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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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Soil bulk density of different tillage treatments in 2008 (A for the early rice season and B for the late rice season).Data are means of three replications; means followed by different letters are significantly different at P<0.05. Sampling was done during the harvest of the early and late rice in 2008.
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pone-0065277-g001: Soil bulk density of different tillage treatments in 2008 (A for the early rice season and B for the late rice season).Data are means of three replications; means followed by different letters are significantly different at P<0.05. Sampling was done during the harvest of the early and late rice in 2008.

Mentions: Regardless of tillage practice, ρb increased with soil depth, but ρb increased more in NT than the other tillage treatments. Among the tillage treatments, ρb varied in the order of RT>CT>NT at 0–5 cm depth (Fig. 1), but varied in the order of NT>CT>RT at 5–10 cm depth for both the early and the late growing season. Compared with NT, ρb was lower at 5–10 cm and 10–20 cm depth under RT and CT. Figure 1 indicated that ρb under RT changed dramatically during the rice growing season, especially at 0–10 cm depth. At 0–5 cm and 5–10 cm depth, ρb under RT were higher in the early rice season than in the late rice season (0.23 vs. 0.13 g cm−3). In both the early and the late rice growing season, ρb under RT was significantly different from that under NT (Tukey HSD. early rice season: 0–5 cm, df = 8 F = 31.907 P<0.05; 5–10 cm, df = 8 F = 20.100 P<0.05; 10–20 cm, df = 8 F = 10.323 P<0.05. Late rice season: 0–5 cm, df = 8 F = 35.083 P<0.05; 5–10 cm, df = 8 F = 43.017; P<0.05; 10–20 cm df = 8 F = 8.089 P<0.05). Because of minimal soil disturbance, ρb under NT increased greatly in the deeper soil layers (Fig. 1). The significant change of ρb in RT may be due to soil disturbance and crop residue incorporation, whereas NT had the crop residue remaining on the soil surface.


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)

Soil bulk density of different tillage treatments in 2008 (A for the early rice season and B for the late rice season).Data are means of three replications; means followed by different letters are significantly different at P<0.05. Sampling was done during the harvest of the early and late rice in 2008.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0065277-g001: Soil bulk density of different tillage treatments in 2008 (A for the early rice season and B for the late rice season).Data are means of three replications; means followed by different letters are significantly different at P<0.05. Sampling was done during the harvest of the early and late rice in 2008.
Mentions: Regardless of tillage practice, ρb increased with soil depth, but ρb increased more in NT than the other tillage treatments. Among the tillage treatments, ρb varied in the order of RT>CT>NT at 0–5 cm depth (Fig. 1), but varied in the order of NT>CT>RT at 5–10 cm depth for both the early and the late growing season. Compared with NT, ρb was lower at 5–10 cm and 10–20 cm depth under RT and CT. Figure 1 indicated that ρb under RT changed dramatically during the rice growing season, especially at 0–10 cm depth. At 0–5 cm and 5–10 cm depth, ρb under RT were higher in the early rice season than in the late rice season (0.23 vs. 0.13 g cm−3). In both the early and the late rice growing season, ρb under RT was significantly different from that under NT (Tukey HSD. early rice season: 0–5 cm, df = 8 F = 31.907 P<0.05; 5–10 cm, df = 8 F = 20.100 P<0.05; 10–20 cm, df = 8 F = 10.323 P<0.05. Late rice season: 0–5 cm, df = 8 F = 35.083 P<0.05; 5–10 cm, df = 8 F = 43.017; P<0.05; 10–20 cm df = 8 F = 8.089 P<0.05). Because of minimal soil disturbance, ρb under NT increased greatly in the deeper soil layers (Fig. 1). The significant change of ρb in RT may be due to soil disturbance and crop residue incorporation, whereas NT had the crop residue remaining on the soil surface.

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