Strong mitigation of net global warming potential (GWP) via short-term aerobic pre-digestion of green manured soil in rice paddy

2020 ◽  
Author(s):  
Hyeonji Song ◽  
Jin Ho Lee ◽  
Songrae Cho ◽  
Hogyeong Chae ◽  
Pil Joo Kim
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Cover Crop ◽  
Short Term ◽  
Input And Output ◽  
Cropping Season ◽  
Aerobic Decomposition ◽  
Soc Stock ◽  
Stock Change ◽  
Net Global Warming Potential

<p> Cover crop cultivation is strongly recommended during fallow season to increase soil organic carbon (SOC) stock. However, since its biomass recycling as green manure can dramatically increase greenhouse gas (GHG) emission, in particular, methane (CH<sub>4</sub>) during rice cropping season, smart cover crop management strategy should be developed. In our previous research, CH<sub>4</sub> emission during cropping season was dramatically reduced via short-term aerobic decomposition before irrigation (Lee et al.). However, due to a fast response rate of aerobic decomposition, the effect of mitigating CH<sub>4</sub> emission could be offset by SOC depletion which results in accelerating global warming. To evaluate the comprehensive impact of the short-term aerobic decomposition on global warming, net global warming potential (GWP), defined as the difference between GWP and SOC stock change was employed. SOC stock change was estimated using net ecosystem carbon budget (NECB), a balance between soil C input and output. The mixture of barley and hairy vetch cultivated during the dried fallow season, and then its whole biomass was incorporated 0-30 days before irrigation for rice transplanting. The aerobic decomposition of cover crop biomass significantly reduced CH<sub>4</sub> emission by 24-85% over control but negligibly influences N<sub>2</sub>O emission. Total C input and output were unaffected by the aerobic digestion. Although carbon emission before flooding dramatically increased after biomass application in aerobic decomposition treatments, the mineralized C losses exhibited no differences among treatments. Based on these results, NECB values were similar in all treatments. This implies the aerobic decomposition did not stimulate SOC depletion, compared to the control. Finally, the net GWP highly decreased by 30-86% by the aerobic digestion due to the significant reduction of CH<sub>4</sub> emission. In conclusion, earlier application of cover crops before irrigation is a smart strategy to decrease methane emission, maintaining soil carbon sequestration effect of cover crop biomasses application.</p>

scholarly journals Net global warming potential and greenhouse gas intensity in rice agriculture driven by high yields and nitrogen use efficiency: a 5 year field study

2015 ◽  
Vol 12 (22) ◽  
pp. 18883-18911 ◽  
Author(s):  
X. Zhang ◽  
Z. Zhou ◽  
Y. Liu ◽  
X. Xu ◽  
J. Wang ◽  
...  
Keyword(s):  
Global Warming ◽  
Food Security ◽  
Nitrogen Use Efficiency ◽  
Global Warming Potential ◽  
Rice Agriculture ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
Greenhouse Gas Intensity ◽  
High Yields ◽  
Net Global Warming Potential

Abstract. Our understanding of how net global warming potential (NGWP) and greenhouse gas intensity (GHGI) is affected by management practices aimed at food security with respect to rice agriculture remains limited. In the present study, a 5 year field experiment was conducted in China to evaluate the effects of integrated soil-crop system management (ISSM) on NGWP and GHGI after accounting for carbon dioxide (CO2) emissions from all sources (methane, CH4, and nitrous oxide, N2O, emissions, agrochemical inputs, Ei, and farm operations, Eo) and sinks (i.e., soil organic carbon, SOC, sequestration). For the improvement of rice yield and agronomic nitrogen use efficiency (NUE), four ISSM scenarios consisting of different nitrogen (N) fertilization rates relative to the local farmers' practice (FP) rate were carried out, namely, N1 (25 % reduction), N2 (10 % reduction), N3 (FP rate) and N4 (25 % increase). The results showed that compared with the FP, the four ISSM scenarios, i.e., N1, N2, N3 and N4, significantly increased the rice yields by 10, 16, 28 and 41 % and the agronomic NUE by 75, 67, 86 and 82 %, respectively. In addition, compared with the FP, the N1 and N2 scenarios significantly reduced the GHGI by 14 and 18 %, respectively, despite similar NGWPs. The N3 and N4 scenarios remarkably increased the NGWP and GHGI by an average of 67 and 36 %, respectively. In conclusion, the ISSM strategies are promising for both food security and environmental protection, and the ISSM scenario of N2 is the optimal strategy to realize high yields and high NUE together with low environmental impacts for this agricultural rice field.

Effect of cover cropping on the net global warming potential of rice paddy soil

Geoderma ◽  
2017 ◽  
Vol 292 ◽  
pp. 49-58 ◽  
Author(s):  
Hyun Young Hwang ◽  
Gil Won Kim ◽  
Sang Yoon Kim ◽  
Md. Mozammel Haque ◽  
Muhammad Israr Khan ◽  
...  
Keyword(s):  
Global Warming ◽  
Paddy Soil ◽  
Global Warming Potential ◽  
Rice Paddy ◽  
Rice Paddy Soil ◽  
Cover Cropping ◽  
Net Global Warming Potential

scholarly journals Technical note: On comparing greenhouse gas emission metrics

2021 ◽  
Vol 21 (6) ◽  
pp. 4699-4708
Author(s):  
Ian Enting ◽  
Nathan Clisby
Keyword(s):  
Global Warming ◽  
Greenhouse Gas ◽  
Global Warming Potential ◽  
Radiative Forcing ◽  
Greenhouse Gas Emission ◽  
Technical Note ◽  
Short Term ◽  
Rates Of Change

Abstract. Many metrics for comparing greenhouse gas emissions can be expressed as an instantaneous global warming potential multiplied by the ratio of airborne fractions calculated in various ways. The forcing equivalent index (FEI) provides a specification for equal radiative forcing at all times at the expense of generally precluding point-by-point equivalence over time. The FEI can be expressed in terms of asymptotic airborne fractions for exponentially growing emissions. This provides a reference against which other metrics can be compared. Four other equivalence metrics are evaluated in terms of how closely they match the timescale dependence of FEI, with methane referenced to carbon dioxide used as an example. The 100-year global warming potential overestimates the long-term role of methane, while metrics based on rates of change overestimate the short-term contribution. A recently proposed metric based on differences between methane emissions 20 years apart provides a good compromise. Analysis of the timescale dependence of metrics expressed as Laplace transforms leads to an alternative metric that gives closer agreement with FEI at the expense of considering methane over longer time periods. The short-term behaviour, which is important when metrics are used for emissions trading, is illustrated with simple examples for the four metrics.

Sign in / Sign up

Export Citation Format

Share Document