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HaifaStream: Water is the key to life and plant nutrition - What should you consider regarding your water source and how to response to the measurements?

Water sources significantly vary in quality. pH is a key factor evaluating nutrients availability. Haifa Group's experts Filippo Correddu and Marco Molenaar are here to highlight the key elements to consider about your water source to achieve the best nutrition for your crop.
Partcipants: 
Filippo Correddu (Interviewer) & Marco Molenaar
Transcript of the episode: 
Filippo Correddu [00:00:07-00:00:30]
Welcome everybody to Haifa Stream Greenhouses podcast. This podcast has been presented to you by IFA Modern Greenhouse Task Force. Hi everybody, this is Filippo from Italy, based in Bologna. Today's topic would be the pH management in the drip line and in root zone. We are going to talk about it together with one of our most prepared agronomists on this topic. Without further ado, I let him present himself and start.
 
Marco Molenaar [00:00:32-00:01:10]
Thank you, Filippo, for inviting me for this topic. First introduction from my side. My name is Marco Molenaar from the Netherlands. I'm working for Haifa, North West Europe, and on a daily basis I am active in the Greenout segment, where I work with and with growers about what soluble fertilizers. The reason why we choose for this topic pH management in a drip line and root zone is that we see on a daily basis that there are many questions and problems rising up. And this is the reason why I put this on the agenda to speak and discuss with each other about this.
 
Filippo Correddu [00:01:13-00:01:30]
Yeah, you're right. Sometimes we give too much attention on nutritional recipes, forgetting that there are many other factors that are driving our nutrients availability and efficiency of our nutrition. You want to start us giving us some advice concerning the approach depending on the water source.
 
Marco Molenaar [00:01:33-00:02:20]
Yes, of course. We see in the market that there are many water sources in the market and every water source contains something where we want to work with, where we must want to work with. And one of these elements is bicarbonate and also looking to pH. This is important information for us as agronomists, but also for the grower to make in the end a good recipe. The first thing is what we must know in front is the water quality. We must have the information on paper to see what's inside the water. And that's always an advice to the grower asking for put something on paper, inform us about it.
 
Filippo Correddu [00:02:21-00:02:33]
Yeah. And so, about the information of water, you were saying that we have different water sources. You can just say some general advice about the type of water sources we can have.
 
Marco Molenaar [00:02:35-00:03:10]
Yes, of course. When we are looking to the different types, then I'm speaking about rainwater or osmosis water, but also some areas where they don't have enough rainwater available and then they must work with municipality water, soil water. And also, there we see big difference. And again, we want to know what is inside the water to make in the end a good recipe. So that is the first question from my side to the markets. Inform yourself, inform your advisor which type of water and what is inside the water for that.
 
Filippo Correddu [00:03:12-00:03:00]
Yeah. And which is your experience in the use and treatment of the pure water, let's say.  The water that is coming from the rain, from osmosis or so on.
 
Marco Molenaar [03:23-00:03:47]
Yeah. When we are looking to the north-west European area, rainwater is what I said, always the best water, there is nothing inside. It can also be a disadvantage, but we have no high pH, we have no bicarbonate inside, so we can do what we want. Collecting rainwater is the best. And if you have this available, then my advice is to work with that for the full 100 percent.
 
Filippo Correddu [00:03:50-00:03:56]
And while you when you are working, for example, like in Italy with the soil depth water, what is your advice?
 
Marco Molenaar [00:03:57-00:04:15]
Then the first thing is again, inform yourself about this quality of the water, of course. And then I want to see a level of bicarbonate, which is active in the water. And I want to see the results on paper. And if we have this information, we can recalculate everything what is the need for the grower in the end.
 
Filippo Correddu [00:04:17-00:04:27]
Okay, thank you. But concerning the parameter you were talking about, so pH and bicarbonate, how they affect the stock solution preparation and how we can react on it?
 
Marco Molenaar [00:04:29-00:05:26]
We must know which type of water do you use for a good tag mixing. And most of the time, this is totally new for a grower in the end, but also here, especially for the tank where we add sulphate and phosphate-based fertilizers. A hard advice from my side to the market is that we must have a pH below five. And if we work with soil water, for example, and we use this water for the tank mixing, where we add sulphate and phosphate-based fertilizers, the pH is rising up. And in front, we must react on that. And what I want to say is we must add some acid inside to decrease the bicarbonate level, to decrease the pH, to have a good balance between the fertilizers which we add in the system. In this tank, sulphate and phosphate-based fertilizers, the pH must be below five. That is an hard advice.
 
Filippo Correddu [00:05:28-00:05:33]
Yeah. And what about the other tank? The tank where we usually add calcium nitrate?
 
Marco Molenaar [00:05:35-00:06:04]
This tank is, in my opinion, totally different. This is a tank, you are speaking about calcium nitrate, but we know that there also is some gulates inside, especially looking to iron gulates. And if we add some acid in this tank where iron gulate is inside, we know that we kill the gulates. For that reason only, we don't advise any acid in this tank. In general, acid is only allowed in the tank where we add sulphate and phosphate-based fertilizers.
 
Filippo Correddu [06:06:08- 00:06:24]
Thank you, Marco. Marco, you come from the Netherlands. In your country, like in many others, it is mandatory to recycle the drainage water. This is an action that could be really green, also for other countries that has no regulation. What is your personal experience concerning the management of the so-called drainage water?
 
Marco Molenaar [00:06:27-00:07:32]
That's it's a very good question, because in our territory, in North-East European area, it's not allowed not allowed anymore to throw water away. What you said is fully true. We use all the drainage water which we create in our system, which means that we must bring the water back into the system. And we see that if a plant is reacting on growth, we see that the pH is also rising up in the root zone and near pH also the level of bicarbonate. We collect this drain water from what we create in the system. We have a tank where we collect this water. And normally we must do something. And in the modern greenhouses, we disinfect also this water. And it can be via heating systems or it can also be via UV systems. And we know that in this segment that we also using some acids to clean the disinfection equipment, which has an effect in the end, what we bring back into the system.
 
Filippo Correddu [00:07:34-00:00:52]
Yeah, so we have looked into water quality and management at the begin and at the end of all, but we can also look to the pH, to the levels inside the root zone. Do these values can give us some data concerning our crop?
 
Marco Molenaar [00:07:54-00:07:57]
You mean what we are sending to the plant or what we have in the root zone?
 
Filippo Correddu [00:07:58-00:07:59]
What we have in the root zone.
 
Marco Molenaar [00:07:59-00:08:33]
Okay, yes. What we want to see on analysis is that we want to have a pH around six in the root zone, because when we are going lower and lower about pH, then also there is a destroying of the roots. The goal in the end is to have a pH of six, which is good for the elements which we want to have available for the plants. The higher the pH, we know that there are some elements lost about availability. In general, we can say the pH of six is perfect for a good available element in the root zone.
 
Filippo Correddu [00:08:35-00:09:01]
Thanks, Marco, for the time you dedicated us and also for your knowledge sharing. You have given us many, many useful information. Let's try to summarize them in the last minutes. We have understood the importance of following the water quality all along its streams in the greenhouse. Where you must have a proper analysis and what is the aim in each one of your water streams?
 
Marco Molenaar [00:09:03-00:09:51]
Yeah, what I said in the beginning is inform yourself about the water quality, inform yourself about the pH and bicarbonate in the end. Every year, at least at once a year, inform yourself. And if we have this information, then we can do everything what is good for the plants in the end. Starting with collecting water, bring it to the lab and see what is the result. That's a starting point. In the second phase is that we want to see the drip water which we are sending to the plants must be also good organized. Sending to the plant a good pH for availability in the end. And last but not least is that we are taking water from the slab to see also there which pH and bicarbonate we have. Also, there for a good availability for elements for the plants.
 
Filippo Correddu [00:09:53-00:10:11]
Yeah, during our speech, we were talking about many tanks. OK, the tanks for the stock solution, the tanks for the pure water and a possible tank also for the drainage water collection Could you summarize them and giving your advice concerning the action we can do in this tank?
 
Marco Molenaar [00:10:14-00:10:19]
And with that, you mean also related to the pH which we are sending, collecting, everything?
 
Filippo Correddu [00:10:20-00:10:034]
Yeah, maybe it's good to know, for example, looking to the pure tank water, Okay, in your country, when you collect maybe some soil depth water, you act with the acid addition directly in this tank?
 
Marco Molenaar [00:10:36-00:11:00]
Yeah, it is a little bit complicated, but speaking about rainwater, this is the quality where we work with. We do not any action collecting water from the soil. Inform yourself, that's the first step. Second one is react on what we see on paper and there with a pH measurement system and an adding system, adding some acid in front. That's the first step.
 
Filippo Correddu [00:11:03-00:11:53]
Then you said about the tank for the stock solution of sulphate and phosphate, where we must have a pH below five to have a better preparation. And then you said that in the other tank, so the one where we usually add calcium nitrate, but also iron chelate, we should leave the things out there. Because adding some acid, as you know, if you don't know the quality of the water, so if you don't know if we have some bicarbonates or not inside, can also kill the chelates. Just to conclude, we have come to the end of the episode. Before the final greetings, could you give us some general pH range looking to various different parts of our greenhouse where we give, collect and the water?
 
Marco Molenaar [00:11:56-00:12:36]
Yes, of course, Filippo. Speaking about the pH of the drip water, of course, it's depending on the crop behind. But in general, I want to see a pH between five and five point, five in the drip water, which we are sending to the plant. The pH in the stock solution, looking to the tanks, calcium nitrate tank together with iron chelate, we do nothing with that. It is what it is. The tank where we add sulphate and phosphate-based fertilizers, I want to see a pH below five. Otherwise, we create some reactions from different fertilizers and to the pH in the root zone. I want to see on paper, unanalyze a pH between five point five and six. In general, there we have an answer for that.
 
Filippo Correddu [00:12:38-00:12:55]
That is all for today's episode. I really want to thank you, Marco, for this opportunity and all the people that are listening to our podcast. This was IFA Stream Greenhouses. This podcast has been presented to you by IFA Modern Greenhouse Task Force. Do not miss the next episode.
 
Marco Molenaar [00:12:56-00:12:56]
Thank you, Filippo.
 
Filippo Correddu [00:12:57-00:13:00]
Thank you, Marco.