Dicyandiamide has more inhibitory activities on nitrification than thiosulfate

PLoS One. 2018 Aug 14;13(8):e0200598. doi: 10.1371/journal.pone.0200598. eCollection 2018.

Abstract

Dicyandiamide (DCD) and thiosulfates are two type of nitrification inhibitors (NIs) that have been widely used in agriculture to improve nitrogen (N) fertilizer use efficiency and mitigate negative effect of N on environment. Little information is available concerning the comparison of the efficacy of DCD and thiosulfate on N transformations in soil. The aim of this study was to compare the effects of DCD and thiosulfate (K2S2O3) on changes of NH4+-N, nitrification inhibition and N recovery in a latosolic red soil. An incubation experiment was conducted with four treatments of control (CK), N, N+DCD, and N+K2S2O3. Soil samples were collected periodically over 50 d to determine concentrations of mineral N, and the amoA gene abundance of ammonia monooxygenase (AMO) for ammonia-oxidizing bacteria (AOB) was estimated by qPCR after 10 d incubation. In the N treatment, 67.8% of the applied N as NH4+-N disappeared from the mineral N pool and only 2.7% and 30.8% of the applied N was accumulated as NO2--N and NO3--N, respectively. Addition of DCD and thiosulfate to the soil prevented NH4+-N disappearance by 63.0% and 13.6%, respectively. DCD suppressed the production of NO2--N by 97.41%, whereas thiosulfate increased accumulation of NO2--N by 14.6%. Application of N along with DCD and thiosulfate inhibited nitrification, respectively, by 72.6% and 33.1%, resulting in the delay of the nitrification process for 30 days and 10 days, respectively. Apparent N recovery in N treatment was 66.2%, which increased by 55.2% and 4.8% by DCD and thiosulfate, respectively. Numbers of AOB amoA gene copy was significantly inhibited by both DCD and thiosulfate, and the stronger inhibition induced by DCD than thiosulfate was recorded. Results indicated that both DCD and thiosulfate were effective inhibitors for NH4+-N oxidation, NO3--N production, mineral N losses and AOB growth. DCD showed a more pronounced effect on nitrification inhibition than thiosulfate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonia / chemistry*
  • Betaproteobacteria / drug effects
  • Betaproteobacteria / growth & development*
  • Guanidines / pharmacology*
  • Nitrification / drug effects*
  • Nitrogen / analysis
  • Oxidation-Reduction
  • Soil Microbiology
  • Thiosulfates / pharmacology*

Substances

  • Guanidines
  • Thiosulfates
  • Ammonia
  • dicyandiamido
  • Nitrogen

Grants and funding

This study was supported by the National Natural Science Foundation of China (No. 41271245), the Engineering Research Center for Wastewater Ecological Treatment and Water-body Remediation of Guangdong Higher Education Institutes (No. 2012gczxA1004), the Project of Science and Technology of Guangdong Province (No. 2014B020206001), Guangdong Special Fund of Applied Research and Development Project (No. 2016B020240009), the Guangdong Hydraulic Technology Innovation (No. 2015-15), and Project of Guangzhou Technological Innovation (No. 201508020073).