The Impact on Agriculture on the Environment Flashcards
Climate Change
Global climate change (GCC) is one of the world’s major long-term challenges. The United Nations Framework Convention on Climate Change (UNFCCC) defines climate change as “a change of climate which is attributable directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.
Caribbean Countries and Climate Change
It is important for Caribbean countries to monitor the effects and understand the importance of climate change. They are very vulnerable countries and least able to adapt to the climate changes that are taking place. The Caribbean Planning for Adaptation to Global Climate Change Project (2002) report on vulnerability and adaptation: A regional synthesis of the vulnerability and adaptation component of Caribbean National Communications, identified some of the impacts that are of major concern to Caribbean territories, including:
- sea level rise and associated impacts, such as storm surges, flooding, landslides, coastal erosion of natural areas and sea defences, inundation of low-lying coastal areas
- increase in the number and intensity of tropical storms and hurricanes
- changes in precipitation patterns and the impacts on freshwater aquifers.
Agriculture and Methane Production
Agricultural methane emissions are emissions from rice production, animals, animal waste, and agricultural waste burning. Methane production from rice fields is a big source of atmospheric methane. The warm, waterlogged soil in such fields provides ideal conditions for the formation of methane. Although some of the methane produced is usually oxidesed by methanotrophic organisms in the shallow overlying water, the bulk of the methane is released into the atmosphere. It should be noted, however, that because the paddy fields are only fully waterlogged for a few months each year, methanogenesis is generally much reduced and, where the soil dries out sufficiently after harvesting, the soil can become a temporary sink for atmospheric methane.
The increase in rice cultivation to meet the needs of growing human populations and exports may result in rising methane emissions from this source. However, technologies and strategies are available that may lessen the human impact via this greenhouse gas source. Such strategies may include the use of more integrated approaches to irrigation and fertiliser application in rice cultivation and the use of varieties of rice that grow under drier conditions. There is potential for the use of improved varieties of rice, capable of producing a much larger crop per unit area, which would allow for a reduction in the area of flooded rice fields, without a decrease in rice production.
The Features of Sustainable Agriculture
What is sustainable agriculture?
Over the years the practice of agriculture has resulted in a number of problems that appear to threaten food production. This has led humans to try and make agricultural practices compatible with sustainable ecological and social systems. This goal is usually called sustainable agriculture and it aims to produce food and food products on a sustainable basis while at the same time repairing the damage caused by destructive agricultural practices.
Sustainable agriculture therefore seeks to integrate the goals of environmental health, economic profitability, and social and economic equity. The principle of sustainable is based on the premise that we must meet the needs od the present generation without compromising the ability of future generations to meet their own needs.
If the Caribbean is to achieve the goal of sustainable agriculture then stewardship of natural and human resources must be a priority. Stewardship of human resources implies:
- meeting social requirements, such as adequate working and living conditions
- considering the needs of rural communities
- considering consumer health and safety both in the present and the future.
Principles of Sustainable Agriculture
Ecological Integrity:
- enhancing the vitality of agricultural systems while maintaining the quality of natural systems
- utilising efficient soil management techniques
- placing emphasis on the use of renewable energy
Social Integrity:
- respecting all forms of life
- recognising and respecting the fundamental dignity of all human beings
- nurturing and preserving the cultural and spiritual integrity of societies
Economic Viability:
- enabling people to produce enough for self-sufficiency and/or income generation
- enabling people to gain sufficient income to compensate for labour costs and other inputs
- enabling people to engage in practices that promote conservation of resource and so minimise risks and costs to address adverse impacts
Adaptability:
- allowing adjustments to be made to constantly changing conditions for farming
- develop, adapt and use new and appropriate technologies
- develop new innovations in social and cultural contexts
Social Equity and Justice:
- ensuring resources and power are distributed so that basic needs of all members of society are met equitably
- assuring the right to use land, adequate capital, technical assistance and markets
- ensuring all people have an opportunity to participate in decision making processes related to agriculture
Threats to sustainable Agriculture: Natural disasters and climate change
Natural disasters as a threat to sustainable agriculture:
Natural disasters are naturally occurring events, or extreme forces of nature, that cause death or destruction of people and/or their property. In the Caribbean examples of natural disasters that affect many people and agricultural activities annually are:
- severe dry weather due to limited precipitation and high temperatures
- floods due to serve precipitation or coastal overtopping
- hurricanes
- volcanic eruptions
Impact of Natural Disasters
Impacts of natural disasters on agricultural systems can be direct of indirect. Direct impacts from floods arise from the direct physical damage to crops and livestock caused by an extreme flooding event. Indirect impacts could be caused by a loss of potential production due to disturbed flow of goods and services, lost production capacities, and increased costs of production. These may appear as low incomes or revenues, decreases in production, environmental degradation and other factors. Loss of crops can also have long-term consequences for the ability to generate income, thus affecting economic sustainability.
Climate Change as a Threat to Sustainable Agriculture
Climate change can pose a serious threat to sustainable agriculture in the Caribbean:
- Climate change may result in local temperature changes that can severely impact weather patterns. severe changes in weather patterns can cause a decline in agricultural productivity. in many instances agricultural ecosystems may not be able to adapt quickly to accommodate the rate at which climate change is taking pace, and this could result in the loss of ecosystems.
- Some farmlands may experience increased incidents of flooding and farmers may lose crops and livestock. This could reduce the economic viability of the sector because of a decline in income and revenue, thus reducing sustainability.
- Natural factors such as changes in volcanic activity and soar output can also affect the Earth’s climate
Threats to Sustainable Agriculture: External Shocks
External shocks: global markets and price fluctuations:
Demand is the amount of a product that consumers are willing and able to buy at various possible proces, once they are free to express their preferences. Supply is the quantity of that product that is offered for sale at various prices, other things being equal. Generally, as prices of a product rise, the supply increases and the demands for that product falls. The reverse is also true.
The difference between the cost of production and the price that buyers are willing to pay in the marketplace is called a profit. In all instances farmers seek to make a profit from their agriculture business so that it is economically sustainaable. In a free market, supply and demand should be in equilibrium. In some instances however, there are expectations to the theory of demand and supply. This is when consumers tend to buy products regardless of the price. When this happens it is referred to as price inelasticity. Usually, trade in the global economy is linked to the various currency exchange rates. Fluctuating exchange rates can significantly impact demand and supply levels.
Imports of Cheap Agricultural Products
Globalisation has a major influence on the agriculture sector in many Caribbean countries. Caribbean economies depend on exports from the agriculture sector for a major part of their income, revenue and foreign exchange earnings. If no global markets were available to sell produce, no revenue would be generated. There would then be no money available to pay workers and jobs would be affected.
However, cheaper imports of agricultural products have the potential to threaten the viability of farms. They could also increase food insecurity, as countries that import large amounts of food may become less self. sufficient in food.
Environmentally sustainable practices: Contour farming, terracing and agroforestry
Why practise contour farming, terracing and agroforestry?
Many Caribbean territories are hilly and agriculture id often practised on these hillsides. A method of soil preparation and farming that reduces the soil erosion caused and promotes soil conservation is required.
Many farmers clear the vegetation before farming. This exposes the soil to the agents of erosion since there is no vegetation to hold the soil particles together. When it rains or when the crops are irrigated, the water runs downhill, the faster it runs the greater the loss of soil. This is a problem because it not only results in the loss of valuable topsoil, but it also increases sedimentation of waterways. Also, when farmers use agrochemicals these are easily leached into the waterways, reducing the water quality. Contour farming, terracing and agroforestry are sustainable practices of soil conservation
Contour Farming
Contour farming is a method of soil preparation where the land is ploughed across a gentle slope following its contours. This slows water runoff during heavy rainfall, reduces soil erosion and allows percolation of water. The rows run perpendicular to, rather than parallel to, the natural slope of the land, generally resulting in furrows that curve around the hillside, which trap water and allow it time to percolate and not run off immediately from which is the planting of different crops in alternation strips along the contours of the land. In this way when one crop is harvested the other remains, protecting the soil and keeping water from running directly downhill.
The effectiveness of contour farming for water and soil conservation depends on the design of the system, the soil type, climatic conditions, the slope of the land and land use of the individual location.
Advantages:
- it reduces sheet, rill and gully erosion
- it reduces runoff and flooding
-it increases soil moisture retention and improves irrigation distribution
Disadvantages:
- it is not suitable for lands with heavy overland flows of water
- the rows are not practical for some farm machinery
Terracing
Terracing is an agricultural practice used on steep slopes. It involves shaping the land to create level shelves of earth to hold water and soil. This method of soil preparation and farming alters the shape of the slope to produce flat areas that provide a catchment for water and a solid area for crop growth.
Advantages:
- it can protect the soil from rapid erosion because it reduces the length of the slope the water has to run over, slowing the flow of water
-level terraces trap and hold rainwater, allowing for the cultivation of water-intensive crops
- terracing creates flat spaces for crops and canal for water to flow
Disadvantages:
- terracing may sometimes require large inputs of labour to construct and maintain
- unmaintained terraces can sometimes lead to mudslides, the creation of gulleys and increased soil erosion. This can be especially disastrous on sandy soils or on extremely steep terrain
- terracing can also reduce soil quality by promoting leaching of some important nutrients from the soil
Agroforestry
Agroforestry is a practice that combines forest trees and shrubs with crops and/or livestock on the same land. The international combination of agriculture and forestry creates integrated and sustainable land use systems. This practice results in a sustainable, diverse, profitable and healthy land use system,
Advantages:
- Agroforestry reduces the need to cut trees from hillsides and so preserves forests
- it can help to reduce the loss of natural biodiversity while at the same time create habitats that support greater biodiversity
- this practice has the potential to reduce the impacts of climate change since the forest tree also serve as a good store of carbon
Disadvantages:
- Agroforestry systems are ecosystem-specific and on low-grade soils may limit the choice of suitable crops and plants
- it may not be suitable for farmers with limited land space since consideration must be given to the competition between trees and food crops
- it may require high investment costs which poorer farmers may not be able to afford
Environmentally Sustainable Practices: Crop rotation and conservation tillage
Crop Rotation: Crop rotation is the practice of growing different crops in succession on the same land over a period of time, occasionally the land is left uncultivated or is planted with a cover crop. This is mainly to preserve the productive capacity of the soil. The goals of crop rotation are to help manage soil fertility and also to help avoid or reduce problems with soil dwelling pests and some soil-borne diseases.
This method is effective because different crops have different nutritional requirements and extract different nutrients from the soil. Growing one crop continuously can deplete the soil of specific nutrients resulting in reduced yields and increasing the need for the farmer to apply agrochemicals to supplement that particular nutrient. This could result in increased costs and water contamination due to runoff and leaching.
Advantages:
controls some pests and disease
- controls some weeds
- improves soil fertility
- restores soil fertility
Disadvantage:
- it can sometimes be challenging to find alternating crops that provide the same economic benefits
- different crops may require different machinery for their cultivation, resulting in some machinery being idle at times
Conservation Tillage
Conversation tillage is a strategy that reduces the physical disturbance of the soil. In this method, special machines are used to cut a narrow furrow in the soil for seeds to be planted. Seeds are planted at the same time that fertilisers and pesticides are applied. With less disturbance of the soil there is less likelihood of erosion as the soil is more stable.
In cnversation tillage. residues from the previous crop are left in the soil, partially covering the soil surface and helping to hold the soil in place. The decomposing organic matter releases nutrients into the soil, improving its fertility. Conservation tillage help to increase the organic matter in the soil, thereby increasing and improving its water-holding capacity. It effectively reduces soil degradation and helps improve crop yields.
Environmentally Sustainable Practices: Pest Control
Pest control in agricultural systems refers to the regulation or management of a species defined as a pest. Pests are harmful to crops, livestock, the environment and the economy. pests are undesirable competitors, parasites or predators in ecosystems. Major agricultural pests in the Caribbean include insects, nematodes, worms, some bacteria and viruses, weeds and vertebrates. There are different methods available for controlling agricultural pests. These include: biological control, genetic control, pheromones and hormones and integrated pest management.
Biological Control
Biological control is the deliberate use of natural enemies of an agricultural pest to reduce its populations. Biological control requires knowledge of the ecosystem, the ecology and behaviour of the target pests and the biological control agent. Biological control agents can target any stage of the pest life cycle. This increases the chances of successful eradication of the pest. Biological control does not involve modification of genes so there are no fears of harmful effects on consumers.
Advantages;
- it does not involve the use of chemicals so no chemical residues are introduced into the environment or its food chains
- natural predators of potential pests are available and once identified are usually target-specific
Disadvantages:
- it involves introduction of a new species, which may attack non-target species
- Sterilised males may have to be introduced frequently
Genetic methods in Pest Control and Disease Control
Pest- and disease-resistant crops are developed by selective breeding measures and require crop varieties that are naturally resistance to particular pests and diseases to be identifies. These varieties are then propagated using special breeding programmes.
Genetic engineering is non-chemical control method. There are certain genes in an organism that can confer pest and disease resistant characteristics. These genes are identified, isolated and the genes are then transferred into the target plant or animal. These newly constituted organisms are then able to reproduce and pass on the genes to their offspring. This means the new organism will have the desired pest-and disease- resistant characteristics.
Advantages:
- the method has no direct impact on non-target species
- it is effective for eliminating pests in low-density populations
- no chemicals are used for controlling the pest and so no chemical residues are left in the environment
Disadvantages:
- it is costly and time-consuming to produce resistant varieties
- selection for commercial features, for example high yields, could at times lead to loss of resistance through natural selection. This then makes it very difficult to control the particular pest or disease
- it is a labour- and technology- intensive process
Integrated Pest Management
Integrated pest management (IPM) is a method used to solve pest problems that minimise risks to people and the environment. It combines several methods to prevent and manage pest problems. Although in IPM the use of pesticides may be an option, when non-chemical methods are used first, pesticides are often not needed. IPM therefore focuses on long-term prevention of pests or their damage by managing the ecosystem. There are five major components common to all IPM programmes:
1. Pest identification
2. Monitoring and assessing pest population and pest damage
3. Development of guidelines for when management action is needed
- Methods for preventing pest problems
- The use of a combination of biological, cultural, physical/mechanical and chemical management tools
Environmentally Sustainable Practices: Organic Farming
General Features of Organic Farming:
Organic farming is a method of crop and livestock production that uses natural resources methods of farming. This means that chemicals, pesticides and other substances that could harm the environment are not used organic farming. Besides pesticides, organic farming does not involve the use of genetically modified organisms, antibiotics and growth hormones.
The principal goal of organic farming is to promote practices that are sustainable and harmonious with the environment. Organic farming uses natural methods of farming like crop rotation, green manure, compost, biological pest control, mechanical cultivation and other natural methods to maintain the fertility and productivity of the soil.
Organic farming is designed to optimise the productivity and fitness of communities within the agro-ecosystem, including soil organisms, plants, livestock and humans. This farming technique promotes and encourages balanced host/predator relationships. Organic residues and nutrients produced on the farm are recycled back to the soil. Cover crops and composted manure are used to maintain the soil’s organic matter and fertility. Preventative insect and disease control methods are practised, including crop rotation, improved genetics and resistant varieties. Integrated pest and weed management, and soil conservation techniques are used in organic farming.
The General Principles of Organic Farming
- protecting the environment, minimising soil degradation and erosion, decreasing pollution, optimising biological productivity and promoting a sound state of health.
- maintaining long-term soil fertility by optimising conditions for biological activity within the soil
- maintaining biological diversity within the system
Advantages:
- Organic fertilsers are cheaper since they include material that are usually considered waste materials on farms and these are often readily available
- Organic fertilisers are slow releasing, slow acting and long lasting because they release nutrients only upon decomposition
- The long-term sustainability of economic and environmental benefits is better when organic fertilisers are used
Disadvantages:
- Crop rotation prevents organic produce from being produced all year long, which means that unlike conventionally grown produce, organic foods may not be available during any given season
- This method of farming does not guarantee that enough food could be produced to meet the needs of large populations. This could lead to food insecurity in some countries.
Hydroponics
Features of Hydroponics:
Hydroponics od often described as ‘the cultivation of plants in water’. It is a technique for growing plants without using soil. Through this technology, plant roots absorb a balanced nutrient solution dissolved in water that meets all the requirements of the plant. Since many different aggregates or media can support plant growth, the definition of hydroponics has been broadened to ‘‘the cultivation of plants without soil’
The practice entails growing plants in a fertilised water solution, on an artificial substrate, in an artificial environment such as greenhouse. Growing plants always need to have a balanced supply of air, water and nutrients. Hydroponics can be classified either as an ‘open system’ or a ‘closed system’. In the ‘open system’ of hydroponics, the nutrient solution is mixed and applied to the plant as required, instead of being recycled. Examples of some open system are growing beds, columns made out of tubular plastics or vertical and horizontal PVC pipes and individual containers, such as pots, plastic sacks and old tyres.
In ‘closed system’, the nutrient solution is circulated continuously, providing the nutrients that are required by the growing plants. Examples of closed systems are those that use floating roots, Nutrient Film Technique (NFT), plastic or polystyrene pots set up in columns and PVC pipes or bamboo.
Advantages and Disadvantages of Hydroponics
Advantages:
- crops can be cultivated throughout the year
- produces cleaner, fresher and healthier products
- crops are grown in a controlled environment
Disadvantages:
- the technique can have high start-up costs if done on a chemical scale
- practising the technique on a commercial scale requires good technical knowledge as well as well as a sound grasp of basic principles
- a constant supply of water is required
