Ammonium nitrate or urea: which is better, when, how to tell them apart

Which is better, ammonium nitrate or urea? Neither in general: which one gives the cheaper kilogram of nitrogen reaching the crop is decided by how and when it is spread. Urea contains 46% nitrogen and ammonium nitrate 34.4%, so in 2025 the nitrogen in urea cost 13.5% less: 44.7 against 51.6 UAH per kilogram (the State Statistics Service's average price for agricultural enterprises, without VAT, delivered). Urea keeps this edge while it loses less than 15-16% of its nitrogen to the air: worked into the soil the same day it loses 3-6%, spread on damp soil that dries in warm weather 20-40%, while ammonium nitrate loses 2-4.3% and acts quickly in a cold spring. Tell them apart by the bag and the quality certificate; do not heat, burn or taste the granules.

What urea and ammonium nitrate are#

Both are granular nitrogen fertilisers, but they are different substances (ureaa, in Ukrainian карбамід, ammonium nitratea, аміачна селітра). Urea, also called carbamide (сечовина), holds all its nitrogen in the amide form. In ammonium nitrate half the nitrogen is nitrate and half is ammonium.

Urea is not a «селітра»: that word names the salts of nitric acid, that is, nitrates, while urea is an amide (Hospodarenko). There are also grades based on ammonium nitrate with 32-33.5% nitrogen, including ones with dolomite, so read the percentage on the bag. Calcium ammonium nitrate (CAN, ВАС) contains 20-28% nitrogen together with calcium carbonate, and calcium nitrate 15.5% nitrogen and calcium: these are other fertilisers with a different composition.

Which one acts faster#

The nitrate half of ammonium nitrate acts quickly; the ammonium half moves less in the soil (Hospodarenko, 2013). Roots take up little urea as a molecule: first the soil enzyme urease converts it to ammonium. On fertile soil with good moisture and temperature this takes 2-3 days. Warmth, moisture and plenty of urease speed up the hydrolysis (Kansas State University, 2021), so in cold soil it goes more slowly; how many days exactly, none of the sources we opened says.

For the common phrase «urea acts more slowly but lasts longer» we found no source: after hydrolysis the nitrogen of urea behaves like ammonium nitrogen. Hospodarenko's textbook sums it up: nitrogen fertilisers applied in good time, before the crop starts taking up nitrogen, have the same value, and how well the ammonium and nitrate forms work depends on the conditions of application.

What a kilogram of nitrogen costs#

The State Statistics Service (Держстат) publishes the average prices agricultural enterprises paid for fertilisers, without VAT and delivered. Per tonne, ammonium nitrate is cheaper, in 2025 in every oblast with data, but a tonne of urea contains 460 kg of nitrogen and a tonne of ammonium nitrate 344 kg, so per kilogram of nitrogen urea is cheaper.

The nitrogen in urea was cheaper by 17.5% in 2023, by 12.6% in 2024 and by 13.5% in 2025. These are last year's average prices, not today's. Freight of 1 000 UAH per tonne adds 2.17 UAH to a kilogram of nitrogen in urea and 2.91 UAH in ammonium nitrate (calculation). The ADAM catalogue (ureaa, ammonium nitratea) has no active offers as of 10.11.2026.

Where the nitrogen goes: losses by how it is spread#

Urea loses nitrogen mainly as ammonia, ammonium nitrate with water. The EU emission inventory gives surface urea 16% of its nitrogen on average and ammonium nitrate 2%, or 4.3% on soils with pH above 7 (EMEP/EEA, 2023). Measured losses from ammonium nitrate did not exceed 4%; from urea they ran from 6 to 47%.

Light rain can increase urea's losses: the surface gets wet and dries again (Montana). The urease inhibitor NBPTa cuts urea's losses by about half on average, but on soil with pH 4.5 only by 18% (Cantarella et al., 2018). We found no field measurements of ammonia loss from urea on Ukrainian chernozems.

Which is better: when urea stops being cheaper#

There is no winner: urea is cheaper per kilogram of nitrogen until its losses eat up the price gap. Across Ukraine in 2025 that line was 15-16% loss (calculated from State Statistics prices and the loss bands above).

Across Ukraine#

Urea worked in the same day is cheaper. On the surface in cool weather it loses 10-16%, so it sits on the line. On damp soil that dries in warmth, ammonium nitrate gives the cheaper nitrogen. The line moves with prices: in 2023 it was 19-20%, in 2024 14-15%.

By oblast, 2025#

«On the line» means that urea's loss range from the table above crosses the line, and the answer depends on how much it loses on your field. Urea worked in the same day is cheaper everywhere except Chernivtsi and Khmelnytskyi oblasts, where it is on the line. Onto snow urea loses 20-25%, and there is no measured band for ammonium nitrate, so we draw no line.

For your ammonium nitrate price#

The table shows the urea price at which a kilogram of nitrogen reaching the crop costs as much as in ammonium nitrate at your price. Both prices must be on the same terms: with or without VAT, delivered or not. For your own oblast or price, you can ask Adama in the chat.

Soil, weather and season#

• <strong>Cold spring, frozen-thawed soil.</strong> The nitrate in ammonium nitrate acts quickly. Urea loses less in the cold (Kansas), but onto snow it lost 20-25%, and it is not spread on damp soil even in the cold (Montana).
• <strong>Frozen soil and rain.</strong> In one Kansas study, 25 mm of water on frozen soil right after spreading washed off about 25% of each fertiliser.
• <strong>Calcareous soil, pH above 7.</strong> Urea's losses rise, ammonium nitrate's only to 4.3% (EMEP/EEA, 2023).
• <strong>Light sandy soil.</strong> Both lose: urea more ammonia (Manitoba), ammonium nitrate its nitrate with rain (Hospodarenko).
• <strong>Waterlogged soil.</strong> Nitrate is lost to denitrification (Arkansas).
• <strong>Acid soil.</strong> The acidity from a kilogram of nitrogen in either is offset by about 2 kg of lime: 1.7 kg for urea and 2.2 kg for ammonium nitrate by Hospodarenko (calculation), 1.8 kg each by Cornell; ammonium sulphate needs three times that.
• <strong>Autumn.</strong> Nitrate from fertiliser applied early washes out with autumn and winter rain (Hospodarenko). In Montana, winter wheat grain held 26% of urea nitrogen from a late-autumn application and 37% from a spring one.

Winter wheat and maize#

The NAAS Myronivka Wheat Institute (2023) sets out three top-dressings for winter wheat grown for seed and names the form of nitrogen for each.

• <strong>The first,</strong> 25-30% of the nitrogen rate, on frozen-thawed soil before growth resumes. The institute names UAN, and calls applying ammonium nitrate «traditional» for many farms; urea is then applied as a solution.
• <strong>The second,</strong> 45-60% of the rate, at the start of stem elongation: nitrogen goes on «mainly in the form of ammonium nitrate».
• <strong>The third,</strong> from heading to grain fill, foliar, with amide nitrogen, that is urea or its mixtures, for seed quality.

Maize: the NAAS Institute of Grain Crops (Steppe, 2021) considers a root-zone top-dressing of N15-20 early in growth under unstable moisture not effective enough and advises replacing it with a foliar urea feed at the 6-7 leaf stage. Rates and solution strengths are on the pages about ureaa and ammonium nitratea, and the nitrogen rate calculatora works out the nitrogen needed per hectare.

How to tell urea from ammonium nitrate#

A document tells them apart reliably. On the bag, read the name, the nitrogen content and the standard: DSTU 7312 for urea, DSTU 7370 for ammonium nitrate. For a batch, ask the seller for the manufacturer's quality certificate.

Appearance gives only a hint. Urea granules are round and semi-transparent, ammonium nitrate granules white with a yellowish or reddish tint, both 1-4 mm (Hospodarenko); fertiliser-grade ammonium nitrate ranges from colourless to grey or brown (PubChem). Ammonium nitrate cakes more easilya: bulk urea keeps without caking for about six months, and then, unlike ammonium nitrate, crusts only on top. A water test will not help: both dissolve readily.

Why the State Register will not help#

As of November 2026, neither urea nor ammonium nitrate needs state registration. The Law «On pesticides and agrochemicals», in the edition of 15.11.2024 in force on 19.10.2026, has an annex listing agrochemicals that may be imported, produced, sold, used and advertised without state registration. It includes urea, ammonium nitrate, calcium ammonium nitrate and UAN. The annex appeared in 2015 (Law No. 867-VIII).

The public file of the State Register of Pesticides and Agrochemicals of 19.10.2026 holds no valid entry for straight urea or ammonium nitrate: the last ones expired on 31.12.2025. Check other things instead: the name, nitrogen content and standard on the bag, and the batch's quality certificate. Under the law, businesses that store, apply or sell agrochemicals insure their liability (Art. 11), and enterprises keep records of them (Art. 14); this applies to both fertilisers.

Storage, and why they are not mixed#

As of November 2026 we found no separate order on storing urea; its standard sets the requirements for the store. For ammonium nitrate there is Ministry of Economy Order No. 775-21: it applies to every business storing 500 kg of ammonium nitrate or more, that is, from 20 bags of 25 kg (calculation).

• On a farm, ammonium nitrate is kept apart from hay, straw, grain, feed and other organic matter: at least 5 m away or behind an inert-material barrier at least 1.5 m wide.
• In bulk it is stored for no more than six months, in bags in the open for no more than a month, protected from rain and sun.
• Fuel, solvents, sulphur, lime, cement and other alkalis are not kept in the same store: with alkalis, ammonium nitrate releases ammonia.
• Urea and ammonium nitrate may be stored in one building if a vehicle aisle is left between the stacks.

They must not be mixed, for example in one spreader hopper (Hospodarenko, Table 3.8): the mixture becomes too hygroscopic (NUBiP Boiarka Professional College guide, 2026).

In the vegetable garden and orchard#

In the garden the logic is the same as in the field. In a cold spring ammonium nitrate acts faster, because its nitrate half is fast-acting. Urea scattered on the surface must be worked in or watered in: about 13 mm of water in one go within 24 hours, from rain or watering, mostly removes the ammonia loss (Kansas State University), while light rain can increase it (Montana). They acidify the soil about equally, about 2 kg of lime per kilogram of nitrogen (calculated from Hospodarenko). We found no trials comparing the two fertilisers on garlic, raspberries or fruit trees. There are no garden rates here: they are on the pages about ureaa and ammonium nitratea. To convert a rate per hectare to a square metre: 1 kg/ha equals 0.1 g/m², so 100 kg/ha is 10 g/m² (calculation).

Common mistakes#

• <strong>Urea on damp soil before warm, dry weather.</strong> The worst case: 20-40% of the nitrogen goes into the air.
• <strong>Counting light rain as working in.</strong> It takes about 13 mm at once within 24 hours.
• <strong>Ammonium nitrate on frozen soil before rain.</strong> In one study it lost as much to runoff as urea.
• <strong>Comparing per tonne.</strong> Compare the price per kilogram of nitrogen.
• <strong>Urea and ammonium nitrate in one hopper.</strong> The mixture quickly takes up moisture.
• <strong>Fire, heat or taste tests.</strong> Dangerous for ammonium nitrate, and the smoke of both is toxic.
• <strong>Ammonium nitrate next to hay, grain, fuel or lime.</strong> From 500 kg, Order No. 775-21 forbids it.

How we checked: on 11.11.2026 a separate check, not by the text's author, reopened every source listed below: the law and Order No. 775-21 in archived copies, the register file, the DSTU standards, the textbook, the institutes' recommendations, the loss studies and PubChem. State Statistics prices come from ADAM's copy of 07.11.2026; the lines and price tables were recalculated. The text was written and checked with the help of AI.