Evaluation of potassium thiosulfate as a nitrification inhibitor to reduce nitrous oxide emissions

Zejiang Cai; Suduan Gao; Minggang Xu; Bradley D Hanson

doi:10.1016/j.scitotenv.2017.10.274

Evaluation of potassium thiosulfate as a nitrification inhibitor to reduce nitrous oxide emissions

Sci Total Environ. 2018 Mar 15:618:243-249. doi: 10.1016/j.scitotenv.2017.10.274. Epub 2017 Nov 10.

Authors

Zejiang Cai¹, Suduan Gao², Minggang Xu³, Bradley D Hanson⁴

Affiliations

¹ National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Qiyang Agro-ecosystem of National Field Experimental Station, Hunan 426182, China. Electronic address: caizejiang@caas.cn.
² USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA 93648-9757, USA.
³ National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Qiyang Agro-ecosystem of National Field Experimental Station, Hunan 426182, China.
⁴ Department of Plant Sciences, University of California, Davis, CA 95616-5270, USA.

PMID: 29128773
DOI: 10.1016/j.scitotenv.2017.10.274

Abstract

Potassium thiosulfate (KTS, K₂S₂O₃) has been shown to function as a nitrification inhibitor, thus has the potential to reduce nitrous oxide (N₂O) emissions and play an important role in effective N management. The objective of this research was to determine the potential effects of KTS on N₂O emissions and N transformation processes in comparison with commercial N transformation inhibitors (stabilizers). A laboratory incubation experiment was conducted using urea and ammonium nitrate (UAN) applied at 150mgNkg^-1 in a Hanford sandy loam soil (coarse-loamy, mixed, superactive, nonacid, thermic Typic Xerorthents). Treatments included three rates of KTS (26, 51, and 102mgS₂O₃^2--Skg^-1), a urease and nitrification inhibitor (Agrotain® Plus), a nitrification inhibitor (N-Serve® 24), and an untreated control. Nitrous oxide emission, soil pH, and mineral N species were monitored for 35days. Total N₂O emissions were reduced significantly by all KTS treatments as a function of KTS rate. At 102mgS₂O₃^2--Skg^-1, KTS reduced N₂O emissions by 48% (0.18% of total inorganic N), which was statistically similar to the N-Serve® 24 treatment (60% reduction) although lower than Agrotain® Plus (78% reduction). The KTS resulted in significantly less unaccounted (total N) loss compared to the commercial inhibitors. If the N₂O emissions reductions observed in this laboratory study are validated in the field, using KTS for this purpose can also provide a fertility benefit and may reduce total chemical inputs into agronomic systems. Future research needs to determine the effectiveness of thiosulfate for improving overall nutrient management while reducing N₂O emissions under field conditions.

Keywords: Greenhouse gases; Nitrifier denitrification; Nitrite; Nitrogen management; Nitrogen transformation inhibitors; Soil pH.