Soil Flashcards
what is soil
a store of water and nutrients for plants and crops
What is soil made of? (5)
- organic remains from dead plants and animals
- mineral particles - mainly from underlying rocks
- soil organisms
- air in the spaces between soil particles
- water in the spaces between soil particles
What is subsistence farming?
Farming for a household or community (mixture of crops/ eco-friendly)
What is commercial farming?
Producing food for large-scale for maximum profit (monoculture/ one type of crop)
What is extensive farming?
uses more land with lower volume of plants ( low output)
What is intensive farming?
Uses more land with a greater density of plants (high output)
Explain Subsistence farming in LEDCs
-small scale
-labour intensive
-use of draft animals (donkeys)
-no burning of fossil fuels
-limited regulation
Explain Commercial farming in MEDCs
- lots of heavy machinery -> damages the soil
- uses of fossil fuels
- increased legislation on commercial farming to reduce the level of pollution
- use of buffers to reduce risk of eutrophication
What will define the texture of soil?
Different % of clay, sand and silt will determine the texture of soil
Finish the statement:
Particles greater than 2mm = ?
pebbles.
if the particle is greater than 2mm it is a pebble
What are the properties of clay soil?
- holds lots of water
- hard to plough
- slow to absorb and release water
- no air pockets for biotic species
What are the properties of sand soil?
- porous
- not much organic material
- lots of air pockets for animals
What is the ideal soil type?
loam
What are the properties of loam soil?
- porous
- lots of air pockets
- retains moisture
- enough organic material for drainage to avoid waterlogging
What are the levels of soil?
- O-Horizon
- A-Horizon
- B-Horizon
- C-Horizon
- R-Horizon -> Bedrock (Parent material)
Explain the properties of the O-Horizon of soil
- newly added organic material
Explain the properties of the A-Horizon of soil
where the dead organic material and fine particles (the humus) build up. It releases soluble minerals absorbed by plants
Explain the properties of the B-Horizon of soil
soluble materials and organic material, tends to be clay, is deposited from the layer above
Explain the properties of the C-Horizon of soil
Weathered rock
what is soil degradation
the change in the soil health status resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries. They do not provide the normal goods and services of the particular soil in its ecosystem
what is the pattern of soil degradation
- Along the equator (hot and dry)
- Sahara desert has soil degradation without vegetation
- Australia deserts - lack of rich soil
- UAE deserts
- Northern China - snow -> lack of soil
why is soil so valuable?
- fertile soil produces crops for increasing populations
- to store and purify water
- stores carbon
- poor soil can lead to famine, forced migration and conflict
what 2 processes cause soil degradation
- soil erosion - wind and water take the soil away when the vegetation is gone
- chemicals end up in the soil and soil becomes less useful in the long run
what are the 3 human causes of soil degradation and erosion
- deforestation -> without plant cover, erosion can sweep the land into rivers. The plants that replace the tress (cotton, soybean), cant usually hold onto the soil, worsening the soil erosion
- agriculture -> when agricultural fields replace natural vegetation, the topsoil is exposed and can dry out. Diversity decreases + nutrients wash out
- use of agrochemicals -> overuse pesticides and other chemicals disrupts the balance of the microorganisms in the soil
what are 4 effects of soil degradation
- desertification
- loss of arable and fertile land
- clogged and polluted waterways (soil and pesticides into waterways, damaging marine ecosystems)
- increased flooding (converted land is less able to soak up water, making flooding more common)
what are the solutions to soil degradation
any 3:
-> using less pesticides/ using natural fertilisers
-> crop rotation
-> Regulations to prevent deforestation
-> regulations against certain agro chemicals
-> addition of soil conditioners
-> wind reduction (planting trees and bushes)
-> improved irrigation
-> stop plowing marginal lands
what 3 major processes causes soil erosion
- sheet wash -> large areas of soil are washed away during heavy storms and in mountainous areas (landslides)
- Gullying -> channels develop on hillsides following rainfall. Over time these become much deeper
- wind erosion
what is soil conditioners, how are they used and how do they help soil
lime and organic materials. Farmers would crush limestone and chalk into the soil to increase the pH and counter soil acidification. Lime has the additional benefit of helping clay particles stick together so they act more like sand, trapping for air for decomposition and soil microorganisms
what is terracing
the method to reduce the steepness of slopes by replacing the slope with a series of horizontal terraces, separated by walls
what are cover crops
fast-growing crops to cover the soil between the rows of main crops to keep the soil particles in place
what is crop rotation
planting new species to improve the quality of the soil. I.e legumes add nitrogen to the soil as the bacteria in their root nodules fix nitrogen from the atmosphere
how do improving irrigation methods improve soil conservation
Trickle flow irrigation systems consist of a network of pipes covering the field, which have small openings next to plants where water comes out dropwise that can be taken by the roots before it evaporates
how is soil formed
Soil is formed by the process of weathering wherein rocks break down by the combined action of wind, water and climate.
What is the nutrient cycle
Nutrient cycles are the intricate pathways through which essential elements move within an ecosystem.
what is the nitrogen cycle
The nitrogen cycle is the biogeochemical cycle whereby nitrogen is converted into various chemical forms
what is soils role within the nitrogen cycle
- Plant and animal wastes decompose, adding nitrogen to the soil.
- Bacteria in the soil convert those forms of nitrogen into forms plants can use. (nitrates)
- Assimilation – nitrates from the soil are absorbed by the roots and are used to make amino acids and proteins which are incorporated into the plants.
- Animals then eat these plants and convert the nitrogen into proteins which may be passed onto the next trophic level
outline the transfers, transformations, inputs, outputs and storages within soil systems (one of each)
inputs: minerals, organic matter, air, water
outputs: leaching - downward loss of nutrients through soil layers, uptake by plants, radiation - albedo effect, erosion
transfers: translocation of materials within the soil, deposition
transformations: decomposition, weathering, nutrient cycling
Storages: organic matter, nutrients, organisms, minerals, air, water
Explain how can soil be viewed as an ecosystem
- Soil connects air, water, rocks, and organisms, providing essential ecosystem services.
- Key soil functions include air quality, temperature regulation, carbon/nutrient cycling, water cycling, waste decomposition, and habitat support.
- Billions of organisms in soil break down organic matter, releasing nutrients for plant growth.
- Micro-organisms like bacteria, algae, and fungi, and macro-organisms like earthworms and insects, contribute to soil health.
- Micro-organisms assist in organic farming by decomposing organic matter and fixing nitrogen, to produce a healthy crop
classify sandy soil, clay soil and loam soil, into ‘high’, ‘low’ or ‘quite low’ in terms of primary productivity
sandy soil = low
clay soil = quite low
loam soil = high
what does the primary productivity of soil depend on? (6)
mineral content
drainage
water-holding capacity
airspaces
biota
potential to hold organic materials
what are cash crops + example
Crops that are grown are often exported for profit and not for the local communities. I.e. oilseeds, coffee, tobacco, peanuts
what is malnutrition
an unbalanced diet with a lack or excess of nutrients
what causes uneven distribution of food production (4)
- climate and ecological conditions determine what will grow where
- land suitability - land available for farming is decreasing due to population growth and urbanisation
- Cash crop LEDC -> crops for export and revenue rather than to feed LEDC populations
- Food Waste in LEDC/MEDC. LEDC -> lack of storage infrastructure. MEDC - at a household or retail level
what 5 factors influence food choices of people and societies
- socio-economic
- cultural
- ecological
- political
- economic
define LIFDC
low income food deficient country
what is the overall pattern and trend of global food deficiency
EU, USA -> no deficiency
Sub-Saharan Africa, South Asia, South East Asia -> high rates of food deficiency
name and describe the following for an intensive commercial system:
- where is it located
- type of farming
- inputs
- outputs
- efficiency (low, medium or high)
- env impact
intensive:
- Western Netherlands
- Intensive commercial
- high labour and tech
- high per hectare and farmer
- high efficiency
- high -> greenhouses for salads and flowers are heated and lit. In dairying, grass is fertilised and cows produce waste
define farmings energy budget
the energy of a farming system
- efficiency of the system (the energy inputs compared to the outputs) = a more scientific and honest look at energy usage in a farming system
what is leaching
minerals are dissolved by water and are washed away. usually in high precipitation or irrgiation levels
what is translocation
movement of soil particles in suspension (liquid)
what is humus
plant and animal material in the process of decomposition - generally the top layer of soil
what can be done to improve env sustainability (4)
- altering human activities (eating less meat, eating more organic and locally sourced produce)
- improving food labels
- government control and monitoring (monitor and control the standards or TNC and food cooperations)
- create buffer zones (introduce buffer zones around food production areas to absorb farm waste)
what are GM crops + example
Genetically modified crops have DNA of one species inserted into the crop species to form a transgenic plant. Golden rice
what is golden rice and why is it beneficial
rice that has been made to synthesise a chemical compound (B-carotene) into vitamin A. It is beneficial because it could stop vitamin A deficiency suffered by 124 million people, however, it has not been yet grown commercially
why are some people against GM crops? (3)
- we do not know what it could release into the environment
- if a GM crop can kill a pest species, will the species die out?
- how it will affect food chains
what is the green revolution
A period of time where the increase of technology and research was made, which lead to increase of agricultural production worldwide.
1940-1960. this was undertaken to produce varieties of agricultural crops that were less prone to disease.
Give an example for the green revolution
In Mexico, increase in technology allowed for an increase in the yield of wheat crops to be exported. This led to a fall in the cost of rice.
What are some criticisms of the green revolution
Some critical of the green revolution varieties as the results has been more fertiliser, irrigation and pesticides have been used on them. These causes beautification, civilisation and the accumulation of chemicals in the food chain. They have also reduced genetic diversity in the crops as most farmers use them
what causes soil erosion
- sheet wash
- gullying
- wind erosion
what is sheet wash
large areas of surface soil are washed away during heavy storms and in mountainous areas - moving as landslides
what is gullying
channels develop on hillsides following rainfall. overtime these become much deeper
what is wind erosion
on drier soils, high winds continually remove surface layer
what is contour ploughing
a technique which ensures that ridges are at right angles to the slope, preventing moisture from running down the hill, reducing erosion
how does soil integrate into aspects of living systems
- hydrosphere
- atmosphere
- lithosphere
- precipitation effectiveness
why is soil fertility important
- fertile soil is a non-renewable soil. Once it is lost, it is gone. Soil formation takes a very long time, therefore needs to be preserved. Fertile soil holds nutrients and water within the soil better than barren soil
name and describe the following for an extensive subsistence system:
- where is it located
- type of farming
- inputs
- outputs
- efficiency (low, medium or high)
- env impact
- Amazon Rainforest
- Extensive subsistence
- Low - labour and hand tools
- Low - enough to feed the family
- High
- Low - only if enough land to move to and time forest to regrow
name and describe the following for an extensive commercial system:
- where is it located
- type of farming
- inputs
- outputs
- efficiency (low, medium or high)
- env impact
- Canadian Prairies
- extensive commercial
- high use of technology and fertilisers
- low per hectare but high per farmer
- medium
high- loss of natural ecosystem, soil erosion, loss of biodiversity
name and describe the following for an intensive subsistence system:
- where is it located
- type of farming
- inputs
- outputs
- efficiency (low, medium or high)
- env impact
- Ganges Valley
- Intensive Subsistence
- high labour, low technology
- high per hectare, low per farmer
- high
- low- Paddy rice has a polyculture, stocked with fish and other crops
what are the 4 material interactions that occur within the soil?
- hydrosphere - water moves through the soil and is evaporated
- atmosphere - particulate matter is deposited on the soil and can blow into the atmosphere
- lithosphere - weathering rocks form soil
- biosphere - plants extract nutrients from the soil and dead material ends up making the soil
what is soil formation dependent on?
- topography (affects soil present in the area)
- living organisms (provide organic component of fertile soil through death and decay)
- atmosphere (a vital part of soil formation process -> soil is more prevalent in environments of high moisture and temperature)
- precipitation effectiveness (balance between precipitation and evapotranspiration. When precipitation is greater than potential evapotranspiration, leaching occurs)
3 inputs of soil
- gas
- water
- solar energy
2 outputs of soil
- leaching
- nutrients through the roots
