animals
fish farms allow species to be controlled and boosted
sustainable fishing - traditional fishing techniques, but catching fewer fish avoiding bycatches

44
Q

how does urban farming help improve food security

A

food grown in cities
give people more direct access to fruit, veg and meat
allotments

44
Q

how does economic growth and expansion of social protection help ensure food security

A

cash transfer to venerable households
food vouchers
health ensurance
school meal programs
FAO estimated that 150 million people worldwide are prevented into falling into extreme poverty due to social protection
2/3 of worlds poor do not have access to regular and predictable forms of social support

45
Q

how does hydroponics improve food security

A

growing plants without need for soil
grown in other materials with water and nutrients flowing through them
bring food security with areas that have poor soil or high levels of erosion
need money and technology

46
Q

how does reducing food waste improve food security

A

more food available for consumption

47
Q

what is post harvest food loss

A

a measurable qualitative and quantitative food loss along the supply chain starting at the time of harvest till it is consumed or other end uses

48
Q

how does post harvest food loss occur

A

due to food waste or due to inadvertent losses along the way

49
Q

what is food loss

A

the inadvertent loss in food quantity because of infrastructure and management limitations of a given food value chain

50
Q

why does food waste lost occur in developing countries

A

poor infrastructure
poor temperature management
low levels of technology
low investment in the food production systems e.g. fridges

51
Q

what are the key factors affecting food loss

A

poor understanding of harvest and how maturity is related to quality and shelf life
poor sorting and grading practices, allowing damaged/decaying food to enter the supply chain and spread decay to other foods
poor temperature management lack of control of relative humidity - leads to deterioration of food
poor quality packaging - provide little or no protection
delays in transport without proper storage
lack of education on post harvesting practices leading to rough handling, mechanical damage

52
Q

what is the gene revolution

A

biotechnology and development in genetic modification
taking genetic DNA from one plant and introducing it to another to make it more resistant to drought, specified pests or diseases
by 2014 about 18 million farmers in 28 countries were growing GM crops on 181 million hectares - 13% of worlds arable land
concerns - possible, largely unknown, implications for human health and the environment
no GM crops grown commercially in the UK, nearly 40 countries have banned cultivation
imported GM crops used mainly for animal feed and some food products

53
Q

what are crop wild relatives

A

wild species closely related to common food crops
vital to food security - contain greater amounts of genetic diversity making them more resilient in the face of climate change, waterlogging, salinization, pests and diseases and other new threats
Adapting Agriculture to Climate Change project - collect seed from the wild plant relatives of 29 common crop plants. used to breed new and useful traits into commercial crops so that the can adapt better to future climates and other threats. aims to safeguard the wild relatives of food crops before they disappear - useful plant are not lost or before we learn how they might be useful to us

54
Q

what is hybridisation and how has it helped to improve food security

A

hybridisation (cross breeding of crops) creating new varieties
mexico - hybrid wheat and maize strains developed to withstand heavy rain, strong winds and disease, maize yeilds doubled and wheat tripled
animals also cross bread - improve tolerance to difficult environmental conditions e.g. aridity
Phillippines - development of rice varities - IR8 - six fold increase in yeilds reported from first harvest, since 1961 when first introduced Asias rice yeilds more than tripled, 10% of India’s padi fields planted with it, venerable to new pests and diseases consequently requiring onging development - IR64 introduced in 2010

55
Q

what is agrochemicals and how have the helped to improve food security

A

chemical fertilisers
doubled crop yields in tropical areas
locust plagues controlled by the pesticides
synthetic hormones developed to control plant size and growth rates - allows growing seasons to be adjusted
punjab - crop spraying helped india double farm yeilds in 50 years but the agrochemicals have infiltrated into water sources contaminating soils and food - alleged that 34000 deaths from cancer in Punjab between 2008 and 2013 may be related to increase use of pesticides

56
Q

What is the problems of the green revolution

A

very high economic and social costs - only richer farmers could afford to run and buy tractors - increases unemployment and rural depopulation
poorer farmers took out loans to buy new seeds and fertilisers needed by the improved varities but were often unable to repay them leading to debt and forcing sale of land
demand for agrochemicals created industrial jobs but theor production could be dangerous
education needed to ensure productive cultivation of HYVs - frequant irrigation and agrochemicals required

57
Q

What is soil erosion

A

geological process - materials worn away and transported
Soil erosion - deterioration of soil
happens due to: ice, wind, water, gravity
Soil particles loosened and washed away in the valleys, oceans, rivers and streams
worsened due to human activities such as agriculture and deforestation
a continuous process that occurs either slowly or at an alarming rate
results in a continuous loss of topsoil, ecological degradation, soil collapse, etc.

58
Q

What causes soil erosion

A

removal of natural vegetation cover, leaving the ground directly exposed to the elements

59
Q

What is the problem with soil erosion?

A

Increased demand for agriculture and converting forests and soybean and wheat - increase soil erosion beyond the soil’s ability to maintain itself
Half of the topsoil on the planet has been lost in the last 150 years
soil quality is affected by other aspects of agriculture
impacts - compaction, loss of soil structure, nutrient degradation, and soil salinity
deforestation in the Amazon rainforest, - soil left unprotected
high amounts of rainfall in the area soil is rapidly eroded
Between 1960 and 2019 soil erosion in the Amazon increased by 600%, and deforestation of 411,000km2
deforestation is leading cause of soil erosion in this area.

60
Q

how are people trying to solve soil erosion

A

planting trees around the Amazon, in an attempt to give the soil something to hold on to
There is a current project in place to plant 73 million trees in the amazon rainforest which started in 2017 - slowed down due to the pandemic and many forest fires being set on newly growing trees.

61
Q

what is the solution to soil erosion

A

areas with many pedestrians, stepping stones or a gravel or mulch path used to cover and protect eroded areas
layer of mulch or compost also can be used in tree and shrub beds or in areas where vegetation is difficult to grow. Cover crops ‘cover’ the soil between the harvest and establishment of main (cash) crops
Crops ‘catch’ available soil nitrogen and prevent nutrient losses (via run-off and leaching).
Soil can be managed is all about conservation - preserving and protecting vegetation cover
afforestation and reforestation provides the best long term solution to soil erosion - once the trees have grown the foliage shades the soil from the sun and intercepts rainfall, and their roots help to bind the soil together and reduce surface runoff.

62
Q

What is salinization

A

build-up of soluble salts in soil
arises in the areas with limited rainfall and high evaporation rates where the upward groundwater brings dissolved salts to the surface
salts are deposited via dust and precipitation
In well-drained areas with sufficient precipitation or efficient irrigation, these salts are leached out of the soil by infiltration and percolation, increasing salinity in the soil.

63
Q

What is the problem of Salinisation occurring?

A

affects crop production and water supply industries
induces the risk of floods and soil erosion
decreases biodiversity
It prevents plant reproduction
Crops grown on saline soils suffer on account of high osmotic stress, nutritional disorders and toxicities, poor soil physical conditions and reduced crop productivity.

64
Q

case study of salinisation

A

almost 100 cities in China are located in areas that contain saline - alkali soils almost 33.3 million hm2 of agricultural land has been abandoned or become less productive due to soil salinisation. China is an important grain producing are but soil salinity has been an environmental problem
Grain production is important - provides economic stability
relieve the pressure of land shortage, large areas of land have been reclaimed around Bohai Bay.

65
Q

what is waterlogging

A

when soil becomes oversaturated with water
no longer oxygen in the soil
plants unable to respire aerobically

66
Q

what are the causes of water logging

A

rainfall exceeds the rate soil can absorb or atmosphere can evaporate
gentle relief restricts throughflow of inflitrating soil water
relief basins or depressions encourage accumulation of water
seepage from rivers, canals and reservoirs infiltrate soils
soils include and impermeable clay layer or iron pan
excessive irriagtion water is used to flood feilds

67
Q

what are the problems of water logging

A

limited oxygen supply to the roots and prevents co2 from diffusing
root function is reduced or stops - roots start to die allowing for rotting and decay
waterlogged soils may have nautally dense texture lacking drainage channles - soil remains wet after rain

68
Q

what is a case study of waterlogging

A

Dhaka, Bangladesh 21.09.23
Dhaka heavily affected with persistent flooding followed by heavy rains - over 30% urban areas experienced severe waterlogging
impacted 3 million people - disruptions and residants had difficulty commuting and acessing essential services impacting livelyhood
poor drainage systems, canals clogged and poorly maintained contributed to flooding
government initiated projects - seweage system upgrades to better manage rainwater and prevent overflow

69
Q

what are possible solutions to waterlogging

A

crop rotation - alternate between deep-rooted and shallow-rooted crops
deep-rooted crops (clover) - penetrate deeper soil layers creating channels for water to move more freely
shallow rooted crops (lettuce) - grown in shorter rotations to aviod excessive water accumilation

70
Q

what are aggregates

A

the arrangement of soil particles
determines the workability and characteristic soil

71
Q

what are the different types of soil structures

A

Granular and crumb structure - Individual particles of sand/silt/clay grouped together in small circular grains
Water circulates very easily
Blocky structure- Soil particles clinging together in nearly square blocks, almost sharp edges
Large blocks -> resists penetration and movement of water -
Prismatic and columnar structure- Soil particles formed in vertical columns or pillars
Water circulates with great difficulty and drainage is poor
Platy structure - Soil particles aggregated in thin plates/sheets, piled horizontally
Piles can overlap which greatly impairs water circulation

72
Q

what happens when soil deteriorates to water

A

prevent movement of water f=through soil
results in large environmental consequences as it increases risk of flooding

73
Q

what does soil deterioration result in

A

desertification - can wipe out acres of arable land and heavily affect agriculture

74
Q

what is soil deterioration cause by

A

Soil erosion - wind can detach the fertile topsoil layer and transports it elsewhere then water washes away mass amounts of dirt, resulting in soil deterioration
Overgrazing - increase in demand of food and meat products which leads to crops not given enough time in between grazing sessions-> can cause deforestation
Urbanisation indirectly causes soil deterioration - largely populated cities create mass amounts of pollution and less agricultural productivity which then affects soil deterioration

75
Q

what are the problems with soil deterioration

A

Cultivation causes physical fracturing and mixing of the soil plus increased aeration - leads to a break down of the organic matter in the soil
During harvest of arable crops, much of the plant matter is removed meaning less organic matter (in the form of decaying plant) is returned to the soil- cause a total reduction in organic matter in the topsoil, therefore few nutrients available to crops, less water holding capacity, soil more at risk of wind erosion, there is less root growth. decrease in organic matter results in deterioration of the structure of the soil, involving particles of soil splitting-off from the aggregates as bonds between the particles become weak due to less organic matter, so can no longer withstand disruptive forces (e.g. rain, wetting and drying). This therefore means that when these degraded soils are exposed to heavy rain, a surface crust is formed which prevents movement of water into the soil and/or emergence of seedlings through the soil.
combination of pressure and sliding forces on the soil cause compaction. forces often applied through driving and grazing livestock. Soils react differently to pressure of these forces depending on their texture (how wet/hard, its depth, shape of contact area)
Most farm vehicles are heavy and travel repeatedly on the same ground, this concentrated weight compacts the wheel ruts which become impermeable to water. Rainwater gathers in roots and then travels downslope causing serious gully erosion.
Ploughs specifically can cause an impermeable layer called a plough pan by the bottom of the machine smearing soil immediately below the depth of a plough furrow

76
Q

what are the solutions to structural deterioration

A

Crop rotation - allows for different types and varieties of plants to grow in the soil each year, allowing the soil to recover from the previous crops, replenishing itself of any nutrients lost.
Permaculture - sustainable form of farming that respects and acknowledges nature. includes practices such as creation of integrative space and the collection of rainwater to recycle, meaning that the soil will not be overgrazed and over farmed.
Agroforestry - Involves growing trees and other plants like bushes around crops as they create their own microcultures which is favorable for crops and also provides protection from wind and heavy rainfall. trees also protect topsoil and help increase fertility of the soil by encouraging growth of other vegetation.
Adapting agricultural practices - Farmers opt for more sustainable practices - prioritising organic farming by reducing or stopping the use of chemical fertilisers and pesticides. Intensive tillage methods avoided - disturbs the structure of the soil, avoid over irrigation - using methods such as drip irrigation to avoid the soil becoming flooded.
Leaving the soil alone - It can take over 500 years for 2.5cm of topsoil to be created, leaving soil alone it may allow for topsoil to slowly replenish, also allow for the nutrients and carbon in the soil to replenish and become stable means soil will stay fertile and is less likely to be eroded as easily