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Water quality starts with filter selection

Filters are an essential component of greenhouse irrigation systems. The main function of filters is to separate suspended or dissolved particles from the water. In irrigation, filters aim to remove particles that affect plant health or the efficiency and uniformity of water distribution.

While every irrigation system should have multiple stages and types of filters, it is important to select the correct filter. Growers should select filters based on the target problem, compatibility with established irrigation system, and filtration costs.

Target problems and filtration options

Here is a look at common water contaminants found in greenhouses and the filters recommended to remove those contaminants.

Organic particles include debris, algae, and pathogens. Most pathogens are extremely small (e.g., viral particles can be less than 1 μm and some fungal structures are slightly under 200 μm) and catching them with a filter would require an extremely small pore size, such as ultra-fine membrane filtration. However, membrane filtration is rarely used for this application because the capital investment and highly technical labor required are costly .

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Researchers at the University of California and Michigan State University have tested slow and rapid sand filters for removal of Phytophthora sp. and Pythium sp. and observed good results. These filters remove pathogens, most likely by a combination of physical and biological mechanisms. Slow sand filters form a biofilm layer (known as schmutzdecke) that reduces or inhibits pathogens through physical barriers and biological control mechanisms. However, media filters can clog if the debris is too coarse (e.g., weeds). Therefore, a coarse pre-filter is recommended. Screen and media filters are effective in removing large organic debris and weeds; they come in a broad range of sizes and are relatively inexpensive.

Inorganic particles or debris include fine granular minerals such as sand, clay, and silt. These contaminants can be removed with paper, sock, screen, or disc filters. Sock filters remove suspended inorganic particles very well. However, they have a small surface area and hence clog easily. Sock filters are recommended as a final stage of filtration. Do not use membrane filtration to remove suspended inorganic particles or organic debris. These contaminants can physically damage the membranes.

Dissolved inorganics include any dissolved salts that are typically listed on your water analysis (for example: iron, carbonates, calcium, sodium, etc.). Membrane filtration is recommended to remove dissolved salts from water. Reverse osmosis will remove all ions except boron from the water. Iron and manganese can also be removed through a combination of oxidation (chlorine or permanganate), followed by filtration with charged filters (e.g., greensand).

Dissolved organics include agrochemicals and humic acids. Granular activated carbon filtration removes a vast amount of agrochemicals from water. Researchers at the University of Florida observed that granular activated carbon was effective at removing several chemicals, including insecticides (acephate, bifenthrin, chlorpyrifos, and imidacloprid), herbicides (glyphosate and triclopyr), plant growth regulators (flurprimidol, paclobutrazol, and uniconazole), and water sanitizers (quaternary ammonium chloride, sodium hypochlorite, and peroxygen). Granular activated carbon filters are recommended when using any water source or irrigation system that has agricultural residues — catchment ponds, recirculated water, or sub-irrigation systems.

Important considerations about filtration in greenhouse irrigation systems

Install multiple stages of filtration — from coarse to fine — to avoid clogging of the system and to increase the efficacy of removing particles. Also, consider the cost. For example, metal screen filters are low in cost and can be used to remove coarse particles. Fiber filters (paper or sock) are a bit more expensive than screen filters, and they are typically used as a last filtration stage. Always filter your water very well before using membrane filters; not doing so will damage the expensive membranes.

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Maintain the filters. Clean the filters frequently to avoid clogging or tearing the filters. Choose filters with automatic backwash when filtering organic and inorganic debris.

Floriculture & Nursery and Research Initiative.



Revolutionary 4.0 opportunity for greenhouse irrigation

Agriculture 4.0 definitely presents many advantages in terms of sustainability and economic and environmental efficiency

Agriculture 4.0 definitely presents many advantages in terms of sustainability and economic and environmental efficiency. Even though it may seem difficult to apply for those who are used to employing traditional methods, digitally managed crops are growing rapidly in greenhouses where the environment is already monitored. 
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The machine is equipped with a self-learning system that calculates the exact length of the greenhouse at the first start. With a view to production with greater efficiency and automation, it is possible to create the daily and weekly wetting schedule that can be modulated continuously, by sector or flow. The power panel is installed on the greenhouse and the commands take place via WI-FI from a smartphone, tablet or PC with the new application.

Idroterm Serre has introduced a new irrigation boom model, i.e. Idrojet smart 4.0 with an innovative web-based control system thanks to which it is possible to program and manage irrigation either wireless via an internal local network using all kinds of devices (smartphone, tablet, pc…) or via cabled ethernet. In addition, thanks to the new Idroterm live cloud services, remote control and diagnosis are possible as well as countless other services (updates, new features, backups and resets).

The project
Products are developed not just “for clients” but mainly “with clients” – this is how the smart boom was born. By collecting the needs and suggestions of those who work in greenhouses everyday and considering that nowadays anything can be done via smartphone, the company opted for a simple smart digital irrigation bar that can be managed via smart wireless.

Idrojet smart 4.0 can be used to create programs, manage sectors both via self-learning or direct inputs, set daily or weekly operations, access logs, monitor accesses and much more. Thanks to predictive programs, it is possible to know remaining irrigation times in real time. A true revolution. 

These booms may be subject to the benefits or tax relief envisaged by the current incentive programs for agriculture 4.0 machinery. 

Technical characteristics
Idrojet smart 4.0 booms are irrigation machines with a recirculating pipe suspension system: the water pipe and power cables “recirculate” on air stirrups without creating obstacles. To ensure machine stability, it slides on a double rail. The recirculation satellite is moved synchronously via cable referrals.

The efficient distribution of water and fertilizers is managed via solenoid vales, which modulate times and flows according to the characteristics of the specific crop. It is possible to manage up to three lines: water, fertilizers and/or high-pressure for treatments.

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The future
Customer feedback has been great, as this revolution simplifies the work while saving time and resources.

In the future, it will be possible to monitor via web platform also Idro-x fertigation machines and the Idroclima climatic computer. The objective is to provide an integrated irrigation/fertilization/climate computer to implement agriculture 4.0 principles more and more. 

Idroterm specializes in the design and manufacture of greenhouses and systems and boasts over 40 years of experience. It has always focused on innovation at the service of protected crops aiming at sustainability. Over the years, Idroterm has developed hydroponic, aeroponic, photovoltaic and biomass heating systems.

In 2021 Idroterm created a new model of Idrojet smart 4.0 irrigation bar  with web-based control system via a dedicated application, where irrigation is managed via Wi-Fi with any mobile device (smartphone, tablet, PC ..)

Idroterm offers a range of cultivation systems and solutions for the optimal management and maintenance of each type of greenhouse and for each type of crop. With turnkey formulas Idroterm is able to offer a precise and professional solution for any need, degree of complexity and size of the structure.

For further information:

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Grodan: more circulation – gives stronger roots

Wijnen Square Crops has been working with Grodan since the mid-1990s and chose the Supreme mat for all their bell peppers two years ago

Wijnen Square Crops has been working with Grodan since the mid-1990s and chose the Supreme mat for all their bell peppers two years ago. Crop manager Jeu Rutten explains how the slab supports the company’s generative cultivation strategy and why the slab is so reliable during the unpredictable crop season.

The company now known as Wijnen Square Crops was founded in 1978 by Jac and Mia Wijnen. With Pieter Wijnen, one of their sons, at the helm, it is a real family business to this day. He and his management team run two sites: an 18 hectare site in Egchel, where cucumbers and mini cucumbers are grown, and the ‘California’ site in Grubbenvorst. There the company produces red and yellow bell peppers, which are sold to leading food retailers in Europe through the Harvest House growers’ cooperative.

California was built in 2009 and consists of three greenhouses of about 11 hectares each. Cultivation manager Jeu Rutten has been working for the company for more than 15 years and is co-managing the activities in Grubbenvorst, where about a hundred employees work in the greenhouses during the high season.

Grodan since

Perfect moisture balance
Wijnen buys the young pepper plants from a local nursery when they are around 45-50 days old. “We have agreed that the young plants are grown in the Grodan Plantop blocks, because a perfect moisture balance can be created in this; they do not stay too wet and do not dry out quickly, and they are the best choice in combination with the Grodan mats”, says Jeu.

 “We have been working together with Grodan as the sole supplier of our growing media since the mid-90s, when we started growing peppers, so you can rightly call that a long-term relationship! I used to have my own nursery and then I even worked with Grodan products. Grodan has a strong reputation and is a very reliable partner.”

Uniform performance
“As soon as the blocks are delivered at the beginning of December, we immediately put them on Grodan slabs on our hanging cultivation gutters,” he explains. “It is important to us that all slabs in the entire greenhouse provide identical performance, so that we can control all plants uniformly at the same time. Each slab must react the same and be equally moist and/or dry, which is very important with such a large cultivation area. Grodan’s products ensure that uniformity and controllability.”

About three years ago, GroSens Sensors were installed in one of the three California greenhouses, to test what added value this would have for monitoring. Jeu says: “A big advantage for us is that the sensors are wireless, which means that they can easily be moved to measure the conditions in the different parts of the greenhouse. We will probably eventually use this system in all three greenhouses in Grubbenvorst.”

He is also satisfied with the support he receives from Grodan: “Their technical advisor usually visits a few times a year and we are often in contact in between.”

Switch to Supreme
This is the third year in a row that Wijnen uses the Supreme mat. “We heard a lot of positive comments about this slab from other growers, and as a company we are always open to trying out new products and developments, which is why we switched to the Supreme slab for all 32 hectares in Grubbenvorst”, explains Jeu up. “A healthy root zone is essential to ensure good plant vitality throughout the season. In general, we have noticed that the Supreme mat supports the development of the roots better; the plants have many nice white roots and they are spread uniformly throughout the slab, rather than just on the sides.”

A better fit in the gutters
One of the great advantages of the 10 cm wide Supreme mat is that it fits well in the gutters of Wijnen. “Because the slab is narrower, more oxygen can circulate around the slab and the water can drain more easily, both of which contribute to a strong root zone. I even think that we had less trouble with Fusarium in the past two years because of that,” he says.

With a height of 10 cm, the Supreme mat is also a lot higher than the 7.5 cm mat that was previously used at Wijnen. “This works really well in conjunction with our watering system which is quite slow, 100cc can take as long as 5 or 6 minutes meaning we are making the most of almost 100% of the slab. The water spreads much more evenly around the roots and it is just as moist between the plants as it is directly under the plants,” says Jeu.

Support for generative control
He explains that at Wijnen they strive for a very active, generative crop control: “We are not afraid to create a more aggressive climate with the temperature and make the plants work a little harder, and the Supreme slab supports that strategy. We can now give the plants an extra drip, for example until 6 p.m. instead of 5 p.m., because the soaking process goes faster at night and the excess water can drain more easily.”

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“In addition, the better drainage gives us more freedom to stimulate fruit set by increasing the EC, because the slab can be rinsed out faster than before, even with our slow drip system. The reactive nature of the Supreme slab gives us more control over both EC and watering,” he continues.

Welcome reliability
“I’ve been in this business for 45 years, but at the start of a growing season I still don’t know exactly how it will go. There are so many unpredictable factors, such as the weather and diseases, so we have to stay focused all year round”, adds Jeu. “The Supreme slab gives us a bit of reliability that is so welcome during the hectic pace of a growing year, and is undeniably an important part of the formula for a high yield of high quality peppers,” he concludes.

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hydroponic system

This hydroponic system was created in order to develop a tomato and pepper production system that improves the profitability of greenhouses.

Likewise, innovation is sought, the commitment to varieties with high added value, with fewer labor needs and focusing production on dates where there is a high demand for the product.

With these objectives, NGS and its R + d + i department have developed an Intensive Vertical Recirculating Hydroponic System for tomato and pepper cultivation.

This system is characterized by incorporating up to 6 tomato plants per m2, three times more plants than those grown in a conventional system. Furthermore, it is not necessary to use a grafted plant, since the cultivation cycle will not last more than 4 or 5 months, thus allowing the farmer to carry out between 2 and 3 cycles a year.

Short cycle hydroponic system

Having short cycles implies that all production can be concentrated in 4 or 5 weeks, thus drastically reducing the harvesting labor, estimating that it can be reduced up to 40% compared to the conventional system.

In this sense, it will no longer be necessary to periodically tread, strip and peel the plant for more than 9 months, nor will it be necessary to harvest every 2 or 3 days for much of this time.

This intensive production model, offered by NGS, obtains between 3 and 5 tomato bouquets per plant and cycle, depending on the variety used, to give a total production per cycle that varies between 15 to 20 Kg / m2.

As the NGS system is recirculating, it offers the possibility of being able to save as much as possible on such important resources as water and fertilizers.

This production model fits very well in tomato crops of “flavor” or “high quality”, varieties that stand out in the market for their high concentration of Brix degrees or sugars. Some of these products are the tomato type Raf, Kumato or Rosa tomato.

Finally, the NGS hydroponic system allows the concentration of salts to be raised to levels above 10 ds / m CE with ease, since no type of soil or substrate is used, obtaining a “Premium” product.

At NGS we continually search for profitable solutions for each farmer in any type of greenhouse.

More about hydroponic system                                                                                     NGSystem

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