As one of the three macronutrients required by plants for healthy growth, potassium is a key component in maximizing crop yields, producing quality crops, and meeting global food security needs.
As maximizing agricultural productivity becomes essential to meeting future global food supply, crop nutrition is becoming more specialized, and the role of potash fertilizer production from various potassium compounds is growing.
What follows is an overview on these potassium compounds and the role they play in promoting balanced crop nutrition for improved agricultural productivity.
The Critical Nature of Potash Fertilizer Production
While nitrogen and phosphorus macronutrients have historically received the most consideration, attention is increasingly focused on potash. Market research firm Research and Markets estimates that the potash fertilizer market will experience significant growth in the coming years, reaching a market value of USD 25.05 billion in 2024 – up from 19.70 billion in just 2018.
The increasing demand for potash fertilizers can be traced back to a few key influences:
A Need for Greater Agricultural Productivity
The world is expected to be home to more than 9 billion people by the year 2050. Experts anticipate that to feed all of these people, food production will have to increase by around 70% (compared to 2007 levels). Since the amount of arable land will stay the same (or decrease as larger populations take over), this will require growers to cultivate substantially more food from the same plots, necessitating significant gains in agricultural productivity.
As agriculture advances and scientists gain a greater understanding of cultivation, they are discovering that optimized agricultural productivity is largely a result of providing a balanced nutrition program specific to the crop, soil, and setting.
This means that more than ever, growers need to tailor their fertilizer programs to the unique needs of their crop and soil, providing the right nutrients in the precise amount, at the right time, and in the right place, a principle known as the 4Rs. As a result, fertilizers and soil amendments are becoming increasingly specialized, incorporating different combinations of macro and micronutrients in varying amounts.
Crops require large quantities of potassium for proper growth. If potassium content is not sufficient, plants are limited both in growth and yield.
Potassium also plays a role in plant stress tolerance. As biotic and abiotic stresses on plants increase, ensuring adequate potassium supply will be crucial. Further, potassium is recognized for its vital role in water use management, which will become increasingly important as water resources are strained and instances of drought escalate.
Higher-Quality Food Demand
In addition to the amount of food needed increasing, so too is demand for higher quality foods; developing nations and higher incomes are demanding more high-quality foods than ever before.
Potassium is known as the “quality nutrient,” because it contributes substantially to quality-related aspects of crops, such as color, taste, size, and more.
Potassium also plays an important role in meeting nutrition requirements for animal nutrition in the meat and poultry industry, and in growing crops for use as animal feed.
Increasing Potassium Deficiency in Soils
Potassium deficiencies in soil have also been on the rise, according to experts, as levels of potassium naturally existing in soil continue to be drawn upon at a rate greater than agronomic input.
A recent study linked the increased prevalence of hypokalemia (low potassium in blood serum) in the United States to agricultural practices that continually remove potassium from soil without adequately supplementing it.
Potassium deficiencies are especially prevalent in regions with sandy soil, as well as those with a low clay content.
Potassium Compounds Used in Fertilizer Production
Historically, the term potash has been used to refer to KCl, or potassium chloride. As other potassium compounds see increased use, however, the term’s meaning is becoming more flexible. And while potassium chloride and potassium sulfate still garner the lion’s share of the market, other potassium compounds are playing a greater role in crop production as well. The most commonly employed potassium compounds in the fertilizer industry include:
Potassium Chloride (KCl)
Potassium chloride (KCl), also known as Muriate of Potash, or MOP, is currently the most commonly used potassium compound in fertilizer production. KCl is used as a straight fertilizer, as well as in compound fertilizer blends and complex fertilizers.
Potassium chloride is chosen for its high quantity of potassium, with the remaining composition consisting of chlorides.
Potassium Chloride Production
Potassium chloride is derived from sylvinite, a mineral composed of sylvite and halite. It is mined either by traditional techniques, or via solution mining.
KCl destined for use as a fertilizer has conventionally been marketed either in the form of a powder, crystals, or compacted granules, but the practice of pelletizing potash into rounded granules has been on the rise.
Potassium Sulfate (K2SO4)
Potassium sulfate (K2SO4) is quickly becoming a popular alternative to potassium chloride fertilizers. Also known as Sulfate of Potash, or SOP, potassium sulfate is ideal for chloride-sensitive crops (or where soils have accumulated excess chlorides), crops that require sulfur, or in soils with a high salinity.
Potassium Sulfate Production
Potassium sulfate is generally not found as a naturally existing compound, and is therefore manufactured either through the Mannheim Process, or more commonly, by processing complex salts. The compound is frequently derived from Potassium Magnesium Sulfate, which naturally occurs in a few places around the world as the mineral langbeinite.
As with potassium chloride, potassium sulfate fertilizer is typically either in the form of a powder, crystals, compaction granules, or rounded granules.
Potassium Magnesium Sulfate (K2SO4 ·2MgSO4)
Potassium Magnesium Sulfate is also known as Sulfate of Potash-Magnesia, or SOPM. Similar to SOP, SOPM is also a good option for chloride-sensitive crops or soils with a high salinity. In addition to providing potassium and sulfur, however, SOPM also provides the important nutrient magnesium.
Potassium Magnesium Sulfate Production
As mentioned, potassium magnesium sulfate occurs naturally as the mineral langbeinite, and can serve as a source of SOP when magnesium is removed. SOPM can be processed into powder, crystals, compaction granules, or rounded granules.
Potassium Nitrate (KNO3)
Also known as Nitrate of Potash or NOP, potassium nitrate provides crops with two of the three primary macronutrients: nitrogen and potassium. Potassium nitrate also serves as an effective fertilizer for chloride-sensitive crops.
Potassium Nitrate Production
Potassium nitrate is produced by reacting potassium chloride (KCl) with a source of nitrate such as sodium or ammonium nitrate. Potassium nitrate is typically provided in the form of crystals for easy dissolution, but it may also be agglomerated/granulated into granules as well.
Other Potassium Compounds Employed in Crop Nutrition
The compounds listed above represent the most commonly used potassium compounds, but a few others are occasionally used as well:
- Potassium Phosphate (KH2PO4)
- Potassium Carbonate (K2CO3)
- Potassium Hydroxide (KOH)
- Potassium Thiosulfate (K2S2O3)
Potash Fertilizer Process Development
As markets become more specialized, specialty fertilizers tailored to their intended application are increasingly becoming the norm. This has ushered in a new wave of development around specialty fertilizer and soil amendment products, incorporating potash and other nutrients in novel ways, and even from unconventional sources.
The FEECO Innovation Center has been at the forefront of this development, working with fertilizer producers to develop new products, enhance existing ones, and build the production lines needed to consistently produce a quality product at commercial scale.
The Innovation Center, having served as the fertilizer industry’s go-to granulation process development facility, is equipped to test all manner of fertilizer granulation tools and techniques, from drying mined potash, to granulating a novel source of potassium into a premium fertilizer product. Testing centers around wet granulation methods, with programs ranging from a single piece of equipment, to a continuous, pilot-scale loop. The facility has been especially integral in assisting development around the growing interest in alternative sources of potash.
Testing results are then used to engineer and fabricate the custom equipment needed to build a complete potash granulation line or other commercial-scale equipment.
Conclusion
Potassium’s role in feeding the growing global population through maximized agricultural productivity is more important than ever. And as growers pursue increasingly specialized crop nutrition programs, potassium in its many forms will continue to grow.
Serving the fertilizer industry since 1951, FEECO is the leading provider of potash and fertilizer granulation equipment, systems, process development, and parts and service support. We continue to assist the industry’s largest players in developing custom potash fertilizer products and the systems they need to produce them. For more information on our fertilizer production equipment or services, contact us today!