Polyhalite's wide range of benefits

Besides its most obvious benefits – it contains four macronutrients and a healthy entourage of micronutrients, and it is proven to positively affect soil quality, soil health and soil biota – there are some further advantages that merit note, as follows:

Human Nutrition

For example, my interest was recently attracted to this article in the Guardian newspaper. Check out the headline and snippet below:

Here we see that there is a concerning decrease in nutrients that we obtain from the crop plants we eat, and this directly affects our health. Calcium in green beans dropped from 65 to 37 mg between the mid and late 20th century. And the amount of other nutrients we obtain from foods has also plummeted. Calcium is very good for bones and teeth, as well as other parts of our body. It is important to make sure plants have enough supply of it, as this helps them to grow while also benefitting the health of the people who eat them.

Another very important nutrient for us to eat is protein. And it is well known that sulfur is  an essential component of many kinds of protein. Plants need to synthesize proteins for their own health. But beyond that, it is important that they are not skimping on protein, as more protein is important for people's diets. For plants to contain optimum amounts of protein, it is essential that the soil where they are grown contains all the sulfur that they need. This is another reason why polyhalite is important. It delivers sulfur in combination with magnesium, calcium and potassium.

Perhaps this is why so many farmers are saying that polyhalite produces vegetables that taste better and look better. To ensure that plants deliver all the nutrients we (the consumers) need, it is not enough to only give them the proper percentages of the famous "NPK" formula. For society to advance healthily into the future, we need to consider the overall nutrient package that our crops are delivering to consumers. We should ensure that, besides NPK, the plants have been grown with proper amounts of micronutrients, sulfur, calcium and magnesium that make them thrive while also providing better nutrition for our diet. 

Soil ECEC (effective cation exchange capacity)

Polyhalite is a natural mineral fertilizer containing the essential metal ions potassium, calcium, magnesium, each chemically paired with a sulfate ion. Sulphate is a relatively large and complex divalent ion compared to simple ions that can be paired with metal ions necessary for plant growth, for example, the chloride found in potassium chloride (aka MOP, or HCl) . The larger size and multiple binding sites of the sulfate ion make it amenable to flexibility in ion exchange processes, allowing for dynamic exchanges with other ions in the soil. This makes polyhalite a natural and effective complement to fertilizers with simple ions, like potassium chloride.

Soil chemistry involves myriad exchanges of ions in many directions, depending on the specific needs of each organism in the soil ecology. Soil is alive with many plant, animal, and fungal organisms, which need various ions in different amounts and at different times. The key word here is "exchange." Just like in human affairs, where exchanges form the basis of our economy, so too in the soil. 

The divalent nature of the magnesium and calcium ions in polyhalite allows them to act like small particles with "two hands," enabling them to form chains and hold soil particles together. Together with the sulfate, they are able to form versatile complexes with soil particles and organic matter, facilitating dynamic ion exchanges that adapt to the changing nutrient requirements of plants and soil microorganisms. This ability to form more complex interactions also leads to clumpier soil with better structure and the right "tilth," which plants thrive in. This flexibility enhances nutrient availability and uptake, contributing to improved soil fertility and plant health. This aspect is evident by looking at the diagrams below. Chemically, the chloride ion really is nothing more than a sphere with a single negative charge. In contrast, the sulfate ion is larger, divalent, more complex, with multiple bonding sites and much more flexibility in its interactions: 

Therefore, while potassium chloride is generally considered safe and effective for crops and soils, sometimes soil might have an excess of chloride ions. In such cases, the application of polyhalite – with its larger, more complex, and divalent sulfate ion, along with its two divalent cations (magnesium and calcium) – can be beneficial in various ways. The sulfate ions will tend to displace the chloride ions, and because sulfate is divalent, larger, and has multiple bonding sites, it helps to makevsoil chemistry more dynamic. In terms of soil ecology, you can think of the sulfate ions as friendly mediators, facilitating interactions between the various components in the soil environment. They play an important role in soil coordination chemistry by forming stable complexes with essential nutrients and minerals, helping to transport them to plant roots. Another way to think about this is to consider sulfate ions as go-betweens, ensuring that nutrients can make their way to where they are needed.

The magnesium and calcium cations in polyhalite also benefit the soil in important ways. These divalent cations act as intermediaries in the complex system of nutrient transport, working alongside the sulfate ions. Because they are divalent, it's like they have "two hands."  They can grab onto something on one side, and something on the other, helping to bridge and connect soil particles, improving soil structure and stability. So you can think of the magnesium and calcium cations are like versatile, unselfish, and amenable people in society, who help with transactions and interactions.

It's also important to note that sulfate is not just a facilitator; Ii is an important macronutrient in its own right. It is a constituent of many protein molecules, making it vital for protein synthesis. Since protein synthesis is essential for plant growth and development, this leads to healthier, better looking and more nutritious crops. 

 A very important parameter in soil ecology is called the "total CEC" (cation exchange capacity), which depends on the amount of organic matter and clay particles in the soil. Small particles of organic matter and clay have surfaces with "exchange sites," which are negatively charged points that positive cations like potassium, magnesium, and calcium can attach to. This is crucial for soil health because these exchange sites hold various nutrients in a dynamic balance until they are needed. It is an extremely complex system of exchange. Then there is also the parameter called ECEC – the effective cation exchange capacity. ECEC is crucial for soil and crop health because it represents the real, effective capacity for cation exchange. Because magnesium and calcium are divalent (having a +2 electrical charge), they bind more tightly with the exchange sites than potassium, allowing potassium to flow more freely to the crop plants where it is needed. Meanwhile, sulfate acts as a sort of mild balancer. As a negatively charged ion, it helps facilitate the movement of cations. This means that sulfate can act as an intermediary, allowing nutrient cations to move with more agility.

Polyhalite's unique composition helps to counteract soil dispersion, a condition where soil particles repel each other, leading to poor soil structure and reduced aeration. Dispersion can be caused by an excess of monovalent cations, like those found in certain fertilizers. By providing a source of divalent cations such as calcium and magnesium, polyhalite promotes aggregation and creates a more stable soil structure. The calcium and magnesium in polyhalite act as bridges, linking negatively charged soil particles and holding them together, much like how supportive structures hold up a building. This bridging effect reduces soil dispersion, enhances aeration, and improves soil tilth, creating an environment where plants can thrive. Field tests have consistently shown that polyhalite outperforms other fertilizers in terms of soil health and crop quality, demonstrating its ability to remedy soils affected by dispersion and contribute to sustainable agriculture.

A case in point: wheat

One crop that has been extensively studied in terms of polyhalite's long-term benefits to soil ECEC is wheat. The sulfur in polyhalite helps plants to develop strong and effective root systems. This allows them to take in more nutrients, including potassium. This is an example of polyhalite's synergistic effects on crop nutrition and soil health. As mentioned above, the calcium in polyhalite is beneficial for the soil's tilth. This term refers to the "perfect" texture of soil – not too hard, not too soft, a bit clumpy, a bit crumbly, which allows for water filtration, root movement, and aeration for soil organisms – again, the specific reasons that tilth is important are highly complex, and yet all farmers know that when soil has good tilth, the crops will surely grow better. By fostering healthier root systems, optimizing nutrient uptake, and improving tilth, polyhalite enables wheat plants to better withstand environmental stresses such as drought, pests, and diseases. This enhanced resilience not only leads to stabler yields but also results in superior crop quality, contributing to the long-term sustainability and profitability of wheat farming operations. Of course, these benefits are not limited to just wheat – as polyhalite is being used increasingly around the world, more studies are appearing in regard to its benefits to soil health, yield, stability, disease resistance, drought resistance, and produce quality in a wide range of cops. The bottom line is, when you have healthy soil, you have not only a more profitable farm, you have higher yields and higher-quality crops for feeding society.

Shelf Life

You're probably aware that food waste is a huge problem in regard to global sustainability. Around one third of all crops  wind up being wasted, never completing the path to enter people's bodies to provide them with nutrients and energy. On their way from the fields to the consumers' tables, grains, fruits and vegetables often deteriorate and become unusable.

Studies have shown that polyhalite adds to the shelf life of food products. This means that it contributes to global sustainability and economics by ensuring that less food gets wasted. This is a further benefit of this multifaceted crop nutrient!

Polyhalite and KCl (MOP): A match made in heaven

Plants need potassium, and farmers have long relied on potassium chloride (KCl, otherwise known as MOP) to meet this need. Now they have another premium, organic and sustainable potassium source: polyhalite – a natural, organic blend made the nature of potassium sulfate, magnesium sulfate and calcium sulfate. As discussed above, the sulfate helps to mitigate soil dispersion while the calcium is also known for enhancing soil structure. And magnesium is vital for the process of photosynthesis. Sulfur is necessary for the synthesis of most proteins, including in the living organisms within the soil biota. So with the advent of polyhalite, farmers can now rely on this premium crop nutrient to add not only an extra dose of potassium, but one that comes packed with other vital nutrients and soil enhancers – totally natural, certified organic, with a very low carbon footprint.

Image credit of chloride and sulfate ions: public domain, https://en.wikipedia.org/wiki/File:Sulfate-ion-2D-dimensions.svg (modified) and https://en.m.wikipedia.org/wiki/File:Chloride_ion.svg.

Other images: screenshots from linked pages.