Is there a Connection Between Controlled Release Fertilizers and Soil Health?

Recent evidence from two separate research groups in China and the Netherlands showed the effect of long-term use of controlled release fertilizers (CRF) on soil’s health. Researchers from China have demonstrated that the long-term use of three types of controlled-release urea positively affected soil health by increasing soil organic content, which in turn gave rise to a higher abundance of bacterial and fungal substances which include plant growth-promoting microorganisms. The research group in the Netherlands demonstrated that CRFs maintained lower salinity levels in soil thus causing less harm to beneficial microflora. These works now add another tier to our understanding of the benefits of CRFs in modern agriculture.

Controlling the release of nutrients promote soil health

The extensive study conducted at the Shandong Agriculture University, was running the course of 12 years (!). The researchers tested three types of controlled release products: polymer-coated urea (PCU), sulfur-coated urea (SCU), and polymer/sulfur dual layer-coated urea (PSCU). The results published in the European Journal of Agronomy (Gao et al., 2023),  confirm that the long-term application of controlled release urea increased soil organic matter and enriched soil microbial communities,  which are crucial factors for robust crop growth and sustainability.

This is BIG news

Cultivated land often suffers from a steady, slow reduction in soil organic matter (SOM). However, this study demonstrated that all the coated products significantly improved SOM by 3.1-5%. SOM is a critical factor in plant nutrition, but also in affecting soil microorganisms.  This research shows that the increase in SOM was the most significant factor in affecting the contribution to environmental factors of bacteria and fungi and to the abundances of plant growth-promoting microorganisms (PGPMs), while inhibiting plant pathogens.

Lowering soil’s salinity also promotes soil health

But the positive impact of CRFs on soil microbiota can be also through maintaining relatively stable and low soil salinity levels.  Streminska et al., 2024, (Wageningen University and Research WUR; WPR-1310), showed that the gradual release of nutrients by CRF, caused less harm to the delicate microflora, especially around young plants, and seedlings.

These findings challenge the often-negative perception associated with mineral fertilizers, showing that coated mineral fertilizers (e.g. CRFs) can be beneficial for the soil environment.

CRFs reduce bacterial plant diseases

The study indicates that the long-term application of controlled release nutrients (or CRFs) inhibits the growth of nitrobacteria, denitrifying bacteria, and plant pathogens, thereby reducing nitrogen losses and plant diseases which leads to better wheat yields. Similar findings were presented at the research conducted at WUR, where it was shown that the use of CRFs directly reduced bacterial diseases in horticulture, suggesting other mechanisms of effect in addition to the increase in SOM.

CRFs improve nutrient use efficiency (NUE)

Market leader in high quality CRFs, ICL Growing Solutions, has long championed CRFs for their efficiency and environmental benefits with a long history of research and trials to prove it. ICL’s CRF technology is similar to that used in the three products tested in the study conducted in China (PCU, SCU and PSCU). ICL also provided the CRFs used in the WUR research. “The results from these two new research works provide another supportive tier to our many years research strategy. Efficient fertilization isn’t just a buzzword; it’s the future of farming,” says Ronald Clemens, CRF Global Marketing and Portfolio Manager at ICL. He emphasizes that nutrient use efficiency (NUE) is increasingly vital due to the EU’s new regulations that aim to tackle environmental issues.

The practice of precision farming

Ronald emphasizes that CRFs are not your ‘cure-all solution’, but rather a piece of a larger puzzle. “CRFs are part of the solution, but ICL is looking at all angles. Bio stimulants, wetting agents, exploring organic blends, you name it”, he says, proving that ICL’s role is not about ‘quick fixes’, but rather operating based on independent research, years of data, multiple crop types, and solid statistics. “Precision farming is a practice, not a concept. Scanning soils, applying fertilizers with precision, that’s the future—and it’s happening now”, Ronald adds.

The next step for nutrient use efficiency

These new findings demonstrate how CRFs can increase crops’ productivity along with improvement of soil health. Ronald: “The positive effect of CRFs on soil micro life also opens new doors for integrating coated fertilizer with bio stimulants derived from plant-promoting microorganisms. This could be a next step in the finetuning and maximizing nutrient use efficiency for agricultural crops.”