Modeling methane emissions from irrigated rice cultivation in<scp>C</scp>hina from 1960 to 2050

Zhang, Wen; Yu, Yongqiang; Huang, Yao; Li, Tingting; Wang, Ping

doi:10.1111/j.1365-2486.2011.02495.x

Cited by 116 publications

(83 citation statements)

References 54 publications

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“…We delivered investigation papers to farmers in all the typical rice cultivation regions of China and summarized the returned data. The details of the data collection and the quality control can be found in the Supporting Information to a previously published paper (Zhang et al, 2011). The amount of farmyard manure applied in each province (Table 2) was part of the investigation's results.…”

Section: A4 Organic Matter Amendment In Rice Paddiesmentioning

confidence: 99%

“…Appendix A describes CH4MOD and the compilation of the model inputs. More detailed information regarding the model development, validation and application has been provided elsewhere by the authors (Huang et al, , 2006Zhang et al, 2011).…”

Section: Ch4mod and Input Variablesmentioning

confidence: 99%

“…Rice cultivation has been recognized as the major anthropogenic activity that accounted for the rapid increase of the atmospheric methane concentration. However, because of the high spatial heterogeneity in methane emissions from rice paddies, huge uncertainty has long been the big problem in making reliable estimations, even after complicated models were developed and applied Zhang et al, 2011;Harvey, 2000). The models used in regional or global studies differ widely in terms of their spatial scales.…”

Section: Introductionmentioning

confidence: 99%

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Uncertainties in estimating regional methane emissions from rice paddies due to data scarcity in the modeling approach

Zhang

Huang

et al. 2014

Geosci. Model Dev.

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Abstract. Rice paddies are a major anthropogenic source of the atmospheric methane. However, because of the high spatial heterogeneity, making accurate estimations of the methane emission from rice paddies is still a big challenge, even with complicated models. Data scarcity is one of the substantial causes of the uncertainties in estimating the methane emissions on regional scales. In the present study, we discussed how data scarcity affected the uncertainties in model estimations of rice paddy methane emissions, from county/provincial scale up to national scale. The uncertainties in methane emissions from the rice paddies of China was calculated with a local-scale model and the Monte Carlo simulation. The data scarcities in five of the most sensitive model variables, field irrigation, organic matter application, soil properties, rice variety and production were included in the analysis. The result showed that in each individual county, the within-cell standard deviation of methane flux, as calculated via Monte Carlo methods, was 13.5-89.3 % of the statistical mean. After spatial aggregation, the national total methane emissions were estimated at 6.44-7.32 Tg, depending on the base scale of the modeling and the reliability of the input data. And with the given data availability, the overall aggregated standard deviation was 16.3 % of the total emissions, ranging from 18.3-28.0 % for early, late and middle rice ecosystems. The 95 % confidence interval of the estimation was 4.5-8.7 Tg by assuming a gamma distribution. Improving the data availability of the model input variables is expected to reduce the uncertainties significantly, especially of those factors with high model sensitivities.

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Section: A4 Organic Matter Amendment In Rice Paddiesmentioning

confidence: 99%

Section: Ch4mod and Input Variablesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uncertainties in estimating regional methane emissions from rice paddies due to data scarcity in the modeling approach

Zhang

Huang

et al. 2014

Geosci. Model Dev.

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“…Actually, the elevated Hg levels only occur in Hg mining areas, urban soil and surrounding region of coal combustion in China, which only covers approximate 800 km 2 and account for about 1% of Chinese cultivation area. However, China is the second-largest area of rice cultivation with rice paddies of approximately 32,000 km 2 , accounting for about 20% of the world's rice-producing area and 23% of all cultivated land in terms of the total area [11]. THg and MeHg concentrations in soils from those majority of the China are lower ranging from 20-200 µg kg -1 and 0.09-0.23 µg kg -1 [12], which are comparable to or slightly higher than that in background soils worldwide which varied between 0.01-0.5 mg kg -1 [12].…”

Section: Introductionmentioning

confidence: 99%

Methylmercury accumulation in rice plants (Oryza sativa L.) In low Hg areas and the potential health - Risk exposing in extreme micro-environments

Tang¹,

Fan²,

Mao³

et al. 2017

Adv Mater Sci

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Recent studies have clearly showed that rice can be another important pathway of MeHg exposure to inhabitants in higher Hg hotspots, such as Hg mining areas in Guizhou Province, China. However, the elevated Hg levels only account for about 1% of Chinese cultivation area and the majority of rice planting areas are ranked the low Hg areas. Therefore, it is important and necessary to verify MeHg accumulation in rice in low Hg areas because rice is the stable daily food in these extensive areas. Importantly, the human health-risk assessment of Hg exposure doesn't consider the extreme values observed. Although these extreme values are fewer, it may result in critical Hg exposure for local inhabitants and may become the determinants or "drivers" of environmental decisions and policies, even though most individuals are exposed to far lower concentrations and risks. This study clearly confirmed rice has the highest ability to accumulate MeHg not only in Hg mining areas also in low Hg areas. The THg and MeHg concentrations in the rice samples collected from northeast plain rice advantage area were lower than that of Xinyang city, and significantly lower than that of reported from the rice from southern China. However, in extreme micro-environments, routine consumption of rice provides a THg and MeHg intake of 11.6 µg kg -1 and 1.8 µg kg -1 of body weight per day, respectively. The MeHg intake was 18 times of RfD of USEPA and 7.8 times of PTWI by JECFA. It clearly demonstrates that a few inhabitants, such as Gouxi and Dashui in Wanshan, are exposed to Hg and MeHg to a much serious health risk.

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“…Additionally, the seasonally flooded rice fields contribute about 5%-19% of total global methane emission, an important greenhouse gas source, to the atmosphere [2,3]. China produced about one third of the world's rice on about one fifth of the world's paddy rice land [4].…”

Section: Introductionmentioning

confidence: 99%

Rice Fields Mapping in Fragmented Area Using Multi-Temporal HJ-1A/B CCD Images

et al. 2015

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Rice is one of the most important crops in the world; meanwhile, the rice field is also an important contributor to greenhouse gas methane emission. Therefore, it is important to get an accurate estimation of rice acreage for both food production and climate change related studies. The eastern plain region is one of the major single-cropped rice (SCR) growing areas in China. Subjected to the topography and intensified human activities, the rice fields are generally fragmented and irregular. How remote sensing can meet this challenge to accurately estimate the acreage of the rice in this region using medium-resolution imagery is the topic of this study. In this study, the applicability of the Chinese HJ-1A/B satellites and a two-band enhanced vegetation index (EVI2) was investigated. Field campaigns were carried out during the rice growing season and ground-truth data were collected for classification accuracy assessments in 2012. A stepwise classification strategy utilizing the EVI2 signatures during key phenology stages, i.e., the transplanting and the vegetative to reproductive transition phases, of the SCR was proposed, and the overall classification accuracy was 91.7%. The influence of the mixed pixel and boundary effects to classification accuracy was also investigated. This work demonstrates OPEN ACCESSRemote Sens. 2015, 7 3468 that the Chinese HJ-1A/B data are suitable data source to estimating SCR cropping area under complex land cover composition.

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Modeling methane emissions from irrigated rice cultivation inChina from 1960 to 2050

Cited by 116 publications

References 54 publications

Uncertainties in estimating regional methane emissions from rice paddies due to data scarcity in the modeling approach

Uncertainties in estimating regional methane emissions from rice paddies due to data scarcity in the modeling approach

Methylmercury accumulation in rice plants (Oryza sativa L.) In low Hg areas and the potential health - Risk exposing in extreme micro-environments

Rice Fields Mapping in Fragmented Area Using Multi-Temporal HJ-1A/B CCD Images

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