Zeolite Biocarrier to Cut Farm Soil N Leaching
Zeolite and Modified Nanoclays in Agricultural Bio-Input Carriers
Nitrogen is a key input in modern agriculture, but the same element becomes a hidden cost of production when it moves beyond the root zone. The farmer pays for the fertilizer, the soil makes only part of it available to the plant, and another portion leaves the cropping system through drainage water or runoff. In light-textured soils, arid regions, and systems where irrigation and fertilization are not precisely synchronized, this loss reduces the farm’s economic efficiency and creates environmental pressure. This is where mineral carriers for biological inputs become important, because they can connect microbial persistence, moisture retention, gradual nutrient release, and reduced nitrogen leaching.
Bio-inputs create real value in the field only when the living microorganism remains stable until application, survives long enough in the rhizosphere after application, and produces a measurable effect on the plant or soil. Solid mineral carriers, especially zeolites and, more cautiously, modified nanoclays, are attractive in this regard because they bring active surface area, porosity, moisture, and ionic interaction into formulation design at the same time. However, technological appeal cannot replace field evidence and safety testing. A successful biological carrier is not merely a material mixed with microbes; it must balance biological quality, application safety, and agronomic performance.
According to the U.S. Geological Survey definition, natural zeolites are hydrated aluminosilicates of alkali and alkaline-earth metals. This structure is the basis for their use in ion exchange, ammonium retention, soil amendment, and as carriers for fertilizers or bio-inputs. Around 40 natural zeolites and more than 150 synthetic zeolites have been identified, and this diversity shows that zeolite behavior depends on mineralogy, purity, particle size, and the type of surface modification. Modified nanoclays should be viewed within the same framework: not as a buzzword for making a technological claim, but as a potential carrier that must be tested using the same criteria of microbial viability, chemical compatibility, contamination control, and field performance. Scientific decision-making in this field begins with material selection, but it ends with product validation.
How Does Natural Zeolite Connect to Biological Carriers and Nitrogen Retention?
From a soil chemistry perspective, zeolite is not just a filler material, because its aluminosilicate framework enables cation exchange and the retention of certain nutrient forms. In agricultural applications, clinoptilolite has a particularly prominent position, as it has been studied in soil and fertilization research as an exchange-based carrier or amendment. This mineralogical difference is directly important for bio-input producers, because two zeolites sold under similar commercial names may have completely different exchange capacities, purity levels, particle sizes, and behavior in soil. Therefore, the first step in designing a zeolite-based carrier is to identify the raw material and measure the properties that affect microbial viability and nitrogen behavior.
Mineral data from 2024 show that natural zeolite has moved beyond the laboratory-idea stage and is already present in real industrial markets. In the Mineral Commodity Summaries 2025 report, U.S. mine production of natural zeolite was reported at 81,000 tons, with domestic sales of 73,000 tons. The same report lists applications such as animal feed, odor control, soil amendments, water purification, fertilizer carriers, fungicide or pesticide carriers, and aquaculture. Globally, natural zeolite production in 2024 was reported at about 1,000,000 tons, with countries such as Slovakia, China, South Korea, Indonesia, and New Zealand included in the production table.
The importance of these data for knowledge-based agriculture is that a mineral carrier must be understood from two angles. The first is access to the mineral material and the possibility of processing it within the production chain. The second is converting that material into a biological product with a defensible claim; in other words, a product that is not merely raw zeolite, but an inoculated, controlled carrier tailored to the target microorganism. For this reason, the existence of a zeolite market is not enough to prove market readiness for a biological carrier, but it does show that the mineral infrastructure and carrier applications have a defined place in official mineral literature.
Clinoptilolite and Modified Zeolite in Reducing Nitrate Leaching
The most important technical distinction in this issue is the difference between ammonium and nitrate behavior. Because of its cation exchange capacity, natural zeolite is better suited to retaining ammonium, but nitrate is an anion and is not adsorbed by natural zeolite as easily. This is why surfactant-modified zeolite, or SMZ, enters the discussion as a way to create anion adsorption capacity. This difference matters in carrier design, because a product that is suitable for ammonium retention is not necessarily the best option for reducing nitrate leaching.
– The Difference Between Ammonium and Nitrate Retention in Carrier Design
In the lysimeter study by Malekian and colleagues on maize, the Iranian zeolite sourced from Semnan Province was identified mainly as clinoptilolite, and surfactant-modified zeolite was tested alongside it. In this experiment, doses of 20 and 60 grams per kilogram of soil and two particle sizes, millimeter-scale and nanoscale, were evaluated for both clinoptilolite and modified zeolite. At the dose of 60 grams per kilogram, the amount of leached NO3-N in the SMZ and natural clinoptilolite treatments was about 26% and 22% lower than the control, respectively. This difference indicates that surface modification can have a stronger effect in reducing nitrate in drainage water, but final carrier selection cannot be based only on the leaching metric.
– Raheleh Malekian, Jahangir Abedi-Koupai, and Sayed Saeid Eslamian, Isfahan University of Technology: “The results indicate that plants may respond better to clinoptilolite as a fertilizer carrier than to modified zeolite.”
The practical value of this quotation is that carrier design should not rely on a single metric. If the only objective is to reduce nitrate in drainage water, SMZ showed a greater reduction in Malekian’s study. However, if plant response and fertilizer-carrier function are also important, natural clinoptilolite had a notable advantage. The same study reported that the dose of 20 grams per kilogram was not effective in reducing leaching or improving plant growth, and that particle size had no significant effect on leaching or growth. Therefore, claims of nanoscale superiority, without independent testing and field data, are not sufficient for zeolite or modified nanoclay.
Field Evidence on Zeolite for Nitrogen Use Efficiency and Water Management
Lysimeter experiments are useful for understanding mechanisms, but agricultural decision-making requires field evidence. In a rice experiment conducted in China from 2018 to 2020, two irrigation regimes, continuous flooding and alternate irrigation, were compared with two zeolite levels: zero and 10 tons per hectare. Compared with the no-zeolite treatment, applying 10 tons of zeolite per hectare reduced the losses of TN, NH4+-N, and NO3−-N in drainage water by 16.0%, 16.9%, and 19.4%, respectively. In runoff, the corresponding reductions for TN, NH4+-N, and NO3−-N were reported at 10.0%, 14.0%, and 5.9%, respectively, while rice yield increased by 3.3%.
– Yanzhi Wang and colleagues, Agricultural Water Management: “Applying 10 tons of zeolite per hectare reduced nitrogen losses through leaching and runoff.”
This study is especially important from an implementation perspective because it did not examine zeolite separately from water management. In the same experiment, alternate irrigation reduced irrigation volume, drainage, and runoff by 22.2%, 20.8%, and 18.9%, respectively. The technical message is therefore clear: a mineral carrier or amendment has greater value when it is coordinated with the irrigation regime and fertilization plan. For arid and semi-arid regions, such a combination of water management and mineral material can improve input efficiency by reducing losses, although extending these findings to orchards, greenhouses, and different soils requires local testing.
In a canola study on sandy soil conducted from 2006 to 2007, four nitrogen levels—zero, 90, 180, and 270 kilograms per hectare—and three zeolite levels—3, 6, and 9 tons per hectare—were evaluated. Applying 9 tons of zeolite per hectare showed higher nitrogen use efficiency than the lower rates, and the greatest growth and seed yield were reported with the combination of 270 kilograms of nitrogen and 9 tons of zeolite per hectare. However, increasing nitrogen can reduce nitrogen uptake efficiency, which shows that zeolite is not a substitute for proper fertilization management. The technical role of zeolite in such a system is to increase the opportunity for nutrient retention and uptake, not to eliminate the need for precise fertilizer recommendations.
– Majid Aghaalikhani and colleagues, Archives of Agronomy and Soil Science: “Applying 9 tons of zeolite per hectare showed higher nitrogen use efficiency than the other doses.”
Microbial Viability in Mineral Carriers and Quality Control Criteria
When zeolite or another mineral carrier enters a bio-input, the main metric shifts from the weight of the mineral material to viability and biological function. CFU/g or CFU/ml is a metric for counting culturable living microorganisms, and the EN 17714:2024 standard defines rules for determining the concentration of microorganisms in plant biostimulants using units such as CFU/g. In a solid carrier, the initial microbial count alone is not enough, because moisture, pH, particle size, pathogenic contamination, heavy metals, and storage stability must also be controlled. Operationally, a biological carrier is reliable only when, after production, transportation, storage, and application, it can still preserve the living population and the claimed effect.
– Viability Testing and Label Claims in Microbial Biostimulants
European Union regulations for biostimulants provide an important framework for separating marketing claims from verifiable claims. Under Regulation (EU) 2019/1009, a plant biostimulant is a product that stimulates plant nutrition processes independently of the product’s nutrient content, with the aim of improving nutrient use efficiency, tolerance to abiotic stress, quality traits, or the availability of confined nutrients in the soil or rhizosphere. A microbial biostimulant must also consist of a microorganism or a consortium of microorganisms referred to in CMC 7. This framework sends a clear message for zeolite-based or mineral carriers: the product must have a specific biological effect, not simply be a mixture of mineral material and microbes.
– European Parliament and Council, Regulation (EU) 2019/1009: “A plant biostimulant must have the effects claimed on the label for the plants specified thereon.”
Within the same regulatory logic, the health and safety of the mineral carrier are part of product quality. For plant biostimulants in the European Union, the limits for inorganic contaminants include Cd at 1.5, Cr(VI) at 2, Pb at 120, Hg at 1, Ni at 50, and inorganic As at 40 milligrams per kilogram of dry matter. For Cu and Zn, the limits are 600 and 1,500 milligrams per kilogram of dry matter, respectively. In microbial biostimulants, Salmonella spp. must be absent in 25 grams or 25 milliliters, and E. coli must be absent in 1 gram or 1 milliliter. These figures show that an inoculated mineral carrier does not become an acceptable product simply by increasing CFU.
– European Commission, Fertilising Products Regulation FAQ 11.0: “There must be no intentional chemical reaction between the component materials and microorganisms belonging to CMC 7.”
This statement is directly relevant to zeolite and modified nanoclays, because surface modification, activation, and microbial inoculation must be controlled for both chemical and biological compatibility. If the mineral material is prepared with a surfactant, activator, or any other formulation component, the final test should not measure only nitrate adsorption or moisture. It must show that the target microorganism remains alive after contact with the carrier, that the product is free of the specified pathogens, that the pH is suitable for the microbe and the plant, and that the claimed effect is observable in the plant or rhizosphere. This approach prevents carrier technology from turning into a purely promotional claim.
The Economics of Zeolite-Based Carriers, from Mineral Price to Formulated Product
The economics of this technology should not be oversimplified by looking only at the price of raw zeolite. In the USGS report for 2024, the price of natural zeolite in the United States was reported in the range of $50 to $300 per metric ton, with an estimated average of $145 per metric ton. This figure refers to the mineral material and does not include sterilization, surface modification, microbial inoculation, CFU testing, pathogen control, heavy metal control, packaging, product registration, or agricultural distribution. Therefore, the economic assessment of a zeolite-based carrier must distinguish between three levels: raw agricultural zeolite, activated or modified zeolite, and a formulated biological product with a testable claim.
– Jason R. Williams, U.S. Geological Survey, National Minerals Information Center: “The price of zeolite depends on the percentage of material, chemical and physical properties, particle size, and type of application.”
This economic caution has practical importance for investors. If the product is sold only as a soil amendment, its competitiveness is measured against minimally processed minerals and bulk transportation costs. If the product is offered as a bio-input carrier or microbial biostimulant, its value depends on microbial viability, reduced nitrogen losses, compatibility with soil, and proof of the label claim. In this model, selling a formulated product with a testable claim is more logical than selling raw mineral material, but that logic is defensible only when quality control and field testing justify the product cost.
Modified nanoclays should be assessed from the same perspective. If nanoclay is introduced as a potential carrier, its advantage must be measured against natural or modified zeolite using shared criteria, not by relying on the appeal of the word “nano.” Metrics such as CFU/g, stability at storage temperature, NH4+ or NO3− release, pH, moisture, particle size, pathogens, heavy metals, and pot or field testing should form the basis of the decision. In this way, the investment decision moves from simply choosing a mineral material to designing a quality-control platform for mineral-based bio-inputs.
Localization Pathway in Iran for Dry and Leaching-Prone Soils
For Iran, the reliable starting point is laboratory and field evidence, not the claim that an industrial market is already ready. In the study by Malekian and colleagues, the Iranian zeolite came from Semnan Province and was reported to be mainly clinoptilolite. The experimental site at Isfahan University of Technology, northeast of Isfahan, was described as having an average annual temperature of 17°C, rainfall of 134 millimeters, and humidity of 38%. These data apply only to that experimental site, but they provide a useful indication for understanding the importance of mineral carriers in dry climates and in water and nitrogen management.
A defensible localization pathway should begin with selecting a domestic mineral material, identifying its mineralogy, and controlling contaminants. After that, the formulation must be made compatible with the target microorganism, and its viability must be measured as CFU/g or CFU/ml at the time of production and after storage. The next stage is testing the release or retention of nitrogen forms, followed by pot and field trials in sandy, saline, dry, or leaching-prone soils. Such a pathway would allow Iran to use existing evidence on domestic clinoptilolite and field studies on zeolite without relying on broad claims about every mineral carrier.
From an implementation standpoint, the first suitable product for development is not necessarily the most complex formulation. Malekian’s evidence showed that surface modification can further reduce nitrate, but plant response to natural clinoptilolite was better. The canola evidence also showed that in sandy soil, the 9-ton-per-hectare dose produced higher nitrogen use efficiency than lower levels. Therefore, the rational pathway is to compare a limited number of formulations in the target crop and soil: a natural clinoptilolite carrier, a modified carrier for reducing leaching, and, if an appropriate testing chain is available, a modified nanoclay carrier evaluated using the same criteria.
Technology Decision-Making for Mineral-Based Bio-Inputs in Iranian Agriculture
The technical conclusion in this field is clear: zeolite can be meaningful both as a soil amendment and as part of a biological input carrier, but these two roles should not be conflated. Reduced nitrogen leaching has been reported in existing studies at specific doses and under specific conditions, and nitrogen use efficiency in sandy soil has also been dose-dependent. At the same time, a biological carrier must address microbial viability, absence of specified pathogens, control of heavy metals, and proof of the claimed effect. Therefore, the investable product is not raw mineral material, but a formulated system that is compatible with soil and irrigation while also meeting biological quality standards.
For Vestra and knowledge-based agricultural players, the right entry point into this field is to build a testing and decision-making chain. This chain should begin with identifying clinoptilolite or another mineral carrier, continue with surface modification or nanoclay selection only if compatibility evidence exists, and then move into microbial inoculation, CFU testing, contamination testing, nitrogen release testing, and field trials. The final economic value is created through reducing ineffective input use, lowering nitrogen losses, increasing the reliability of bio-inputs, and making it possible to present precise claims to farmers. This pathway moves zeolite and modified nanoclay beyond the level of raw materials and turns them into measurable tools for designing a more precise generation of biological inputs.
