Fertilizer International 508 May-Jun 2022
31 May 2022
Liquid fertilizers
PRODUCT TRENDS
Liquid fertilizers
Liquid fertilizers are emerging as a high growth, multibillion dollar market. Their growing use is linked to trends such as no-till farming and the greater adoption of precision agriculture. Leading producers and products are highlighted.
Compelling benefits
The use of liquid fertilizers has increased dramatically in recent years. Liquid products offer undeniable practical advantages. They are also cost-effective – providing savings in materials, handling and application costs.
Liquid fertilizers are high performing products, typically offering more precise and environmentally responsible crop fertilization. They are fully compatible with irrigation systems and can be applied simultaneously with other crop inputs such as pesticides and fungicides. Their ability to deliver nutrients to crops more precisely improves nutrient use efficiency. This, in turn, can result in higher yields and crop quality improvements.
“The number-one top benefit of fluid fertilizers is high value – their overall benefit relative to costs. And the totality of the benefits associated with fluid fertilizers far outstrips any difference in the purchase price of specific crop nutrients,” comments the US-based Fluid Fertilizer Foundation.
The Foundation highlights the following benefits in particular:
- Logistical advantages: Fluid fertilizers provide unequalled handling convenience/efficiency and timeliness in crop production practices.
- Accurate, uniform, and precise application: This provides optimum crop nutrient distribution within a field, portion of a field and fertilizer band.
- Unparalleled flexibility, versatility and adaptability: Fluids are compatible with all crop production systems, all application methods, and any application timing.
- Unsurpassed agronomic efficiency: This offers superior agronomics, environmental stewardship and profitability.
Based on these merits, the Fluid Fertilizer Foundation advises that: “High value [liquid fertilizers] provide for prosperity – low cost [solid fertilizers] do not!”
Market drivers
In terms of what’s been driving their adoption, a shift from solid to liquid fertilizers is seen by some as a logical market trend due to the following characteristics:
- Liquids offer high precision nutrition with improved nutrient uptake and efficiency
- Have a low water requirement
- Makes good use of existing drip, sprinkler or flood irrigation systems and infrastructure
- Handling safety – products are safer for both the irrigation system and farmers
- Products are ‘cleaner’ with less impurities and are heavy metal free
- They are also flexible – offering more application choices to farmers
- Liquids can be applied without a lot of supervision or knowledge
- And have the potential to improve farmer incomes by avoiding inefficient fertilization and delivering better produce for less labour.
The specific benefits of liquid fertilizers versus granular fertilizers and water-soluble fertilizers are listed in Tables 1 and 2, respectively.
There are specific circumstances which will also tend to favour liquid fertilizers over water-soluble fertilizers. Liquid products, for example, can offer advantages to growers faced by the following:
- Increasing field size (or total area) to be fertigated
- Decreasing number of fertigations
- Decreasing water availability (and/or tank size)
- Increasing labour costs
- Desire or need to reduce the risk of human error
- Lower market premium for liquids compared to water solubles
- Increasing health & safety and a focus on product handling.
Greater adoption of liquid fertilizers is not solely down to changing product preferences either. The supporting infrastructure for reliably delivering liquid products also needs to be in place. The availability of customised/tailor-made liquid formulations is improving thanks to an increasing number of manufacturers and distributors who are now servicing the liquid fertilizer market – and are equipped and skilled to be able to deliver these products to growers.
Growers, in turn, are more receptive to buying liquid fertilizers if these are shown to deliver consistent crop benefits and:
- Support good profitability (e.g. for export crops, cash crops) and are reasonably priced relative to their granular and water-soluble alternatives
- Provide more concentrated nutrient solutions
- Are delivered in a form that is quick, easy and safe to handle.
Liquid fertilizers are generally associated with technically sophisticated and mature farming systems. Yet advocates also highlight the potential for greater adoption in emerging agricultural economies. Developing markets could, for example, benefit from liquid fertilizers due to:
- Falling groundwater levels and increased water scarcity
- Need to improve both nutrient use efficiency (NUE) and water use efficiency (WUE) of crops while boosting farmer income and profits.
- Increases in the area grown under drip irrigation due to favourable government policies
- Rises in the area of horticulture, floriculture and vegetable crops under fertigation, and the crop area under protected agriculture (green house cultivation)
- The rapid mechanisation of agriculture favours the injection of liquid fertilizers in soils
- Improving knowledge on soil fertility and fertilizer use.
Handling & storage
Liquid fertilizers are commonly sold as small packs (1-10 litres) or 770 litre- and 1,000 litre-size intermediate bulk containers (IBCs); 200 litre-size drums are also used. These liquids are typically transported to the farm in bulk tankers, in bulk flexibags inside a shipping container, or in IBCs. Storage tanks, such as stainless steel tanks (with or without a mixer), containment tanks and flexible tanks, are used for on-farm storage. These can be insulated and heated to avoid precipitation. Refilled IBCs are another storage option. Investment decisions for the grower include:
- Whether to rent or buy storage tanks from the supplier
- The need for pumping equipment
- Buying custom blended, ready-to-use nutrient solutions
- Investing in blending and mixing equipment for higher volume consumption of liquid fertilizers.
Application methods
A major advantage of liquid fertilizers is their suitability for a wide range of application methods. They can be applied easily via:
- Fertigation – drip irrigation, overhead pivots and sprinklers, in-furrow (flood) irrigation
- Foliar treatments
- Soil application – banding and injecting
- Top dressing.
Drip irrigation is arguably the most efficient way of delivering liquid fertilizers. This method maximises both water use and nutrient use efficiency by ‘spoon feeding’ crops. The use of liquids also minimises the risk of equipment blockages.
Liquids are effective in the drip irrigation of both small and large fields and are very simply to use. Application can be as simple as ‘connecting the IBC and opening the valve’, for example. Overhead pivots and sprinklers are more commonly used for pasture, field crops (potatoes, onion, carrots etc) and/or larger growing areas.
Foliar application of liquid fertilizers can be made from a tank-mix with pesticides. This method is better suited to lower dose applications (e.g., micronutrients). Providing nutrients in concentrated liquid form is also ideal for the low water volumes used to spray crop leaves.
Soil injection of liquid fertilizers allows very precise and even nutrient applications close to the crop. This is especially useful for less mobile nutrients such as phosphorus, calcium and magnesium. Suitable equipment is available for injecting liquid fertilizers at sowing. Liquids can also be injected via a mechanical weeder. When injecting liquids, however, care must be taken not to damage crop roots or inject too close to seeds or seedlings.
A top dressing of liquid fertilizers can be made pre-planting and at pre- and post-emergence. This phased application of nutrients helps improve nutrient use efficiency, particularly for nitrogen. Even and precise applications of liquid fertilizer can be achieved using specially designed nozzles mounted on spray machinery.
Product categories
Liquid fertilizers can be grouped into four main categories:
- Pure liquid fertilizers. These are chemicals that exist in a natural liquid state. Anhydrous ammonia (87-0-0) is the most common type and is typically soil injected using specialised equipment. Other categories of liquid fertilizer, in contrast, are concentrated pre-dissolved solutions of solids.
- Liquid fertilizers without a solid/watersoluble equivalent. Examples include thiosulfates and ammonium polyphosphate. Their solid equivalents are usually unstable and are therefore not sold or marketed.
- Liquid fertilizers which do have a solid/water-soluble equivalent. Examples include urea ammonium nitrate (UAN), a solution of urea and ammonium nitrate, and calcium ammonium nitrate (CAN), a solution of calcium nitrate and ammonium nitrate.
- Suspension or emulsion fertilizers. These are thixotropic liquids which are fully flowable when pumped but behave as a gel when static. Nutrients are mixed and suspended using a complex suspending agent to ensure homogeneity. By combining the high nutrient concentrations of water-solubles with the application benefits of liquids, this product category bridges the gap between liquid fertilizers and water-soluble fertilizers.
Selected products and producers
Primary ammonium nitrate (AN) production has been growing on average at 4-5 percent annually over the last two decades, rising (on a nutrient basis) to around 21 million tonnes N in 2019 (Fertilizer International 503, p30). Some 17 percent of this total is consumed in the production of urea ammonium nitrate (UAN) solutions.
UAN is manufactured by mixing non-concentrated AN solution with dissolved urea. The resulting solutions are generally offered in three different concentrations: 28 percent, 30 percent or 32 percent nitrogen content, respectively. The most popular form – 32 percent N – consists of a solution of 45 percent ammonium nitrate and 35 percent urea diluted with 20 percent water. UAN solutions are adjusted to neutral pH (7) using ammonia and nitric acid.
Major UAN producing countries include the US, Russia, Canada, Trinidad and Belarus. Around one third of international production was traded in 2019, with countries in Europe and the Americas being the main import destinations.
In the US, a preference for liquid fertilizers – when combined with tight regulations on the storage, transport and direct application of ammonia – has led to a rapid increase in demand for UAN solutions. As a result, the North American nitrates market is heavily skewed towards UAN. North America is also the most advanced global market for liquid fertilizers in general. Important liquid product manufacturers and distributors include:
- CF Industries
- CVR Partners
- Nutrien
- Koch Fertilizer
- Tessenderlo Kerley
- SQM
- AgroLiquid
- Kugler
- Triangle
- FoxFarm.
CF industries is the region’s largest UAN manufacturer. It produced 6.8 million tonnes of UAN (32%) in 2021 from its Donaldsonville, Port Neal, Verdigris, Woodward and Yazoo City sites in the US and Courtright site in Canada. CVR Partners also produced 1.2 million tonnes of UAN in 2021 from its Coffeyville, Kansas, and East Dubuque, Illinois, plants.
Nutrien sold 4.7 million tonnes of nitrogen solutions, nitrates and sulphates in 2021. The company markets the calcium ammonium nitrate product CAN17 as a flexible and fast-acting liquid fertilizer. CAN17 is a non-pressurised, odourless liquid that is simple to store and apply to a variety of crops. Nutrien and its predecessor companies have been selling this longstanding and established liquid product to fruit, vegetable and nut growers since 1995. Its key properties are as follows:
Nitrate-nitrogen. The 11.6 percent nitrate-nitrogen provides fast-acting N for immediate uptake, while the 5.4 percent ammonium-nitrogen offers a longer term and prolonged N reserve for crop feeding.
Soluble calcium. The 8.8 percent soluble Ca content improves water penetration, allowing available N and moisture to move easily into the root zone. Calcium is also critical for crop quality, promoting healthy cell development in fruits, roots and tubers.
Non-volatile. Unlike UAN solutions, all of the nitrogen in CAN17 is non-volatile, so avoiding nutrient losses and lost nitrogen investment.
Non-pressurised. Unlike liquid ammonia, CAN17 isn’t stored under pressure. That makes storage and application easier. The product is also less corrosive to equipment than many other nitrogen fertilizers.
Easy to apply. The product can be sprayed onto the soil surface with a ground rig, for example, or injected into the main line of irrigation systems.
Koch Fertilizer manufactures markets and distributes more than 10 million tonnes of nitrogen fertilizer products in North America annually. These include the liquid products UAN (32% and 28%), anhydrous ammonia, ammonium thiosulfate (ATS) and ammonium polyphosphate (APP). UAN is offered with the company’s proprietary Anvol™ or Centuro™ nitrogen stabilizers to help prevent nitrogen losses from leaching, denitrification or volatilisation.
Koch is a major global anhydrous ammonia (82-0-0) supplier to fertilizer distributors and retailers around the world. This is manufactured at five North American plants and distributed via an extensive terminal and transportation network. The company also offers Centuro™ as a next-generation nitrification inhibitor for anhydrous ammonia.
Koch is also a major North American ATS supplier, offering three grades (12-0-0-26, 11-0-0-24, 15-0-0-20) targeted at corn and soybean growers. The company recently commissioned a two-million-gallon ATS terminal at its Fort Dodge site in Iowa. The new ATS storage tank is is connected to the site’s existing automated UAN loadout infrastructure and is insulated with an internal coating to enable winter storage. ATS can be mixed with UAN or water at Fort Dodge to generate customised fertilizer blends for a single truck. The terminal will support 24-hour loading and will load a truck in approximately 20 minutes.
The extra storage and loading capacity at Fort Dodge allows Koch to supply customers throughout the corn belt with the ATS produced by Koch affiliate Flint Hills Resources at its Pine Bend refinery in Minnesota. This has the capacity to produce around 100,000 short tons of ATS annually.
“In the last few years, retailers and farmers have had difficulty finding adequate supply of ATS, and at the same time demand continues to grow,” said Scott McGinn, Koch Fertilizer executive vice president. “By building on our relationship with Flint Hills Resources and our terminal expertise, we can provide additional ATS capacity to the region and better serve our customers into the future.”
Koch also supplies liquid APP produced at its Brandon, Manitoba site in Canada. The Brandon plant is also a manufacturing centre for UAN and ATS.
Thiosulphates are becoming more widely-used as liquid sulphur fertilizers in the broad acre and speciality crop market in North America and Europe. Their use is also on the increase in Latin America.
Tessenderlo Group is a global leader in speciality liquid fertilizers and manufactures four main thiosulphate products:
- Ammonium thiosulfate, Thio-Sul® (12% N + 26% S)
- Potassium thiosulphate, KTS® (25% K + 17% S)
- Calcium thiosulphate, CaTs® (6% Ca +10% S)
- Magnesium thiosulphate, MagThio® (4% Mg + 10% S)
- Thio-Sul® is suitable for most irrigation systems and, alongside nitrogen, delivers sulphur in the unique thiosulphate form. It can be added to urea ammonium nitrate (UAN) to improve nitrogen use efficiency by reducing nitrogen losses.
- KTS® , another of Tessenderlo’s leading thiosulphate products, is marketed as a high-analysis potassium and sulphur fertilizer for fertigation. It is suitable for booster or starter formulations and can also be applied as a foliar fertilizer when crop demand for potassium is high.
Thiosulphates offer sulphur in both immediately plant-available form and in slower release form available to plants over a longer period of time. Thiosulphates also have a modest acidification effect, benefitting crops growing on alkaline (calcareous) soils. Providing sulphur to crops by applying thiosulphates offers a number of specific benefits:
- Enhances crop protein and chlorophyll content
- Assists the synthesis and functioning of enzymes in the plant
- Optimises fertilizer efficiency by stabilising nitrogen
- Improves availability of nutrients in the soil, particularly phosphorus and micronutrients and their uptake by the crop
- Energy efficient assimilation in the plant
- Provides prolonged sulphur nutrition
- A controlled and localised pH adjustment effect in the soil.
Thio-Sul® has the most effective acidification effect because it combines the ammonium cation with thiosulfate. Thio-Sul® can be combined with UAN solutions to provide two main benefits:
- It brings sulphur as a nutrient into the mix – the correct N/S ratio being very important for most crops
- It acts as nitrogen stabiliser improving nitrogen use efficiency.
Studies have shown that both Thio-Sul® and CaTs® have the ability to inhibit the urease reaction, potentially reducing nitrogen loss through ammonia volatilisation, as well as slowing down nitrification and thus reducing the loss of nitrogen though nitrate leaching.
CaTs® , as well as offering a nitrate- and chloride-free source of calcium, and providing thiosulfate sulphur, also acts as a soil conditioner. Being a highly-soluble liquid form of calcium – unlike gypsum – CaTs® is effective at penetrating the soil profile where it acts as a flocculant, opening up soil pores and improving soil structure and drainage. It can also help displace undesirably high levels of sodium in soils.
HEALTHY SOILS EQUAL HEALTHY PROFITS
Edgard Jauregui and Dr Karl Wyant of Heliae® Agriculture explain how crops can benefit from the inclusion of PhycoTerra® – a soil microbial food – as part of a customised liquid fertilizer programme.
Waking up the microbiome
Due to the lack of a proper food source, roughly 75 percent of microbes in soils are dormant or asleep. While dormant, these microbes cannot do their usual job, such as optimising nutrient availability and helping to alleviate water stress on the farm.
To overcome this problem, Arizona-based Heliae® Agriculture has developed PhycoTerra® , a superior soil microbial food manufactured from natural sources. This tailor-made microalgae product, manufactured using the company’s proprietary technology, provides an ideal, balanced meal for the soil microbiome, including bacteria and fungi.
By feeding the dormant microbes in the soil, PhycoTerra® helps improve soil structure, nutrient availability, and water holding capacity on farm fields. A living soil is a healthy soil and – by waking up the microbiome – the application of PhycoTerra® helps the soil profile develop a diverse and thriving microbial ecosystem (Figure 1). This is important, given that an active microbiome is crucial for both healthy soils and therefore healthy farmer profits.
PhycoTerra® can be easily mixed with liquid fertilizers alongside other common crop inputs. This makes it simple to incorporate into existing nutrient management plans as a soil health building component. PhycoTerra® is also pasteurised and therefore safe and easy for retailers and growers to store and handle.
Benefits of liquid fertilizers
Liquid fertilizers help maintain crop productivity and long-term soil fertility by adding crucial nutrients to the soil. Different formulations can be applied at different crop stages during the growing season to match crop nutrient demands. Examples include:
Ammonium polyphosphate (e.g., 10-34-0) applied with seed as a ‘starter’ or ‘popup’ phosphorus source to fuel early plant growth at the start of the season.
Liquid nitrogen products (e.g., UN32, UN28, AN20, ATS, etc.) applied as a side-dress on corn to help meet the rapid mid-season increase in nitrogen demand.
Specialty liquid fertilizers (e.g., KNO3 , KTS, CAN17, CN9) used to improve the quality and size of fruit and nuts as these crop develop and mature.
Liquid fertilizers are associated with high nutrient use efficiency because application timings can be closely aligned with actual plant demand. Nonetheless, liquid fertilizers can still benefit from the addition of a component, such as PhycoTerra® , that specifically promotes soil health and biological integrity (Figure 2). Its inclusion alongside liquid fertilizers has been shown to optimise nutrient availability in the crop.
Holistic soil management – by taking account of overlapping physical, chemical and biological properties – helps improve soil health and field performance. Custom liquid fertilizer blends can adopt this holistic approach by incorporating a soil microbial food. This helps integrate and achieve several soil management goals via a single product application.
Optimising liquid fertilizers
Another distinct advantage to liquid fertilizers is the degree of customisation that is possible by blending different components together. This flexibility and adaptability allows the final liquid mixture to deliver additional benefits beyond just crop fertilization, including waking up the soil microbiome and improving soil health. Adding PhycoTerra® to liquid fertilizer programmes allows growers to optimise their crop inputs by combining the addition of both nutrients and a pasteurised microbial food to soils (Figure 2).
PhycoTerra® is easily mixed with liquid fertilizers such as 10-34-0 or UN32. This not only provides the nutrients the crop needs but also allows the grower to improve their soil health at the same time. Applying these enhanced liquid blends allows the same farm infrastructure (e.g., tank, irrigation, liquid planter kit, etc.) to accomplish more work in the field without any extra complications.
Demonstrated soil quality improvements
Research trials and field results have repeatedly demonstrated the benefit of mixing PhycoTerra® with a liquid fertilizer programme. Many opportunities exist throughout the season to awaken soil microbes – from the beginning of the season with a high phosphate starter, to a mid-season side-dress nitrogen application. Doing so helps provide crops with the nutrients they need by improving soil health and quality. Adding a soil health building component to liquid fertilizer programmes is now becoming easier thanks to innovative technologies such as PhycoTerra® .
KTS® is one of the most concentrated forms of liquid potassium and sulphur available in the market. When combined with liquid ammonium polyphosphate (APP), it can be applied as a very effective starter fertilizer early in the plant’s growth cycle. The presence of KTS® can improve phosphorus use efficiency by regulating the rate at which polyphosphates are transformed into orthophosphates and becomes plant available.
The new liquid potassium nitrate product Ultrasolution K® (3-0-10) from SQM is targeted at almond and strawberry growing – markets in which water quality and efficiency are a priority. This clear solution of chloride-free potassium and nitrate-nitrogen is compatible with most fertilizers and pesticides, according to SQM, making the product ideal for liquid blending or tank mixing in the field.
Europe is another major liquid fertilizer market. The region produces and consumes UAN in large quantities. France is a large-scale, well-established consumer of UAN, importing around 1.9 million tonnes annually, around half the EU total. Major European UAN producers include:
- Achema
- Azomures
- Fertiberia
- Nitrogenmuvek
- Yara International.
- Other key European producers of liquid products include:
- Tessenderlo Kerley International
- Van Iperen
- Compo Expert
- Valagro
- Agrii.
Van Iperen, through its sister company Euroliquids, owns and operates north Europe’s largest liquid fertilizer plant in the port of Rotterdam. This ISO-certified 90,000 t/a capacity plant produces high quality liquid products in more than a 100 different formulations.
Euroliquids has been producing liquid fertilizers for more than three decades, having started as a supplier to the Dutch hydroponics sector. Its Rotterdam site includes 90,000 cubic metres of storage capacity and a quality testing and R&D lab that develops new formulations. Products are packaged in cans and bottles ranging from one litre to 1,000 litres in size. These are marketed and sold under Van Iperen’s FoliaStim, Meru, Maroa, Nitrofol and Pinta liquid fertilizer brands.
Norway’s Yara International, the world’s largest NPK and nitrates manufacturer, produced 917,000 tonnes of UAN in 2021. The company also markets a comprehensive range of nitrogen and NPK solutions under its Chafer liquid fertilizer brand. Many of these incorporate sulphur.
Yara’s Chafer Nuram liquid nitrogen fertilizer, for example, combines two sources of nitrogen (both ammonium and ureic) that provide both rapid and longer-term release properties. Although primarily designed to be soil applied, the range includes liquid grades suitable for foliar applications and precision placement on salad and vegetable crops.
In European countries like the UK, Yara’s liquid products are backed by comprehensive support infrastructure. This includes a network of production and storage sites offering prescription liquid blends and the manufacture of on-farm GRP (glass reinforced plastic) storage tanks. Advice on bespoke sprayer nozzles and stream bars, specifically designed for top dressing arable and grass crops, is also available.
