There are several reasons why farmers around the world are increasingly leaning towards the use of plastics as covers for fruit trees, especially to protect their crops from environmental damage caused, to a large extent, by global warming.
Reports of damage caused by intense storms, extreme droughts, floods and even fires seem to be on the increase, a situation that worries and keeps farmers on alert, not only in large agricultural regions such as California in the United States, Chile or Spain but also around the world where extreme weather variations have negatively affected food production.
According to Borja Devís, Agricultural Engineer from the Polytechnic University of Valencia, Spain, and Area Manager of the agricultural plastics division of the Armando Álvarez Group, it’s important to consider this climatic-data mainly in the markets of Chile, Uruguay, Egypt, Italy, and the west coast of the United States, as reports are issued annually in fields all over the world, to implement drastic measures to help protect crops and ensure sustainable agricultural development.
Main fruit trees covered
Among the fruit trees that have grown the most in protected production are cherries, but there are also grapes and kiwi, which have increased exponentially over time.
To get an idea of how fast the growth and importance of these fruits have been in the agricultural industry, over the last twenty years grapes and cherries have grown by approximately 40% to 50% in terms of production per million metric tons, which is an excellent figure.
For example, in Chile, the cultivation of cherries has been successful thanks to the different protection methods that have been implemented to preserve the production levels and quality of the fruit; as a result, Chile has managed to stand out as a producer and exporter of quality cherries.
Chile’s strategy has been to implement the model of high ceilings and tunnels, which reduce the risk of crops and fruit being affected by inclement weather or problems during critical periods such as flowering and fruit set.
When should cherry trees be protected?
The temperature factor must be considered, as there is a variation of two or three degrees between the inside and outside of the tunnel, so it’s necessary to analyse the time of year to establish the appropriate regulations and avoid compromising the integrity of the crop.
It should also be considered that, depending on the area, there may be more or less rain than expected, strong winds or some other factor as a consequence of pests or climate change, so it’s vital to be aware of the changes that may occur. To learn more about this topic, we recommend our article on cherry production.
What about the cultivation of grapes?
For decades, grapes have been grown under covers as an alternative that has many advantages and benefits, such as shortening ripening times to produce higher quality grapes faster, being able to satisfy the growing demand of consumers, aside from being a cheaper option that’s also easier to handle.
Although there are a variety of options of tree covers on the market, when it comes to choosing plastics, we must look for films with good spectral-radiometric properties to guarantee optimal results (regarding fruit ripening and harvesting times, yield and berry quality) and also to meet the crop’s requirements, avoiding excessive solar radiation or high temperatures that compromise the entire crop.
The objective is to produce an ideal thermal effect so that the grape plant ripens in less time. However, there are plastics that due to their chemical composition can reduce the range of solar radiation transmission to the plants, which can delay the process sometimes, resulting in grape crops with longer stems, so the objective producers want to achieve with the vineyard must be considered. For more information on this subject, we recommend reviewing our article on cultivating grapes under cover.
According to Borja Devís, in addition to the popular cherry and grape crops, more intensive work is now being done with kiwi crops, mainly in Italy, thanks to the implementation of different structures with plastics designed with special materials to optimise conditions and protect the crop from bacteria and other external agents.
Why is it necessary to protect fruit trees?
One of the main reasons is because growers must avoid risking all the work done during the growing season year, as well as the income that can be earned, because of the effects of unexpected climatic phenomena.
Also, because it’s necessary to guarantee production, which will allow securing agreements with food supply chains while avoiding possible penalties in case of failure to deliver on time or to meet the quantities and quality stated in the agreement.
Additionally, there is a commitment with the final consumer who expects to receive quality products in the ideal quantities to satisfy their market’s demand.
What are the benefits of fruit tree covers?
One of the most important benefits of fruit tree covers is that trees are protected from extreme temperatures as well as from other environmental factors such as relative humidity, rain, hail, wind and frost that can cause severe damage to the crops.
Another benefit of covering fruit trees is that the harvest can be brought forward or delayed, depending on the requirements and what you want to achieve during the growing season.
The quality and condition of the trees and fruit are improved, the colour of the fruit is brighter, there is a significant reduction in the use of water and pesticides, and the fruit obtained for export has a better proportion compared to conventional outdoor cultivation methods.
There are several types of plastics, materials and structures that can be used to cover fruit trees, the key is to know how to protect them and which plastic films to choose to achieve the expected results.
For example, when it comes to table grape crops, some people wonder how many days the harvest can be brought forward by using plastic covers. On average, the harvest can be brought forward by 10 to 15 days, depending on weather conditions and other environmental factors.
The important thing is that, while there is an advance, the harvest cycle wouldn’t be shortened or interrupted, so the plant would not be stressed, and the results would not be compromised.
What kinds of structures are most popular?
Today, growers generally rely on roof-type structures or high tunnels for their protected crops. For example, in the United States, crops grown under covers have tripled since 1979 and sales have increased 30-times over the same period. This trend is expected to continue as demand for fresh horticultural produce continues to flourish.
By using these structures, especially for fruit trees, the following can be achieved:
- Increased quantity and quality of produce
- Creation of a special protective environment for severe weather events such as hail or frost.
- The temperature of the soil can be raised more quickly once the spring season arrives.
- Use of the right amount of water to avoid compromising the integrity of the soils when fungal diseases occur because of waterlogged soil.
- Protection of fruit trees from pests, animals, and frost.
In the case of countries where hailstorms are frequent, it’s advisable to use a resistant material such as laminated raffia, which provides better protection for the crop and, if there are any openings, there’s a guarantee that they won’t break completely.
In regions with low temperatures and strong cold winds, the most ideal measure is to look for plastic covers with thermal properties.
For more information, we recommend reading our article on high tunnels.
Aspects to consider when choosing fruit tree covers
Generally, when you plan to look for the ideal structures to protect fruit trees, the key is to consider three fundamental pillars:
- Research and development
- Knowledge and expertise
Concerning technology, it’s crucial to be familiar with the latest trends in plastic extrusion technology used to manufacture different types of materials, be it low-density polyethene or other materials such as laminated raffia or nets.
It’s also essential to analyse the different finishes of the plastic, whether it comes with central and lateral reinforcements, perforated, with lacing, or with metal eyelets. This will depend on planting specifications, investment capacity and the needs of the individual agricultural producer.
In the case of research and development, it’s important to choose plastics made of different materials that can be adapted to the different needs of each crop, such as the following:
- Adequate transmission and diffusion of sunlight to the crops.
- Resistance to pesticides, since sometimes the plastics used deteriorate more quickly because they don’t perform well when pesticides are applied.
- Mechanical properties, which can be adapted to each type of crop, as some trees grow more than others.
- Plastics that can handle the incidence of UV rays, protecting the integrity of leaves and fruits.
Knowledge and expertise are also essential because it’s necessary to know how to choose the right material, depending on the variety of trees to be grown, the type of structure and how it’ll be used so that it doesn’t end up compromising the objectives to be achieved with the crop.
However, on this last point, you can also seek advice from plastics experts who can guide you in choosing the best material depending on the specific requirements of your crop. In this regard, feel free to contact us without any obligation.
What about the return on investment?
Nowadays, the use of plastic films for fruit tree covers is fundamental to seek a return on investment in some fruit species such as grape, cherry or banana and it’s also, responsible for the successful marketing of other fruits such as kiwi, mango, peach, papaya or Japanese medlar, to mention a few examples.
There are different possibilities for each agricultural producer, depending on the business philosophy, technology, strategies to be implemented and the price that the final cost of the product can withstand.
Growers who are dedicated to the cultivation of fruits, especially in areas of North America, Latin America and Europe, must face certain challenges to keep their crops in optimal conditions, not only due to climate change but also because of the incidence of other factors such as insects and pests that can affect their final production.
As a result, it’s important to analyse every aspect that comes into play regarding cultivation, for example, how the type of fruit tree chosen and the latitude where it’s planted will directly influence the decisions that need to be made to determine the details relevant to the cost and conservation of the crops.
Producers must consider that global demand for fruit, regardless of the time of year and climatic conditions, continues to increase.
This ever-increasing demand for fruit forces growers to redefine their strategies, not only to be able to grow year-round but also to maintain their market leadership and guarantee quality products.
For more information on this topic, we recommend reading our eBook on fruit cultivation and the use of plastics to increase production.
What is the most recommended thickness for a plastic film?
Everything will depend on the soil, the region where it’s located and the type of crop to be planted, as well as other climatic factors. However, to establish an approximate, one could say that a plastic film can range between 120 and 150 microns in thickness, which can be applied to grape or cherry crops.
Are plastic films for fruit tree covers recyclable?
This is a common question when talking about using plastic films to cover fruit tree crops. These plastic films are recyclable, and today more producers are looking for alternatives that are environmentally friendly and can be recycled without inconveniences once they have served their purpose.
One aspect that shouldn’t be overlooked is any metal parts that may be attached to the plastic, must be carefully pulled out from the plastic before the it is removed and taken to the recycling centre. Currently, new materials are being developed with new formats to try to make recycling more efficient by eliminating certain parts such as eyelets and metal grommets used typically for securing the covers on the structures.
Certainly, the use of plastic films for fruit tree covers not only allows growers to protect their crops from any weather event but also helps to increase fruit quality indices, thus maximising yield levels.
It’s worth mentioning the importance of choosing the right material and structure for the crop to thrive so those producers can take full advantage of it. For more information on this topic, we recommend watching our webinar on this subject. We also recommend listening to our podcast on the use of plastic covers for fruit trees.