Report to Dairy Australia

Transcription

1 Report to Dairy Australia BACKGROUND PAPER: ENVIRONMENT & NATURAL RESOURCES AUGUST 2009 REGIONAL OVERVIEW THE LOWER MURRAY DARLING BASIN 1

2 The Lower Murray Darling Basin covers the area north of the Great Dividing Range in Victoria and NSW to the Murrumbidgee River, and the Murray region of South Australia. It includes the Victorian, New South Wales and South Australian shares of the Murray River, and is dominated by a series of river systems running north from the Great Dividing Range to the Murray River. These river systems and catchments include the Avoca, Loddon, Campaspe, Goulburn Broken, Ovens, Kiewa and Mitta Mitta systems. Other river systems and catchments in the region include the Murrumbidgee River and Eastern Mt Lofty Ranges catchment. For the purposes of this document, the Lower Murray Darling Basin encompasses the Catchment Management Regions of: Goulburn Broken Vic. Murray NSW Murrumbidgee NSW North Central Vic. North East Vic. South Australian Murray Darling Basin The Lower Murray Darling Basin covers an area of 302,000 km 2 (30,200,000 hectares) of which: 21,558,012 hectares or 71% of the area are agricultural holdings; An estimated 386,000 hectares are dairy farm holdings, or about 1.8% of agricultural land; 11,000 farm businesses irrigated 564,970 hectares in ; 2,589 dairy farm businesses irrigated 84,920 hectares, equivalent to 15% of irrigated land in the region. DISCLAIMER: This report is published for information only. It is published with due care and attention to accuracy, but Dairy Australia accepts no liability if, for any reason, the information is inaccurate, incomplete or out of date. The information is a guide only and professional advice should be sought regarding the reader's specific circumstances. 2

3 The Lower Murray Darling Basin region covers all or parts of the following bioregions 1 and subregions: TABLE 1: Lower Murray Darling Basin bioregions & subregions Bioregion Subregion NSW South Western Slopes (NSS) Northern Inland Slopes (NSS1) Lower Slopes (NSS2) Murray Darling Depression (MDD) Murray Mallee (MDD2) Murray Lakes and Coorong (MDD3) Darling Depression (MDD6) Riverina (RIV) Murrumbidgee (RIV2) Murray Fans (RIV3) Victorian Riverina (RIV4) Robinvale Plains (RIV5) Murray Scroll Belt (RIV6) Victorian Midlands (VM) Goldfields (VM1) The major environmental challenges in the Lower Murray Darling Basin are: 1. Environmental flows in river systems; 2. Dryland, groundwater and river salinity; 3. Nutrients and water quality impacts; 4. Land management issues including biodiversity, pest plants and animals; 5. Soil acidity and sodicity. 1 Bioregion in essence means a geographic area characterised by a combination of physical and biological characteristics, for example, terrain, climate and ecological communities. It can be defined as: a territory defined by a combination of biological, social, and geographic criteria, rather than geopolitical considerations; generally, a system of related, interconnected ecosystems. Bioregions are a useful way to analyse patterns of biodiversity. The definition of a particular bioregion depends on the scale at which its characteristic features are measured. 3

4 Major land management issues identified by dairy farmers in the Murray Dairy region during the 2000 and 2006 Dairying for Tomorrow Surveys of NRM Practices on Dairy Farms were: TABLE 2: Major land management issues identified by dairy farmers Major land management issue % respondents mentioning 2000 % respondents mentioning Noxious weeds n.a. 38% 2. Irrigation induced salinity 39% 29% 3. Other 19% 26% 4. Soil acidity 37% 18% 5. Surface crusting or surface compaction 41% 17% 6. Wet soils pugging 33% 17% 7. Dryland salinity 8% 7% 8. Acid sulphate soils 8% 5% 9. Soil erosion 9% 4% Communities, farmers, government and business are already working hard to respond to these land management issues and protect natural ecosystems and the values they provide. 4

5 1. ENVIRONMENTAL FLOWS Low flows, water extraction from rivers for agricultural and urban use, along with water quality issues, have resulted in levels of stress for rivers and wetlands within the Lower Murray Darling Basin. However, there is large variation in the level of stress experienced by river basins in the region, with classification of rivers basins 2 ranging from largely un to substantially. The Environment Index (ARCE) for assessment of river condition has four sub indices: catchment disturbance; hydrological disturbance; habitat, and; nutrient and suspended sediment load. TABLE 3: Assessment of River Condition (ARC) ARC Environment Index ARC Biota Index Hydrological disturbance index Catchment disturbance index Habitat index Nutrient and suspended load index Campaspe Reference condition Substantially Substantially Goulburn Reference condition Kiewa Largely un Reference condition Largely un Largely un Loddon Substantially Significantly impaired Substantially Substantially Substantially Lower Murray Reference condition Murray Riverina Basin Significantly impaired Murrumbidgee Significantly impaired Substantially Ovens Largely un Reference condition Largely un Upper Murray Largely un Reference condition Largely un National Land and Water Resources Audit Assessment of River Condition 5

6 The Sustainable Rivers Audit initiative of the Murray Darling Basin Commission released its first report in June 2008 presenting report cards on river ecosystem health for each of the 23 valleys in the Murray Darling Basin. The reports were based on observations of fish, macro invertebrates and hydrology from 2004 to The Sustainable Rivers Audit River Health Check reports rated the river valleys in dairying areas of the Lower Murray Darling Basin as being in either poor or very poor health (see highlighted valleys in table below). Comment was made in the reports that the condition assessments and ecosystem health partly reflect the very dry conditions that have prevailed in the Lower Murray Darling Basin before and during the audit period. However, even with due allowances for the drought, the assessment team consider the ratings area realistic indication of underlying conditions. TABLE 4: Health Rating of the River Valleys in the Murray Darling Basin Health rating Valley Rank Good Paroo 1 Moderate Border Rivers, Condamine 2 Poor Namoi, Ovens, Warrego 3 Gwydir 4 Darling, Murray Lower, Murray Central 5 Very Poor Murray Upper, Wimmera 6 Avoca, Broken, Macquarie 7 Campaspe, Castlereagh, Kiewa, Lachlan, Loddon, Mitta Mitta 8 Murrumbidgee, Goulburn 9 There are a number of Living Murray Icon Sites within the Lower Murray Darling Basin. They were chosen for their high ecological value and also their cultural significance to indigenous people and the broader community. Aside from the River Murray Channel, all of The Living Murray s icon sites are listed as, or are part of, Wetlands of International Significance under the Ramsar Convention. The Lower Lakes, Coorong and Murray Mouth extend over approximately 140,000 hectares, covering 23 different wetlands types, from very fresh to saltier than the sea. Where the River Murray meets the sea, it is one of the 10 major havens for large concentrations of wading birds in Australia, and is recognised internationally as a breeding ground for many species of waterbirds and native fish. 6

7 The Gunbower Koondrook Perricoota Forest covers around 50,000 hectares and is home to many threatened native plants and animals. It is located downstream of Torrumbarry Weir, between Echuca and Swan Hill. The forest wetlands are important breeding places for waterbirds and native fish. The Barmah Millewa Forest is the largest River Red Gum forest in Australia, covering 66,000 hectares of floodplain between Tocumwal, Deniliquin and Echuca. Many threatened native plants, birds, fish and reptiles make this forest and its wetlands their home. The River Murray Channel is the main artery of the River and extends over 2,000 kilometres (river distance) from Hume Dam near Albury to Wellington in South Australia. The Channel forms the link between the forests, floodplains, wetlands and estuaries along the River Murray and provides habitat for many native plants, fish and animals. The Chowilla Floodplain is one of the only parts of the lower Murray floodplain not used for irrigation, so preserving much of its natural character. Covering 17,700 hectares and three states, it is immediately downstream of the junction of the Murray and Darling Rivers. The Lindsay Wallpolla Islands and their floodplains cover almost 20,000 hectares. They support many threatened plants and animals and a number of native fish. Hattah Lakes is most notable for its 17 semi permanent freshwater lakes. The lakes form part of the 48,000 hectare Hattah Kulkyne National Park. There are also a number of other wetlands of national significance within the Lower Murray Darling Basin: TABLE 5: Wetlands of significance Lower Murray Darling Basin Bioregion Subregion Important Wetlands Murray Darling Depression (MDD) Murray Lakes and Coorong (MDD3) Tookayerta & Finniss Catchments Darling (MDD6) Depression Talyawalka Anabranch & Teryawynia Creek Riverina (RIV) Murrumbidgee (RIV2) Black Swamp and Coopers Swamp Lowbidgee Floodplain Lower Mirrool Creek Floodplain Mid Murrumbidgee Wetlands Tuckerbil Swamp Murray Fans (RIV3) Wakool Tullakool Evaporation Basins Werai Forest 7

8 Murray Scroll Belt (RIV6) Banrock Swamp Wetland Complex Gurra Lakes Wetland Complex Loch Luna Wetland Complex Loveday Swamps Pike Mundic Wetland Complex Riverland Wetland Complex Spectacle Lakes The competing demands for water mean that it is necessary to provide and manage environmental flows to ensure river health is protected. A number of programs, plans and legislative instruments assist with this. The Restoring the Balance in the Murray Darling Basin program (buy back) will provide $3.1 billion dollars over ten years to purchase water entitlements from willing sellers and is a component of the Australian Government s Water for the Future plan. Further detail on the buy back is provided in both the Water Availability and Water Policy Background Papers. River Health Strategies The National River Health Program has a focus on monitoring and evaluating river condition (river health). This work includes the development of nationally agreed ways to measure the condition of Australia's rivers. The Victorian Government has developed the River Health Program to tackle the causes of poor river health affecting two thirds of Victoria s rivers. In Victoria, environmental flows are provided through the water allocation framework. This includes: Imposing environmental flow conditions on Bulk Entitlements for urban and rural water authorities; Providing Bulk Entitlements for the Environment in special cases, where some flexibility in use is required e.g. wetland watering; Specifying environmental flow regimes to be provided in Stream Flow Management Plans for priority unregulated rivers; and Establishing clear management rules for other unregulated rivers that will protect the environment. For environmental flows, the Victorian River Health Strategy: Identifies what must be considered in assessing an environmental flow requirement: it addresses all components of the flow regime, is determined using best available scientific 8

9 knowledge, and must be a flow regime that would maintain an ecologically healthy river system. The Department of Sustainability and Environment provides guidelines for assessing environmental flow requirements. Sets direction on management of environmental water, including assessing the environmental effectiveness of the current provisions and reviewing the current management arrangements. Outlines the mechanisms in Victoria s water allocation framework which protect environmental flows. These include Bulk Entitlements, Streamflow Management Plans, management rules for other unregulated rivers, and the implementation of catchment caps. Provides principles and directions for improving the condition of flow stressed rivers. These include such actions as reviewing the operation of water management systems and using trading rules to improve environmental outcomes. If the community identifies a river as being a high priority, a Stressed River Plan will be developed, which will identify, amongst other things, the environmental improvements required and how they will be achieved. Sets direction on how to protect environmental flows while still enabling new development. This includes measures like using trade to improve the environmental outcomes, water efficiency and water re use and recycling. New allocations may still occur, but guidance is provided on the conditions that must be fulfilled first. As well as a Victorian River Health Strategy there are a number of Regional River Health Strategies: Goulburn Broken Regional River Health Strategy; Mallee Regional River Health Strategy; North Central Regional River Health Strategy; North East Regional River Health Strategy. High Priority Rivers have been identified through the Regional River Health Strategies. A key component of the Victorian Government Our Water Our Future action plan commits to undertaking works that will significantly improve flows for high priority rivers including the Snowy and Murray rivers, including the Murray tributaries, the Broken, Goulburn, Campaspe and Loddon rivers. Stream Flow Management Plans Stream Flow Management Plans are developed with local communities to manage the water resources of unregulated waterways that are under stress, or where there is a demand for more development. A Stream Flow Management Plan ensures that all surface water in a catchment is managed in an orderly manner, providing for the stream s environmental needs as well as an agreed, reliable and equitable water distribution between users. A number of Stream Flow Management Plans are being developed around the state under the Water Act 1989 and complement Environmental Water Reserves. 9

10 A Stream Flow Management Plans includes: Environmental flow needs; Rules for sharing available stream flows between users when water is scarce; Monitoring and metering programs; The amount of extra water that can be allocated, and rules for allocating it; Conditions under which licenses may be traded or transferred. Under the legislative basis for Stream Flow Management Plans the Victorian Government acts to ensure that unregulated rivers and streams that are not significantly stressed remain this way by: Recognising the ecological stress caused by summer extractions of water and banning the issue of new summer licences; Issuing new licences from July to October only, when spare water is under the sustainable diversion limit for the catchment; Introducing state wide management rules for licensees who extract water in summer. Water Sharing Plans In New South Wales, under the Water Management Act 2000, water sharing plans must be consistent with government policy in relation to the environmental objectives for water quality and river flow. Catchment action plans are strategic, statutory plans under the Catchment Management Authorities Act 2003 that provide a framework for natural resource management in a catchment. Plans include provisions that relate to water quality. Environmental Protection (Water Quality) Policy In South Australia, the Environmental Protection (Water Quality) Policy 2003 is subordinate legislation supporting the Environment Protection Act The policy provides for the development of environmental values and water quality objectives for South Australian waters. The policy outlines additional regulations for point source and diffuse pollution to ensure achievement of water quality objectives. Environmental values are the qualities of waterways that need to be protected from pollution to support healthy aquatic ecosystems and social and economic uses. Environmental values prescribed in the Environmental Protection (Water Quality) Policy 2003 are consistent with the National Water Quality Management Strategy and determine the application of water quality criteria. Environmental values must be considered in the assessment of water licences. 10

11 Future challenges and implications environmental flows Climate change predictions for the Lower Murray Darling Basin suggest rainfall runoff will be significantly reduced in the medium to long term. Under a scenario of reduced river inflows, governments will struggle to meet environmental flow commitments and will need to balance environmental benefits against economic returns from irrigation. This scenario will increase the pressure on dairy to justify its use of water in areas with significantly high environmental values. Governments will actively encourage water to move to the best economic use (to maximise the return per megalitre). In some areas the economic return from preserving significant environmental assets maybe higher than the returns from dairy. Campaigns by environmental non government organisations targeting industries that use water to grow pasture are likely to intensify in the future. 2. SALINITY & SALINISATION The Lower Murray Darling Basin is geologically and climatically prone to concentrating salt in the landscape 3. The Basin s flat terrain, low rainfall and high levels of evaporation have combined to concentrate salt in the soil and groundwater over the past 65 million years. Land use changes since European settlement mean that less of the rainfall that soaks into the ground is used by vegetation in dryland areas, causing a gradual filling of shallow aquifers, bringing this natural salt to the land surface and to the rivers. Meanwhile, problems of rising watertables and soil salinisation arose soon after the establishment of the first irrigation schemes in the 1890s. It is estimated that 96,000 hectares of the Murray Darling Basin s irrigated land are salt affected and 560,000 hectares have watertables within two metres of the land surface. Within the Lower Murray Darling Basin, it is estimated that 447,000 hectares have watertables within two metres of the land surface. The impacts of salinity in the region can be categorised in three types: Dryland salinity; Irrigation induced salinity; River salinity. During drought conditions there is a decline in rainfall and irrigation infiltration entering the groundwater system. More salt remains within the soil rather than discharging to rivers and irrigation drains as happens in wetter years. Salt accumulates in the lower Murray floodplains rather than being regularly flushed to the river by flooding. Drought normally delivers low salinity outcomes for the Murray River providing that river flows are adequate to flush and dilute salt loads entering the river from saline aquifers and wetlands. The operation of salt interception schemes is also an 3 The Salinity Audit of the Murray Darling Basin, Murray Darling Basin Commission

12 important contribution to reducing river salinity by intercepting saline water before it enters the rivers. For most of , river flows were sufficient to dilute salt loads, particularly in the lower Murray. However, extremely low storage levels in autumn/winter reduced downstream deliveries, leading to rising salt concentrations late in DRYLAND SALINITY The majority of dryland salinity in the Lower Murray Darling Basin is "secondary salinity". That is, the result of clearing of native vegetation, which has resulted in leakage of groundwater past the root zone, causing groundwater tables to rise in many areas; as the water rises, it brings with it natural salt stored in the soil. Land salinisation occurs naturally ( primary salinity ) in parts of the Murray Darling Basin in the form of saline seepages and scalds. Seven per cent of dairy farmers in the Murray Dairy region nominated dryland salinity as the major land management issue during the 2006 Dairying for Tomorrow Survey of NRM Practices on Dairy Farms. IRRIGATION INDUCED SALINITY Irrigation salinity occurs when there is a localised rise in the level of groundwater caused by the application of large volumes of irrigation water. This problem is compounded by the replacement of native vegetation with crops and pastures that use less water. Irrigation salinity is made worse when water used to irrigate is derived from salty rivers or groundwater. High watertables (often described as shallow watertables ) can lead to waterlogging, salinisation of low parts of the landscape, and increased salt accession to rivers and streams. High watertables and waterlogging can also affect and alter native vegetation and biodiversity values across the lower lying areas and wetlands. Problems of rising watertables emerged soon after the establishment of the first irrigation schemes in the region: along the South Australian Murray in the 1890s; in parts of the Murrumbidgee Irrigation Area in the 1920s; and in the early 1950s in the Wakool Irrigation District. Twenty nine per cent of dairy farmers in the Murray Dairy region nominated irrigation induced salinity as the major land management issue during the 2006 Dairying for Tomorrow Survey of NRM Practices on Dairy Farms. 12

13 TABLE 6: Estimated areas* (ha) of land with depth of watertable less than 2 m under current and predicted to have shallow watertables for year 2020 and year 2050 scenarios 4. CMA Region worst case 2050 worst case Goulburn Broken Mallee North Central North East Murray Murrumbidgee , ,500 SA Murray Darling Basin n.a. Total 446,624 * Area excludes irrigation and urban areas and those with substantial contiguous forest or woodland coverage. RIVER SALINITY River salinity is caused by saline discharges from areas affected by dryland, irrigation and urban salinity flowing into creeks and rivers. Over time, if salinity within catchments worsens, the quality of river water declines. For the Murray River, apart from variations over time that are related to river flow, there is a marked downstream increase in salinity levels as a consequence of both natural and human activities. Evaporation from the generally slow moving river is one factor. Downstream of Euston in South Australia, there are relatively steady inflows of saline groundwater, which can have salinities of up to 50,000 EC. (The EC unit is a measure of electrical conductivity, commonly used to indicate the salinity of water.) Such inflows are particularly significant in the South Australian section of the river. These natural processes can be exacerbated by drainage flows from irrigation areas and rising groundwater levels due to irrigation. Problems have emerged in the much more extensive areas of dryland farming, with rising watertables bringing saline groundwater close to and to the surface, resulting in land salinisation. Especially at times of low or base flows, shallow saline watertables can contribute most of the water in streams. Drought conditions have been a major contributor to generally low river salinity levels and a reduction in watertable levels in recent times in the Lower Murray Darling Basin. For example, lower Murray River salinities averaged 377 EC in or less than half the long term average. 4 National Land & Water Resources Audit s Australian Dryland Salinity Assessment

14 National Action Plan for Salinity and Water Quality The National Action Plan for Salinity and Water Quality was a joint Australian, state and territory government plan to tackle two major natural resource management issues. The Plan ceased in June 2008 and invested $1.4 billion over seven years to support action by communities and land managers in 21 highly affected regions. It supported practical remedies such as the protection and rehabilitation of waterways, improvements to native vegetation, engineering works, and land and water use changes and was jointly delivered with the Natural Heritage Trust. Basin Salinity Management Strategy The Basin Salinity Management Strategy guides communities and governments in working together to control salinity in the Murray Darling Basin and protect key natural resource values within their catchments. It establishes targets for the river salinity of each major tributary valley, and the Murray Darling system itself, that reflect the shared responsibility for action both between valley communities and between states. The targets are a way of measuring the progress towards achieving the Strategy's key objectives of: 1. Maintaining the water quality of the shared water resources of the Murray and Darling rivers; 2. Controlling the rise in salt loads in all tributary rivers of the Murray Darling Basin; 3. Controlling land degradation and protecting important terrestrial ecosystems, productive farm land, cultural heritage and built infrastructure; and 4. Maximising net benefits from salinity control across the Basin. An important step in the 15 year Basin Salinity Management Strategy has been the establishment of end of valley salinity targets for each tributary catchment and a Basin target at Morgan in South Australia. These targets define the limits to acceptable increases in salinity and average salt loads, over the period 2001 to 2015, for each of the major catchments within the Murray Darling Basin. End of valley targets are measured at defined points near the downstream ends of each catchment. The Murray Darling Basin target is to maintain the salinity at Morgan at less than 800 EC units for 95 per cent of the time. For comparison, in most situations, water salinity of more than 700 EC is unsuitable for irrigating most horticultural crops, while 800 EC is the accepted maximum level for domestic supplies in larger towns and cities. Victorian Government Salinity Strategy The Victorian Salinity Program was established in 1987 with the release of Salt Action Joint Action. Under this program, dryland salinity management plans, strategies, or land and water management plans were prepared for major catchment areas of northern and south west Victoria between the late 1980s and mid 1990s. They focused on dryland salinity but recognised the links to other natural resource issues. In 1999, the Victorian Government s document Salinity Management in Victoria: Future Directions identified Victorian salinity targets for the next 15 years: 14

15 1. By 2015, there will be a real reduction in the environmental and economic impacts of salinity. 2. By 2005, critical recharge zones within catchments will be identified, with 40 to 60 per cent of these critical areas revegetated by By 2005, a quarter of agricultural production will be produced from natural resources that are managed within their capacity. By 2015, this will increase to half the value of agricultural production. Catchment Management Authorities have been given responsibility for overseeing Salinity Management Plans, leading to further integration of salinity with other natural resource issues. There are a number of Salinity Management Plans within the region, including: Shepparton Irrigation Region Land and Water Management Plan (SIRLWMP); Goulburn Broken Dryland Salinity Management Plan (GBDSMP). Future challenges and implications salinity & salinisation A number of future challenges remain around salinity and salinisation for the region, some of which may have implications for the sustainability of agriculture, including dairy farming, into the future including: Fully understanding the overall salinity impacts of future climatic outcomes; Assessing the salinity impacts of future changes in irrigated land use and management brought about by agricultural commodity and water markets; Considering a pricing policy for irrigation water that provides further incentives to use water efficiently and minimise drainage and groundwater accessions; Irrigation impact zoning; Developing more effective linkages between salinity and other natural resource management initiatives. 15

16 3. NUTRIENTS & WATER QUALITY Eutrophication is the enrichment of waterways with nutrients, in particular phosphorus and, to a lesser extent, nitrogen. The major sources of these nutrients in waterways are: The catchment's natural rocks and soils; Sediments on the beds of rivers and lakes from which nutrients are released under certain physical and chemical conditions, as when the sediments are disturbed or oxygen is depleted; Discharges from diffuse or non point sources, especially in run off from agricultural land and forests where soils are allowed to erode and where there is high fertiliser use; and Discharges from point sources, such as effluent from sewage treatment works, industrial activities (especially food processing plants and abattoirs), feedlots and other intensive agricultural operations, fish farms, drainage from irrigation areas, and stormwater run off from urban areas. High nutrient concentrations in waterways can contribute to problems within the Lower Murray Darling Basin, including: Algal and aesthetic scums; Toxic blue green algal outbreaks or blooms ; Detrimental impacts on other flora and fauna; Taste and odour problems in domestic water supplies; Algae blocking trickle irrigation systems and other equipment; and Water plants taking over waterways and blocking water movement. The most serious of the problems resulting from high nutrient levels is blue green algae, which, given favourable conditions, can reproduce at a very high rate to form blooms that can dominate the local aquatic environment. In addition to nutrients, other major factors contributing to algal blooms are calm water conditions, low winds, sunlight and warm water temperatures (usually associated with slow moving or stagnant water). Efficient use of all sources of nutrients, including dairy effluent, reduces nutrient loss from point and diffuse (non point) sources. Nutrients, such as nitrogen and phosphorus, are crucial drivers of dairy pasture production and losing nutrients is not in the interest of farm profitability or sustainability. Dairy effluent can be a valuable resource as it contains key nutrients including nitrogen, phosphorus and potassium. Cost benefit studies suggest that the cost to install and run an effluent system will be covered within four to seven years of installation. 16

17 Other on farm management actions likely to reduce diffuse nutrient loss include: Fencing off and revegetation of waterways; Nutrient budgeting, soil testing and targeted fertiliser use; Installation of feed pads; Construction and maintenance of laneways; Identification of and management of high risk areas for nutrient loss. Since 2001 there has been a 50 per cent increase in the protection of waterways on Australian dairy farms. Over the last 10 years more than half of all dairy farms have implemented a revegetation program and remnant vegetation is now more likely to be fenced off. Effluent systems have been upgraded on 46 per cent of dairy farms over recent years, with higher incidences on farms with larger herds. Since 2000, there has been a clear trend in all dairy regions towards using pond systems to manage milking shed effluent (from 54 per cent to 73 per cent) and now few farms (11 per cent) allow effluent to drain directly to paddocks. Encouragingly, this trend is particularly evident on heavily stocked farms and where herd sizes are larger. Pond systems typically incorporate multiple ponds and are generally cleaned out regularly. Most dairy farmers (56 per cent) allowed effluent and run off from feed pads to drain directly to paddocks in 2000, but this now occurs on substantially fewer farms (24 per cent). Compared to 2000, effluent is retained on a significantly higher proportion of dairy farms by applying it to land (88 per cent compared to 79 per cent). On 46 per cent of these farms, effluent is always applied to the same areas, representing 15 per cent of land on average. Few however test the nutrient value of effluent (16 per cent). While many dairy farmers have upgraded their effluent systems over the past few years, 59 per cent believe there is room for improvement and 31 per cent intend to make changes over the next two years. A high 81 per cent of this group believes it will be important to receive independent advice and support when they make changes to their system. Future challenges and implications nutrients & water quality Improving nutrient use efficiency on farm. Approximately per cent of phosphorus and nitrogen brought onto dairy farms is surplus to outputs (Accounting for Nutrients, June 2009). Excess phosphorus may accumulate in the soil or be lost through surface runoff or leaching. Excess nitrogen can be lost through leaching or volatilisation, sometimes as nitrous oxide (a significant greenhouse gas); More effective management of effluent systems. Only 20 per cent of farms in the Murray Dairy region passed a 2006 Environmental Protection Authority dairy shed effluent audit (EPA per. comm.); 17

18 Increased community concern about nutrient loss from dairy farms (an example is the Dirty Dairy: campaign in New Zealand); Increased requirement to demonstrate responsible use of nitrogen fertilisers given the link between excess nitrogen use and increased nitrous oxide emissions. 4. BIODIVERSITY Biodiversity is the variety of life: the different plants, animals and micro organisms, their genes and the ecosystems of which they are a part. It is in our best interests and the interests of future generations to conserve biodiversity and our resources within healthy and diverse ecosystems. Negative impacts on biodiversity lead to a reduction in the complexity, diversity and functions of ecosystems. The Australian Terrestrial Biodiversity Assessment 2002 was Australia's first comprehensive assessment of terrestrial biodiversity. It provided the basis for an improved understanding of biodiversity values, biodiversity management requirements and investment opportunities. TABLE 7: Summary of overall biodiversity condition and trend Bioregion Overall condition 5 NSW South Western Slopes (NSS) The South Western Slopes of NSW are some of the most highly cleared and altered lands in the state, with most of the remaining areas of native vegetation in the more heavily fragmented areas remaining only in small, isolated patches. Substantial clearing is continuing within the bioregion and the rates have been increasing in some parts, with increased clearing of particular concern along the western margin of the bioregion. As a result of habitat loss resulting from clearing, major declines and collapse of faunal groups are occurring, including ground mammals, aquatic assemblages (particularly frogs) and woodland birds. Concomitant with direct loss of biodiversity values has been significant loss of ecosystem services, including breakdown of soil structure and declining water quality. Dryland salinity now affects significant areas in the bioregion and at current rates is predicted to increase dramatically over the next two decades affecting up to a quarter of the NSW South Western Slopes bioregion National Land and Water Resources Audit Biodiversity Assessment 18

19 Murray Darling Depression (MDD) Riverina (RIV) The Murray Darling Depression is generally considered in poor condition and deteriorating further as a result of current land use practices. Factors operating at the subregional level are significant in determining the overall rating for the bioregion. Salinity is an increasing problem for land throughout the region and is largely attributable to overclearing and inappropriate land use practices by landholders. This includes unsustainable water extraction from rivers and inappropriate irrigation regimes for soils that are prone to salinity. Over 60% of the bioregion has been cleared for agriculture and grazing on native pastures is the dominant land use in the area. Logging of the extensive River Red Gum forests has been ongoing over the last century. Clearing and fragmentation of habitat and intensive land use are other threats to the landscape. The average landscape health of the bioregion is five. For the Riverina bioregion this means an intermediate ranking where although moderate areas of native vegetation remain, including most of the subregional ecosystems, connectivity in native vegetation is low and relatively little of the native vegetation is conservatively managed. Victorian (VM) Midlands Much of the bioregion is degraded as the result of fragmentation of remnant vegetation, and continues to decline. Where forest does remain, most has been severely impacted upon by extensive past logging for timber and fuel, particularly in the goldfields, which has resulted in an effective absence of old growth forest from the Box Ironbark Forest Complexes. Threats which continue to impact on the bioregion include the ongoing results of fragmentation for remnant vegetation, grazing pressures, weed invasion, timber harvesting, altered fire regimes, loss of hollow bearing trees, and the impacts of feral animals including goats, rabbits, foxes and cats. Dairy farms in the Lower Murray Darling Basin are not generally noted for their high levels of biodiversity. However, a number of government and dairy industry programs have successfully promoted the benefits of shelter belts and riparian protection to provide shade, wind protection and to help prevent soil erosion. Over 55 pre cent of Australia s dairy farmers implemented a revegetation program between 2000 and 2006 (Dairying for Tomorrow Survey of NRM Practices on Dairy Farms, May 2006). Providing a more comfortable environment for stock was a key driver. Studies from Gippsland suggest restoring 10 per cent of land to vegetation can have net productivity benefits, especially as the number of extreme temperature days increase. 19

20 There may be opportunities for farms in the future to use abandoned or marginal land for carbon sequestration. Well planned forestry strips or blocks interspersed with productive paddocks would provide shelter and shade as well an income from carbon sequestration. Noxious weeds Nationally, noxious weeds affect more than one third of dairy farms and are a major land management issues for all regions. In the Murray Dairy region, 38 per cent of dairy farmers nominated noxious weeds as the major land management issue on their farm 6. Generally the intensive nature of dairy farming justifies treatment of weeds with chemicals. However areas of land that are no longer irrigated or used for intensive farming may not be treated. These areas are likely to act as a seed bank for re infesting adjacent pasture areas. Feral and pest animals Feral and pest animals are not currently a significant economic issue in the Lower Murray Darling Basin. However, as environmental conditions or farming systems change, new pests may migrate to the area, or existing pests may become more prevalent. An example is the rapid growth in economically significant infestations of Redheaded Cockchafers in Gippsland and Western Victoria. Whilst Redheaded Cockchafers are not currently recognised as a significant pest in the Lower Murray Darling Basin, they are an example of a pest species becoming much more important as environmental conditions change. National Strategy for the Conservation of Australia's Biological Diversity Australia's first national biodiversity strategy, the National Strategy for the Conservation of Australia's Biological Diversity, was prepared by the Australian and New Zealand Environment and Conservation Council (ANZECC) and endorsed by the Council of Australian Governments in 1996.The strategy fulfilled Australia's obligations under the international Convention on Biological Diversity. A review of the National Biodiversity Strategy has been conducted by the Natural Resource Management Ministerial Council and a new strategy is expected to be endorsed in November Future challenges and implications biodiversity, pest plants and animals A number of future challenges remain around biodiversity for the region, some of which may have implications for the sustainability of agriculture, including dairy farming, into the future including: Weed and pest management on abandoned or under utilised land; Emergence of new pests and weeds in response to changed environmental conditions; Salinity and rising watertable impacts on biodiversity in seriously affected catchments within the Lower Murray Darling Basin; Use of marginal land for carbon sequestration ( may be an opportunity or a threat); 6 Dairying for Tomorrow Survey of NRM Practices on Dairy Farms, May

21 Degradation of aquatic habitats as a consequence of increased sodicity. 5. SOIL ACIDITY & SODICITY Acid Soils Australia has naturally acid soils. Intensive farming inevitably tends to make soils more acid. Pasture improvement and nitrogen fertilisation of crops have increased the rate of acidification. If soils are allowed to become extremely acid, there is a risk of irreversible soil texture change. If subsoils are allowed to acidify, treatment is extremely difficult and costly. Acid soil problems can cause poor establishment, growth and persistence of pastures and crops. These soils are characterised by plant nutrient imbalances, toxicities and deficiencies that reduce plant growth. Aluminium toxicity is the major problem associated with acid soils. As soil becomes more acid, aluminium becomes more available to the plant and stunts root growth. Symptoms of reduced growth in acid soils are often subtle and can be explained away by other factors, such as poor season or inadequate fertiliser. It is only over a period of time (usually decades) that major problems become apparent. Acid soil problems are likely to develop In high rainfall areas (greater than 500mm/rainfall) with dry summers; In annual pasture systems; With lightly textured soil; With legume rotations; Where there is a history of nitrogenous fertiliser use; and Where there is high product removal of plant and animal products. The key to maintaining productivity in these situations is the application of lime to neutralise the acidity. The Lower Murray Darling Basin region contains some areas with high levels of soil acidity, however it is less of an issue for farmers in these areas than it is for dairy farms in Western Victoria and Coastal New South Wales. The proportion of dairy farmers identifying soil acidity as a major land management issue on their farm fell from 37 per cent in 2000 to 18 per cent in 2006 in the Murray Dairy region. This may be a reflection of increased understanding about soil acidity and greater uptake of remedial measures such as liming. 21

22 FIGURE 1: Surface soil (A horizon) and subsoil ( m) with a ph above or below 5.5 (from Dolling et al. 2001). Soil ph based on modelled ASRIS ph data representing 250 m by 250 m cells. Acid Sulphate Soils Acid sulphate soil is the common name given to soils containing iron sulphides. The iron sulphides are contained in a layer of waterlogged soil. This layer can be clay or sand, and is usually dark grey and soft. The water prevents oxygen in the air reacting with the iron sulphides. This layer is commonly known as potential acid sulphate soil (PASS) because it has the potential to oxidise to sulphuric acid. Acid sulphate soils are not a major issue in the Lower Murray Darling Basin and are generally confined to the River Murray, adjacent wetlands and the Lower Lakes (Lakes Alexandrina and Albert) close to the Murray Mouth. These areas are being seriously impacted by a combination of low water levels and the presence of acid sulfate soils. The newly exposed acid sulfate soils with sulfuric and sulfidic materials may lead to serious environmental impacts including acidification, mobilisation of heavy metals, anoxia and the production of noxious gases. 22

23 Soil Sodicity Soil sodicity is a widespread form of land degradation. It affects nearly a third of all soils in Australia (including a third of all agricultural soils), causing poor water infiltration, surface crusting, erosion and waterlogging. Some dairy areas within the Lower Murray Darling Basin are impacted by soil sodicity. In saline soils, sodium forms a salt with chlorine. The presence of salt in the soil reduces the availability of water to plants and at high enough concentrations can kill them. In sodic soils, much of the chlorine has been washed away, leaving behind sodium ions (sodium atoms with a positive charge) attached to tiny clay particles in the soil. As a result, these clay particles lose their tendency to stick together when wet leading to unstable soils which may erode or become impermeable to both water and roots. Run off from sodic soils carries clay particles into waterways and reservoirs causing water turbidity, or cloudiness. In addition, run off from sodic soils is more likely to carry higher levels of nitrogen and phosphate into waterways and reservoirs. These are the nutrients that contribute to algal blooms, another significant environmental problem. To increase productivity of sodic soils, land managers can apply gypsum or, in the case of acid sodic soils, lime, or a combination of both. Future challenges and implications soil acidity and sodicity Unlike the extensive grazing industries, the intensive nature of dairy farming makes it economically viable to treat soil acidity and sodicity. 23

24 However, if there is a shift to more extensive dairy farming systems with increased area devoted to cropping or annual pastures, remedial treatment of soil acidity and sodicity may become less frequent. The challenge for the future will be ensuring farmers maintain remedial treatments on land that may not be as intensively managed in the future. Risks associated with failure to maintain remedial action include o o Slow declines in productivity due to increased surface crusting, hard setting and waterlogging; Poor pasture persistence and growth due to changes in nutrient availability; and o Damage to dairy s reputation as a responsible user of natural resources due to increased sediment and nutrient loss to waterways. 24

25 o APPENDIX 1: Assessment of River Condition Environment & Biota definitions ARCE Description Largely un minimal disturbance from catchment land uses such as conservation, some types of forestry, low levels of grazing or cropping limited changes to the hydrological regime limited changes to the physical habitat (e.g. riparian vegetation reasonably intact, no dams or levees and very little sediment deposition) loads of suspended sediment, total nitrogen and total phosphorus close to natural catchment dominated by land uses that disturb the river to some extent, such as dryland cropping and grazing some changes to the hydrological regime as a result of impoundments or abstraction some changes to physical habitat, e.g. riparian vegetation reduced to 50 75% original coverage, dams upstream but not in the reach, and some sediment deposition loads of suspended sediment, total nitrogen and total phosphorus above natural Substantially catchment land uses with moderate to severe disturbance such as intensive cropping and irrigated land uses ARCB substantial changes to the hydrological regime as a result of impoundments or abstractions substantial changes to the physical habitat including loss of 50 75% riparian vegetation, connectivity affected by nearby dams or levees, and substantial sediment deposition moderate to high loads of suspended sediment, total nitrogen and total phosphorus Reference condition Significantly impaired Stream macro invertebrates should be in similar numbers and of similar types to those at reference sites Between 20 50% of the expected macro invertebrates have been lost. 25