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HaifaStream: Stock solution - the nutritional base for your crop. Simple tips & tricks

Badly mixed fertilizers can result with a layer of sediments at the bottom of your tank. Haifa Group's experts Juan Manuel Diaz Martinez and Janusz Wysowski are here to provide some simple tips to achieve a well dissolved stock solution, avoid unexpected challenges and even save time doing so.
Juan Manuel (Interviewer) & Janusz
Transcript of the episode: 
Juan Manuel [00:00:08-00:00:34]
Welcome to Haifa Stream Greenhouses. This podcast has been presented to you by IFA Modern Greenhouse Task Force. I'm Juan Manuel from Haifa, Mexico, and today we are with Janus, a senior commercial agronomist and crop advisor at Haifa, Northwest Europe, located in Poland. In today's podcast, we will talk about simple action to help you manage a better stock solution when mixing fertilizers.
Janusz [00:00:36-00:01:41]
Thank you, Juan Manuel. Hello and thank you for listening to our podcast. My name is Janus Wesowski. I am a commercial agronomist and I live in Poland and Haifa, Northwest Europe. The subsidiary office is located in Belgium. As you mentioned, Juan Manuel, our topic for today will include tips for making a better stock solution in your fertilizer tanks. We all knew the basis that we cannot mix together calcium and sulphur nor phosphate due to precipitation in the tank blocking the irrigation system. For that reason, we are using three separate tanks. Tank A for a calcium, tank B for a phosphate and sulphur fertilizers, and tank C for acids. And even then, when you have different separate tanks and you think that you use every fertilizer correctly, we still can see farmers face unexpected challenges.
Juan Manuel [00:01:43-00:01:57]
Okay, in the Genus, we see it across many regions. Will you please share some tips with our listeners on how they can solve or even better avoid such challenges?
Janusz [00:01:59-00:02:28]
Well, first, it's very basic and very easy that you need to steer the tank solution. You need to steer the tank solution for better solubilizing of the solution. Because in many cases, farmers are using electric stirrers, too easier they work. The badly mixed solution can easily lead to a layer of sediment at the bottom of the tank. This is interrupting water flow and reducing the fertilizer concentration in the solution.
Juan Manuel [00:02:30-00:02:41]
Genus, we often see mixing tanks in remote locations having no electricity. What will you recommend in such cases?
Janusz [00:02:43-00:03:32]
Okay, normally in a greenhouse, there's no problem. But sometimes you have an open field, a fertilized area, and then, yes, you don't have electricity. I remember once I visited the grower and he was mixing the solution using a shovel. It took a lot of time and energy for him and he was looking for a better solution. What we did was to provide him with an adductor nozzle. It's also known as a jet pump or a venturi pump. It is a very simple plastic device. You can easily connect it to any water hose and it is creating a strong turbulence at the end of the hose. This is leading to a much faster, better and easier dissolution of the fertilizers.
Juan Manuel [00:03:35-00:04:00]
Okay, I think it's a great solution. I like the fact that it's cheap and simple, making it easily available for any farmers. Also, I need to mention that it's very important not to add the whole sum of fertilizer at once. But rather than to slowly pour, it's had the water pressure dissolve the solution.
Janusz [00:04:01-00:04:00]
Correct, yes. In my work, I often meet farmers who ask how can they increase the concentration of the fertilizer in the solution.
Juan Manuel [00:04:12-00:04:18]
Mostly for technical reason. In your opinion, what advice will you give to these farmers?
Janusz [00:04:20-00:06:07]
Okay, the standard concentration in the tank. It's a 10%. We are making the concentrated stock solutions. If you want to make higher concentration, it is possible, but it can be tricky for many reasons. It has really harmful potential because it really depends on the water quality in use. Depends from the nutrients, from the requirements of the crop that you need. It depends on the pH and also the other factors of influence. First thing you will need to do is check if there are no precipitations in the tank. Because if you create 20% stock solution, it can lead to the precipitation. If it's really happened, then you need to maybe go to the 15% or 12% because it is not always possible. Second, what is also important, you need to know that there are difference between different fertilizers coming from different producers. Or even from the same producer, it might have different physicochemical composition. I give you an example. For instance, at Haifa, we have two different potassium nitrate products. One, Multi-K Fast, has a pH level of 4 and another product Multi-K GG has a pH level of 9. I have even seen a potassium nitrate producer declaring pH anywhere between 3 and 11. So you never know what is the pH of this product. So farmers should be careful, use quality producer only and properly check solubility before taking such actions.
Juan Manuel [00:06:09-00:06:20]
Thank you, Janus. Actually, pH is another critical thing to consider when making fertilizer solution. Do you have some words of advice regarding pH?
Janusz [00:06:23-00:06:47]
Yes, I have another example, another story regarding pH. I came by a farmer who was regularly dissolving MKP, the monopotassium phosphate, but he has recently changed suppliers and suddenly he started having precipitation in his tank. We sent the samples to lab analyzers.
Juan Manuel [00:06:49-00:06:55]
Was the new MKP impure? Was a different pH level?
Janusz [00:06:56-00:07:27]
Actually, we checked that everything was fine with the new MKP and everything was fine with the old MKP. It appeared that he was mixing fertilizer of two different suppliers at very high concentration of 20%. Making the same mix and 10% did not lead to any precipitation at all. Farmers should really be careful using high concentration because little changes can lead to big problems.
Juan Manuel [00:07:29-00:07:40]
Better safe than sorry. Let me take you back to pH. How do you address pH management when making stock solution?
Janusz [00:07:41-00:10:29]
In my country, in Poland for example, we have very high level of bicarbonate in our water, approximately 200 ppm, so it's about 3.5 millimoles and sometimes it goes higher. Then we need to acidify the water, usually using nitric acid. It is recommended to check pH every time we fill the tank and even on a weekly basis. The pH value at the A tank, so in Poland it's the calcium tank, should be around 6. You should check the pH because it's very important to not go too low in the A tank with the pH. If you don't know what is the water quality and you are adding extra acid to the A tank, you should not do this because it is better to have the higher pH than go too low with the pH in the E tank. But in the B tank, the phosphate, it should be around 5. If the values are higher, we need to reduce the pH level using the acid, especially if we plan to make a higher fertilizer concentration. The right pH should help reduce the chance of precipitation as lower pH improves solubility. There is another story. A farmer always used 5 liters of nitric acid per tank. Over time he stopped checking the pH as he got used to 5-liter dosage. After some time, he checked and found the pH of 4.5 in his A tank. As I said, it should be around 6. What happens was two things. One, the stability of nitric acid is rather poor. The quality depends on quality and time of storage. Concentration can be higher or lower pending that it is not uniform. 2.5-liter dosage was indeed for a full tank of 1,000 liters of water. But the farmer filled the tank before being fully empty. So actually, he was diluting only 700 or 800 liters of water rather than a cubic meter, a 1,000 liter. He was putting too much nitric acid and not enough water. From time to time the pH was going down. My best recommendation is to always check the pH level when you are filling your tanks.
Juan Manuel [00:10:31-00:10:53]
Thank you. Thank you, Janus. This is really helpful information. Really, really helpful. There are no shortcuts when making the fertilizer solution. Will you finalize by sharing a short summary of the top five rules for making fertilizer solution the right way?
Janusz [00:10:55-00:12:00]
Yeah. You should not forget to steer the solution. It's very important. Whether using an electrical steerer or a ductile nozzle. Steer the solution. Then don't go over the concentration of the solution without checking the smaller pot before. You should make a checking in a small quantity. Then you need to know your water. Check the pH level and bicarbonate frequently. Also, what is important, and we didn't speak about this is keep it warm. You need to avoid using water under 10 degrees Celsius. If your water is colder than that, first fill the tank to 30-40 percent and let it warm up to the greenhouse temperature before mixing the fertilizers. The last comes first. If you are mixing several elements, keep potassium nitrate to the last because the potassium nitrate cools the water when dissolving.
Juan Manuel [00:12:02-00:12:22]
 Okay. Okay. Good points. This is the conclusion. Thank you again, Janus, for these great tips. Thank you for being with us at Haifa Modern Greenhouses podcast. The rest of the audience, please follow us in the next episode of Haifa Stream Greenhouses. Thank you.
Janusz [00:12:23-00:12:24]
Thank you very much.