The effect of nitrification inhibitors on soil ammonia emissions in nitrogen managed soils: a meta-analysis
Nitrification inhibitors (NI) retain nitrogen (N) in the ammonium (NH4 +) form longer in soil providing more time for plant uptake of NH4 +. They can also reduce production of the greenhouse gas nitrous oxide (N2O) by inhibiting nitrification and subsequent denitrification processes. However, this extended retention of N in the NH4 + form in the soils treated with NI can increase ammonia (NH3) emission. Studies conducted so far provide conflicting results on the effect of NI treatment on NH3 emissions. Here we have collated results available to date from peer-reviewed literature (46 data set from 21 studies from 1970 to 2010) and categorized the reported results into three groups—increase, no change, and decrease in % applied N lost as NH3 (hereafter NH3 loss) in NI treatments. Significant increase in NH3 loss in NI treatment was observed in both pasture and cropping soils and from both applied urine and urea with NI (e.g., dicyandiamide (DCD), ATC [4-amino- 1.2,4-triazole]). This increase in NH3 loss was between 0.3 and 25.0 % (n = 26, mean 6.7 ± standard error 1.3 %). No change in NH3 loss with DCD was also observed in some soils (n = 14), while a small number of studies reported a decrease which was between −0.3 and −4.1 % (n = 6, −1.3 ± 0.6 %). Overall, the soils with higher pH and lower cation exchange capacity (CEC) lost more NH3 with NIs irrespective of land use and type of N input. The combined addition of both NI and urease inhibitor reduced NH3 loss compared to sole NI application (n = 4, −5.9 ± 1.3 %). Collectively, the analysed results from the small number of available data sets reported suggest that NH3 loss significantly increases with NI application, depending on soil properties such as soil pH and CEC. More studies are needed both to quantitatively determine the effect of NIs on NH3 loss and to mitigate the loss.
KeywordsNitrification inhibitor Ammonia emission Nitrous oxide emission Urease inhibitor Soil pH Soil cation exchange capacity
We are grateful to Johannes Laubach, Donna Giltrap for constructive and valuable comments, and Anne Austin for editing and New Zealand Ministry for Science and Innovation for funding.
- Forster P, Ramaswamy V, Artaxo P, Berntsen T, Betts R, Fahey DW, Haywood J, Lean J, Lowe DC, Myhre G, Nganga J, Prinn R, Raga G, Schulz M, Van Dorland R (2007) Changes in atmospheric constituents and in radiative forcing. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Climate Change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, CambridgeGoogle Scholar
- Francis DD, Vigil MF, Moiser AR (2008) Gaseous losses of nitrogen other than through denitrification. In: Schepers JS, Raun WR (eds) Nitrogen in agricultural systems. Agronomy monograph 49. American Society of Agronomy Madison, WI, USA, pp 255–279Google Scholar
- Hargrove W (1988) Evaluation of ammonia volatilization in the field. J Prod Agric 1:104–111Google Scholar
- Hauck RD, Bremner JM (1969) Significance of the nitrification reaction in nitrogen balances, biology and ecology of nitrogen. National Academy of Sciences, Washington, DC, pp 31–39Google Scholar
- IPCC—Intergovernmental Panel on Climate Change (2006) Guidelines for national greenhouse gas inventories. Available at http://www.ipcc-nggip.iges.or.jp/public/2006gl/index.html [verified 16 Dec 2011]. Geneva, Switzerland
- Nelson DW (1982) Gaseous losses of nitrogen other than through denitrification. In: Stevenson FJ (ed) Nitrogen in Agricultural Soils. American Society of Agronomy, Madison, WI, USA, pp 327–363Google Scholar
- Saggar S, Luo J, Giltrap DL, Maddena M (2009) Nitrous oxide emission from temperate grasslands: process, measurements, modelling and mitigation. In: Sheldon AI, Barnhart EP (eds) Nitrous oxide emissions research progress. Nova Science Publisher, New York, pp 1–66Google Scholar
- Singh J, Bolan NS, Saggar S, Zaman M (2008) The role of inhibitors in controlling the bioavailability and losses of nitrogen. In: Naidu R, Bolan NS, Megharaj M, Juhasz A, Gupta S, Clothier B, Schulin R (eds) Chemical bioavailability in terrestrial environment. Elsevier, Amsterdam, pp 329–362CrossRefGoogle Scholar
- Zaman M, Blennerhassett JD (2010) Effects of the different rates of urease and nitrification inhibitors on gaseous emissions of ammonia and nitrous oxide, nitrate leaching and pasture production from urine patches in an intensive grazed pasture system. Agric Ecosyst Environ 136:236–246CrossRefGoogle Scholar