Urease and Nitrification Inhibitors—As Mitigation Tools for Greenhouse Gas Emissions in Sustainable Dairy Systems: A Review

Abstract

Currently, nitrogen fertilizers are utilized to meet 48% of the total global food demand. The demand for nitrogen fertilizers is expected to grow as global populations continue to rise. The use of nitrogen fertilizers is associated with many negative environmental impacts and is a key source of greenhouse and harmful gas emissions. In recent years, urease and nitrification inhibitors have emerged as mitigation tools that are presently utilized in agriculture to prevent nitrogen losses and reduce greenhouse and harmful gas emissions that are associated with the use of nitrogen-based fertilizers. Both classes of inhibitor work by different mechanisms and have different physiochemical properties. Consequently, each class must be evaluated on its own merits. Although there are many benefits associated with the use of these inhibitors, little is known about their potential to enter the food chain, an event that may pose challenges to food safety. This phenomenon was highlighted when the nitrification inhibitor dicyandiamide was found as a residual contaminant in milk products in 2013. This comprehensive review aims to discuss the uses of inhibitor technologies in agriculture and their possible impacts on dairy product safety and quality, highlighting areas of concern with regards to the introduction of these inhibitor technologies into the dairy supply chain. Furthermore, this review discusses the benefits and challenges of inhibitor usage with a focus on EU regulations, as well as associated health concerns, chemical behavior, and analytical detection methods for these compounds within milk and environmental matrices.

Smart fertilizers: What should we mean and where should we go?

“…Their use showed many benefits for what concerns inhibitors, although little is known about their potential to enter the food chain (Byrne et al, 2020), even if this phenomenon has been already…”

“…The authors also reported that both in planta toxicity assays and V. fischeri bioluminescence inhibition test only showed detrimental effects at very high doses, which are nearly impossible to be found in agricultural conditions. Also, for NBPT urease inhibitor, a plant uptake in maize, pea, and spinach has been observed (Cruchaga et al, 2011;Zanin et al, 2015), with potential inhibition of leaf and root urease activity (Byrne et al, 2020). In this context, the challenge is to find eco-friendly, non-toxic, and low toxicity for plants and chemically stable inhibitors, efficient at low concentrations, compatible with urea fertilizers, and having sustainable costs.…”

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

“…This indicates that ammonium-based compound fertilisers could potentially be a similar mitigation measure to the use of urea + NBPT to reduce N 2 O emissions from temperate grassland. The addition of inhibitors incurs extra costs and there are issues around acceptability from farmers and milk processors due to perceptions around residues [20,33]. However, a recent study investigating the potential for residues observed no residue issues associated with the use of NBPT with urea [34].…”

Development of One-Step Non-Solvent Extraction and Sensitive UHPLC-MS/MS Method for Assessment of N-(n-Butyl) Thiophosphoric Triamide (NBPT) and N-(n-Butyl) Phosphoric Triamide (NBPTo) in Milk

“…In Ireland, the use of urea with NBPT is encouraged as a mitigation measure to reduce both ammonia and nitrous oxide emissions [ 2 ]. In 2005, it was reported that 54% of non-CO 2 greenhouse gas emissions were produced by agriculture [ 3 , 4 ]. Studies have also shown that NBPT enables efficient utilisation of urea by delaying urea hydrolysis, making N available to crops/plants, thereby enhancing agricultural yield and profitability but reducing ammonia losses.…”