C and N accumulations in soil aggregates determine nitrous oxide emissions from cover crop treated rice paddy soils during fallow season

Prabhat Pramanik; Md Mozammel Haque; Sang Yoon Kim; Pil Joo Kim

doi:10.1016/j.scitotenv.2014.05.046

C and N accumulations in soil aggregates determine nitrous oxide emissions from cover crop treated rice paddy soils during fallow season

Sci Total Environ. 2014 Aug 15:490:622-8. doi: 10.1016/j.scitotenv.2014.05.046. Epub 2014 Jun 2.

Authors

Prabhat Pramanik¹, Md Mozammel Haque², Sang Yoon Kim², Pil Joo Kim³

Affiliations

¹ Division of Applied Life Science (BK 21 Program), Gyeongsang National University, Jinju 660-701, South Korea. Electronic address: prabhat2003@gmail.com.
² Division of Applied Life Science (BK 21 Program), Gyeongsang National University, Jinju 660-701, South Korea.
³ Division of Applied Life Science (BK 21 Program), Gyeongsang National University, Jinju 660-701, South Korea. Electronic address: pjkim@gnu.ac.kr.

PMID: 24880551
DOI: 10.1016/j.scitotenv.2014.05.046

Abstract

Combination of leguminous and non-leguminous plant residues are preferably applied in rice paddy soils to increase the rate of organic matter mineralization and to improve plant growth. However, organic matter addition facilitates methane (CH4) emission from rice paddy soil. Mineralization of organic nitrogen (N) increases NO3-N concentrations in soil, which are precursors for the formation of nitrous oxide (N2O). However, N2O is a minor greenhouse gas emitted from submerged rice field and hence is not often considered during calculation of total global warming potential (GWP) during rice cultivation. The hypothesis of this study was that fluxes of N2O emissions might be changed after removal of flooded water from rice field and the effect of cover crops on N2O emissions in the fallow season might be interesting. However, the effects of N-rich plant residues on N2O emission rates in the fallow season and its effect on annual GWP were not studied before. In this experiment, combination of barley (non-leguminous) and hairy vetch (leguminous) biomasses were applied at 9 Mg ha(-1) and 27 Mg ha(-1) rates in rice paddy soil. Cover crop application significantly increased CH4 emission flux while decreased N2O emissions during rice cultivation. The lowest N2O emission was observed in 27 Mg ha(-1) cover crop treated plots. Cover crop applications increased N contents in soil aggregates especially in smaller aggregates (<250 μm), and that proportionately increased the N2O emission potentials of these soil aggregates. Fluxes of N2O emissions in the fallow season were influenced by the N2O emission potentials of soil aggregates and followed opposite trends as those observed during rice cultivation. Therefore, it could be concluded that the doses of cover crop applications for rice cultivation should not be optimized considering only CH4, but N2O should also be considered especially for fallow season to calculate total GWP.

Keywords: Cover crops; Global warming potentials; Methane; Nitrous oxide; Soil aggregates.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants / analysis*
Carbon / analysis*
Crops, Agricultural / growth & development*
Environmental Monitoring*
Nitrogen / analysis*
Nitrous Oxide / analysis*
Oryza / growth & development*
Soil / chemistry*

Substances

Air Pollutants
Soil
Carbon
Nitrous Oxide
Nitrogen