This section describes the aerial application, risk factors and management options (pilot management options and plan provision options) for the three types of aerial applications. A summary table of management options is provided for each aerial application type (fertilisers, agrichemicals and VTAs), which identifies:
- Potential adverse effects.
- Risk factors.
- Exposure pathway.
- Pilot management options.
- Options for plan provisions and consent conditions (note this is not provided for VTAs).
When identifying the appropriate management option, it is also important to assess the key considerations and section 32 requirements when developing plan provisions and controls to manage the adverse effects of the agricultural aviation industry.
Fertilisers
Fertilisers are substances that are applied to land to improve the productivity of plants for primary production, which includes pastoral farming (sheep, beef, deer and dairy), horticulture, viticulture, and forestry. They are critical to the success of primary production and therefore contribute to GDP and the economic well-being of communities. Fertilisers are also used on sports fields and golf courses. About 600,000 tonnes of fertiliser is applied by air annually in New Zealand, both by fixed wing aircraft and helicopters.
There is a wide range of fertilisers used for different purposes, in both solid and liquid forms. The most common types are superphosphate and nitrogen based fertilisers. Essential nutrients to retain soil balance, such as potassium and sulphur, magnesium and cobalt, are also applied as fertilisers or added to fertiliser mixes.
The ACVM (Exemptions and Prohibited Substances) (ACVM (E&PS)) Regulations 2011 defines a fertiliser and requirements and conditions for fertilisers. Relevant definitions in these regulations are as follows:
Fertiliser
- means a substance or biological compound or mix of substances or biological compounds that is described as, or held out to be for, or suitable for, sustaining or increasing the growth, productivity, or quality of plants or, indirectly, animals through the application to plants or soil of—
- nitrogen, phosphorus, potassium, sulphur, magnesium, calcium, chlorine, and sodium as major nutrients; or
- manganese, iron, zinc, copper, boron, cobalt, molybdenum, iodine, and selenium as minor nutrients; o
- fertiliser additives; and
- includes non-nutrient attributes of the materials used in fertiliser; but
- does not include substances that are plant growth regulators that modify the physiological functions of plants.
Fertiliser additive
- a non-nutrient substance added to a fertiliser, or applied to land by itself, that—
- improves the supply and uptake of nutrients; or
- increases the biological activity of soil; or
- modifies the physical characteristics of a fertiliser to make it more fit for its purpose;
but
- does not include substances that are plant growth regulators that modify the physiological functions of plants.
These definitions are considered appropriate for incorporation into plan provisions. Agricultural lime is applied to condition and change the pH of the soil and under these definitions is considered to be a fertiliser additive.
For other definitions of fertiliser see the Technical Information relating to the Agricultural Aviation Industry.
Relevant legislation relating to fertilisers
Fertilisers are managed under both the HSNO and ACVM Acts. While not specifically mentioned or provided for in the RMA, fertilisers can also be managed under the RMA as they fall within the definition of contaminants.
Regional councils are responsible for managing fertiliser discharges to air, onto or into land and/or water. The application of fertiliser, including aerial applications, is generally provided for in regional plans as a permitted activity, subject to conditions.
Territorial authorities are primarily responsible for the management of land use activities which can include the control of hazardous substances. As most fertilisers are classified as hazardous substances they are managed under the HSNO Act. However if councils consider that HSNO controls are not sufficient to meet the purpose of the RMA, then councils can address this through their district plans. District plans should address the storage of fertilisers. HSNO Act regulations are also relevant in this regard and are discussed further in Technical Information relating to the Agricultural Aviation Industry. Under the ACVM Act, the requirements for end users are outlined in the ACVM (E&PS) Regulations.
Aerial Application of fertiliser
Superphosphate is typically applied from the air at rates of between 100 and 300kg/ha over complex topography where no other application methods are viable. Superphosphate fertilisers tend to be of variable quality in terms of particle size and size range. Nitrogen based fertilisers (and other high analysis fertilisers) tend to be applied over more productive, and hence more uniform land for both pasture and cropping. Nitrogen based fertilisers are also usually more uniform and consistent in terms of particle size.
Maximising the productivity gains from fertiliser application requires evenness of application across the target area. Achieving an even application within the target area has an impact on the precision of application (i.e. the requirement to confine the fertiliser to the target area). There are a range of systems, equipment and techniques required to consistently and reliably achieve an even application of fertiliser and this also enables fertiliser applications to be confined to the target area.
There are a number of publications setting out best practice for fertiliser application including:
- Safety Guideline: Farm Airstrips and Associated Fertiliser Cartage, Storage and Application.
- Code of Practice for Nutrient Management (COPNM).
- The Fertmark Code of Practice for the Sale of Fertiliser in New Zealand .
- The Aerial Spreadmark Code of Practice (Part A and Part B).
For more information on these codes and standards see Technical Information relating to the Agricultural Aviation Industry.
Risk factors of aerial application of fertilisers
The key risk factors for aerial application of fertiliser are particle size, wind speed and wind direction. It is important to recognise that not all fertiliser has the same physical characteristics. The particle size of fertilisers varies, which directly affects the ballistic property of the substance and how it falls when discharged. Coarser particle size means that the product trajectory will be more predictable, whereas a smaller particle size presents a greater likelihood of off-target drift and dust.
Wind speed at the time of application influences how far the fertiliser will travel from the point of release. At a given wind speed, small particles will move down wind further than large particles. Wind direction determines the direction in which the fertiliser particles will travel. Both wind speed and wind direction needs to be factored in by the pilot, along with the product quality and particle size to determine flight paths, to avoid sensitive areas, and to ensure the product is applied to the target area. An operator can verify the track flown and where they have discharged fertiliser. However to accurately verify where the product has landed requires information on wind speed (which influences how far the product will go from the track flown) and wind direction which determines the direction the fertiliser particles will travel from the point of release.
Management options for the aerial application of fertilisers
The risk management section sets out the general framework for a risk management approach for aerial applications. This section provides guidance on how to apply this approach specifically to manage the discharge of fertilisers. Table 5identifies management options for plan provisions and consent conditions to manage the adverse effects from the aerial application of fertilisers based on the type of adverse effect, relevant risk factors and the exposure pathway. It also identifies the measures pilots can take to minimise risks and potential adverse effects from the aerial application of fertilisers.
Table 5: Risk management approach for aerial application of fertiliser
Potential adverse effects | Risk factor | Exposure pathway | Pilot Management Options (see Technical Information relating to the Agricultural Aviation Industry Information relating to the Agricultural Aviation Industry and the Aerial Spreadmark Code Spreadmark Code) | Options for plan provisions and consent conditions |
Health effects which may include:
|
|
Indirect:
Direct:
|
Indirect:
Direct:
|
|
Contamination of crops and plants including sensitive crops and organically farmed properties;
|
Fertiliser type:
|
Indirect:
|
Indirect:
|
|
Contamination of domestic or commercial water supplies where it renders the drinking water non-potable |
Fertiliser hazard and type:
|
Indirect:
Direct:
|
Indirect:
|
|
Contamination of indigenous flora, fauna, habitat areas and reserves where the inherent values of these areas are damaged or lost |
Ecotoxicity of fertiliser:
|
Indirect:
Direct:
|
Indirect:
|
|
Contamination of wetlands, surface water bodies, and coastal and marine environments where it causes:
|
Fertiliser type and hazard:
|
Indirect:
Direct:
|
|
|
Contamination of groundwater |
|
Indirect:
Direct:
Direct and indirect:
|
|
|
Contamination of soils/ land which may cause death of flora and fauna |
|
Indirect:
Direct:
|
||
Amenity values |
|
Indirect:
Direct:
Noise:
|
|
|
All potential adverse effects |
|
Agrichemicals
The term ‘agrichemical’ is commonly used to describe a range of substances that control pests. Agrichemicals are applied to land, water or crops to control pests in primary production activities of pastoral farming (sheep, beef, dairy and deer), horticulture, viticulture and forestry.
Examples of agrichemicals include:
- Herbicides to control unwanted plants, including some that are specific for aquatic use in water;
- Insecticides to control insects such as clover flea or potato psyllid;
- Fungicides to control fungus e.g. rust, mildew, moulds; and
- Plant growth regulators e.g. Hi Cane.
Agrichemicals are usually discharged into air rather than applied directly onto the target species. Under the RMA such applications are classed as a discharge of contaminants to air, land or water.
Agrichemical applications can be by both fixed wing aircraft and helicopters, and vary due to a range of factors so plan provisions need to be appropriate, flexible and applicable across the range of situations. Aerial application of agrichemicals range from total vegetation control (e.g. pre-plant herbicide application in cropping and forestry) where confining the spray to the target area is the first priority, through to application of a biological insecticide as a biosecurity requirement (e.g. Painted Apple Moth eradication in Auckland). In the latter case, large urban areas were sprayed with small spray droplets in specific local wind conditions to achieve the required target penetration and coverage.
The terms agricultural chemicals, agricultural compounds and pesticides are often used to describe the same or similar groups of products. The terminology and definition used in a plan is important so it is clear exactly what substances fall within the parameters of any regulation.
The most commonly used definition in RMA plans is the definition from NZS 8409:2004 Management of Agrichemicals (NZS 8409) which defines agrichemicals as:
“Any substance, whether inorganic or organic, man-made or naturally occurring, modified or in its original state, that is used in any agriculture, horticulture or related activity, to eradicate, modify or control flora and fauna. For the purposes of this Standard, it includes agricultural compounds but excludes fertilisers, vertebrate pest control products and oral nutritional compounds.”
This definition is considered appropriate to incorporate into plan provisions.
Pesticides are not defined in regulations or the HSNO or ACVM Acts. Pesticides can include a wider range of substances than the definition of agrichemical in NZS8409. Pesticides generally include any chemical mixture of substances intended for preventing, destroying or controlling any pest. For example, VTAs or timber treatment chemicals would be classed as a pesticide, but not as an agrichemical as defined in NZS 8409. For other definitions see the Technical Information relating to the Agricultural Aviation Industry.
Aerial Application of Agrichemicals
Aerial application of agrichemicals normally involves mixing it with water in a spray tank according to the rate and concentration specified on the product label[2]. It is then applied using a boom fitted to the aircraft that has the appropriate number and type of nozzles fitted. The nozzles regulate the flow rate and determine the droplet size produced. Getting an even spray pattern from an aircraft, whether fixed wing or helicopter, depends on the way in which the spray boom and nozzles are mounted on the aircraft.
Most aerial spraying of agrichemicals in New Zealand involves herbicide application where it is important to ensure maximum deposition onto the target, while minimising off-target drift. The application equipment used, the way this equipment is fitted and the type of aircraft can significantly affect the extent to which off-target drift is minimised.
Sometimes a different technique is needed, where lateral movement of small droplets in the spray is used to obtain large swath widths and horizontal droplet deposition. Examples of this technique in New Zealand include fungicide application to broad-acre crops and control of pest incursions such as the Tussock Moth and Painted Apple Moth. This technique can produce very good target coverage but containing such spray in the target area is more difficult.
There are existing industry best practice standards for agrichemical application. The most relevant is NZS 8409.This performance standard applies to any agrichemical application, including aerial methods. NZS 8409 was developed by Standards New Zealand and sets out the requirements for the safe, responsible and effective management of agrichemicals. EPA has approved NZS 8409 as a Code of Practice under the HSNO Act and by complying with the standard you are considered to have met ACVM conditions. NZS8409 is one of the Codes of Practice that form part of the AIRCARE™ Accreditation programme.
Risk factors of aerial application of agrichemicals
There are a number of potential adverse effects that can arise from agrichemical applications and the nature of these effects will vary depending on the combination and level of risk factors for the operation. The relevant risk factors for the discharge of agrichemicals include:
- The chemical being used, hazard class and type, and exposure to it.
- The concentration and rate of application of the chemical.
- The timing of the application.
- Location of sensitive activities.
- The proximity of people – timing and location.
- The location of the application and use, including mixing sites.
- Weather conditions.
- Spray quality.
- Target identification.
- The permeability of the soil.
- Whether non-target animals are present (e.g. when applying to pasture).
In seeking to avoid or minimise adverse effects from the discharge of agrichemicals, these risk factors must be assessed and addressed in the context of the relevant exposure pathways.
Exposure pathways and management options
The exposure pathways for agrichemicals can be either:
- Indirect – off target drift, leaching, overland flow; or
- Direct – application on subject areas, point source discharges (e.g. spillages).
Off target drift - Spray drift and drift hazard
Drift hazard is defined in NZS 8409 as the hazard associated with drift and consequent trespass which may result in an adverse effect to human health, animal health or the environment.
Every spray application of agrichemicals will result in some degree of spray drift as it is not possible to have zero drift due to the range of variables. However, the most important issue from a risk managementperspective is what risk the spray drift poses and how the risk can be avoided or minimised.
Appendix G of NZS 8409 provides a drift hazard guidance chart. Technical Information relating to the Agricultural Aviation Industry includes a potential draft hazard scale from NZS 8409. This table highlights the range of variables that need to be considered such as wind speed and direction, height and application, and sensitive areas. It also identifies ways to address these hazards which requires knowledge of all the variables that are relevant to the agrichemical application at the time. Table 4.1 in the Technical Information distinguishes between pre-determined and real-time factors and identifies that the most significant factor causing adverse effects from off target spray drift is almost always wind direction – a real-time factor.
Plan provisions relating to the discharge of agrichemicals need to ensure they recognise these options so that they are assessed at the time of application.
Management options for the discharge of agrichemicals
The risk management section sets out the general framework for a risk management approach for aerial applications. This section provides guidance on how to apply this approach specifically to manage the discharge of agrichemicals.
For each potential adverse effect, table 6 identifies the relevant risk factor, exposure pathway and management options to manage potential adverse effects for both the pilot and councils. The extent to which a risk factor applies and management options need to be considered varies according to the nature of the receiving environment and the potential adverse effect.
Table 6: Risk management approach for aerial application of agrichemicals
Potential adverse effects | Risk factors | Exposure pathway |
Pilot management options (see Technical Information relating to the Agricultural Aviation Industry Agricultural Aviation Industry) |
Options for plan provisions and consent conditions |
Health effects caused or possible:
|
Indirect:
Direct:
|
Indirect:
Direct:
|
|
|
Potential toxicity to bees and other pollinators, including beneficial insects (insects that perform valued services like pollination and pest control) |
|
Indirect:
|
|
|
Contamination of crops and plants including sensitive crops and organically farmed properties. Effects include:
|
|
Indirect:
|
|
|
Contamination of domestic or commercial water supplies where it renders the drinking water non-potable |
Chemical type and hazard class:
|
Indirect:
Direct:
|
|
|
Contamination of indigenous flora and fauna, habitat areas and reserves where the inherent values of the areas are damaged or lost (Note: in considering effects consideration should be given to whether the application is specifically for the control of environmental weeds in areas of native vegetation / reserve land) |
|
Indirect:
Direct:
|
|
|
Contamination of wetlands, surface water body and coastal and marine environments where it causes:
(Note: in considering effects consideration should be given to whether the application is specifically for the control of environmental weeds in wetlands and other waterbodies). |
|
Indirect:
Direct:
|
|
|
Contamination of groundwater |
|
Direct:
Indirect:
Direct and indirect:
|
|
|
Contamination of soils/ land |
|
Direct:
Indirect:
|
|
|
Amenity values Offensive and/or objectionable effects such as:
|
Direct:
|
|
||
All potential adverse effects |
|
Vertebrate Toxic Agents
This section provides background information on the safe and responsible management of the most common aerial application of VTAs – 1080 applied as cereal bait or carrot bait[5]. VTA (as defined in the ACVM Standard for Vertebrate Toxic Agents) is “a toxic substance used to kill or reduce the viability of vertebrate animals. It does not include attractant or repellent substances that are not toxic”. VTAs, commonly referred to as baits, are substances, inorganic, human made or naturally occurring, modified or in its original state, that are used to kill, control or limit the viability of vertebrate pests, including possums, rats, rabbits, mice and mustelids. These substances are sometimes known as vertebrate pest control products and include products that have a negative effect on reproduction.
This section does not provide options for managing VTAs in district and regional plans. The Parliamentary Commissioner for the Environment (PCE) found that where controls and consent conditions are imposed under the RMA they often create unnecessary inconsistency or duplication with controls under the HSNO Act. Therefore, councils are encouraged to pursue this matter under the HSNO Act and to refer to relevant resources such as:
- ERMA’s 2007 Reassessment of 1080.
- ERM/EPA Annual Reports on 1080.
- EPA 5 year review of the aerial use of 1080.
- Managing Hazardous Substances – interface between the Hazardous Substances and New Organisms Act and the RMA.
- Parliamentary Commissioner for the Environment Report on 1080.
Aerial application of VTAs
Aerial application of 1080 usually involves the 1080 substance contained within cereal bait or it is added as a soluble concentrate on site with carrot bait. Bait containing 1080 is principally used to manage possums in the Conservation estate to protect indigenous flora and fauna and on primary production land to control possums as vector carriers of TB to cattle. Rabbits are also controlled by using 1080 and Pindone.
Guidelines and standards for aerial 1080 are available on the EPA’s website. In addition, the main users of 1080, such as the Department of Conservation (DOC) and TBfree New Zealand have developed their own Standard Operating Procedures (SOP’s), and other bodies have developed best practice measures for the aerial application of VTAs, including:
- Aerial 1080 Pest Control Industry Guidelines, National Pest Control Agencies.
- Guidelines for the Safe Use of Sodium Fluoroacetate (1080), Department of Labour.
- Code of Practice for the Aerial Application of Vertebrate Toxic Agents.
Note that management of VTAs is not included within NZS8409: 2004 Management of Agrichemicals, therefore the standard is not an appropriate management tool for VTAs.
Risk Factor of aerial application of VTA
ERMA’s Decision (now EPA) for the reassessment of 1080 (Table C1) has already assessed the level of risk for the application of VTAs and has accordingly set national controls to manage the potential risks. Hazard classifications for sodium fluoroacetate (1080) and formulated substances containing 1080 are given in Section 7 of the reassessment.
Overview of management options for the aerial application of VTAs
The application of 1080 is regulated under the HSNO Act by the EPA, with the EPA risk assessment controlling its use. There are also controls on their use under the ACVM Act, which is administered by MPI.
The former Environmental Risk Management Authority (ERMA), now the EPA, undertook a reassessment of 1080 in 2007. This assessment provides full information on the product, risks and controls which must be met by operators. It looked at the broader environmental effects of 1080, and identified that existing hazardous substance controls are adequate to control the adverse effects of 1080 on public health and the environment. This assessment recommended that more effort should be put into ensuring that the existing controls are complied with by all users of 1080 through implementation of best practice guidelines and standards. For more information, see the 1080 webpage on the EPA website.
While the application of VTAs is considered a discharge of contaminants to air, land or water under the RMA,additional controls under the RMA (through consent conditions or district or regional plan provisions) should only be used to address a resource management issue which a council considers is not adequately controlled by the EPA under the HSNO Act.
The following table sets out a risk management approach for use of VTAs. It is based on the ERMA (now EPA) reassessment of 1080 in 2007 and provides examples of how pilot management options give effect to controls under the HSNO Act.
Table 7: Risk management approach for VTA (1080) use
Potential adverse effects |
Risk factor* |
Exposure pathway (Nature of risk) |
Examples of pilot management options addressed under the HSNO Act (see Technical Information relating to the Agricultural Aviation Industry) |
Adverse human health effects (both short and long term) (Note: risks to public health from 1080 are covered by the HSNO Act public health permission) |
B Minor/ Improbable |
Exposure of occupationally exposed persons during the handling of treated carrot and apple baits in the field and from handling cereal pellets if Personal Protection Equipment is not worn correctly. Nature of risk:
|
|
Effects following direct exposure to pellets during aerial operations and coated baits on:
|
A – D D A - C |
Nature of risk:
|
|
Effects following indirect exposure on non-target food producing animals. |
** |
Nature of risk:
|
|
** Not included in ERMA Decision
[1] These refer to the HSNO Classification Codes. A full list is available on the EPA website.
[2] Note that Appendix C3.2 of NZS 8409 specifies use outside of conditions (off-label use)
[3] Note that just because a product does not have a high 9 classification under the HSNO Act it does not mean that it does not pose a risk to the environment. This is because the HSNO Act only considers acute effects for classification which could be problematic when considering other impacts such as reproductive effects.
[4] Aquatic herbicides are used to control weeds in some wetlands. This activity is typically undertaken by DOC, MPI, regional councils, territorial authorities, farmers and contractors. The use of aquatic herbicides onto or into water is not a matter for regional and district plans, as it is controlled by the EPA pursuant to section 95A of the HSNO Act.
[5] This guidance note does not address applications of other VTAs, such as pindone pellets, or non-aerial methods of applying VTAs.