Research ArticleAGRICULTURE

Acclimation of methane emissions from rice paddy fields to straw addition

See allHide authors and affiliations

Science Advances  16 Jan 2019:
Vol. 5, no. 1, eaau9038
DOI: 10.1126/sciadv.aau9038
  • Fig. 1 CH4 emissions from two rice cropping systems, as affected by straw incorporation and experimental duration.

    Results are shown for field experiments in a double rice system (A) and a middle rice system (B), and for a pot experiment (C) and an incubation experiment (D) using soils from both systems. −S, no straw incorporation in the field; +S, straw incorporation in the field; −S−S, no straw addition to −S soils; −S+S, straw addition to −S soils; +S+S, straw addition to +S soils. “*” and “**” denote significant effects of straw addition within the year at P < 0.05 and P < 0.01, respectively. Different characters represent significant differences (P < 0.05). Error bars represent SD (n = 3).

  • Fig. 2 Results of a meta-analysis on the effect of straw incorporation on CH4 emissions and rice growth in short-term (≤5 years) and long-term (>5 years) experiments.

    Results for CH4 emissions (A); results for rice growth (B). The total number of observations included in each category is displayed in parentheses. Error bars indicate 95% confidence intervals.

  • Fig. 3 The abundance of methanogens and methanotrophs as affected by straw incorporation.

    Results are from a pot experiment on soils of a double rice (A and C) and a middle rice system (B and D). −S−S, no straw addition to −S soils; −S+S, straw addition to −S soils; +S+S, straw addition to +S soils. Different characters represent significant differences (P < 0.05). Error bars represent SD (n = 3).

  • Fig. 4 Aboveground biomass and root biomass as affected by straw incorporation.

    Aboveground biomass in a double rice system (A) and a middle rice system (B). –S, no straw incorporation; +S, straw incorporation. “**” denotes significant effects of straw addition within the year at P < 0.01. Root biomass (C) and aboveground biomass (D) in a pot experiment. –S–S, no straw addition to –S soils in pots; –S+S, straw addition to –S soils in pots; +S+S, straw addition to +S soils in pots. Different characters represent significant differences within rice system (P < 0.05). Error bars in all panels represent SD (n = 3).

  • Fig. 5 Comparison between observed effects of straw incorporation on CH4 emissions from rice paddies and IPCC estimates.

    Both the observed effects and IPCC estimates are plotted against experimental duration. Results are based on 94 observations; observations from our field experiments are indicated by black circles. IPCC estimates are based on 94 matching observations of straw incorporation rates. “**” denotes significance at P < 0.01.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/1/eaau9038/DC1

    Supplementary Text

    Fig. S1. CH4 emissions from two rice cropping systems, as affected by straw incorporation and experimental duration.

    Fig. S2. Daily average air temperature during the rice growing season.

    Fig. S3. CH4 emissions from two rice cropping systems, as affected by straw incorporation.

    Fig. S4. CH4 emissions from two rice cropping systems, as affected by straw incorporation.

    Fig. S5. Model-averaged importance of the predictors of the straw addition effect on CH4 emissions and rice growth.

    Fig. S6. The correlation between straw incorporation rate and experimental duration for studies included in our meta-analysis.

    Table S1. Soil properties in two rice cropping systems, as affected by 12 years of straw incorporation.

    Table S2. Overview of the straw incorporation studies included in our meta-analysis.

    Dataset S1. Overview of all experimental observations from straw incorporation experiments that were used for the meta-analysis on CH4 emissions and rice plant growth.

    References (4063)

  • Supplementary Materials

    The PDF file includes:

    • Supplementary Text
    • Fig. S1. CH4 emissions from two rice cropping systems, as affected by straw incorporation and experimental duration.
    • Fig. S2. Daily average air temperature during the rice growing season.
    • Fig. S3. CH4 emissions from two rice cropping systems, as affected by straw incorporation.
    • Fig. S4. CH4 emissions from two rice cropping systems, as affected by straw incorporation.
    • Fig. S5. Model-averaged importance of the predictors of the straw addition effect on CH4 emissions and rice growth.
    • Fig. S6. The correlation between straw incorporation rate and experimental duration for studies included in our meta-analysis.
    • Table S1. Soil properties in two rice cropping systems, as affected by 12 years of straw incorporation.
    • Table S2. Overview of the straw incorporation studies included in our meta-analysis.
    • References (4063)

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • Dataset S1 (Microsoft Excel format). Overview of all experimental observations from straw incorporation experiments that were used for the meta-analysis on CH4 emissions and rice plant growth.

    Files in this Data Supplement:

Stay Connected to Science Advances

Navigate This Article