A deep dive into ammonium nitrate fertilizer: Uses, benefits, and safety

It has been a fundamental part of human plant cultivation since the dawn of agriculture to mineralize food crops. Farmers used bird dung to fertilize years before synthetic fertilizers became available, but after, much improved yields followed. Since nitrogen is the bottleneck of every fertilizer, ammonium nitrate fertilizers have been commonly used around the world because of their high nitrogen level (34%).

Ammonium nitrate fertilizer can be used in a variety of climates due to its slower-release ammonium (NH4+) and readily available nitrate (NO3-) combination. It is believed to be less damaging and more agronomically beneficial than urea. It contributes to the growth of plants and to crop yield. But ammonium nitrate is hazardous, and in case of mishandling, has led to serious accidents, including fatalities, and destruction of property. These hazards are widely known, and there are numerous measures to mitigate them.

Growcycle is a well-known retailer of agriculture and horticulture products. The company offers a range of fertilizers, including potassium and ammonium nitrate fertilizers. And it presents the complete solution for what the modern grower needs to be successful in a shifting marketplace.

What is Ammonium Nitrate Fertilizer?

Ammonium nitrate is an attractive source of Nitrogen-containing nutrients because of the high level of ammonium in the ammonium nitrate and because the nitrate form is also present. In the form of nitrates in the soil, it is quickly taken up by the roots of plants. Ammonium, however, is first oxidized to nitrate and then taken up quite slowly.

Ammonium nitrate is also being used increasingly by vegetable farmers as an instant source of nitrate nutrition for plants, and by animal farmers for pasture and hay fertilization. Ammonium nitrate is frequently formulated with other fertilizers; however, due to its propensity to absorb moisture from the air, these combinations cannot be retained for extended durations. 

Ammonium nitrate also has high solubility, making it particularly suitable for fertigation and foliar applications.

Related: Maximizing growth with fertigation: A guide to efficient nutrient delivery

Properties of Ammonium Nitrate Fertilizers

Ammonium nitrate, or AN, is a key chemical product that is primarily used to make high-quality fertilizers. Below are the key properties of ammonium nitrate fertilizers.

• Chemical Composition

An acid-base reaction of ammonia and nitric acid produces ammonium nitrate.

HNO3 + NH3 → NH4NO3

The Harber process is when atmospheric nitrogen is mixed with hydrogen to produce ammonia, and this is subsequently converted to nitric acid by the Ostwald process. Upon forming the solution, excess water is evaporated, and a liquid ammonium nitrate of 98-99% is obtained. That liquid ammonium nitrate is then turned into granules or beads, which are distributed for use as fertilizer or other purposes.

• Physical Properties

Ammonium nitrate is a colourless crystalline salt which is available in granule or prill form. Being highly water soluble, it is also highly available to plants once dissolved. It is hygroscopic as it has the property to absorb moisture. It melts at 229°F – 257°F, but does not have a definite boiling point as it decomposes rapidly. The molecular weight of ammonium nitrate is 80.04 g.

• Nitrogen Release Mechanism

Plants receive nitrogen from ammonium nitrate (NH4NO3) in two forms: nitrate (NO3-) and ammonium (NH4+). In the process of applying ammonium nitrate to soil water, nitrate ions are readily transported from the roots to the stems of plants. Amonium ions, unlike nitrate ions, do not easily enter solution because they attach themselves to the clay particles. This causes nitrogen to be released slowly for plants. Still, both processes can be beneficial for the growth and development of the plant.

• Explosive Potential

Since ammonium nitrate is an oxidizing agent, it can readily discharge oxygen into the atmosphere. This can make it an unstable explosive when mixed with flammable materials. When combined with fuels such as fuel oil and aluminum powder, or with explosives such as TNT, it readily forms explosive mixtures such as Amatex, Amatol, Minol, and Tovex. Pure ammonium nitrate is not particularly stable, but large shock, friction, or confinement may lead to detonation.

• Thermal Properties

Ammonium nitrate, when heated above its decomposition temperature, decomposes to form nitrogen and oxygen gas along with heat and energy. If the ammonium nitrate is confined, the reaction can be hazardous. In terms of thermal conductivity, ammonium nitrate has a very slow process. As a result, heat can accumulate in specific parts of a bulk storage of ammonium nitrate, raising the danger of thermal breakdown and detonation.

• Environmental Interaction

The nitrates in ammonium nitrate readily dissolve in water and are free to move to the soil profile. This process leaches out and drains away excessive nitrates into the groundwater. Ammonium nitrate application on soils can produce nitrous oxide (N₂O), a potent greenhouse gas, by microbial processes, resulting in global warming. But when handled responsibly, ammonium nitrate fertilizers can help plants thrive beyond the wildest dreams of their preindustrial ancestors.

Uses of Ammonium Nitrate Fertilizers

Ammonium nitrate (AN) is a widely used fertilizer in plants and agriculture because of its high capacity for nutrient supply. The uses for ammonium nitrate fertilizers are as follows.

• Nitrogen Source

One of the primary uses of ammonium nitrate in plants is as a source of nitrogen. Since ammonium nitrate also contains 34% nitrogen, its application can enhance photosynthesis, protein production, and growth of plants. Ammonium nitrate fertilizers are used as additives for wheat, maize, barley, and various fruits which are planted by gardeners or farmers.

• Boost Crops Yield

Because ammonium nitrate contains both ammonium and nitrate, it is superior in quick productivity and total crop production. In animal production, ammonium nitrate fertilizer is applied on fields in order to improve pastures and grasslands and essentially increase grass production. This enhances the quality of the feed for animals such as cattle.

• Maintain Soil Nutrient Needs

Ammonium nitrate fertilizers keep the plants’ nutritional needs up by providing approximately the same, stable quantities of nitrogen in ammonium or nitrate form. Double Availability This double availability restores the nutrient level of nitrogen, increases soil fertility, and promotes vigorous plant growth.

• Improve Soil Fertility

Ammonium nitrate can be applied directly to any low-concentration nitrogen areas that have been impoverished by intensive farming. It enhances soil fertility and enables farmers to maintain soil health over time, which subsequently enables crop production without causing soil degradation.

Types of Ammonium Nitrate Fertilizers

While ammonium nitrate comes in both liquid and granular forms, the most commonly used forms are as follows:

1. Liquid Ammonium Nitrate

White crystal ammonium nitrate that moves in water is called liquid ammonium nitrate (LAN). But it does not have flammable material, it will prevent the burning of flammable material. It can be used to produce fertilizers and explosives. It supplies an immediately available source of nitrogen by promoting rapid growth in plants. Liquid ammonium nitrate allows two application methods, foliar spray and fertigation. With LAN, less waste buildup occurs, and the uptake of nutrients is maximised.

2. Granular Ammonium Nitrate

The white prills or granules of ammonium nitrate fertilizer are also known as granular ammonium nitrate. It is the simplest, most widely available form of ammonium nitrate fertilizer. It allows quick nitrogen release to plants, improving and boosting their growth. A granular form of ammonium nitrate fertilizers can be applied by fertilizer spreaders on large areas of crops or fields. This type of ammonium nitrate fertilizer product can be used for numerous vegetables, fruits, turf, and lawns.

3. Calcium Ammonium Nitrate

One such nitrogen fertilizer product is calcium ammonium nitrate (CAN), which contains the same amount of long-lasting ammonium as fast-acting nitrate. This provides a more continuous supply of nitrogen to the crop, enhancing nitrogen use efficiency, and winter or summer application is possible. Besides nitrogen, CAN gives calcium, which is important for building cell walls and roots, as well as the health of plants as a whole. Unlike other fertilizers, it will keep a balanced pH inside the plants to increase their growth.

4. Coated Ammonium Nitrate

Granular ammonium nitrate coated with polymer or glue is known as coated ammonium nitrate. The disadvantage of this type of ammonium nitrate fertilizer is that it performs poorly compared with other types of fertilizers because of the presence of a coating layer that prevents the release of the nitrogen. But nitrogen is released in time, and coating ammonium nitrate increases plants` utilization of the nutrients. Because it provides plants with a slow, steady stream of nitrogen, it also reduces the regularity of fertilizer application. This variety of fertilizer can be beneficial in various agricultural steps such as row, turf, and ornamental.

Top Ammonium Nitrate Fertilizers

Top ammonium nitrate fertilizers are well-known for giving plants the nitrogen they need to grow strong and produce high yields.

1. Hi-Yield Ammonium Calcium Nitrate

Hi-Yield Ammonium Calcium Nitrate is one of the best ammonium nitrate fertilizers for plants. It provides a strong combination of vital elements, particularly calcium (Ca) and nitrogen (N), that are important for plant growth. Perfect for vegetable gardens, especially with tomatoes and peppers, this mixture is essential for preventing Blossom End Rot, a common problem with tomatoes.

Blossom End Rot occurs by a calcium deficiency, which produces physiological abnormalities rather than plant sickness. It frequently occurs during rapid fruit expansion stages, when adequate calcium fails to reach the fruit's end. Gardeners may efficiently handle this difficulty by using Hi-Yield Ammonium Calcium Nitrate. They can use it as a soil (side dress) application or as a foliar spray, giving various solutions for optimum plant health and output.

2. Plant-Prod Ammonium Nitrate

Plant-Prod Ammonium Nitrate is Growcycle's second-most recommended ammonium nitrate fertilizer. It offers a high-nitrogen formula for plant and crop growth. Its high nitrogen concentration, adaptability, and rapid nutrient availability make it a good choice for farmers trying to increase crop yield and plant health. It can be combined with other nutrients to make unique fertilizer mixtures, allowing farmers to adjust their applications according to the requirements of particular crops and soil types.

Benefits of Using Ammonium Nitrate Fertilizers

Here are some suggested ways to maximize the benefits and minimize the risks of ammonium nitrate fertilizer:

• Proper Storage

Appropriate storage is needed to avoid the detrimental effects of ammonium nitrate fertilizers. These fertilizers must always be kept in a cool, dry, well-ventilated place, away from heat, fire, and direct sunlight. Place the fertilizer in a moisture-proof container with a tight cover to prevent disturbing the compound or changing its chemical form. Most importantly, the authorization of ammonium nitrate should be under local law since it will also cause ignition and contamination in some cases.

• Secure Handling

Wear the appropriate personal protective equipment (PPE) when handling ammonium nitrate, including a dust mask, safety glasses, and gloves. Do not inhale the dust while using, and always rinse hands thoroughly after use to avoid skin and respiratory infection. Check to see that storage facilities are well-ventilated, and store in sealed containers to avoid moisture intake, which can cause the fruit to decompose and clump.

• Proper Application and Timing

Before applying the ammonium nitrate fertiliser, you should make a complete inspection of the soil to get an estimate of the nitrogen that crops need. Then select the method of application — banding, broadcasting, or fertigation, for example. Irrespective of the type of application method, it is always recommended to spread the fertilizer uniformly over the crop surface to maintain uniformity in nutrient spreading.

Ammonium nitrate fertilizer is best applied during the growing season, when plants are active, or after planting, when nitrogen is in high demand. But the heavy rain is capable of running off fertilizer, so heavy rain can be avoided while applying fertilizer.

• Blending

Mating with micronutrients and phosphorus, potassium amnium mixed as multiple demand nutrients fertiliser, which is in favor of the growth of the plants. So, always mix ammonium nitrate with other fertilizers, and make sure it remains mixed from cradle to plow to provide a balanced diet and to dilute the nitrate of concern, which could leach into plant roots and from there into groundwater.

Best Practice to Apply Ammonium Nitrate Fertilizers

While ammonium nitrate makes a great fertilizer and is fairly safe for most people to use, there are risks and considerations to its use:

• Explosive Potential

Ammonium nitrate is a powerful oxidizer that can be highly explosive under certain conditions. Due to its occasional use in illegal and industrial explosives, it is subject to strict handling, storage, and shipping regulations. It is of the utmost importance to adhere to safety regulations and correct storage if accidents are to be avoided and preservation must be carried out safely.

• Fire Hazards

Ammonium nitrate fertilizers may pose a fire hazard due to their explosive nature upon exposure to heat, toxic substances, or confined spaces. Ammonium nitrate decomposition can result in toxic gases. Correct storage in cool, ventilated rooms and removal from flammable material is important in helping to minimize these fire hazards and maintain safety.

• Health Hazards

When swallowed or inhaled, ammonium nitrate may irritate the digestive system and respiratory tract. Contact with the skin may also be damaged by burning or irritation. To minimize these risks and ensure safe application practices, the necessary protection equipment, including masks and gloves, is to be used during manipulation.

• Environmental Concerns

When ammonium nitrate is overspread, it may be washed into bodies of water by irrigation water, where it is an environmental pollutant to water, and not even the most eutrophic water should contain it. It reduces the amount of oxygen and endangers aquatic species. Overadoption may lead to the soil becoming unhealthy and too acidic. Proper management practices are critical in limiting these effects and ensuring sustainable agricultural operations.

• Contamination Risks

The danger of poisoning from ammonium nitrate fertilisers comes from exposure to heavy metals, pesticides, or other chemicals during their production, transport, or storage. These fertilizers are capable of affecting soil and crop quality and food safety as well when they are polluted. Appropriate handling and storage techniques can prevent contamination of products.

The Bottom Line

Ammonium Nitrate is a powerful agricultural fertilizer that provides plants with high nitrogen content to ensure optimal growth and crop yield. The combination of ammonium and nitrate in ammonium-nitrate fertilizers allows rapid nutrient absorption, thus making them life-saving fertilizers for various crops. Still, ammonium nitrate should be handled and stored carefully, given its explosive nature and hazardous features.

Growcycle, a reliable supplier, provides the best quality ammonium nitrate fertilizers and the tools farmers need to optimize productivity. By appropriately selecting fertilizer and weighing the advantages and disadvantages of ammonium nitrate, farmers may improve soil fertility and support sustainable agricultural practices.

Disclaimer: This material is for informational purposes only and should not be relied on for legal, medical, financial, or any other form of professional advice.

About the Author

Victor Miller

Environmental Journalist Focused on Sustainable Agriculture

Victor Miller is an environmental journalist at Growcycle, specializing in sustainable agriculture. With a passion for storytelling, he highlights the latest trends, innovations, and practices that promote ecological balance and responsible farming.