Developing the first-of-its-kind biodegradable CRF coating

The challenge of developing a biodegradable CRF coating

Controlled-release fertilizers (CRFs) rely on coating technology to regulate the supply of nutrients over time. By controlling the movement of moisture into the granule and the subsequent release of dissolved nutrients, the coating helps provide consistent nutrition throughout the fertilizer’s intended longevity.

Developing a biodegradable coating adds another dimension to this process.

The coating must maintain its nutrient-release function while also meeting defined biodegradability requirements. Achieving both characteristics requires careful selection of materials, precise formulation and extensive testing.

For ICL’s research and development teams, this was one of the central challenges behind eqo.s.

Susan Sijstermans, Senior Specialist Product Development at ICL, was closely involved in developing the technology.

As Susan explained during the development process:

“To create a coating that degrades, but at the same time protects the granule core is quite a contradictive concept.”

Overcoming this challenge required more than identifying a biodegradable material. The team needed to develop a coating capable of meeting the performance requirements of controlled-release fertilizers while also being suitable for commercial production.

From research concept to coating technology

The development of eqo.s began with a focus on urea-based controlled-release fertilizers and the need to develop coating materials capable of meeting evolving environmental requirements.

ICL’s R&D team investigated potential coating materials, screening different options and evaluating their suitability for controlled nutrient release.

Susan is testing the quality of the granules in the lab.

Each potential solution needed to be assessed against several requirements, including nutrient-release characteristics, biodegradability, material properties and suitability for manufacturing.

The research involved an iterative process of material selection, formulation development and laboratory testing.

Promising formulations were evaluated further to determine whether they could provide the required release characteristics and perform consistently under different conditions.

However, developing a successful laboratory formulation was only part of the challenge.

The technology also needed to be suitable for production at a commercial scale, while maintaining the quality and consistency expected from ICL’s controlled-release fertilizers,

Collaboration across research, engineering and agronomy

Developing eqo.s involved specialists from several disciplines working together to address different aspects of the technology.

ICL’s scientists focused on coating materials and nutrient-release performance, while engineers examined how the technology could be incorporated into fertilizer manufacturing processes.

Agronomists evaluated the performance of fertilizers incorporating eqo.s under turfgrass growing conditions, while quality specialists assessed product consistency and manufacturing requirements.

Fertilizer granules with eqo.s technology.

This collaboration was essential to translating the initial research into a coating technology with practical applications.

Susan described the importance of involving different departments throughout the development process:

“We need to speak the same language in order to come up with the best possible outcome.”

The work demonstrates the breadth of expertise involved in fertilizer technology development, from material science and engineering through to agronomic performance and product quality.

Testing nutrient-release performance

Maintaining reliable nutrient release was a fundamental requirement throughout the development of eqo.s.

In controlled-release fertilizers, coating characteristics influence the rate at which nutrients become available. Differences in coating composition and structure can affect release patterns and the duration of nutrient supply.

For professional turf management, consistent nutrient availability is particularly important because excessive growth fluctuations can affect turf quality, maintenance requirements and playing surface performance.

Antonio Gil (R&D Engineer) in the lab in Heerlen.

Laboratory testing therefore formed an important part of the development process.

ICL’s R&D teams evaluated nutrient-release characteristics under controlled conditions to assess whether the coatings could provide the required release patterns over their intended longevity.

These tests helped identify suitable formulations and provided a basis for further evaluation.

However, laboratory results alone could not establish how fertilizers incorporating the coating would perform under practical growing conditions.

Evaluating eqo.s under field conditions

Field testing was an essential stage in evaluating eqo.s technology.

Unlike controlled laboratory environments, turfgrass growing conditions vary considerably according to factors such as temperature, moisture availability, soil characteristics and management practices.

The technology therefore needed to be evaluated beyond the laboratory to understand its performance under different environmental conditions.

Fertilizers incorporating eqo.s have been assessed through field research, including independent turf trials in Europe and Australia.

Research has also examined nutrient-use efficiency, turf quality and nitrogen losses.

R&D team from left to right: Petra Vannuys (Scientist Product Development), Susan Sijstermans (Senior Specialist Product Development), Jesus Hernandez (R&D Manager CRF Engineering) & Antonio Gil (R&D Engineer).

These studies have provided evidence of the ability of fertilizers incorporating eqo.s technology to deliver controlled-release nutrition under practical conditions.

Independent testing has also been undertaken to evaluate coating biodegradability against relevant ISO standards.

Together, laboratory research, biodegradability testing and agronomic trials have contributed to the development and evaluation of eqo.s technology.

Developing the technology for commercial production

One of the important challenges in fertilizer innovation is translating laboratory research into a technology that can be manufactured consistently.

A coating formulation may demonstrate promising characteristics in laboratory tests, but commercial production introduces additional requirements.

Coating materials must be suitable for the manufacturing process, while finished granules need to meet the required standards for quality, consistency and nutrient-release performance.

For eqo.s, this has required collaboration between ICL’s R&D, engineering, manufacturing and quality teams.

The development process has involved considering not only the characteristics of the coating itself but also how the technology can be incorporated into commercially produced fertilizers.

This is an important distinction. Developing a new coating material is one achievement; producing fertilizers incorporating that coating consistently and at scale introduces further technical challenges.

Continuing the development of controlled-release fertilizers

The development of eqo.s builds on decades of experience in controlled-release fertilizer technology while introducing biodegradability as an additional characteristic of the coating.

It demonstrates how research into coating materials can extend beyond nutrient-release performance to consider the environmental characteristics of the materials themselves.

For ICL, eqo.s represents an important stage in the continued development of controlled-release nutrition, bringing together expertise in material science, fertilizer engineering, manufacturing and agronomy.

The research also provides a foundation for further development as coating technologies and the requirements of professional turf management continue to evolve.