ENVIRONMENTAL ISSUES UNIT 4
Environmental issues in food production Food Production Environmental issues Primary Production Land degradation (erosion) Use of chemical products- Pesticides and Herbicides Irrigation Salinity Volume of water used Secondary production By-products Wastage Packaging
Primary Production: the sustainable way… Sustainability in Agriculture means using farming practices that maintain the lands productivity so it is available for future generations. There are four main ways the land’s productivity can be sustained Managing the use of water Managing the use of chemicals Preventing Land Degradation Implementing Organic Farming Irrigation Salinity Herbicides Pesticides Erosion Improving Soil health Benefits to producer, consumer and environment. There is a common misconception that organics is a new fad or something reserved for left-wing hippies, greenies or the well-to-do. Sustainable farming: Instead of spraying chemicals to get rid of pests, it is about growing plants that attract beneficial insects. Instead of applying fossil-fuel-based fertilisers to the soil, which destroys the soil's capacity to regenerate, a technique is to lace the fields with legumes, which naturally help to fix nitrogen in the soil1. This approach shows promise for the future of food.
Managing the use of water Irrigation is the artificial application of water to the land or soil. Australia is the driest inhabited continent, and irrigated water is needed to supplement low rainfall to assist in growing crops and pasture. Agriculture uses 65-75 per cent of the water consumed in Australia per annum and irrigation uses 90 per cent of that. In 2004-05, the value of produce from irrigated agriculture was estimated at $9.1b. Australia exports around 65% of its agricultural production to international markets. Sustainable Irrigation systems are implemented so that water can be conscientiously used and used to improve the productivity of farms. Dryland farming- relies on rainfall. Common crops produced using irrigation include rice, cotton, canola, sugar, various fruits and other tree crops and pasture, hay and grain for use in beef and dairy production. http://www.csiro.au/Outcomes/Water/Water-Book/Chapter-8-Irrigation.aspx
Where does the water for irrigation come from in Australia? In general, water for irrigation comes from two main sources Surface water- drawn from rivers, lakes, weirs and dams- e.g Murray Darling system (VIC, WA, NSW) Underground aquifers- e.g Great Artesian Basin. (NT 82%, SA 46%) Water taken from river systems (rainfall) or underground Water used for agriculture Too much water us used Land clearing of large water using trees. Water table rises causing salinity in the earth. Salty water runs off plants back in to rivers and destroys crops. Food production and profits are effected Major river systems used for irrigation in Australia include the Murray-Darling system. A major source of ground water in Australia is the Great Artesian Basin. Although the Murray-Darling Basin receives only 6% of Australia's annual rainfall, over 70% of Australia's irrigation resources are concentrated there, which makes up around 90% of the resources in the basin. It contains 42% of the nation's farmland and produces 40% of the nation's food. It can be seen that, in Australia as a whole, over 70% of water is devoted to irrigation. The Murray Darling Basin is Australia’s largest irrigation region. In 2007-08 the MDB had irrigated production to the value of $5.1 billion, or 41 per cent of Australia’s total value of irrigated food production. The Great Artesian Basin is the largest and deepest artesian basin in the world, covering 23% of the Australian continent. The basin provides the only reliable source of fresh water through much of inland Australia. The basin is 3,000 metres (9,800 ft) deep in places and is estimated to contain 64,900 cubic kilometres (15,600 cu mi) of groundwater. rrigation is the process through which water is channelled onto land to support the growth of crops or pasture. It accounts for 70 per cent of water used in Australia each year, or 10,442 gigalitres, and is essential for the production of many crops, such as rice. One-third of irrigators around Australia are growing pasture for grazing. However, the industries that use the most water per hectare are rice (12.4 megalitres) and cotton (6.7 megalitres). The Queensland cotton producer, Cubby Station, has storages that hold as much water as Sydney Harbour. Nearly three-quarters of the irrigation done in Australia occurs in the Murray-Darling Basin, where 1,472,241 hectares of land is irrigated. There are 12 other major irrigation areas, including the Ord River region in north-west Western Australia, the Burdekin-Haughton Irrigation Area in Queensland, and the Sunraysia Irrigation Area in north-east Victoria. Irrigators channel water from a number of sources. Surface water, which comes from rivers and dams, is used by 71.5 per cent of irrigators. The number of irrigators using recycled or re-used water has increased 49 per cent between mid-2002 and mid-2004. About 4.8 per cent of agricultural establishments buy extra water for irrigation, while 3.4 per cent have sold water. The benefits of irrigation are obvious. The Australian Natural Resources Atlas says irrigated production accounts for approximately 26 per cent of the total gross of production from agriculture – up to $7.2 billion. The Murray-Darling Basin Commission estimates the value through processing beyond the farm gate increases four-fold. The costs of irrigation, particularly those to the environment, are becoming easier to quantify. For example, irrigation is linked to increased salinity and turbidity of water. In some regions, it has significantly altered and sometimes led to the reversal of the flow patterns of water in rivers. In turn, that puts the plants and animals that depend on river ecosystems at risk. A number of challenges face the industry. As demand for water increases, less will be available for irrigation. Work is under way to define water ownership rights and set up water trading and pricing schemes. Irrigators are also working to use water more efficiently through reducing storage losses, distribution losses and application losses. The key question the industry must answer is: is irrigation sustainable? Irrigators must justify the costs, both economic and environmental, against their output.
Where the water comes from in the Murray- Darling basin
How is the water controlled How is the water controlled? Through Channels, Locks, Barrages and Pipes Dams- Construction of the Hume Dam, above Albury, was begun by New South Wales and Victoria in 1919. it is a gated concrete gravity dam with four earth embankments and twenty-nine vertical undershot gated concrete overflow spillways. It is estimated to s estimated to hold approximately six times the volume of water in Sydney Harbour. Weir’s- a barrier across a river designed to alter the flow of rivers to prevent flooding, measure discharge, and help render rivers navigable. Barrages and Locks- At times the rivers are closed with constructed to keep the inflow of sea water out of the fresh water or to control the flow. Supporting Irrigation systems ‘Weirs/locks/barages- these help in Storing water in the wetter winter/spring months and later releasing it during the drier summer/autumn months to meet supply requirements. Making releases from the most downstream storage first to minimise losses due to spill. Making timely releases from major sources to accurately match water supply with demand, with close attention paid to the time it takes for flow to travel along the Murray. Channels and canals are built to help move water from natural waterways to supply water to crops.
Water lost? All plants, whether irrigated or rain fed, transpire water from the leaves to reduce the temperature when exposed to the sun. This is called the hydrological cycle - the movement of water from the atmosphere to the earth and back again.
Poor water management = Salinity Salinity is salinisiation of soil, surface water or ground water due to human activity such as agriculture. Overuse or poor management of irrigation water on crops Irrigation on inappropriate soil Leakage of surface water and the rising water table containing salts Since European settlement, the landscape has changed dramatically in a very short time due to the clearing of native vegetation for grazing, cropping and other agriculture. These land use practices have substantially increased the amount of water leaking into the groundwater beneath the root system. Since there is more water going into the ground than is being removed, the watertable is rising to the surface. Where the groundwater contains salt or intercepts the vast stores of ancient salt in the landscape, this salt seeps to the surface of the land, and into the rivers and streams.
Salinity = Damage Inefficient irrigation and drainage systems are a major cause of excess leakage and increase the risk of salinity and waterlogging in irrigation areas. The build up of salts in the soil profile reduces the plant’s ability to take up water, limiting plant growth. Plants absorb water by osmosis, taking in salt particles to draw water from the soil. If the salt content of the surrounding soil/water medium is too high, water can no longer move into the plant roots. When salinity has affected a landscape, warning signs appear. These include sick or dying trees and declining vegetation.
SALINISATION- Salinity one of the greatest challenges facing agriculture today. Irrigation systems provide an input of water too quickly for drainage systems result in dissolved mineral salts being brought to surface of soil. Salinity (total concentration of water soluble salts in soil) makes it hard for plants to withdraw water from the soil, making them wilted, retarding growth and product yield.
Salinity = The costs Direct costs of increasing salinity to agricultural producers include: reduced farm income reduced water quality for stock, domestic and irrigation use reduced productivity of agricultural land animal health problems e.g. saline water supply breakdown of soil structure, increased erosion and nutrient loss loss of beneficial native flora and fauna decreased land value When salinity has affected a landscape, warning signs appear. These include sick or dying trees and declining vegetation.
Strategies to effectively use irrigated water Laser Leveling- This is where GPS technology is used to ensure the correct level or slope is created. It results in better irrigation and reduced water use. This allows the farmer to flood irrigate. Maintain and repair breaks and channels and pipes- Seepage and leaks can cause a great water loss and channels that are kept maintained will not lose water. Channels that are concrete lined lose much less water. Capturing irrigation water and reusing it- Draining the surface or subsurface movement of excess water from the paddock or farm. When capturing irrigation water in channels and dams, it can then be cleaned and reused. Strategy 1: Laser levelling. Laser levelling refers to moving soil to achieve a uniform level of the surface while providing a downward slope to improve water movement. The topsoil is generally removed and stored at a nearby site and the subsoil levelled with a small rate of fall down the paddock or bay. The topsoil is then evenly re-applied to produce a level paddock with a rate of fall suitable for flood irrigation of the soil type involved. Laser levelling allows you to flood irrigate paddocks that may not have been previously suitable. It can also improve the efficiency of your irrigation system by reducing height differences across the paddock and providing a constant fall for ease of water movement down the bay. Strategy 2: If crops are irrigated then a lot of water that is taken from a river or dam can be lost through seepage, evaporation and transpiration, before it actually gets to the farm. Recent documentation of the effectiveness of water conveyancing in the Murray-Darling Basin from river to farm gate shows that up to 85% of water can be lost when open earthen channel supplies are used. On the other hand, as little as 5% can be lost when new fully piped systems are used and managed well. Strategy 3: Drainage runoff results from either over irrigation or natural rainfall that failed to infiltrate the soil. When flood irrigating, a proportion of the applied water will always leave the paddock as runoff if distribution uniformity is maximised. Collecting this water as it moves into the tail drain makes it possible to irrigate further paddocks or store it in ponds for later use. Reclaimed water should be monitored for salt levels because increased salinity is greatly detrimental to both the plants and soils. As well as irrigation methods, irrigation scheduling methods are also attracting greater attention. The majority of farms once tended to only use their own knowledge or observation techniques but now on-farm tools and alternative scheduling methods are also being used. Some tools used to determine when to irrigate include; evaporation figures or graphs, tensiometers and soil probes. Strategy 4:Drip irrigation Developments in irrigation technology have led to the invention of sub-surface drip irrigation where drip lines are buried 10-20 centimetres below the ground to uniformly wet the area. This method allows water and nutrients to be applied directly to the root zone enabling the producer to manage and optimise water use.
Strategies to effectively use irrigated water Monitoring water quality- Salinity and any ion in large quantities can be toxic to plants and has potential to cause soil structural problems. Awareness and management of water quality issues can lead to improvement in production levels. Monitoring moisture in the soil- Seepage and leaks can cause a great water loss and channels that are kept maintained will not lose water. Channels that are concrete lined lose much less water. Using just enough water (e.g drip irrigation)- drip irrigation is far more controlled. Water is slowly provided to a very specific area, close to the roots of the plant, by a network of drip emitters.. This method of irrigation is precise and economical. The flow of water is so slow that it is easily absorbed into the ground. In a well-tuned system there is little opportunity for excess water running off and being wasted. Strategy 2: Monitoring soil moisture ranges from digging a hole in the ground and making a visual assessment to installing soil moisture sensors connected to a data logger that feeds information back to your computer. Automated systems that log moisture content at frequent intervals give the most benefit for scheduling irrigation but they require a reasonable level of skill to graph and interpret the readings and are relatively expensive. Strategy 3:Drip irrigation Developments in irrigation technology have led to the invention of sub-surface drip irrigation where drip lines are buried 10-20 centimetres below the ground to uniformly wet the area. This method allows water and nutrients to be applied directly to the root zone enabling the producer to manage and optimise water use.
Activities Review the two case studies and the strategies used for using irrigated water for farming. Conduct a Pluses, Minuses and ∆ Delta (things you would change) on both approaches. What happens to the land if water is not managed properly? Explain how Salinity occurs (use a diagram) What impact does salinity have on the land and its ability to grow crops? List some strategies that farmers can undertake to prevent salinity form occurring.
Land Degradation https://www.youtube.com/watch?v=403sT9CGRl0&list=PLMBtu4eImX JgpilF8vURg1xwRqb45m2BN https://www.youtube.com/watch?v=a1nqiOpz1Xc Deterioration to land whereby quality is no longer useful. Problem in Australia, due to loss of nutrients, salts and acids and soil erosion. Soil erosion due to wind and water leads to loss of
Soil erosion How can erosion be minimised? Soil erosion due to extreme weather conditions such as drought and poor land management. It is also caused by deforestation and clearing. How can erosion be minimised? Minimising the amount of tillage so the soil is not dug up and exposed to water and the wind. Leaving stubble to cover and protect the soil after harvest. Planting windbreaks or shelter belts Giving soil nutrients to improve crop growth, Raising banks to prevent water run off Avoiding crops near rivers and on slopes, investigating hydroponics (food grown without soil) Govt’s can reduce soil erosion by controlling urbanisation (land for food production can be lost by building houses)
DEFORESTATION: Plants hold soil in place and when removed the wind and water can erode or remove the top soil. Results in soil erosion leading to barren land. Trees and forests protect soil from rain erosion by providing shade or mulch. Top level of soil washed away or may dry out from sun damage. Removing trees for paper production for packaging etc impacts on oxygen in atmosphere as plants take in CO2 and breathe out O2.
Poor Soil Health Soil Acidification Occurs when plants take up nutrients and release acidic waste from their roots. Once acidic crops and pastures do not grow very well Caused by increased use of fertilisers and manure. Inefficient irrigation Strategies to improve soil health Undertake reguler pH tests Add lime to the paddocks to help lower the pH and to counteract high acid levels.
Poor Soil Health Loss in Nutrients Occurs when soil is depleted of its nutrients Crops grown in soil with poor nutrients has a lower yield and therefore less profit for the producers Caused by Intensive cropping and continually using the same soil to grow the same crops. Strategies to improve soil health Using a crop rotation system that includes a legume crop that fixes the nitrogen in the soil, making it available to assist growth of cereal crops. This also reduces weed and pest problems and the need for artificial chemicals and fertilizers.
Use of Chemicals in Primary production Why use Chemicals? To protect the food supply from weeds, pests and disease that may spoil the crop To maximise product yields To reduce waste and increase profits Three main categories Fertilisers Pesticides Herbicides Farmers need to keep the environment free from weeds, pests and disease.
Fertilisers Most commonly applied by aerial spraying A substance that provides nutrients to grow or improve soil and used to produce more crops Most commonly applied by aerial spraying Environmental concerns: Overuse can increase the acidity of the soil If not carefully applied they can cause spray drift which can contaminate nearby crops and communities. Can run off paddocks after rain and contaminate waterways and threaten the life of birds and animals. Strategies for better use: Aerial spraying should be done on days with little wind to prevent spray drifting on to other paddocks. Aerial spraying should fly low to prevent spray drift. Use land-based spraying methods such as hand or tractor spraying. Crop rotation Farmers need to keep the environment free from weeds, pests and disease.
Herbicides A chemical substance used to kill plants or inhibit their growth. Biodegradable Can leave residues on foods and are rigorously tested to ensure they are not harmful (FSANZ) Environmental concerns: can lead to run off in the waterways that kill fish or encourage growth of algae. Strategies for better management: reducing amount used. Farmers need to keep the environment free from weeds, pests and disease.
Pesticides A chemical substance used to kill specific pests on specific crops. Varying toxicity level Can leave residues on foods and are rigorously tested to ensure they are not harmful (controls) Environmental concerns: can lead to run off in the waterways that kill fish or encourage growth of algae. Nitrogen from products may be released into the atmosphere and become a major pollutant as well as contributing to acid rain. Strategies for better management: reducing amount used, crop rotation, regular monitoring to determine necessity of use. Farmers need to keep the environment free from weeds, pests and disease.
Controls: Strict controls include- NRA (National Registration Authority) which assesses and registers all chemicals used in agriculture and animal farming. AQIS(Australian Quarantine and Inspection Service) inspects, monitors and investigates imported and exported foods according to govt regulations. Commonwealth Dept. of Primary Industries and Energy surveys foods to test for residues of chemicals and contaminants.
USE OF CHEMICALS: USE OF PESTICIDES- Chemicals such as fungicides (kill fungi in crops), herbicides (kill plants or hinder growth and poisonous to humans) and insecticides (to kill pests which harm crops) absorbed into soil can be harmful and difficult to remove. USE OF FERTILISERS- Added to soil to increase productivity however excess amounts harmful eg. nitrogen enhances plant growth but run off into waterways kills marine life such as algae.
Watch this… https://www.youtube.com/watch?v=Mqrb FdJChzM
Extra resources for better understanding A 14 minute advertisement documentary of the pesticide DDT (one of the major pesticides introduced in 1945.) DDT is still used today to control malaria in some countries however it has now been banned in many countries due to its very deadly effects. https://www.youtube.com/watch?v=RmeqHs4svbQ An article about the still existent damaging effects of DDT in Australia, since its ban in 1987. http://www.abc.net.au/local/stories/2007/10/09/2054547.htm
Organic farming- going back to the traditional… Organic farming as we know it came about as a reaction to the wide adoption of intensive farming around the time of WWII as a result of technological advances made earlier in the century and food shortages experienced during the war. Conventional farming relies on chemical inputs and a highly mechanised approach, whereas organics is about farming the natural way.
Conventional VS Organic Farming Use of chemicals on crops and soil- Conventional farming uses chemical fertilisers made from fossil fuel derivatives that are used to add nutrients to the soil. Conventional farming uses chemical pesticides, herbicides and fungicides to control pests and weeds. Organic farming controls invasive species through a mixture of companion planting, crop rotation, use of cover crops, natural pest control, hand weeding and animal grazing. Environment- Conventional farming is often intensive and farmers try to get the most productivity out of the ground with little regard to its environmental impact. Organic farming aims to balance productivity with environmental impacts.
Conventional VS Organic Farming Seeds Conventional farming may include the use of genetically modified (GM) seeds. GM seeds have had their genetic makeup changed in a lab to create foods that have certain desirable characteristics such as vegetables that take longer to go brown or are pest resistant. Organic farming does not allow GM seeds and requires seeds to be organically grown. Organic farmers will often save seeds from previous crops and use rare seed varieties, preserving the biodiversity of our food. Animals Conventional animal farming allows the use of antibiotics and hormones, residues of which end up being consumed by humans. Conventional farming also allows factory farming and practices that compromise animal welfare Organic animal farming uses organic feed for the animals and does not allow the use of antibiotics or hormones. Organic certification also includes strict animal welfare regulations
It’s issues such as these that people are starting to care more about… Organic Products! $655M industry (2013-2014) in Australia and projected to grow 12% over the next 5 years. Global demand for organic products is rising with increasing health consciousness, growing concern for the environment, income growth and the increased convenience of organic food.
How do you know who really does organic? There are currently no laws or regulations in Australia to protect the use of the word 'organic' being used on product labels. You can only be certain that you are purchasing truly organic or biodynamic produce and products if it has been certified organic by one of the seven recognised certification bodies that are accredited and audited by the Australian Quarantine Inspection Service (AQIS). – Products have been produced in accordance with specific organic standards. Farmers have to prove organic strategies, e.g crop rotations, weed control, pest management, biodiversity, water management, animal health etc.
Why Change? Why change from traditional to organic? What are the benefits? Why people care? Benefits Disadvantages Producer Consumer Environment