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Goulburn Broken Catchment Management Strategy

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Regional Catchment Strategy 2013-2019

Land

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The majority of land in the Catchment is privately owned, with 1.4 million hectares used for dryland agriculture and 270,000 hectares used for irrigated agriculture. Major industries include dairying, irrigated horticulture and viticulture, dryland grazing and cropping, timber production, thoroughbred and standardbred horse breeding, food processing, tourism and recreation. There are 800,000 hectares of public land (Montecillo 2012). Major land-use is shown in Figure 3.3.

Figure 3.3: Goulburn Broken Catchment Landuse

The term 'land' includes considerations of geology, geomorphology (study of landforms and the processes that shape them) and soils. Soils are a component of land. Soil health is the capacity of soil to function as a vital living system that sustains biological and economic productivity, promotes environmental quality, and maintain plant and animal health. Soil health is synonymous with sustainability (Doran and Zeiss, 2000).

The ecosystem services provided by land and soil underpin sustainable land use and fundamental ecological processes in the catchment for rural communities. Whilst there is an extensive list of services (Bennet et al, Dominati et al) most are not readily amenable to being managed and even if they were there would be too many.  For this reason it is important to focus on a selection of key services-that underpin our environment and region while not losing sight of the need to look at the soil as a system, not a set of discrete issues to be dealt with in isolation.  The services of interest are soil carbon, soil structure, soil biology and soil hydrology.

Settlement and economic development of the region has increased the rate of soil loss several hundred fold above the rates prior to European settlement, degraded soil structure, depleted soil carbon, simplified soil biodiversity and accelerated soil acidification. As the soil ecosystem functions degrade so do the services they provide and at the same time, the disservices increase.

Land degradation leading to loss of ecosystem services from soils and associated decreases in the function and productive capacity of soils is a pressing ecological and economic concern in the region. Whilst production has increased and landholders have shown the capacity to adapt to changing climatic and economic conditions, it s becoming increasingly difficult to maintain viable production systems without large amounts of energy inputs, evidence of both the long term decline in terms of trade and  the long term decline in the capacity of soils to provide services.

Appropriate land use and good management, matched to land capability, are essential to ensure that these resources are available for future generations. The variable qualities of soil (such as depth, texture, acidity, stoniness) and land (slope, aspect, geology) affect their capability to support different land uses without degradation of the soil resource.

There are three key landscapes and dominant soil types that support these land-uses, as described in Table 3.4 and  shown in Figure 3.4 . These are based on the Victorian Geomorphic Framework that combines information about landforms and landscapes. These provide a useful basis for understanding land-use across the Catchment.

Table 3.4: Landscapes and dominant soil types across the Goulburn Broken Catchment (source Victorian Resources Online: http://vro.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/ landform_geomorphological_framework)

Landscape and Dominant Soil Type Description

Eastern Uplands (including Victorian Highlands and Northern Valleys and Plains)

The Eastern Uplands has extensive native forests, parks and production forestry. Private land is primarily used for production for dryland agriculture including grazing. Primary production occurs on the fringes of the highlands in the cleared valleys and plains.

Shallow (generally stony) finely structured loam to clay soils with high organic matter are found in the Highlands, while valleys and plains soils are sand to loam surfaces over weakly structured clay loam to heavy clay subsoils

Western Uplands

The Western Uplands comprise a diversity of land-uses and farming practices including mixed farming (grazing and cropping), forestry and irrigated agriculture (mainly horticulture). Dryland farming is the dominant agricultural land-use with nature conservation interspersed as state forests and parks across the region.

The sedimentary rocks generate texture contrast soils.

Northern Riverine Plain (Riverine Plains and North-East Plains and Slopes)

The Northern Riverine Plain comprises nearly 70% of Victoria’s irrigated agriculture. This is supported in the Shepparton Irrigation Region (SIR) by an irrigation supply and drainage network with regulated water delivery. Water is also extracted directly from waterways to support irrigated production across the Catchment. Dryland agriculture farming includes mixed farming; livestock production and cropping. The distribution of cropping to livestock production varies according to soil type and climatic factors.

In the Riverine Plains soils generally have a loamy (fine sandy) surface over a clay subsoil.

 Figure 3.4: Goulburn Broken Catchment Geomorphic Management Units

Current condition

Catchment condition of key land and soil health indicators; salinity and invasive plants and animals, is variable (see GB CMA 2012 pg.16). The Irrigation Region Salinity condition rating is good and land health, including dryland salinity is satisfactory. However the invasive plant and animal condition rating is poor.

40% of the catchment has strongly to very strongly acidic soils (ref?). Over half of this is on private land and experiences accelerated rates of acidification.  There is more than 400,000 ha of soils at high to very high risk of soil erosion, mainly from soils on sedimentary and granitic rises. Soil biology is sub optimal across most of the cleared part of the catchment as are levels of soil carbon.  There is in excess of 600,000 ha of sodic soils in the Goulburn Broken region (ref?).  These dominate the riverine plains, are poorly structured and prone to sealing and are difficult to manage when wet or dry, a situation made worse in areas of high water table.

The variable qualities of soil (such as depth, texture, acidity, stoniness) and land (slope, aspect, geology) affect their capability to support different land-uses without degradation of the soil resource. Land management for soil health, as well as pest plant and animal invasion relies on collaborative partnerships between private and public land managers.

Management

While there are many management activities undertaken on both private and public land across the Catchment to improve the condition of natural resources, the focus of land management (consistent with the technical definition of land), is on soil condition.  This encompasses the:

  • Protection or enhancement of the soil capital from the major degrading processes erosion, organic matter decline, acidification, contamination, compaction, salinisation and biodiversity decline.
  • Restoration or preservation of services from soil, soil carbon, soil structure, soil biology and soil hydrology
  • Protection of other terrestrial and aquatic assets by reducing the impact of soil acidity, soil sodicity (including soil salinity), and water erosion.

Many organisation including DPI, DSE, G-MW and the Goulburn Broken CMA work with individuals and community groups to improve land management, while DSE, Parks Victoria, Goulburn Broken CMA and the community through Crown Land Committees of Management and other community groups including CMNs, work to restore and protect public land.  This work is done through a range of programs including Beyond SoilCare and the funding of Landcare networks and other community groups.  Activities undertaken contribute to one or more of these aspects, often with direct benefits to farm productivity.  

Within the Agricultural Plains SES, efficient water use on farm helps to minimise salinity, water logging and nutrient impacts by reducing surface run off and seepage to the watertable. Australian and Victorian Government and individual investment made in significant infrastructure assets, supports land and soil assets deemed best matched to irrigated agricultural production. A predicted outcome of this modernisation program is more land under dryland production, but the impact of this change on land and soil health is unknown.

Land managers undertake activities including whole farm planning, land class fencing, matching land capability to land management, stabilise soils, manage soil acidity, increase soil carbon, promote perenniality of the agricultural landscape, encourage soil biological activity, improve irrigation layout, install groundwater bores, drain land with high water tables, promote regeneration and revegetation of native vegetation.

Significant effort across public and private land also occurs in the management of invasive pest plants and animals. Partnerships between Parks Victoria, DPI, Indigenous groups, community groups and landholders all contribute to the delivery of activities that improve the land asset, but which also contribute achieving outcomes for biodiversity and water across the Catchment.

Significant threats

Significant changes occurring in the Goulburn Broken Catchment reflect the ongoing competition for land for various purposes.  Land-use change such as an increase in the number of absentee landholders (for example in the Commuting Hills SES) can result in increased threats from invasive pests and plants that affect the productive capacity and biodiversity (GB CMA 2010) on land in the Catchment. Key invasive plant species across the Catchment include Blackberry, Paterson's Curse, Serrated Tussock, Gorse, Willow and Arrowhead. An emerging invasive plant species of concern is Chilean Needle Grass. Key threatening invasive animal species include Foxes, Feral Cats, Rabbits and European Carp.  The risk to land from invasive plants and animal species is also likely to increase with climate variability.    

The main threats to soils in the Goulburn Broken Catchment come from inappropriate land use or management practices on soil of high to very high risk from  erosion, organic matter decline, acidification, contamination, compaction, salinisation and biodiversity decline. The main threats from soil are erosion, acidification, contamination, compaction and salinisation.  The link between the state of biodiversity in the catchment and the condition of the soil is still poorly understood. 

The increase in disservices from the soil \threatens the broader biophysical and economic health of the catchment. The relationships between the soil, its condition and other natural assets are summarised in Table 4.

Table 4: The relationship between soil threats to Catchment components or assets

Soil threat

System component and asset class

 

Rivers

Wetlands

Species populations & communities

Terrestrial habitat

Water and wind erosion

Y

Y

Y

Y

Salinity/sodicity

Y

Y

Y

Y

Waterlogging

   

Y

Y

Soil acidity

  Y? Y?  

Soil structure deterioration

  Y?    

Soil fertility and organic carbon

Y?

Y?

Y

Y

Soil biodiversity

   

Y

Y

Soil and water contaminants

Y

Y

Y?

Y?

Note: Entries marked with a question make (?) indivate procesees that are poorly understood

Guiding current thinking

The Goulburn Broken Dryland Landscape Strategy (GBCMA 2009), Shepparton Irrigation Region Catchment Implementation Strategy (GB CMA,2010), Regional Invasive Plants and Animals Strategy (GB CMA 2010), Soil Health Action Plan (GB CMA 2006) and Mid Goulburn and Upper Goulburn Sustainable Irrigation Action Plan (GB CMA 2008) provide a basis for action on land and soil.

Key policies that guide the current direction for Land are the Victorian Soil Health Strategy, the Victorian Irrigation Drainage Program Strategic Direction 2010-2015 (DSE 2010), the Biosecurity Strategy for Victoria (Government of Victoria, 2009) and the Invasive Plants and Animals Policy Framework.

Asset identification and prioritisation

The identification of specific land assets, and a subsequent process for prioritisation of identified assets, is problematic because of the ubiquitous nature of soils and their condition.  There are some principles that can be used to guide the identification of both the location and activity(ies) to for land.  These principles are built on an acknowledgement that:

  • the range of activities and enterprises available to land managers is limited.  The need is to reduce soil disturbance, increase perenniality and manage soil biology with the same attention we pay to soil chemistry .
  • land managers are committed to improving the condition of the land they manage
  • land managers are innovative and, given the right opportunities, will continue to adapt their systems to meet the needs of the catchment, their farm and their business

The principles guiding investment in soil health are:

  • Farmer to farmer learning, with emphasis placed on demonstrations and group supported activities
  • The importance of seeking solutions to problems from the land managers point of view
  • Ensuring that solutions are evidence based, both in the science of land management and the engagement with and response of the land manager community
  • Supporting improved communication around soil and land health management so that the community is aware of opportunities and are engaged in the ongoing improvement in soil and land condition.
  • Promoting whole of landscape approaches to soil and land health, including farming and land manager activities to manage the soil that are complementary to the biophysical and economic condition of the catchment.