Nitrogen fertilisers with urease inhibitors reduce nitrous oxide and ammonia losses, while retaining yield in temperate grassland

Abstract

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Ammonium-Based Compound Fertilisers Mitigate Nitrous Oxide Emissions in Temperate Grassland

“…The basis behind stabilised urea formulation in comparison to CAN is to reduce soil NO 3 − concentrations by delaying oxidation of ammonia to nitrate, which may ultimately lead to reductions in N 2 O emissions as previously reported in a number of studies [11][12][13]18,19,32]. The current study examined four compound fertilisers with contrasting nitrate to ammonium ratios as well as CAN and urea + NBPT, and our results showed that significantly lower cumulative N 2 O emissions were associated with lower nitrate to ammonia ratios compared to high ratios under high WFPS condition.…”

“…However, the extent and timing of the N 2 O fluxes depend on fertiliser formulation and rate as well as other soil characteristics and microsite conditions, which are also known to play an important role [10]. Compared to ammonium-based, nitrate-based fertilisers are considered to produce higher N 2 O emissions due to the immediate availability of the nitrate substrate for denitrification in wet temperate grassland soils [11][12][13]. For this reason, changing from nitrate fertiliser to urea plus urease inhibitor-based fertilisers has been put forward in Ireland as an important strategy for reducing N 2 O emissions [14].…”

“…For this reason, changing from nitrate fertiliser to urea plus urease inhibitor-based fertilisers has been put forward in Ireland as an important strategy for reducing N 2 O emissions [14]. However, straight urea may lead to N loss via NH 3 volatilization, which can contribute to indirect emissions [13,15]. Relative to calcium ammonium nitrate (CAN), stabilized N fertilisers containing urease and nitrification inhibitors have recently been recommended to increase N use efficiency (NUE) and decrease N 2 O release into the atmosphere by reducing the amount of N available for soil microorganisms [12].…”

“…Soil moisture is an important factor affecting the magnitude of N 2 O emissions from fertilised soil by limiting oxygen concentrations in soil [23] and determining the extent of mineral N accumulations [24]. Several studies reported rapid and peak emissions of N 2 O when the water-filled pore space (WFPS) of the soil is greater than 60%, anaerobic soil moisture condition whereby soil NO 3 − is reduced to NO 2 − , N 2 O, and N 2 via facultative anaerobic bacteria [10,12,13].…”

Managing nitrogen to keep food production within environmental limits

“…Increasing sale shares of enhanced-efficiency fertilizers, such as fertilizers amended with N inhibitors or slow-release fertilizers could on average increase NUE while maintaining yields (Abalos et al, 2014;Chen et al, 2018;Krol et al, 2020). Mandatory targets for the fertilizer industry regarding the production, efficiency and sales of enhanced-efficiency fertilizers could thus increase NUE while avoiding high transaction costs associated with regulating millions of farmers (Kanter and Searchinger, 2018).…”