Regional Policy Statement for Taranaki |
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Part B Section 5 — Land and soil | 5.1 Erosion | 5.2 Soil health |
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5.3 Hazard substances and contaminated sites | ||
5. Land and soil
This section identifies resource management issues of regional significance, which have their primary effect on Taranaki's land or soil resources. These issues are grouped under the headings of:
- protecting our soil from accelerated erosion
- maintaining healthy soils
- managing the effects of hazardous substances and contaminated sites.
5.1 Protecting our soil from accelerated erosion
Background to the issue
Soil is one of Taranaki's most important resources. This thin layer at the earth's surface is the source of food and fibre, and sustains the growth of our plants and animals. Soil also plays a role in sequesting carbon. Soil erosion leads to land degradation and loss of soil productivity, capability and versatility. Other offsite effects of erosion range from reduction in water quality and degradation of aquatic habitats from increased siltation, and downstream flooding from aggradation of riverbeds, to damage to archaeological sites which are addressed in other sections of the Regional Policy Statement.
Soils are subject to natural processes of erosion. However, human activities, particularly where inappropriate land management practices occur, may cause accelerated erosion. Inappropriate land management practices may include pastoral livestock grazing, earthworks associated with roading and tracking, disturbance of indigenous vegetation or harvesting of plantation forests on erosion-prone land without appropriate management to avoid or mitigate erosion.
Erosion-prone lands are those lands that because of their geology, soil type, slope angle and aspect, climate and vegetation cover, are more prone to erosion than other areas. In Taranaki these areas are found predominantly in the inland hill country where shallow soils have formed on sandstone, siltstone and mudstone slopes, and on the coastal sand country where land adjacent to the coast is influenced by wind-blown sand, forming sand dunes and sand flats.
Approximately 92% of Taranaki land is sustainably managed and does not carry a severe or high risk of accelerated erosion in the long term so long as good management practices are continued. Natural erosion rates are high on the slopes of Mount Taranaki but the human impacts in the Egmont National Park are negligible. Natural erosion rates are also low on the ring plain and the western fringe of the hill country. However, the inland hill country and the coastal sand country are particularly susceptible to 'unsustainable' land use activities (activities that carry a severe or high risk of erosion in the long term). This is because the geology, soil type, slope angle and aspect, climate and vegetation cover found in these areas make them more prone to erosion.
Hill country areas most susceptible to erosion are those steeper areas cleared for pasture - generally on slopes greater than 28˚. In areas planted for plantation forestry, accelerated erosion rates are higher than natural erosion rates but not as high as erosion rates under pasture. Areas that remain bush-clad, including indigenous forests managed for a sustainable yield harvest, generally have the lowest rates of erosion. Areas that remain in native bush have the lowest rates of erosion as they have a constant closed forest canopy. Erosion rates of land under plantation forestry are higher because a plantation forest does not maintain a constant closed canopy due to its rotational life history. The time period a plantation forest is without a closed forest canopy is minimal however (typically 4 to 5 years) which is why a plantation forest is more beneficial for protecting certain classes of land from erosion than other land uses such as pasture. Natural erosion rates are moderate in the coastal sand country, but can be exacerbated by land use activities that expose topsoil to wind causing blow-out and the re-deposition of the underlying sand in localised areas.
The significant issue in relation to protecting soil from accelerated erosion in Taranaki is:
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AER |
Promoting sustainable land use to address accelerated erosion on erosion-prone land, with a particular focus on the hill country and the coastal sand country. |
Objective
AER OBJECTIVE 1
To maintain and enhance the soil resource of the Taranaki region by avoiding, remedying or mitigating the adverse effects of accelerated erosion on soil resources.
Policies
Sustainable land use and management practices
AER POLICY 1
Encourage land use and management practices that will promote the sustainable use and development of land and soil resources and minimise soil erosion by:
(a) avoiding, where practicable, practices that cause accelerated erosion; and
(b) remedying or mitigating the adverse effects of accelerated erosion where it occurs.
Erosion-prone land
AER POLICY 2
Priority will be given by the Taranaki Regional Council to encouraging sustainable land management practices that avoid, remedy or mitigate adverse effects arising from soil disturbance and vegetation disturbance activities on erosion-prone land, with particular focus on:
(a) accelerated erosion of soil in the hill country; and
(b) localised accelerated blow-out and re-deposition of sandy soil in the coastal sand country.
Explanation of the policies
Most land use activities in Taranaki are carried out in a sustainable manner that causes little or no accelerated erosion. Even where there is potential for an activity to result in accelerated erosion, the adoption of certain techniques, or the taking into account the susceptibility of the land to soil erosion, can avoid, remedy or mitigate any potential soil loss. Policy 1 seeks to encourage sustainable land uses and practices and in so doing avoiding, remedying or mitigating the adverse effects of accelerated erosion. Consideration of what constitutes 'sustainable land uses and management practices' depends on the nature and scale of the activity and the susceptibility of the land and soil resource to accelerated erosion, and may range from pastoral farming, mixed livestock and forestry production forestry, soil conservation plantings, land retirement to indigenous forest protection.
Policy 2 recognises that the potential for accelerated erosion is most significant in the hill country and coastal sand country. Therefore, the Taranaki Regional Council will focus its efforts in these areas.
Related policies
All policies relating to Section 6.2 [Surface water quality], and Section 8.1 [Natural character of the coast]; Policy 1 of Section 8.2 [Coastal water quality]; all policies in Section 9 [Indigenous biodiversity]; policies 1, 2 and 3 of Section 11 [Natural hazards].
Methods of implementation
The Taranaki Regional Council will:
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Maintain a regional plan or plans with objectives, policies and methods of implementation that address accelerated erosion.
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Consider and if appropriate apply regional rules to regulate soil and vegetation disturbance activities that cause or exacerbate erosion.
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Implement the Sustainable Land Management Programme to improve physical sustainability in the hill country and the coastal sand country by: (a) liaising with and consulting with interested land users; (b) preparing property plans in conjunction with landowners whose land is susceptible to erosion, containing property-specific advice on sustainable land management practices and erosion control techniques; and (c) providing on-going technical advice, information and other assistance to plan holders promoting physical sustainability.
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Consider the use of financial incentives, such as the provision of plant material at low cost to landowners, for land stabilisation and soil conservation purposes.
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Provide advice and information, including guidelines to landowners, resource users and the public to: (a) promote awareness of soil erosion issues; (b) encourage the adoption of sustainable land management principles and practices to avoid, remedy or mitigate the adverse effects of soil and vegetation disturbance activities, including the retention of topsoil, the promotion of soil accumulation techniques and low-till sowing; and (c) promote appropriate planting throughout Taranaki in order to prevent the exacerbation of soil erosion and encourage the use of industry recognised guidelines or Codes of Practice such as the Logging Industry Research Organisation's Forestry Code of Practice and other relevant industry guidelines.
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Support, as appropriate, the work of the Taranaki Tree Trust, district councils, the Department of Conservation, and other appropriate organisations in the protection or retirement of areas of indigenous forest on highly erosion-prone land.
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Monitor and gather information on the state of physical sustainability, pressures on soil resources, and responses to management.
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Territorial authorities may wish to consider the following method:
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Control, through appropriate provisions in district plans, or conditions on resource consents, earthworks and site development not dealt with in regional plans, to avoid or mitigate the actual or potential adverse effects of accelerated erosion on land and soil resources where such control is necessary and appropriate to achieve the purpose of the Act. |
Principal reasons for adopting the objective, policies and methods
The objective, policies and methods of implementation recognise that soil is one of Taranaki's most important resources. They establish a policy framework to maintain and enhance the soil resource by reducing the incidence of accelerated erosion. The objective has been adopted to maintain and enhance soil resources, but it may not always be possible or practicable to enhance soil resources at all sites or places when carrying out activities, for example earthworks. In such situations, the Council will apply the policies and methods to minimise soil loss and maintain the overall soil resources of the Taranaki region. Their aim is to ensure that Taranaki land and soil resources are sustainably used in the long term.
The policies and methods principally focus on promoting and supporting the voluntary adoption of sustainable land management practises with a particular focus on erosion-prone areas - these being the hill country and coastal sand country. The principal methods of implementation are the Taranaki Regional Council's Sustainable Land Management Programme, advice and information services and financial incentives. A limited range of regional rules is currently applied as a back up measure to control potentially significant adverse effects from soil or vegetation disturbance activities. These rules apply regardless of whether the vegetation disturbance is associated with forestry, farming or any other land use. The rules have been targeted to very specific situations and provide certainty to landowners. The Council will continue to consider the application and appropriateness of such rules over the term of this Regional Policy Statement and during the review of its regional plans. The policies and methods build on current approaches to this issue. They have proven to be successful to date in terms of public acceptance and achievement of desired environmental outcomes and are considered to be the appropriate approach having regard to their efficiency and effectiveness and their benefits and costs.
Given the proven success of the current approaches, it is considered appropriate to allow each territorial authority the discretion to include further rules as a backstop.
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Environmental results anticipated AER ER 1 By 2016, increase the area of privately-owned land in the hill country that is sustainably managed (i.e. land used within the land use capability classification) from 85% to 89%. AER ER 2 Reduce the area of exposed soil on privately-owned land in the coastal sand country. |
Click here to read about the Taranaki Regional Council's sustainable land management programme.
5.2 Maintaining healthy soils
Background to the issue
Soil health refers to the biological, chemical and physical state of the soil and the maintenance of soil ecosystems. Unlike the impact of accelerated erosion on soil, soil health problems may not be immediately evident, but are no less important.
Taranaki is one of the most intensively farmed regions in New Zealand and this places considerable demand upon its soil resources. Maintenance of soil health is fundamental to the environmental and economic well-being of Taranaki. While there are currently few major problems relating to soil health in the region, there is a potential for serious soil health issues such as soil compaction, nutrient depletion, residual soil contamination, and the excessive use of fertilisers to emerge in the future if sustainable land management practices are not adopted.
Under natural conditions, soil compaction (or soil structural degradation) is rare. Ninety-seven percent of Taranaki's soils have very low to moderate vulnerability to soil compaction. Although Taranaki's soils, particularly its volcanic and organic soils, are generally more resistant to compaction than other soil types, they are not immune to damage - particularly when worked or heavily stocked under wet conditions. Soil compaction increases soil bulk density, reduces aeration and decreases infiltration, which in turn reduces pasture growth and leads to increased nutrient loss through run-off. Compaction is reversible if the source of compaction is removed. The rate of recovery depends on subsequent pasture and stock management, climate and soil type factors.
Soil contains essential mineral elements required by plants or animals. An inevitable consequence of farming is that, at some time in the future, soils will be unable to sustain high levels of production unless those nutrients are replaced. Soil depletion refers to reducing soil nutrients down to a level where their potential to sustain natural and physical resources is adversely affected. Investigations by the Taranaki Regional Council, however, confirm that neither dairy farming nor sheep and beef farming have caused long-term decline in soil nutrient levels in Taranaki soils to date.
Current soil contamination issues relate to the risk of certain contaminants altering the physical, chemical or biological condition of the soil and entering the food chain (Soil contamination may occur in other ways such as when chemicals are spilt or disposed of incorrectly, from the use, transportation or storage of hazardous substances and contaminated sites (these sources are addressed separately in section 5.3 below).) Diffuse source soil contamination is a side effect associated primarily with the widespread application of fertilisers and agrichemicals - whether through the primary active ingredient (agrichemical residues) or a by-product (eg, fluoride and cadmium). Investigations in Taranaki show that there are no significant levels of fertiliser or agrichemical residues in Taranaki soils that pose a risk to human or animal health. However, there is potential for adverse effects as a result of inappropriate land management practices applied over time.
Intensive land use and the desire to optimise nutrient levels in the soil to increase the land's productivity have led to the problem of excessive phosphate in most Taranaki soil. This in turn results in run-off from land to surface water or leachate into groundwater reducing water quality (this is largely addressed in sections 6.2 and 6.3.
The significant issues in relation to maintaining healthy soils in Taranaki are:
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HSO |
Potential effects of intensive land use on soil compaction.
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Potential soil nutrient depletion.
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Potential residual soil contamination. |
Objective
HSO OBJECTIVE 1
To maintain soil health in the Taranaki region by maintaining soil nutrients at appropriate levels and avoiding or minimising soil compaction and soil contamination caused by inappropriate land management practices.
Policy
Sustainable land management practices
HSO POLICY 1
Encourage land management practices that:
(a) avoid, remedy or mitigate soil compaction and residual soil contamination, and maintain soil nutrients at appropriate levels;
(a) safeguard the life supporting capacity of soils;
(b) maintain and optimise soil versatility and productivity; and
(c) protect human and animal health.
Explanation of the policy
Policy 1 recognises that, while soil structural degradation, nutrient depletion and residual soil contamination are not of immediate concern in Taranaki, there is a long term risk that irreversible degradation in soil health may occur if appropriate land management practices are not adopted or continued to address soil compaction and residual soil contamination, and to ensure that soil nutrients are maintained at appropriate levels (not too high, not too low).
Related policies
Policies 1 and 2 in Section 5.3 [Hazardous substances]; Policies 1 and 2 in Section 6.2 [Surface water quality]; Policies 1 and 2 in Section 9.1 [Indigenous biodiversity].
Methods of implementation
The Taranaki Regional Council will:
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HSO |
Maintain a regional plan or plans with objectives, policies and methods of implementation that address soil health.
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Provide advice and information, including guidelines to landowners and resource users to: (a) promote recognition of soil health issues; (b) encourage the adoption of practices and techniques that maintain soil nutrients at appropriate levels and avoid, remedy or mitigate soil compaction and residual soil contamination; and (c) encourage the use of industry recognised guidelines, New Zealand Standards or codes of practice and other relevant industry guidelines that promote sustainable soil management, such as: NZS8409: 2004 Management of Agrichemicals (developed by NZ Agrichemical EducationTrust and published by Standards New Zealand), and the Code of Practice for Nutrient Management 2007 developed by FertResearch. |
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HSO |
Advocate, as appropriate: (a) to industry that they reduce or avoid the use of those elements in agricultural compounds that have the potential to cause residual soil contamination; (b) to industry that they establish or continue to revise standards in relation to the use of agrichemicals, fertilisers, or other agricultural compounds; (c) to the farming community that they incorporate soil health and nutrient budgeting within their on-farm environmental management systems; and (d) to government departments or agencies that they introduce, or amend, regulations in relation to the importation of or manufacturing standards associated with the use of agrichemicals, fertilisers, or other agricultural compounds as they relate to soil health issues. |
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HSO |
Monitor and gather information on the state of soil health, pressures on soil health, and management responses to soil health issues. |
Territorial authorities may wish to consider the following method:
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HSO |
Control, through appropriate provisions in district plans, or conditions on resource consents, land use for the purpose of preventing or mitigating any adverse effects of the use of hazardous substances where such control is necessary and appropriate to achieve the purpose of the Act.
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Principal reasons for adopting the objective, policies and methods
The objective, policies and methods of implementation establish a policy framework for soil health issues in the Taranaki region. Their aim is to increase awareness of soil health issues and promote sustainable land management practices that minimise the risk of any long-term degradation of soil health in Taranaki.
Given that there are no immediate soil health issues in the Taranaki region, the policies and methods focus on non-regulatory methods such as information and advocacy. Regular monitoring will provide information on any changes in soil health status or trends. The policies and methods build on current approaches to this issue and their efficiency and effectiveness and their benefits and costs have been appropriate to date.
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Environmental results anticipated HSO ER 1 No significant adverse change in the soil structure of land in the Taranaki region. HSO ER 2 Nutrient levels of soils on land in the Taranaki region are maintained at appropriate levels. HSO ER 3 No significant adverse increase in residual contaminant levels in soils on land in the Taranaki region. |