Where substitution for nitrogen involves, an anhydrous ammonia gas with 82% nitrogen is 35% lower per unit of nitrogen than the urea type (46% nitrogen), using 2023 U.S. Corn Belt farm statistics. Application of 200 kg/ha liquid ammonia (US $120) is comparable to the manufacture of 430 kg of urea (US $185) (12.5 t/ha), but nitrogen is 75% used and 25% less lost in ammonia fertilizer than with urea (50%). Tests by the Brazilian Agricultural Research Corporation Embrapa showed that when sugarcane plantations shifted to liquid ammonia, emissions of nitrous oxide decreased from 8.2 kg/ha to 3.1 kg/ha, resulting in 62% reduction in carbon tax costs.
From the economic point of view, liquid ammonia’s volume during transportation and storage is 60% reduced in comparison with urea (density 0.68 kg/L and 0.75 kg/L), and after the usage of ammonia fertilizer by Iowa farms, transportation price per year reduces from 43,000 US dollars/thousand hectares to 17,000 US dollars. But liquid ammonia injection requires special equipment (mean cost of $50,000), and small farmers’ payback period is five years, while the government of Indian state Punjab has reduced the cost of equipment purchase to $28,000 through subsidies, and utilization rate has increased from 12% to 41% over a period of three years. As can be seen from FAO statistics, global penetration ratio for ammonia fertilizer was a mere 18% of total nitrogen fertilizer and was largely held back by infrastructure investment.
Environmentally speaking, the residual nitrate concentration of ammoniated soil is 40% less than that of ammonium nitrate (85 mg/kg vs. 142 mg/kg), yet leakage risk must be further contained – the 2022 spill of an ammonia tank in Buenos Aires, Argentina, drove the pH of the local water up to 10.2 and the mortality rate of the fish to 90%. With the use of closed injection technology (pressure of 20 bar), loss in ammonia volatilization could be reduced to 5% from 15%, but at the cost of increasing the equipment’s energy by 30% (45 kWh per day). Yara International’s slow-release coating technology doubles the fertilizer cycle from 30 days to 60 days, reduces topdressing frequency of corn planting by 50%, and reduces labour costs by 28%.
In crop suitability, the conversion efficiency of ammonia fertilizer in soil pH 6.5-7.5 was the most effective, the increase rate of wheat yield was 22% (versus 17% for urea), but the inhibitory effect of denitrification bacteria on rice paddies imposed a 12% risk on yield. Field tests in Northeast China’s black soil area showed that soil organic matter decreased by 0.3% after five successive annual applications of ammonia fertilizer, and 7.5 tons/ha of straw need to be returned to the field every year in order to keep maintaining soil fertility. In vegetable and fruit cultivation, the proportion of nitrate nitrogen in ammonia fertilizer is 58% lower compared to ammonium sulfate, and the vitamin C in tomatoes is 9% higher, but the cost of equipment conversion reduces the profitability of small greenhouse by 4.2%.
Regarding substitution limits, ammonia fertilizers do not produce phosphorus and potassium, and compound fertilizers still take up 63% of global fertilizer use. The Egyptian 2024 Nile Delta project proved that the application of ammonia fertilizer and diammonium phosphate together increased cotton yields by 11% compared to the use of compound fertilizer alone but at a combined cost that was 19% more. In harsh climates, the temperature interval for ammonia use (10-30°C) is 23% lower than that for urea (5-35°C), and the annual cost of ammonia failure events due to spring cold in Manitoba, Canada, is $4.7 million.
In the future technological path, the production cost of green ammonia (renewable energy hydrogen synthesis) has decreased from $800 / ton in 2020 to $520 / ton in 2024, and if it crosses the $400 barrier, it will be lower than traditional synthetic ammonia (average price of $450). Australia’s “Hydrogen Valley” initiative is set to produce 1 million tons annually of green ammonia in 2030 that will replace 17% of imported urea into the nation and reduce its carbon emissions by 89%. However, complete replacement with ammonia fertilizer requires a two-way input of application safety (300 ppm IDLH concentration) and equipment intelligence (automatic leak monitoring system unit cost of $12,000), and there exists merely 12% IoT sensor-enabled world ammonia fertilizer equipment.