5. Application Questions
Discuss the challenges of managing terrestrial food production systems sustainably.
- Continual increase in human population means there is a greater demand for food. - Intensive farming methods are often used to meet this increasing demand. Challenges from the environmental impacts from intensive / commercial farming methods can include: - Use of pesticides that kill non target organisms and can reduce overall biodiversity. - Use of some non-biodegradable chemicals e.g. DDT which can bioaccumulate and biomagnify building up concentrations through the food chain. - Use of fertilizers that can result in nutrient run off that causes eutrophication of waters reducing biodiversity. - Monoculture farming that increases risk of disease affecting all crops/animals. - Soil degradation e.g. excessive irrigation can increase nutrient run-off and also cause salinization. Impacts can be reduced by adopting pollution management strategies through legislation or education e.g.: - Legislation can be used to reduce the amount of growth hormones/drugs used in animal husbandry- restrict the amount of pesticides/fertilizers used that in turn limits pollution being leached into nearby water courses. - Reduce the use of pesticides by removing pests/weeds manually/using biological predators. - Avoiding application of fertilizers near water courses. - Use of buffer zones to absorb pollutants/pesticides/fertilizers from run-off. - Adoption of crop rotation scheme to prevent build-up of soil pests without use of pesticides.
Explain why soil can be viewed as a dynamic ecosystem.
- Ecosystems are a community of living organisms and the physical environment that they interact with. - Soil is a dynamic open ecosystem as it has inputs, flows and outputs. - It contains an array of different organisms, ranging from microorganisms to larger organisms, such as worms, insects and moles. - Leaves and organic debris on the surface of the soil is broken down by decomposers. - The dead organic matter is consumed and is further broken down by insects and earthworms. - The earthworms move the decomposed material further down into the soil horizon. - They help to aerate the soil, making the soil a suitable habitat for other organisms. - Decomposition produces nutrients that can be absorbed by plants. - They provide a food source for other organisms and in turn provide a food source to birds. - Some soils contain nitrogen fixing bacteria that live symbiotically with legumes and provide nitrogen for the plant.
Evaluate the relative environmental impacts of two given food production systems.
- Food production and the supply chain can have wide-ranging positive and negative impacts on the environment. - Negative impacts include: escalating water and land use, soil erosion and degradation through loss of fertility or desertification, loss of biodiversity, and intensive use of energy with associated greenhouse gas emissions. Factory Farming - Reduces the amount of land needed for meat production, however, these farms are a serious air and water pollutant. - The waste of these animals ends up in the nature and poses a constant risk of drinking water contamination and seriously affects the air quality of the nearby areas. - One solution for the problem with animal waste lays in its use for production of biofuel which can then be used for production of electricity but this practice is the exception rather than the rule. Mass Meat Production - Main contributors to carbon dioxide emissions which in turn are the main cause of the climate change. - The meat industry is estimated to be responsible for about 9 percent of total carbon dioxide emissions which are a result of emissions of various gases from the farms as well as from the microbial activities after application of animal waste as fertilizers. Animal Husbandry - Poses a serious threat to the local ecosystems and biodiversity due to the use of the land for grazing and animal feed production. - As much as one quarter of the Earth's surface is used for grazing and about one third of arable land is used to produce animal feed. - As a result, the wildlife species struggle with lack of habitat, while some are even threatened with extinction.
Explain why there is still hunger in some places when enough food is being produced to feed the entire world population.
- Poverty prevents people being able to afford food. - Uneven production of food in which location of high food production does not match where large populations live, - Inadequate transport infrastructure prevents food produced reaching the market. - Loss of crops during storage or transport due to lack of refrigeration. - Competition for alternative use of crops to feed cattle. - Extreme water events which destroy crops. - War can make it difficult to get food where it is required.
Explain the relationship between soil ecosystem succession and soil fertility.
Fertile soils develop over a long time. - The amount of time required for soil formation varies from soil to soil. - First, lichens, which grow on rock, appear in a destroyed region. - The lichens help break down the rock. - Then, as lichens die and decompose, and weathering breaks apart rock, soil begins to form. - As soil becomes richer, small plants like mosses and ferns appear, and the lichens start to disappear. - The soil continues to become richer as plants continue to die and decompose, and flowering plants and grasses appear, bringing insects to the region. - In time, shrubs and small trees cover the region, creating a suitable habitat for reptiles, birds, and mammals. - As the shrubs and trees grow, smaller plants die from lack of sunlight and add more organic material to the soil. - Eventually, the shrubs and trees die because taller trees cover the region. - This all happens gradually over a long period of time.
Compare and contrast the inputs, outputs and system characteristics for two given food production systems.
Intensive Charolais Beef Production in France Inputs: High use of energy for food distribution/ capital/ technology/ labour/antibiotics and hormones. Outputs: Cheap meat/high habitat destruction to make bigger fields/eutrophication/high pollution runoff/high soil losses from erosion. Nomadic Cattle Grazing of the Himba Inputs: Nomadic grazing moving from place to place gives land a chance to recover/no capital/low use of labour + water/ no use of technology or fertilisers. Outputs: Himba cattle provide meat, milk and fuel/owning cattle gives status/low yields.
Discuss the links that exist between sociocultural systems and food production systems.
Shifting Cultivation - Slash and burn- widely used by those who can't afford other methods of land clearance. - Fertilisers in the soil will last and people are forced to move after it has been depleted. - Low population = affected by cultural beliefs. Extensive Subsistence Farming - High demand for food due to high population which allow for high labour inputs. - High rainfall and warm temperatures support it. Agribusiness - After WWII, concerns for self-sufficiency were raised; smaller farms were combined to create large areas to plant the same crops. - Maximises productivity and profit to compete in a global market.
Discuss the influences of human activities on soil fertility and soil erosion.
Soil is a non-renewable resource that once it is eroded it is not renewed. - Soil erosion is the permanent change of the main characteristics of soil that could see it lose its fertility, pH, color, humus content or structure. - Soil erosion occurs naturally by wind or harsh climatic conditions but human activities include overgrazing, overcropping and deforestation. Overgrazing - Occurs when farmers stock too many animals such as sheep, cattle or goats on their land. - The animals damage the soil surface by eating the vegetation and either digging into wet soil or compacting dry soil with their hooves. Overcropping - When the land is being continuously under cultivation and is not allowed to lie fallow between crops. - This constant farming of the land reduces the soils ability to produce valuable humus for soil fertility as it is constantly being plowed or stripped for crop growth. - The soil becomes drier and less fertile. Deforestation - The cutting down of large areas of forests leaving an open, exposed landscape. - Occurs for many reasons, such as the sale of wood, charcoal or as a source of fuel, while cleared land is used as pasture for livestock, plantations of commodities, and settlements. - The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and aridity (drying of soil). Urbanization - Requires the removal of vegetation and top soil for construction. - Heavy machinery compact the soil surface making the soil impermeable to water. - Water moves over the soil removing valuable topsoil. Monoculture - Leads to soil exhaustion. - These lost nutrients are replaced by the use of chemical and organic fertilizers but are expensive.
Compare and contrast the structure and properties of sand, clay and loam soils, with reference to a soil texture diagram, including their effect on primary productivity.
Soil structure depends on: - Soil texture- the amount of sand and clay. - Dead organic matter. - Earthworm activity. Clay: - Fertile in temperate locations. - In tropical areas clay is permeable and easily penetrated by roots. - Nutrient deficient / easily leached in tropics. The more clay present in soil the higher the force needed to pull a plough. Different soil types have different levels of primary productivity: - Sandy soil - low - Clay soil - quite low - Loam soil - high Primary productivity of soil depends on: - Mineral content - Drainage - Water-holding capacity - Airspaces - Biota - Potential to hold organic materials
Compare and contrast terrestrial versus aquatic food production systems.
Terrestrial - Most food is harvested from relatively low trophic levels (producers and herbivores). Aquatic - Most food is harvested from higher trophic levels where the total storages are much smaller. - Energy conversions along the food chain may be more efficient in aquatic systems, the initial fixing of available solar energy by primary producers tends to be less efficient due to the absorption and reflection of light by water. The Second Law of Thermodynamics states that energy goes from a concentrated form to a dispersed form, the availability of energy to do work therefore diminishes on the system becomes increasingly disorder. - It explains how energy transformations in living systems can lead to loss of energy from the system.
Analyse tables and graphs that illustrate the differences in inputs and outputs associated with food production systems.
Terrestrial farming systems can be divided into several types: - Commercial Farming: Farming for profit- involves one crop. - Subsistence Farming: Food is produced only to feed the farmer and family- no sale for profit. Commercial and subsistence farming can be intensive or extensive. - Intensive Farms: Take up a small area of land but aim to have very high outputs per unit area of land. - Extensive Farms: Large in comparison to the money and labor put into them. Organic farming prohibits the use of genetically modified organisms (GMOs), chemical fertilizers and restricts the use of chemical pesticides. Nomadic herding involves moving with animals such as cattle and goats, in search of suitable grazing areas. Shifting agriculture is a method of cultivation involves clearing land, typically tropical forest by cutting and burning (often referred to as slash and burn).
Evaluate the soil management strategies of a given commercial farming system and of a given subsistence farming system.
The North American Prairies - Use of tillage methods: Yes - Use of monoculture: No, they grow a range of foods - Intensive use of soil: Possible- although may not have the resources required to do this - Intensive irrigation: No - Use of pesticides: Sometimes, but will depend on funds available - Use of marginal land: Yes, high labour is used to clear and farm the area but uses limited inputs of fertilisers/water/pesticides Commercial Farming - Use of tillage methods: Yes - Use of monoculture: Yes - Intensive use of soil: Yes to try and maximise output and profits. - Intensive irrigation: Yes - Use of pesticides: Yes, extensive use - Use of marginal land: Yes, i..e drain wetlands and use high levels of fertilisers/pesticides/water
Evaluate strategies to increase sustainability in terrestrial food production systems.
To achieve sustainable food production, many different factors need to be considered: - Political commitment to sustainable development with the will to make changes, such as new legislative and economic support for sustainable farming systems. - Understanding of the ecology of farming systems and how they are interconnected to the wider environment, which can be used to inform policies and guidelines that support sustainable farming. - Change in social and individual behaviour. - Local produce and use of farmers markets. - Growing indigenous crops. - Monitoring multi-nationals. - Buffer zones (nutrient run-off). - Use of polyculture instead of monoculture farming involves growing multiple crops rather than focusing only on one. - Reduction of meat production.
