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Emissions of CH4 and N2O under different tillage systems from double-cropped paddy fields in Southern China.

Zhang HL, Bai XL, Xue JF, Chen ZD, Tang HM, Chen F - PLoS ONE (2013)

Bottom Line: Compared with other treatments, NT significantly reduced CH4 emission among the rice growing seasons (P<0.05).Conversion of CT to NT significantly reduced the cumulative CH4 emission for both rice seasons compared with other treatments (P<0.05).The mean value of global warming potentials (GWPs) of CH4 and N2O emissions over 100 years was in the order of NT<RT<CT, which indicated NT was significantly lower than both CT and RT (P<0.05).

View Article: PubMed Central - PubMed

Affiliation: College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China. hailin@cau.edu.cn

ABSTRACT
Understanding greenhouse gases (GHG) emissions is becoming increasingly important with the climate change. Most previous studies have focused on the assessment of soil organic carbon (SOC) sequestration potential and GHG emissions from agriculture. However, specific experiments assessing tillage impacts on GHG emission from double-cropped paddy fields in Southern China are relatively scarce. Therefore, the objective of this study was to assess the effects of tillage systems on methane (CH4) and nitrous oxide (N2O) emission in a double rice (Oryza sativa L.) cropping system. The experiment was established in 2005 in Hunan Province, China. Three tillage treatments were laid out in a randomized complete block design: conventional tillage (CT), rotary tillage (RT) and no-till (NT). Fluxes of CH4 from different tillage treatments followed a similar trend during the two years, with a single peak emission for the early rice season and a double peak emission for the late rice season. Compared with other treatments, NT significantly reduced CH4 emission among the rice growing seasons (P<0.05). However, much higher variations in N2O emission were observed across the rice growing seasons due to the vulnerability of N2O to external influences. The amount of CH4 emission in paddy fields was much higher relative to N2O emission. Conversion of CT to NT significantly reduced the cumulative CH4 emission for both rice seasons compared with other treatments (P<0.05). The mean value of global warming potentials (GWPs) of CH4 and N2O emissions over 100 years was in the order of NT

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CH4 flux under different tillage during the rice growing seasons (A, B for the early rice season and the late rice season in 2007; C, D for the early rice season and the late rice season in 2008, respectively).Vertical bars represent standard errors of the mean (n = 3).The arrows in the figures indicate the time of field operation.
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pone-0065277-g003: CH4 flux under different tillage during the rice growing seasons (A, B for the early rice season and the late rice season in 2007; C, D for the early rice season and the late rice season in 2008, respectively).Vertical bars represent standard errors of the mean (n = 3).The arrows in the figures indicate the time of field operation.

Mentions: For the early rice season, paddy soil was the atmospheric source of CH4 under all treatments in both years. The flux of CH4 showed a single peak pattern characterized by three stages (Fig. 3−a, b). The first stage was the increasing stage of CH4 emission. The flux of CH4 showed a continuous increase under all the treatments and attained the highest fluxes during the aeration stage. The CH4 emissions from both CT and RT displayed similar trends and were higher than that from NT (Fig. 3−a, b). The second stage was the decreasing stage of CH4 emission. The flux of CH4 decreased rapidly from the aeration stage to the flooding stage during the early rice season. The emission fluxes in 2007 and 2008 were in the same order of RT>CT>NT and significant differences among the treatments were observed in 2008 (P<0.05). The third stage was characterized by stable CH4 emission. The flux of CH4 remained at a low level and tended to be stable from the flooding stage to the harvest stage. In 2008, the cumulative emissions were 228.3, 276.3 and 188.1 kg ha−1 for CT, RT and NT, respectively and were 17.9%, −1.7% and 16.2% lower in 2007, respectively. The difference between 2007 and 2008 was possibly due to weather differences.


Emissions of CH4 and N2O under different tillage systems from double-cropped paddy fields in Southern China.

Zhang HL, Bai XL, Xue JF, Chen ZD, Tang HM, Chen F - PLoS ONE (2013)

CH4 flux under different tillage during the rice growing seasons (A, B for the early rice season and the late rice season in 2007; C, D for the early rice season and the late rice season in 2008, respectively).Vertical bars represent standard errors of the mean (n = 3).The arrows in the figures indicate the time of field operation.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672096&req=5

pone-0065277-g003: CH4 flux under different tillage during the rice growing seasons (A, B for the early rice season and the late rice season in 2007; C, D for the early rice season and the late rice season in 2008, respectively).Vertical bars represent standard errors of the mean (n = 3).The arrows in the figures indicate the time of field operation.
Mentions: For the early rice season, paddy soil was the atmospheric source of CH4 under all treatments in both years. The flux of CH4 showed a single peak pattern characterized by three stages (Fig. 3−a, b). The first stage was the increasing stage of CH4 emission. The flux of CH4 showed a continuous increase under all the treatments and attained the highest fluxes during the aeration stage. The CH4 emissions from both CT and RT displayed similar trends and were higher than that from NT (Fig. 3−a, b). The second stage was the decreasing stage of CH4 emission. The flux of CH4 decreased rapidly from the aeration stage to the flooding stage during the early rice season. The emission fluxes in 2007 and 2008 were in the same order of RT>CT>NT and significant differences among the treatments were observed in 2008 (P<0.05). The third stage was characterized by stable CH4 emission. The flux of CH4 remained at a low level and tended to be stable from the flooding stage to the harvest stage. In 2008, the cumulative emissions were 228.3, 276.3 and 188.1 kg ha−1 for CT, RT and NT, respectively and were 17.9%, −1.7% and 16.2% lower in 2007, respectively. The difference between 2007 and 2008 was possibly due to weather differences.

Bottom Line: Compared with other treatments, NT significantly reduced CH4 emission among the rice growing seasons (P<0.05).Conversion of CT to NT significantly reduced the cumulative CH4 emission for both rice seasons compared with other treatments (P<0.05).The mean value of global warming potentials (GWPs) of CH4 and N2O emissions over 100 years was in the order of NT<RT<CT, which indicated NT was significantly lower than both CT and RT (P<0.05).

View Article: PubMed Central - PubMed

Affiliation: College of Agronomy and Biotechnology, China Agricultural University, Key Laboratory of Farming System, Ministry of Agriculture, Beijing, China. hailin@cau.edu.cn

ABSTRACT
Understanding greenhouse gases (GHG) emissions is becoming increasingly important with the climate change. Most previous studies have focused on the assessment of soil organic carbon (SOC) sequestration potential and GHG emissions from agriculture. However, specific experiments assessing tillage impacts on GHG emission from double-cropped paddy fields in Southern China are relatively scarce. Therefore, the objective of this study was to assess the effects of tillage systems on methane (CH4) and nitrous oxide (N2O) emission in a double rice (Oryza sativa L.) cropping system. The experiment was established in 2005 in Hunan Province, China. Three tillage treatments were laid out in a randomized complete block design: conventional tillage (CT), rotary tillage (RT) and no-till (NT). Fluxes of CH4 from different tillage treatments followed a similar trend during the two years, with a single peak emission for the early rice season and a double peak emission for the late rice season. Compared with other treatments, NT significantly reduced CH4 emission among the rice growing seasons (P<0.05). However, much higher variations in N2O emission were observed across the rice growing seasons due to the vulnerability of N2O to external influences. The amount of CH4 emission in paddy fields was much higher relative to N2O emission. Conversion of CT to NT significantly reduced the cumulative CH4 emission for both rice seasons compared with other treatments (P<0.05). The mean value of global warming potentials (GWPs) of CH4 and N2O emissions over 100 years was in the order of NT

Show MeSH
Related in: MedlinePlus