Agricultural irrigation in China

Zhu, Xiufang; Li, Yizhan; Li, Muyi; Pan, Yaozhong; Shi, Peijun

doi:10.2489/jswc.68.6.147a

Cited by 69 publications

(49 citation statements)

References 47 publications

(31 reference statements)

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“…The detailed survey methodology is described in Text S4. It should be noted that cropland irrigation used here did not include water applied for aquaculture that accounts for less than 5% of agricultural irrigation (Zhu, Li, Li, Pan, & Shi, ). Cropland irrigation rates (mm/year) at the prefectural level were then calculated as cropland irrigation amounts divided by sowing areas.…”

Section: Methodsmentioning

confidence: 99%

Weakened growth of cropland‐N₂O emissions in China associated with nationwide policy interventions

Shang

Zhou

Smith

et al. 2019

Global Change Biology

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China has experienced rapid agricultural development over recent decades, accompanied by increased fertilizer consumption in croplands; yet, the trend and drivers of the associated nitrous oxide (N2O) emissions remain uncertain. The primary sources of this uncertainty are the coarse spatial variation of activity data and the incomplete model representation of N2O emissions in response to agricultural management. Here, we provide new data‐driven estimates of cropland‐N2O emissions across China in 1990–2014, compiled using a global cropland‐N2O flux observation dataset, nationwide survey‐based reconstruction of N‐fertilization and irrigation, and an updated nonlinear model. In addition, we have evaluated the drivers behind changing cropland‐N2O patterns using an index decomposition analysis approach. We find that China's annual cropland‐N2O emissions increased on average by 11.2 Gg N/year2 (p < .001) from 1990 to 2003, after which emissions plateaued until 2014 (2.8 Gg N/year2, p = .02), consistent with the output from an ensemble of process‐based terrestrial biosphere models. The slowdown of the increase in cropland‐N2O emissions after 2003 was pervasive across two thirds of China's sowing areas. This change was mainly driven by the nationwide reduction in N‐fertilizer applied per area, partially due to the prevalence of nationwide technological adoptions. This reduction has almost offset the N2O emissions induced by policy‐driven expansion of sowing areas, particularly in the Northeast Plain and the lower Yangtze River Basin. Our results underline the importance of high‐resolution activity data and adoption of nonlinear model of N2O emission for capturing cropland‐N2O emission changes. Improving the representation of policy interventions is also recommended for future projections.

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Section: Methodsmentioning

confidence: 99%

Weakened growth of cropland‐N₂O emissions in China associated with nationwide policy interventions

Shang

Zhou

Smith

et al. 2019

Global Change Biology

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“…Heavy state investment in irrigation projects such as canals, reservoirs and wells, starting in 1949, increased the effective irrigated area from 44.9 million ha in 1980 to 62.9 million ha in 2006 (Zhu et al . ). In 2006, the agricultural tax that required farmers to pay taxes on grain production was abolished by the central government, resulting in higher levels of disposable income for many farm households (Veeck and Shui ).…”

Section: Methods and Study Sitementioning

confidence: 97%

Making sense of climate change: hybrid epistemologies, socio‐natural assemblages and smallholder knowledge

Burnham

Zhang

2015

Area

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This paper uses a mixed-method approach to investigate smallholder perceptions of climate change in the Loess Plateau region of China. We combine qualitative and quantitative research methods with climate data analysis to gauge the climatic changes smallholders have perceived over the last 30 years, as well as how these changes have been experienced. At two research sites, each method produced markedly different results. Drawing on the work of feminist political ecologists and other geographers, we suggest that the dissonance between data sets generated using different research methods arises because each method produces knowledge that is partial and situated. To explain the contradictions between smallholder perceptions of climate change across the qualitative and quantitative methods and their disagreement with the climate record, we adopt aspects of assemblage theory and the dwelling perspective to suggest that smallholder knowledge of climate change is structured through their observations of and interactions with dynamic, networked socio-natural assemblages. We argue that a better understanding of the conduits through which perceptions and experiences of climate change come into being, and hence how climate knowledge is shaped, is necessary to account for the multiple epistemologies through which climate change is known.

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“…Irrigation supplies both IHg and MeHg, which are calculated using (1) THg concentration and % MeHg (of THg) measurements of surface water obtained from various locations in China (Table ), (2) the volume of water required to generate a flooded water column calculated from the model dimension, and (3) the average number of irrigation periods (~6) required to maintain the flooded water column over ~5 months of rice growing (Maclean et al, ). We use surface water mercury concentrations given that surface water is the major source of irrigation to Chinese rice paddies (X. Zhu et al, ). Mercury transfer between the model reservoirs and biogeochemical rates within individual reservoirs are based on first‐order differential equations; d M /d t = k × M .…”

Section: Methodsmentioning

confidence: 99%

Present and Future Mercury Concentrations in Chinese Rice: Insights From Modeling

Kwon

Selin

Giang

et al. 2018

Global Biogeochemical Cycles

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We construct a rice paddy biogeochemical cycle model to investigate processes governing rice mercury sources and to understand factors influencing spatiotemporal variability in Chinese rice mercury concentrations. The rice paddy model takes atmospheric mercury deposition, simulated from a global atmospheric chemistry transport model (GEOS‐Chem), and soil and irrigable surface water mercury concentrations obtained from literature and calculates rice inorganic (IHg) and methylmercury (MeHg) concentrations. We use ranges of GEOS‐Chem‐simulated future atmospheric mercury deposition—no policy and strict policy to regulate mercury emissions from Chinese coal‐fired power plants under the Minamata Convention on Mercury—to simulate future rice IHg and MeHg concentrations. Sensitivity analyses suggest that rice IHg and MeHg concentrations are more sensitive to the process of soil desorption than infiltration of recently introduced mercury (atmospheric and irrigation source). The rate of internal methylation via microbial activity has the largest modeled influence on rice MeHg concentration. We find that soil mercury, rather than atmospheric deposition, explains observed spatial variability in rice IHg and MeHg concentrations and captures locations of rice mercury hot spots (>20 ng/g; China National Standard Limit). Under our future scenarios, the Chinese median rice IHg and MeHg concentration increases by 13% and decrease by 18% under no policy and strict policy, respectively. Regions with the largest percentage decline in rice IHg and MeHg concentrations under strict policy are in central China, which have high rice mercury concentrations, rice production, and consumption. Our study suggests that addressing Chinese rice mercury contamination requires attention to contaminated soil and regulation of anthropogenic mercury emissions.

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Agricultural irrigation in China

Cited by 69 publications

References 47 publications

Weakened growth of cropland‐N₂O emissions in China associated with nationwide policy interventions

Weakened growth of cropland‐N₂O emissions in China associated with nationwide policy interventions

Making sense of climate change: hybrid epistemologies, socio‐natural assemblages and smallholder knowledge

Present and Future Mercury Concentrations in Chinese Rice: Insights From Modeling

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Agricultural irrigation in China

Cited by 69 publications

References 47 publications

Weakened growth of cropland‐N2O emissions in China associated with nationwide policy interventions

Weakened growth of cropland‐N2O emissions in China associated with nationwide policy interventions

Making sense of climate change: hybrid epistemologies, socio‐natural assemblages and smallholder knowledge

Present and Future Mercury Concentrations in Chinese Rice: Insights From Modeling

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Product

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Weakened growth of cropland‐N₂O emissions in China associated with nationwide policy interventions

Weakened growth of cropland‐N₂O emissions in China associated with nationwide policy interventions