Journal article

Dissimilatory nitrate reduction to ammonium dominates nitrate reduction in long-term low nitrogen fertilized rice paddies

Arjun Pandey, Helen Suter, Jim He, Hangwei Hu, Deli Chen

Soil Biology and Biochemistry | Elsevier Ltd | Published : 2019

Abstract

Dissimilatory nitrate reduction to ammonium (DNRA) and diazotrophic N2 fixation contribute to nitrogen (N) supply in rice paddies, whereas denitrification contributes to N loss. Continuous N fertilization in rice paddies is known to increase denitrification and reduce N2 fixation, however little is known about its effect on DNRA and the NO3− partitioning between DNRA and denitrification. Here, we investigated the rates of DNRA, denitrification and N2 fixation, and their relevant microbial gene abundances, in long-term high and low N fertilized rice paddies using a 15NO3− tracer, an acetylene reduction assay and quantitative PCR analysis, in laboratory incubation studies. We observed that DNR..

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Grants

Awarded by ACIAR


Awarded by ARC


Funding Acknowledgements

This research was funded by ACIAR (Grant No. SMCN/2014/044) and ARC (Grant No. DP160101028). We acknowledge the Melbourne Trace Analysis for Chemical, Earth and Environmental Sciences (TrACEES), The University of Melbourne for analytical support. We gratefully thank Grahame Hunter, Soe Thura (both from International Fertilizer Development Center, Myanmar), Aung Myo Thant and Aung Kyaw Myint (both from Yezin Agricultural University, Myanmar) for their technical and logistic support.