Effects of Integrated Rice-Frog Farming on Paddy Field Greenhouse Gas Emissions

Kaikai Fang; Xiaomei Yi; Wei Dai; Hui Gao; Linkui Cao

doi:10.3390/ijerph16111930

Effects of Integrated Rice-Frog Farming on Paddy Field Greenhouse Gas Emissions

Int J Environ Res Public Health. 2019 May 31;16(11):1930. doi: 10.3390/ijerph16111930.

Authors

Kaikai Fang¹, Xiaomei Yi², Wei Dai³, Hui Gao⁴, Linkui Cao⁵

Affiliations

¹ School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. fangkaikai@sjtu.edu.cn.
² School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. yixiaomei@sjtu.edu.cn.
³ School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. dw0728@sjtu.edu.cn.
⁴ School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. hgao13@sjtu.edu.cn.
⁵ School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China. clk@sjtu.edu.cn.

Abstract

Integrated rice-frog farming (IRFF), as a mode of ecological farming, is fundamental in realizing sustainable development in agriculture. Yet its production of greenhouse gas (GHG) emissions remains unclear. Here, a randomized plot field experiment was performed to study the GHG emissions for various farming systems during the rice growing season. The farming systems included: conventional farming (CF), green integrated rice-frog farming (GIRF), and organic integrated rice-frog farming (OIRF). Results indicate that the cumulative methane (CH₄) emissions from the whole growth period were divergent for the three farming systems, with OIRF having the highest value and CF having the lowest. For nitrous oxide (N₂O) emissions, the order is reversed. IRFF significantly increased the dissolved oxygen (DO), soil redox potential (Eh), total organic carbon (TOC) content, and soil C:N ratio, which is closely related to GHG emissions in rice fields. Additionally, the average emissions of carbon dioxide (CO₂) from soils during rice growing seasons ranged from 2312.27 to 2589.62 kg ha^-1 and showed no significant difference in the three treatments. Rice yield in the GIRF and OIRF were lower (2.0% and 16.7%) than the control. The CH₄ emissions contributed to 83.0-96.8% of global warming potential (GWP). Compared to CF, the treatment of GIRF and OIRF increased the GWP by 41.3% and 98.2% during the whole growing period of rice, respectively. IRFF significantly increased greenhouse gas intensity (GHGI, 0.79 kg CO₂-eq ha^-1 grain yield), by 91.1% over the control. Compared to the OIRF, GIRF decreased the GHGI by approximately 39.4% (0.59 kg CO₂-eq ha^-1 grain yield), which was 44.2% higher than that of the control. The results of structural equation model showed that the contribution of fertilization to CH₄ emissions in paddy fields was much greater than that of frog activity. Moreover, frog activity could decrease GWP by reducing CH₄ emissions from rice fields. And while GIRF showed a slight increase in GHG emissions, it could still be considered as a good strategy for providing an environmentally-friendly option in maintaining crop yield in paddy fields.

Keywords: fertilization; global warming potential; integrated rice-frog farming; methane; nitrous oxide; structural equation model.

Publication types

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

MeSH terms

Agriculture / methods*
Animals
Anura*
Carbon Dioxide / analysis
Greenhouse Gases / analysis*
Methane / analysis
Nitrous Oxide / analysis
Oryza*
Random Allocation
Seasons
Soil / chemistry

Substances

Greenhouse Gases
Soil
Carbon Dioxide
Nitrous Oxide
Methane