Case Studies: VolcaMin Clinoptilolite Zeolite in Action

The negatively charged structure of clinoptilolite can attract and hold positively charged nutrients. These include:

• Ammonium
• Potassium
• Calcium
• Magnesium

Rather than all of these nutrients remaining freely dissolved in soil water, some can be held on exchange sites and subsequently exchanged back into the soil solution. This can help keep nutrients within the active root zone.

Nitrogen is an essential plant nutrient, but it can also be susceptible to loss from agricultural systems. Clinoptilolite has a particularly strong affinity for ammonium, allowing it to retain ammonium ions within its structure. This is one reason nitrogen retention and recovery are among the most commonly investigated agricultural applications of zeolite.

The porous structure of VolcaMin can influence water retention, infiltration and capillary distribution. The aim is not simply to hold as much water as possible. A productive root zone needs a balance between moisture availability and drainage. The original VolcaMin case-study data reports that the material can hold water higher in the soil profile while continuing to allow drainage through the soil.

Unlike organic amendments that decompose over time, clinoptilolite is a stable mineral. The original VolcaMin information describes it as a permanent amendment that does not physically break down or become consumed by microbial decomposition. A more useful way to interpret this is that the mineral can provide long-lasting nutrient-exchange and physical properties within the soil.

Before application, the mangoes were grown in soil conditions described as having:

• inconsistent plant growth
• poor water retention
• nutrient leaching
• inconsistent yields
• slower plant development

These conditions can be particularly challenging in tropical environments where heavy rainfall can move water and soluble nutrients rapidly through the soil profile.

VolcaMin was incorporated into the root-zone soil at a reported concentration of 1% to 5%, alongside fertiliser. Three months after application, the case study reported visibly healthier foliage and improved tree growth, with improved foliage and fruiting observed across the farm.

Reported Benefits included:

• Improved water and nutrient retention: The porous structure of VolcaMin can help retain water within the growing environment, while its CEC provides exchange sites for positively charged nutrients.
• Improved nutrient availability: Ammonium, potassium, calcium and magnesium can be retained on the zeolite's exchange sites and remain available for exchange within the root zone.
• Reduced nutrient loss: Retaining nutrients within the root zone may reduce their movement through the soil profile, particularly in soils with low CEC.

In soils lacking VolcaMin, water and soluble fertilisers quickly pass through the soil profile without anything to retain or attract them. This is particularly problematic in soils with low cation exchange capacity (CEC), where nutrients are prone to leaching away, rather than being held in place for plant uptake. This can contribute to:

• Nutrient Leaching: Without VolcaMin, valuable nutrients are easily washed away by rainfall or irrigation, reducing plant access to essential elements. This leaching process is especially pronounced in tropical climates where heavy rainfall can wash away large quantities of nutrients.
• Poor Plant Nutrition: With fewer nutrients retained in the soil, plant available nutrition is poor, leading to stunted growth and low crop yields.
• Water Retention Issues: While drainage is typically good, the absence of VolcaMin means water retention is inadequate. This can cause water to run off quickly, leaving the soil dry and underhydrated.
• Environmental Impact: The runoff water, now contaminated with excess nutrients, can contribute to water pollution, especially in nearby streams and rivers. This nutrient contamination is a significant environmental concern.

In contrast, when VolcaMin is incorporated into the soil, it acts as a nutrient magnet, attracting and holding onto water and soluble fertilisers. The zeolite's negative ionic charge naturally binds with positively charged nutrients like ammonium, potassium, calcium, and magnesium, making them available to plants over time. This can contribute to:

• Nutrient Retention: VolcaMin holds valuable nutrients in the soil profile, preventing them from leaching out. These nutrients are exchanged onto the VolcaMin and made available to the plants as needed, improving overall plant nutrition.
• Better Plant Nutrition: With more nutrients available and easily accessible, plants can harvest these resources efficiently. This leads to better growth and healthier plants, contributing to higher yields.
• Improved Water Distribution: VolcaMin enhances capillary water distribution throughout the soil or growing media. More water is held higher in the profile, preventing excessive drainage and ensuring a consistent water supply to the plant roots.
• No Impact on Hydraulic Conductivity: Despite its ability to hold nutrients and water, VolcaMin does not impede soil drainage. The soil remains well-drained, which is critical for preventing root rot and other waterlogging issues.
• Environmental Benefits: By reducing nutrient leaching and runoff, VolcaMin helps mitigate the environmental impact of farming. Less nutrient contamination in runoff water reduces the risk of polluting local waterways, contributing to more sustainable farming practices.

Improved Nitrogen Recovery

Nitrogen is a cornerstone nutrient for plant development, but its high mobility in soil often results in significant leaching losses. 

Trials conducted at Cornell University in the USA demonstrated the potential of VolcaMin to improve nitrogen recovery and reduce nitrogen leaching in a sand-based growing profile.

Recovery of Applied Nitrogen in Grass: The trial measured the percentage of applied fertiliser nitrogen (N) that was recovered in bent grass clippings from sand profiles, comparing sand without VolcaMin with sand amended with VolcaMin.

In the sand profiles without VolcaMin, between 62% and 70% of the applied fertiliser N was recovered in the grass clippings.

When 10% VolcaMin was added to the sand, a greater proportion of the applied fertiliser N was recovered in the bent grass clippings, with 75% to 93% of the applied N being recovered.

This difference was most noticeable at the lower nitrogen application rate.

Reduced Nitrogen Leaching: Adding 10% VolcaMin to the sand also resulted in substantially less nitrogen leaching:

• Nitrate (NO₃⁻) leaching was reduced by 88%.
• Ammonium (NH₄⁺) leaching was reduced by 99%.

Together, these results demonstrate that, under the conditions of this trial, adding 10% VolcaMin to the sand increased the proportion of applied nitrogen recovered in grass clippings while substantially reducing nitrate and ammonium leaching.

The findings highlight VolcaMin's potential to retain nitrogen within the root zone, reduce nutrient losses and keep nitrogen available for plant uptake.

Enhanced Potassium Uptake

Potassium is critical for flowering, bud initiation, and fruit development, and is one of the most expensive nutrients to supply. VolcaMin's natural affinity for potassium ensures it remains stored in the soil for efficient plant use. 

The importance of VolcaMin's ability to retain and supply potassium was demonstrated in a 2003 trial on a commercial trellis tomato crop (cv. Red Ruby).

The trial was conducted on Shepparton Fine Sandy Loam soils, with VolcaMin applied at a rate of 1.4 t/ha.

Compared with the untreated control, the VolcaMin treatment resulted in a significant increase in medium- and large-grade fruit.

Petiole sap analysis also revealed higher potassium levels in the VolcaMin-treated plants. The higher potassium levels were associated with:

• Increased flower and bud initiation
• Improved fruit yield

Potassium availability plays an important role in flowering, fruit development and overall crop yield. By retaining potassium within the soil and making it available for plant uptake, VolcaMin can help maintain access to this important nutrient throughout the growing season.

Improved Trace Element Uptake

Trace elements like phosphorus, copper, manganese, calcium, magnesium, and zinc are essential for plant metabolism and growth. However, their availability can often be limited in poor soils.

The VolcaMin-treated plots recorded a 65% increase in production compared with the untreated plots.

Improved Nutrient and Trace Element Concentrations The trial also recorded substantial increases in the concentrations of several nutrients and trace elements within the plant tissues:

• Phosphorus (P): Increased by 100%
• Copper (Cu): Increased by 100%
• Manganese (Mn): Increased by 450%
• Calcium (Ca): Increased by 50%
• Magnesium (Mg): Increased by 30%
• Zinc (Zn): Increased by 30%

These results indicate that, under the conditions of this trial, VolcaMin was associated with increased production as well as higher concentrations of several essential nutrients and trace elements in the plant tissue.

VolcaMin can help improve the soil's ability to retain and cycle nutrients, potentially increasing their availability within the root zone and supporting plant uptake.

VolcaMin Zeolite on Clipper Malting Barley Trial – Australian Agricultural Technology, Barooga, NSW

A trial on Clipper malting barley was conducted by Australian Agricultural Technology at Barooga, NSW, to evaluate the effects of VolcaMin on fertiliser performance and yield.

The results demonstrated significant improvements in fertiliser conversion and crop outcomes:

• Incorporation of VolcaMin increased barley yield:
  • By 16% when used with DS (Diammonium Sulfate).
  • By 18% when used with DAP (Diammonium Phosphate).
• The DAP plus VolcaMin treatment yielded 34% more than the DS alone treatment.
• VolcaMin with DAP enhanced seeds per head, filler number, yield, and protein content of the barley.

• Increases water infiltration and promotes even capillary distribution throughout the soil profile.
• Holds more water higher in the root zone, improving availability to plants.
• Drains freely without clogging or blocking the soil.

• Encourages microbial life and improves soil microflora populations.
• Boosts cation exchange capacity, making more nutrients available to plants.
• Provides a mild liming effect, buffering soil acidity.

• VolcaMin’s structure is permanent and does not physically break down over time.
• Application can be built up gradually in the soil for long-term benefits.

• VolcaMin APPLIED @ 125 Kg/HA COST @ $300fT = $37.50/HA
• INCREASED YIELD (+ 10%)
• 7.5 T /HA @ $109.00fT = $817.50

The application of VolcaMin resulted in a 10% increase in yield, producing an additional 7.5 tons per hectare valued at $817.50.

• The VolcaMin treatment had a significantly higher number (P=0.007) and yield (P=0.003) of medium-grade fruit, as well as a significant increase (P=0.042) in large fruit yield.
• The total fruit number was significantly (P=0.071) higher in the VolcaMin treatment, although there was no significant total yield increase.

• Significantly higher number and yield of medium-grade fruit
• Significant increase in large fruit yield
• Higher potassium levels in petiole sap led to more flower, bud initiation, and fruit development.
• Potassium is a key driver of flowering and yield, and VolcaMin’s ability to store potassium in the soil for efficient plant use contributed to the improved crop performance.
• Although there was no significant total yield increase, the VolcaMin treatment resulted in higher fruit quality and a better distribution of medium and large fruits.

The trials discussed in this article were conducted under different conditions, using different crops, soils, application rates and fertiliser programs. A result observed in one trial should not automatically be interpreted as a guaranteed result in another agricultural system. Before using VolcaMin, consider: