Adapted from an ARTICLE submitted 06/09/2007 to Fruit Grower magazine:
Authored by the NetPro Sales and Consulting Team
Contact: 1300 NETPRO (638 776)
You have assessed the benefits of canopy netting, and you reckon you want to trial some; or you have seen canopies in action, and have decided to go the whole hog and cover the entire orchard. Now a whole heap of new questions arise: What type of structure is best? What type of canopy? And who are you going to get to install it? Where can you get materials, and where can you go for advice?
There are many factors that typically need to be looked at when you come to the stage of installing canopy netting, and this page is intended to guide orchardists on some of the more common issues. The NetPro Group has a huge amount of collective experience in the area of canopy netting; the background and experience of our staff and contractors ranges from product development and sales, through orchard and rural business owners, to rural supplies and construction. We are ideally placed to advise and assist clients towards achieving the best type of protective structures to best achieve their aims.
In designing a structure to fulfil the unique needs of each client, we assess a number of key criteria. Following is an overview of the type of information our consultants gather from a client during phone conversations and site visits.
What is the main purpose of the structure? What are the main problems the canopy is required to solve? Each purpose needs to be prioritised in respect of importance to the client – in terms of management issues, fruit / product quality (blemishes, colour, maturity, sugar content), and pack-out / profit. Some common problems canopies can solve include sunburn, wind damage, bird and pest control, hail protection, insect control and water saving. Overall, a canopy structure tends to have some measure of a greenhouse effect, creating a microclimate in the space underneath.
What type of machinery needs to operate under the canopy? This affects the height of canopy; also, roadways and sufficient headland area need to be planned for.
What is the terrain like? Of particular interest are the soil type, and the local topography. If possible, it is also handy to have a diagram or mud-map of the area to be covered.
Other factors that may affect overall design once the main purpose has been catered for include: size of the area to be netted; powerlines and boundaries, local prevailing and seasonal weather conditions, site access issues, and management issues such as organic standards, or the need to retract parts of the canopy or walls (the pitch system can be easily modified for canopy retraction).
|The patented pitch system withstood
1.25 hours of severe hail in the storms of 2005.
|Retractable Pitch system installed prior to 2002|
Answers to these four topical questions all influence the suggestions made by our consultants on net type, canopy structure, pole types, cables and anchoring devices. During scheduling of a project, our Project managers take a number of other factors into account, including council approvals, other contractors, harvesting and orchard work-schedules, and weather conditions. Our field expertise works in with our sales and consulting expertise, interacting with the client to create a seamless construction phase with minimal disturbance to the operation of the orchard.
Canopies play an important part in reducing the water consumption by providing an environment that reduces evapotranspiration. Along the same theme, canopies have been developed as Dam Covers to protect irrigation resources. The NetPro dam covers consist of cables suspended across the dam and covered with shade-cloth. Keeping the cover low, at dam-wall height, reduces wind resistance and expense.
Canopies are excellent for Environment manipulation and can be used for producing fruits outside of their normal climatic range; this can aid in farm diversification.
Canopies markedly reduce wind damage. Windbreaks can be incorporated as part of the canopy design or designed as stand-alone structures; either way, canopies and windbreaks are important tools in reducing wind damage to trees and fruit, and reducing spray drift to surrounding areas.
|Views of Hail net systems installed.|
A: It cannot be categorically stated that canopy netting protects against frost - it can be used with other frost-mitigation tools; but many other factors come into play, including the local topography, daytime temperatures, and the type of net used.
A: Nets exclude insects and other pests to varying degrees; for example, fruit fly netting was designed to exclude fruit fly, and it does this very effectively. Other net types will have some success also, with clients noting a reduction in spraying regimes. There is also potential for the reduced use of other chemicals used to control orchard growth phases, such as defoliation and fruit-thinning. If you are looking at organic production, it is a good idea to mention this from the start, as it will affect choices on some materials.
A: Different nets have different shading properties. This depends not only on the density of the net, but also on its colour – be it black, white, grey or red etc. Other variables to consider are the crop and its requirements, the climate and sunshine hours etc, as different crops in different areas respond differently to various levels of shade. This is where it becomes important to research your requirements carefully – our consultants are very knowledgeable on these subjects and have a great deal of practical experience.
A: In considering this aspect, weigh up the cash flow issues associated with all your development being paid for in the first couple of years, against faster tree development under net, earlier maturity and volume of production etc. A general rule of thumb is that if your rows are going to be 3m or wider, you can retain the option to net later. On the other hand, if you can invest up-front, you will have larger returns sooner from your investment.
A: Because of the way bees see and navigate, they will not generally fly through a net, and pollination results will reflect this reduced activity. As with an organic development, doors or sides can be left open for bees to enter during the pollination stages; birds and beneficial insect predators can also be given access in this way. Alternatively, hives can be placed inside the canopy structure during pollination stages – this has been done during DPI trials to good effect.
A: Many orchard workers find the microclimate under the net to be more comfortable; under coloured net such as red it can be difficult to discern colours but sunglasses tend to solve this problem. Orchard owners have reported improved picking volumes; and along with the greater pack-out due to better fruit quality, this can have a marked effect on the bottom line.
|Hail protection in action – the hail is held by the nets and as it melts the net resumes its original flat shape.|
Most often, crops need to be protected from predation by birds and insects; or protected from the elements, such as sun, wind, and hail damage. In most cases, permanent canopies are very effective in this primary function.
The Water for Profit program run by Growcom quantified the reduced demand for water in Summer vegetables grown under a hail-netting canopy with a 20% shading factor, in a trial run in early 2007. They found that “Data from the weather stations show that ETo demand inside the net has been reduced by 20%.” (ETo = evapotranspiration). Other growers have claimed up to 30% water savings but this is not a scientifically produced & documented result.
Solar radiation, wind speed, and humidity can be altered to favour crops grown on the edge of seasons, or crops grown outside of their normal climatic zones. The 1997 DPI report AP320 reported findings that netting can increase humidity by up to 10% and reduce windspeed by 50% or more. The “Sunraysia” newspaper (15 Aug 2007), quotes Paul Scopelliti of Belvedere Fruit Growers: “Under the netting the young trees develop quicker, are happier, are producing marketable fruit two years earlier, and are producing five times the volume of the same variety planted on the same day, outside.”
A summary of the 2002 DPI report “To net or not to net?” included the points that under canopies, fruit quality is improved and is more uniform, leading to higher pack-out percentages through reduced damage by birds, sunburn and wind-rub. A major summarising point for the case of netting was that they found financial certainty is improved through risk cutting (increased crop reliability), and cutting costs such as fruit sorting, orchard maintenance, and insurance. This allows more reliable crop forecasting and budgeting, and perhaps access to more lucrative markets.
A: McMahon Brothers, near Stanthorpe in Queensland, have been BFA A-grade certified for seven years. Over the last few years, they have been producing Summer-season crops such as tomatoes, lettuce, celery, snowpeas and zucchinis – all marketed as Organic. About 3 years ago, McMahon Brothers commissioned an insect exclusion structure from NetPro P/L, specifically for growing their organic tomatoes. The netting is classed as an “allowable input” by the certifying bodies; and in fact, it was looked on favourably because of the potential to reduce disease without chemical sprays (“non-allowable inputs”).
|Suspended Pitch Screenhouse - total insect exclusion|
“We grew our best organic tomatoes under exclusion netting” says Jeff McMahon. He went on to explain how the netting excludes the insect vectors of disease, and how the plants grew much better because of the micro-climate created under the netting. The warmth, shading and reduced wind meant that they were using up to 50% less water on the crop.
Another grower outside Stanthorpe who has an insect exclusion structure is Red Jewel Fruit Management Pty Ltd (Red Jewel Strawberry Runners). While not organic, they installed the netting purely as a management tool for disease control over their foundation nursery. Red Jewel Strawberry Runners produce strawberry plants for shipment all over Australia. One of the issues facing the strawberry industry is the strawberry lethal yellow virus which is transmitted by insect vectors. Inside the insect exclusion structure, they have had no incidence of infection since installation 3 years ago; and almost 100% insect exclusion. Ian Mungall, of Red Jewel Strawberry Runners, believes this is a far more effective control than chemical sprays, which he estimates would have 95% effectiveness. “While chemical sprays fall in effectiveness towards the end of the cycle”, says Ian, “netting is there 24/7 with good protection”. In addition to the insect control, Red Jewel Strawberry Runners has found that reproduction from the foundation-plants is better in the exclusion structure due to the microclimate reducing plant stressors.
These two case studies illustrate the effectiveness of netting in an organic production setting. The net would not always have to be insect exclusion - NetPro stock a product designed specifically for Fruit Fly exclusion, and the Q nets and birdnets have their advantages also. However, insect-exclusion net best suits the purposes of the two growers above. NetPro have built structures for a number of growers and seedling producers for quarantine and disease protection – please contact us for further references. In organic production systems, the main point is that netting can assist in the reduction of pests; and if used appropriately in the management cycle, all of its other benefits can be brought to play in producing the best crop possible.
|Part of a NetPro crew finish clipping a canopy installation.|
A: The Headquarters in Stanthorpe, Queensland are open between the hours of 7am and 5pm on weekdays only, excluding Qld Public Holidays.
|Netpro headquarters - Stanthorpe QLD.|
Our distributors can be contacted individually to confirm hours of operation – their details can be obtained from NetPro Headquarters (above).
A: NetPro Pty Ltd has been constructing canopies for almost two decades, and has grown to be one of the largest in the field and somewhat of an authority on protective canopy projects. NetPro has always had a commitment to Research & Development, and this is borne out by our facilities in Stanthorpe, Qld. Our extensive expertise in the field is disseminated through our large crew of trained canopy installers throughout Australia and New Zealand, giving consistency of product and workmanship. We have taken the steps to ensure one-on-one engagement time with each client to understand their requirements and create user-friendly structures uniquely suited to their situations. NetPro has a team of trained consultants and salespeople to assist in the development of each new structure and to provide technical support, repairs and parts for existing structures.
|Dam cover at wall height drastically reduces wind loads||NetPro truck drives under a large canopy installation||A stand-alone windbreak system|
NetPro has always committed a good proportion of resources to research and development of a number of important and unique components of our protective canopy systems. We are proud of our ongoing achievements in the areas of Anchoring systems, Net types, Cables, Components and Fixings. We have developed a variety of canopy structures, including the flat canopy, the pitch canopy, and the retractable waterproof system – each with their own particular strengths. For example, the proven patented pitch system has performed well during severe hail-storms in the decade since they were first installed. We work closely with our suppliers worldwide to design and develop more efficient and effective components, tools and net.
NetPro is here to stay, and it is our excellent record in the field that gives clients and finance corporations alike the confidence to invest in a NetPro structure.
Success Stories View all
As major investors in the Australian horticulture industry, Rewards Group Ltd needs to ensure maximized returns on all funds invested, particularly in orchard infrastructure. Accordingly, our choice of contractors is critical to the final success of any project.
We currently have 250 acres of net – about 80% of our orchard area. Without the protective canopy, we wouldn’t be able to supply our market requirements. Quality is important to us and we wouldn’t be able to meet the specifications of our customers without net.
We particularly liked the product offered by NetPro – high quality was our main criteria. The option of wooden posts was also an important feature because of the highly-corrosive conditions in the feedlot environment. We were able to work through the construction plan and the materials options during the quoting process.
We chose NetPro to construct our protective canopies, as we know NetPro have been around for some time, we know their work and there are plenty of examples of their work around – we like the consistency of standard. In addition, NetPro are recognized by the Finance bodies, and it is much easier to get finance for a structure.
I think it has made all the difference to the quality of our product – it has saved us from bird attack and from hail damage." Since 2001, Robert Channon Wines have won 23 trophies, 17 gold medals, 26 silver and 55 bronze medals.
We live in North Queensland and have a nine metre pool. We needed to replace the pool cover but most local businesses we contacted wanted to replace it with a shade sail and the one quote we received to fabricate a new cover to our design seemed exceedingly high.
In 2003, Golden Valley Orchards were offered the opportunity to work with the NCEA (National Centre for Engineering in Agriculture) and NetPro Pty Ltd on a research project evaluating the effectiveness of (amongst others) NetPro's dam-covers.
"I think it has made all the difference to the quality of our product – it has saved us from bird attack and from hail damage." To date, Robert Channon Wines have won 23 trophies, 17 gold medals, 26 silver and 55 bronze medals since 2001."
Initially the idea of the net canopy over the landfill was discussed with Netpro as they are a local company and at the time Netpro was considering advancing into this area (protection of landfills). Netpro assisted Council with a very reasonable price which allowed the project to proceed.
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