Intensive Rain Hampers the Effectiveness of Nitrification Inhibition in Controlling N2O Emissions from Dairy Slurry-Fertilized Soils

Jordi Escuer-Gatius,Hanna Vahter,Alar Astover,Karin Kauer,Ülo Mander,Kaido Soosaar,Merrit Shanskiy

doi:10.3390/agriculture10110497

Jordi Escuer-Gatius, Hanna Vahter + Show 5 more

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https://doi.org/10.3390/agriculture10110497

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Abstract

Nitrification inhibitors have been proposed as a tool to mitigate nitrous oxide (N2O) emissions from agriculture, which are caused mainly by fertilization. The nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) was tested in a winter rapeseed field after dairy slurry application in Central Estonia. N2O emissions were monitored using the closed chamber method. Soil and leachate chemical parameters were also analyzed. N2O emissions increased from pre-slurry application values of 316 and 264 µg m−2 h−1 for the control and treatment plot, respectively, to maximum values of 3130.71 and 4834 µg m−2 h−1, with cumulative emissions during the study period of 12.30 kg ha−1 for the control plot and 17.70 kg ha−1 for the treatment plot. The intense precipitation period that began with the application of the slurry resulted in changes in soil moisture and water-filled pore space (WFPS), modifying the nitrification/denitrification balance. Positive significant correlations (p = 0.016 and p = 0.037, for the control and treatment plot, respectively) were found between N2O fluxes and WFPS. Future studies should consider the role of nitrifier and denitrifier communities in order to better assess in-field nitrification inhibitor effectiveness.

Highlights

Climate change is one of the most pressing environmental issues of our time
Nitrification is the aerobic oxidation of ammonia or ammonium into nitrates, and it is divided into two steps: the first is the oxidation of ammonium to nitrites, and the second is the oxidation of nitrites to nitrates
A delay in the effectiveness of Dimethylpyrazole phosphate (DMPP) is not universal, it could be sometimes masked by an insufficient sampling frequency during the first days after application

Summary

Introduction

N2 O only accounts for approximately 6% of total annual anthropogenic GHG emissions, while carbon dioxide (CO2 ) represents 76%, N2 O has a global warming potential 265 times (over 100 year period) that of CO2 [2]. It currently constitutes the most important ozone-depleting substance [3]. N2 O emissions from the soil are the product of three main processes: nitrification, denitrification, and nitrifier denitrification [6,7,8,9,10,11]. Nitrification is carried out by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) [12].

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