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New phosphate type stays where neededNew phosphate type stays where needed

A non-water-soluble form isn’t released until plant roots call for it.

Willie Vogt

June 8, 2022

4 Min Read
Close-up of young corn plants
PHOSPHATE ON DEMAND: A new form of phosphate — struvite — is being marketed under the brand Crystal Green. The product provides phosphate to crops as roots release citric acid in a more controlled fashion. And struvite is not water-soluble, keeping it where it’s applied.Willie Vogt

Phosphate is an essential plant nutrient, but it can be problematic. In its most common form, the nutrient is water-soluble, which makes it mobile. And it gets the blame for algal blooms and other negative press because it doesn’t stay put. But a different kind of phosphate may help solve that problem.

Ostara uses new technology to create this phosphate form. An expansion in St. Louis will build beyond that in the next few years. Ron Restum, chief commercial officer at Ostara, explains the new compound, why it’s different and what it means for the crop nutrition market.

The form of phosphate Ostara is making, called Crystal Green, is a struvite-based mineral. “Struvite is magnesium ammonium phosphate,” he notes. “MAP and DAP are ammonium phosphate, but Crystal Green is magnesium ammonium phosphate, which makes it a very different material.”

Attaching magnesium to the molecule makes this phosphate citric acid-soluble. “This is not a water-soluble fertilizer,” Restum says. “Every nutrient has to go into a solution before the crop can take it up. Essentially, crops drink nutrients, and Crystal Green solubilizes via root exudates.”

He says Crystal Green is released into a soluble form only when citric acid exudes from crop roots, whereas DAP and urea turn into a soluble form by water. “We call it root-activated because roots naturally exude organic acids. It’s what they do to try to solubilize nutrients in nature. They’re looking for nutrients, so they’re leaking acids all day,” he says.

For Crystal Green, roots grow all around the product and start releasing acids. That’s when the product will become soluble, not before. And the plant will take up the phosphate like a straw as needed. “That’s what makes it different and what gives it its efficiency. It isn’t susceptible to the typical loss mechanisms,” Restum notes.

Other benefits of Crystal Green include:

  • enhanced nutrient availability, since it only releases nutrients when roots need them

  • 100% plant available when it interacts with roots

  • no soil fixation, which can tie up to 80% of applied conventional phosphate

Ostara expands from start

The concept of Crystal Green as a product started when Ostara developed a process for helping wastewater treatment plants solve a problem with struvite. Struvite builds up in the wastewater treatment process, but Ostara developed an approach that removes unwanted nutrients.

Restum says Ostara works with 25 wastewater treatment operations around the world, solving the problem and capturing struvite for use in crops; however, building a business from wastewater treatment isn’t immediately scalable.

“The amount of product coming out of one of these wastewater treatment plants — like Chicago’s, one of the largest on earth — isn’t enough,” Restum says. Ostara has reactors running full time, which might produce 3,000 to 5,000 tons of Crystal Green. However, he says that’s not enough.

“We produce that all over the world, and we sell every ton of it,” he says. But demand continues to rise, and that drove Ostara to seek other ways to make Crystal Green.

Ostara needed to find a concentrated ammonium phosphate source and then add other ingredients to make Crystal Green. “That’s what we do in Florida at about 30,000 tons a year,” he says. “That plant is already sold out.” But the company needs more, hence the investment in a facility in St. Louis.

The St. Louis investment will produce more than 200,000 tons of product a year. The facility will come on line by the end of 2023, and Restum says it’s a start at meeting the higher demand. The plant is an old Koch Agronomic Services facility, which was idle but has the infrastructure Ostara needs to make the finished Crystal Green product.

Continued growth

A facility that has not only the granulation tech, but also rail lines and transportation support to move product from plant to market is a lot easier to buy than build. The move to St. Louis will create a second plant with built-in infrastructure. But Restum says the company isn’t stopping there.

“As we expand, which we plan on, as soon as Plant 2 is probably darn near ready to turn the switch to start production, we’re going to be looking for Plant 3 and looking to find an infrastructure [like we have in St. Louis],” he says.

Restum says the global market for Crystal Green could be as high as 10 million tons yearly. When the second plant comes on line for Ostara, the two will be producing 231,000 tons running wide open. “At both facilities, we have got to be really methodical about how we move into the market so we can be disciplined.”

The key will be geography and crops, but he notes the primary customer will be the farmer who is at a specific innovation level. “We don’t have to make stories that ‘one size fits all’ and say, ‘Here’s the strength of our product,’” he says, adding that the aim would be to match true need to the market. This may mean telling a farmer not to use the product on one field, but instead choose a field more suitable for greater results.

You can learn more about this different approach to phosphate by visiting ostara.com.


About the Author(s)

Willie Vogt

Executive Director, Content and User Engagement

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