Natural Zeolite for Soil Amendment

Q: How does zeolite reduce nutrient loss in soil?

The cation exchange capacity of clinoptilolite (CEC 1.6–2.0 meq/g) temporarily retains applied NH₄⁺ and K⁺ and releases them slowly as the crop demands, which reduces leaching and ammonia volatilization. He et al. (2002, Plant and Soil) reported reduced ammonia volatilization in calcareous sandy soil, and Jarosz et al. (2022, Applied Sciences) reported improved nutrient use efficiency. The benefit is most noticeable in sandy soils with low native CEC.

Q: Which particle size (mesh) should be used for soil mixing?

Powder (100 mesh, <150μm) is generally considered for broadcast field incorporation and fertilizer coating, while Fine Granule (30×50 mesh, 0.3–0.6mm) is generally considered for potting mixes and container blends. Powder has a larger contact area with the soil and reacts faster, while fine granules maintain aeration and drainage and hold their form longer inside containers. Please refer to the application-based product selection guide.

Q: How much should be applied?

In general, field topsoil incorporation is considered at about 1–5% of soil volume and potting-mix blending at about 5–15%, with the upper end applied for sandier soils. The precise application rate is best determined through pilot testing that reflects the soil's current CEC and pH analysis and the crop type.

Q: Can it be used in organic farming?

KMIZEOLITE natural clinoptilolite is OMRI Listed (KMI-10365) and permitted as an organic (NOP) input, and it holds certifications including FDA GRAS, TSCA, and EN-71-3 PASS. However, the scope of certification may vary depending on the cultivation environment, so please verify on the certifications page before adoption; test samples are also available on request.

Nutrient loss and low water retention in sandy soils and cultivated land

Sandy soils with a high sand fraction and cultivated land subjected to long-term continuous monocropping have a low cation exchange capacity (CEC), often in the range of 2–5 cmol/kg, so applied nitrogen (NH₄⁺) and potassium (K⁺) leach quickly below the root zone along with irrigation and rainfall. As a result, fertilizer efficiency falls, and at the surface, urea- and ammonium-form nitrogen volatilizes as ammonia (NH₃) gas, lowering the proportion of applied nutrients that crops actually take up. In sandy soils, a substantial portion of applied nitrogen can be lost to leaching and volatilization within a single growing season, increasing the application rate needed to achieve the same yield and adding to the nitrate-nitrogen burden on groundwater.

In addition, soils with insufficient water retention dry out quickly after irrigation, making it difficult to match irrigation frequency and nutrient-supply timing. Clinoptilolite has a porous framework (porosity of about 50%) that can absorb a substantial proportion of its weight in moisture (on the order of tens of percent depending on the study), so mixing it into soil is reported to increase plant-available water-holding capacity (Ramesh & Reddy, 2017; Cataldo et al., 2021). On such sites, an approach that raises the soil's own nutrient-storage capacity and water-holding capacity through a soil amendment is more effective than simply increasing fertilizer, and for certified organic cultivation it is also necessary to confirm whether the material is permitted (OMRI and similar).

That said, because clinoptilolite has a negatively charged framework, it is inherently strong at retaining cations such as NH₄⁺, K⁺, and Ca²⁺, and does not directly hold anions such as phosphate or nitrate. Therefore, the nutrient-retention effect discussed on this page is strictly a cation-exchange mechanism, and is premised on indirect nitrogen conservation through NH₄⁺ retention rather than direct adsorption of nitrate-nitrogen itself.

How clinoptilolite works in soil

Natural clinoptilolite has micropores of 4.0–7.0 Å within its crystal lattice and a cation exchange capacity (CEC) of 1.6–2.0 meq/g (≈ 160–200 cmol/kg). The permanent negative charge created when Al substitutes for Si in the framework electrostatically holds nutrient cations such as NH₄⁺ and K⁺, then releases them again when the soil-solution concentration drops, acting as a buffering nutrient reservoir. Clinoptilolite has a particularly high selectivity for NH₄⁺ and K⁺, which favors the retention of these two nutrients (Cataldo et al., 2021; Ramesh et al., 2011). Because the zeolite's CEC is added to the soil's own CEC, leaching of applied nitrogen and potassium is reduced and the nutrient use efficiency (NUE) of fertilizer is improved.

① Nitrogen conservation and volatilization suppression through cation exchange

The suppression of ammonia volatilization in sandy and calcareous soils has been directly reported. He et al. (2002, Plant and Soil) reported that mixing clinoptilolite into calcareous sandy soil significantly reduced ammonia volatilization and increased the soil's retention of exchangeable NH₄⁺ (He, Z.L. et al., Plant and Soil, 2002). NH₄⁺ held in the lattice, instead of escaping through leaching, is supplied slowly to plants through the nitrification process, so surface NH₃ volatilization and subsurface nitrate-nitrogen (NO₃⁻) leaching are eased simultaneously. The key point is that clinoptilolite does not adsorb NO₃⁻ itself but rather captures nitrogen at the NH₄⁺ stage, thereby reducing the nitrate leaching load as a result—exactly consistent with the cation-exchange mechanism of unmodified zeolite (Influences of clinoptilolite on nitrate leaching and plant growth, J. Hazard. Mater., 2011).

② Simultaneous improvement of water retention and aeration through porosity

Clinoptilolite is a porous mineral with porosity reaching about 50%, so mixing it into soil increases plant-available water while its high particle rigidity resists compaction and maintains aeration and drainage structure. Studies on potting and growing-media blends report that adding zeolite improves the nutrient-holding capacity of the medium and plant growth (McConnell et al., HortTechnology, 2001; Polat et al., 2004).

③ Nutrient use efficiency and yield

The comprehensive review by Jarosz et al. (2022, Applied Sciences) summarizes that natural zeolite functions as a soil amendment that increases soil nutrient use efficiency and crop yield, and notes that the effect depends strongly on soil type, fertilization regime, and application rate (Jarosz, R. et al., Applied Sciences, 2022). Ramesh & Reddy (2017) summarized that, in terms of water and nutrient retention, zeolite is suitable as a supplementary material for sustainable agriculture (Water, Air, & Soil Pollution, 2017). However, excessive application can actually inhibit growth, so an appropriate application rate based on soil analysis is a prerequisite.

KMIZEOLITE's natural clinoptilolite is 97% pure, mined and processed at the Amargosa Valley mine in Nevada, USA, with a specific surface area of 40.0 m²/g, a stable pH range of 3.0–10.0, and a hardness of 4.0–5.0 Mohs, so it does not break down in either acidic or alkaline soils and persists within the soil structure for a long time. For animal-feed use it is regulated under U.S. FDA GRAS (21 CFR 582.2729), and for other general uses under 21 CFR 182.2729.

KMIZEOLITE key properties

Item	Value
Clinoptilolite purity	97%
Cation exchange capacity (CEC)	1.6–2.0 meq/g
Specific surface area	40.0 m²/g
Pore diameter	4.0–7.0 Å
Stable pH range	3.0–10.0
Hardness	4.0–5.0 Mohs
Thermal stability	700°C
Specific gravity	1.89
Bulk density	45–54 lbs/ft³
Certifications	OMRI KMI-10365, FDA GRAS, TSCA, EN-71-3

Application examples for natural zeolite as a soil amendment

In soil amendment, the key is to distribute zeolite evenly throughout the root zone (the 0–20 cm topsoil layer). Below are representative application scenarios and the application-rate ranges that are generally considered (exact values are determined through soil analysis and pilot testing).

Full tillage incorporation (open field): Broadcast powder to fine granules over the soil surface, then incorporate into the topsoil with a rotary tiller or plow. Consider about 1–5% by soil volume (roughly on the order of several to tens of t/ha when converted for a 20 cm topsoil depth and specific gravity), applying the upper end for sandier soils.
Planting-hole and ridge incorporation: When planting seedlings or fruit trees, mix locally into the planting hole or ridge to reinforce nutrient and water retention during early establishment. This concentrates the effect in the root zone while reducing material use compared with full incorporation.
Potting-mix and growing-media blending (horticulture): Blend Fine Granule (30×50 mesh) at about 5–15% of the growing-medium volume to increase the water retention and nutrient-buffering capacity of pots and plug trays. There is research showing that zeolite-amended media improve nutrient-holding capacity and growth in container cultivation (McConnell et al., 2001; Polat et al., 2004).
Slow-release fertilizer carrier: Pre-charge zeolite with NH₄⁺ and K⁺, or apply it together with fertilizer, to slow nutrient release and reduce leaching losses. NH₄⁺-charged clinoptilolite is used as a slow-release nitrogen source that gradually releases NH₄⁺ from its lattice.
Pilot application: Apply a small sample to part of the target field and compare it against an untreated plot under identical growing-season and management conditions. It is efficient to vary the application rate (1%, 3%, 5%) by plot, observe the response, and then set the rate for full application.

Recommended particle size and product specifications

In the soil-amendment field, Powder (100 mesh) is suitable for soil mixing and fertilizer coating, while Fine Granule (30×50 mesh) is suitable for potting mixes and containers. Refer to the table below to select the product group that fits your application.

Product group	Mesh	Particle size	Typical uses
Powder	100 mesh and finer	<150μm	Pozzolan, feed, powder adsorption
Fine Granule	30×50 mesh	0.3–0.6mm	Water treatment, filtration, soil
Medium Granule	14×40 mesh	0.4–1.4mm	Filter media, bedding, litter
Coarse Granule	8×14 mesh	1.4–2.4mm	Swimming pools, de-icing, large-scale filtration
Extra Coarse	4×8 mesh	2.4–4.8mm	Packed beds, air scrubbers

→ View products by mesh size · Application-based product selection guide

Pilot testing and field review points

When applying zeolite in the soil-amendment field, be sure to confirm the following items together.

Assess field conditions: Analyze the soil's current CEC and pH.
Design basis: Determine the mixing ratio appropriate for the crop type and growth stage.
Operating conditions: Determine the existing fertilizer application rate and nutrient loss rate.
Maintenance: Confirm the irrigation frequency and soil drainage conditions.
Regulatory check: Where organic certification is required, confirming OMRI Listed (KMI-10365) is essential.
Application-rate calibration: Because excessive application can actually inhibit growth, first determine the appropriate ratio through a 1/3/5% plot comparison.
Field-specific notes: Clinoptilolite does not biodegrade in soil, so once mixed in, it remains effective as a nutrient buffer layer across multiple growing seasons (no need to reapply each season). He et al. (2002) reported reduced ammonia volatilization and increased exchangeable NH₄⁺ in calcareous sandy soil; the 2011 J. Hazard. Mater. study reported reduced nitrate leaching and improved plant growth; and Jarosz et al. (2022) reported improved nutrient use efficiency and yield. Actual effects vary with soil type, CEC, and fertilization regime, so do not transfer the cited figures directly—verify them on your own field against an untreated plot.

→ View TDS (Technical Data Sheet) · View MSDS (Material Safety Data Sheet)

Soil amendment FAQ

How does zeolite reduce nutrient loss in soil?

The cation exchange capacity of clinoptilolite (CEC 1.6–2.0 meq/g) temporarily retains applied NH₄⁺ and K⁺ and releases them slowly as the crop demands, which reduces leaching and ammonia volatilization. He et al. (2002, Plant and Soil) reported reduced ammonia volatilization in calcareous sandy soil, and Jarosz et al. (2022, Applied Sciences) reported improved nutrient use efficiency. The benefit is most noticeable in sandy soils with low native CEC.

Which particle size (mesh) should be used for soil mixing?

Powder (100 mesh, <150μm) is generally considered for broadcast field incorporation and fertilizer coating, while Fine Granule (30×50 mesh, 0.3–0.6mm) is generally considered for potting mixes and container blends. Powder has a larger contact area with the soil and reacts faster, while fine granules maintain aeration and drainage and hold their form longer inside containers. Please refer to the application-based product selection guide.

How much should be applied?

In general, field topsoil incorporation is considered at about 1–5% of soil volume and potting-mix blending at about 5–15%, with the upper end applied for sandier soils. The precise application rate is best determined through pilot testing that reflects the soil's current CEC and pH analysis and the crop type.

Can it be used in organic farming?

KMIZEOLITE natural clinoptilolite is OMRI Listed (KMI-10365) and permitted as an organic (NOP) input, and it holds certifications including FDA GRAS, TSCA, and EN-71-3 PASS. However, the scope of certification may vary depending on the cultivation environment, so please verify on the certifications page before adoption; a sample request for testing is also available.

Inquiries and sample requests

If you are considering applying zeolite in the natural zeolite for soil amendment field, please contact us through the channels below.

Notice

Whether the material is suitable may vary depending on field conditions, regulations, and test results. Before actual application, testing and review appropriate to the field conditions must always be carried out first. Zeolite should be understood not as a cure-all for the field in question, but as a material that supports existing processes.