Your search found 20 records
1 Asare, D. K.; Sammis, T. W.; Smeal, D.; Zhang, H.. 1995. Atrazine dynamics in a field irrigated soil. In Heatwole, C. (Ed.), Water quality modeling: Proceedings of the International Symposium, April 2-5, 1995, Hyatt Hotel Orlando, Orlando, Florida. St. Joseph, MI, USA: ASAE. pp.31-40.
(Location: IWMI-HQ Call no: 333.91 G000 HEA Record No: H018692)
A study was conducted to assess atrazine transport and distribution in a field soil in relation to four levels of early-season irrigation, with the overall objective of developing water management strategies to minimize the potential for atrazine pollution of water resources. The specific objective was to use the measured atrazine data to evaluate and compare the performance of two conceptually different contaminant transport models, IRRSCHM and LEACHP. The measured atrazine transport and distribution in soil profiles were directly related to levels of early-season and seasonal irrigation water. Generally, the measured and predicted atrazine data agreed within one order of magnitude, suggesting that both models gave reasonably good approximation of measured soil atrazine. IRRSCHM, a field-capacity and mixing-cell management oriented model, performed better than LEACHP, a classical deterministic model that uses Richard's and Convection-Dispersion Equations for simulating water and pesticide dynamics.
2 Oweis, T.; Zhang, H.. 1998. Water-use efficiency: Index for optimising supplemental irrigation of wheat in water scarce areas. Journal of Applied Irrigation Science, 33(2):321-336.
(Location: IWMI-HQ Call no: P 4947 Record No: H023308)
3 Zhang, H.; Oweis, T. 1999. Water-yield relations and optimal irrigation scheduling of wheat in the Mediterranean region. Agricultural Water Management, 38(3):195-211.
(Location: IWMI-HQ Call no: PER Record No: H023644)
(Location: IWMI-HQ Call no: PER Record No: H024000)
5 Zhang, H.; Oweis, T. Y.; Garabet, S.; Pala, M. 1998. Water-use efficiency and transpiration efficiency of wheat under rain-fed conditions and supplemental irrigation in a Mediterranean-type environment. Plant and Soil, 201:295-305.
(Location: IWMI-HQ Call no: P 777 Record No: H024283)
6 Zhang, H.; Wang, X.; You, M.; Liu, C. 1999. Water-yield relations and water-use efficiency of winter wheat in the North China Plain. Irrigation Science, 19(1):37-45.
(Location: IWMI-HQ Call no: PER Record No: H025348)
(Location: IWMI-HQ Call no: PER Record No: H028271)
8 Zhang, H.. 2003. Improving water productivity through deficit irrigation: examples from Syria, the North China Plain and Oregon, USA. In Kijne, J. W.; Barker, R.; Molden. D. (Eds.). Water productivity in agriculture: limits and opportunities for improvement. Wallingford, UK: CABI; Colombo, Sri Lanka: International Water Management Institute (IWMI) pp.301-309. (Comprehensive Assessment of Water Management in Agriculture Series 1)
(Location: IWMI-HQ Call no: IWMI 631.7.2 G000 KIJ Record No: H032649)
(Location: IWMI-HQ Call no: PER Record No: H035403)
(Location: IWMI-HQ Call no: PER Record No: H036717)
(Location: IWMI-HQ Call no: PER Record No: H037855)
(Location: IWMI-HQ Call no: PER Record No: H038418)
13 Scott, C. A.; Zhang, F.; Mukherji, A.; Immerzeel, W.; Mustafa, D.; Bharati, Luna; Zhang, H.; Albrecht, T.; Lutz, A.; Nepal, S.; Siddiqi, A.; Kuemmerle, H.; Qadir, M.; Bhuchar, S.; Prakash, A.; Sinha, R. 2019. Water in the Hindu Kush Himalaya. In Wester, P.; Mishra, A.; Mukherji, A.; Shrestha, A. B. (Eds.). The Hindu Kush Himalaya assessment: mountains, climate change, sustainability and people. Cham, Switzerland: Springer. pp.257-299.
(Location: IWMI HQ Call no: e-copy only Record No: H049103)
(28.3 MB)
14 Song, P.; Zheng, X.; Li, Y.; Zhang, K.; Huang, J.; Li, H.; Zhang, H.; Liu, L.; Wei, C.; Mansaray, L. R.; Wang, D.; Wang, X. 2020. Estimating reed loss caused by locusta migratoria manilensis using UAV [Unmanned Aerial Vehicle] -based hyperspectral data. Science of the Total Environment, 719:137519. [doi: https://doi.org/10.1016/j.scitotenv.2020.137519]
(Location: IWMI HQ Call no: e-copy only Record No: H049853)
(3.89 MB)
Locusta migratoria manilensis has caused major damage to vegetation and crops. Quantitative evaluation studies of vegetation loss estimation from locust damage have seldom been found in traditional satellite-remote-sensing-based research due to insufficient temporal-spatial resolution available from most current satellite-based observations. We used remote sensing data acquired from an unmanned aerial vehicle (UAV) over a simulated Locusta migratoria manilensis damage experiment on a reed (Phragmites australis) canopy in Kenli District, China during July 2017. The experiment was conducted on 72 reed plots, and included three damage duration treatments with each treatment including six locust density levels. To establish the appropriate loss estimation models after locust damage, a hyperspectral imager was mounted on a UAV to collect reed canopy spectra. Loss components of six vegetation indices (RVI, NDVI, SAVI, MSAVI, GNDVI, and IPVI) and two “red edge” parameters (Dr and SDr) were used for constructing the loss estimation models. Results showed that: (1) Among the six selected vegetation indices, loss components of NDVI, MSAVI, and GNDVI were more sensitive to the variation of dry weight loss of reed green leaves and produced smaller estimation errors during the model test process, with RMSEs ranging from 8.8 to 9.1 g/m;. (2) Corresponding model test results based on loss components of the two selected red edge parameters yielded RMSEs of 27.5 g/m2 and 26.1 g/m2 for Dr and SDr respectively, suggesting an inferior performance of red edge parameters compared with vegetation indices for reed loss estimation. These results demonstrate the great potential of UAV-based loss estimation models for evaluating and quantifying degree of locust damage in an efficient and quantitative manner. The methodology has promise for being transferred to satellite remote sensing data in the future for better monitoring of locust damage of larger geographical areas.
(Location: IWMI HQ Call no: e-copy only Record No: H050237)
(0.86 MB)
This study investigates the effect of payments for ecosystem services (PES) programs on common pool resource management in the context of village collective-managed irrigation systems (VMISs) in China. Drawing on institutional bricolage theory, we propose that the functioning of a PES program depends on its combination with local institutions. We infer transaction cost-reduction and trust-strengthening mechanisms as the two pathways for institutional bricolage to illustrate the process whereby a PES program enables a VMIS to internalise positive externalities. Based on data from a field survey at the household level, our empirical results confirm that a PES program is an effective means of improving the performance of VMISs in terms of environmental, economic, and equitable benefits, because it aligns benefits for the village collective with those for the overall society. We conclude that a PES program is of greater benefit to communities with local institutions and that PES programs and local institutions exert an interactive impact as they reinforce each other's effect on common pool resource management.
(Location: IWMI HQ Call no: e-copy only Record No: H050243)
(12.90 MB) (12.9 MB)
Extraction of drainage networks is an important element of river flow routing in hydrology and large-scale estimates of river behaviors in Earth sciences. Emerging studies with a focus on greenhouse gases reveal that small rivers can contribute to more than half of the global carbon emissions from inland waters (including lakes and wetlands). However, large-scale extraction of drainage networks is constrained by the coarse resolution of observational data and models, which hinders assessments of terrestrial hydrological and biogeochemical cycles. Recognizing that Sentinel-2 satellite can detect surface water up to a 10-m resolution over large scales, we propose a new method named Remote Sensing Stream Burning (RSSB) to integrate high-resolution observational flow location with coarse topography to improve the extraction of drainage network. In RSSB, satellite-derived input is integrated in a spatially continuous manner, producing a quasi-bathymetry map where relative relief is enforced, enabling a fine-grained, accurate, and multitemporal extraction of drainage network. RSSB was applied to the Lancang-Mekong River basin to derive a 10-m resolution drainage network, with a significant reduction in location errors as validated by the river centerline measurements. The high-resolution extraction resulted in a realistic representation of meanders and detailed network connections. Further, RSSB enabled a multitemporal extraction of river networks during wet/dry seasons and before/after the formation of new channels. The proposed method is fully automated, meaning that the network extraction preserves basin-wide connectivity without requiring any postprocessing, hence facilitating the construction of drainage networks data with openly accessible imagery. The RSSB method provides a basis for the accurate representation of drainage networks that maintains channel connectivity, allows a more realistic inclusion of small rivers and streams, and enables a greater understanding of complex but active exchange between inland water and other related Earth system components.
17 Li, K.; Zhang, H.; Li, X.; Wang, C.; Zhang, J.; Jiang, R.; Feng, G.; Liu, X.; Zuo, Y.; Yuan, H.; Zhang, C.; Gai, J.; Tian, J. 2021. Field management practices drive ecosystem multifunctionality in a smallholder-dominated agricultural system. Agriculture, Ecosystems and Environment, 313:107389. (Online first) [doi: https://doi.org/10.1016/j.agee.2021.107389]
(Location: IWMI HQ Call no: e-copy only Record No: H050334)
(6.12 MB)
Agroecosystems provide multiple goods and services that are important for human welfare. Despite the importance of field management practices for agroecosystem service delivery, the links of socioeconomic factors, management practices and ecosystem multifunctionality have rarely been explicitly evaluated in agroecosystems. Here we used a county-scale database with 100 farmer households and their farmlands, and analyzed the relative importance of management practices, soil abiotic environment and soil biota on multifunctionality under three distinct (‘smallholder’s viewpoint’, ‘sustainable soils’ and ‘equal weight’) scenarios. Furthermore, we also analyzed the effect of smallholders’ socioeconomic factors on management practices. Our results found that smallholders’ high inputs of fertilizers and agrochemicals were associated with their high agricultural income and less farmland area, but total land area had a positive effect on straw incorporation. Total soil biota index was positively related to multifunctionality, however, management practices (fertilizer input, agrochemical input, organic fertilizer amount and straw incorporation) had stronger effect on multifunctionality than that of soil biota or the abiotic environment. Their strength varied with distinct scenarios. Our work suggests that increasing organic materials (organic fertilizers and crop residues) and decreasing agrochemicals are beneficial for maintaining or increasing ecosystem multifunctionality in smallholder-dominated agroecosystems. Moreover, improving management practices of smallholders needs to take into account the effects of their socioeconomic factors.
18 Qiao, X.; Schmidt, A. H.; Xu, Y.; Zhang, H.; Chen, X.; Xiang, R.; Tang, Y.; Wang, W. 2021. Surface water quality in the upstream-most megacity of the Yangtze River Basin (Chengdu): 2000–2019 trends, the COVID-19 lockdown effects, and water governance implications. Environmental and Sustainability Indicators, 10:100118. [doi: https://doi.org/10.1016/j.indic.2021.100118]
(Location: IWMI HQ Call no: e-copy only Record No: H050539)
(2.99 MB) (2.99 MB)
Water is essential for a sustainable economic prosperity, but rapid economic growth and intensive agricultural activities usually cause water pollution. The middle and lower reaches of China’s Yangtze River Basin were urbanized and industrialized much earlier than the upper reach and have been suffering from water pollution. In the past two decades, economic growth accelerated in the upper reach due to several national economic initiatives. Based on analyzing water quality changes from 2000 to 2019 and during the COVID-19 lockdown in 2020 for Chengdu in the upper reach, we hope to provide some water governance suggestions. In 2019, water at 66% of 93 sites in Chengdu did not achieve the national III standards using measurements of 23 water quality parameters. The top two pollutants were total nitrogen (TN) and fecal coliform (FC). From 2000 to 2019, water quality was not significantly improved at the non-background sites of Chengdu's Min Basin, and the pollution in this basin was mainly from local pollutants release. During the same period, water quality deteriorated in Chengdu’s Tuo Basin, where pollution was the result of pollutant discharges in Chengdu in addition to inter-city pollutant transport. During the COVID-19 lockdown, water quality generally improved in the Min Basin but not in the Tuo Basin. A further investigation on which pollution sources were shut down or not during the lockdown can help make pollution reduction targets. Based on the results, we provide suggestions to strengthen inter-jurisdictional and inter-institutional cooperation, water quality monitoring and evaluation, and ecological engineering application.
19 Ali, W.; Zhang, H.; Mao, K.; Shafeeque, Muhammad; Aslam, M. W.; Yang, X.; Zhong, L.; Feng, X.; Podgorski, J. 2022. Chromium contamination in paddy soil-rice systems and associated human health risks in Pakistan. Science of the Total Environment, 826:153910. [doi: https://doi.org/10.1016/j.scitotenv.2022.153910]
(Location: IWMI HQ Call no: e-copy only Record No: H051385)
(1.81 MB)
Chromium (Cr) contamination in paddy soil-rice systems threatens human health through the food chain. This study used a new dataset of 500 paddy soil and plant tissue samples collected in the rice-growing regions of Sindh and Punjab Provinces of Pakistan. Overall, 97.4% of grain samples exceeded the Cr threshold values of 1.0 mg kg-1, determined by the China National Food Standard (CNFS). The Cr in paddy soil, 62.6% samples exceeding the China natural background threshold value (90 mg kg-1) for Cr concentration in paddy soil, and lower than the (pH-dependant > 7.5 threshold value for Cr 350 mg kg-1) as determined by China Environmental Quality Standards (EQSs) for paddy soil (GB15618-2018). Geographically weighted regression (GWR) modelling showed spatially nonstationary correlations, confirming the heterogeneous relationship between dependent (rice grain Cr) and independent paddy soil (pH, SOM, and paddy soil Cr) and plant tissue variables (shoot Cr and root Cr) throughout the study area. The GWR model was then used to determine the critical threshold (CT) for the measured Cr concentrations in the paddy soil system. Overall, 38.4% of paddy soil samples exceeding CT values confirm that the paddy soil Cr risk prevails in the study area. Furthermore, the GWR model was applied to assess the loading capacity (LC), the difference between the CT, and the actual concentration of Cr in paddy soil. Loading capacity identified potential paddy soil Cr pollution risk to rice grain and assessed the risk areas. Overall LC% of samples paddy soil Cr risk areas grade: low-risk grade I (34.6%); moderate-risk grade II (15.8%); high-risk grade III (11.2%); and very high-risk grade IV (38.4%) have been assessed in the study area.
The human health index, total hazard quotient (THQ « 1), indicates no potential health risk originating from Cr exposure to the population. However, the excess Cr level in paddy soil and rice grain is still a concern. The current study's results are also valuable for the national decision-making process regarding Cr contamination in the paddy soil-rice system.
20 Dang, C.; Zhang, H.; Singh, V. P.; Zhang, S.; Mu, D.; Yao, C.; Zhang, Y.; Lyu, F.; Liu, S. 2024. Tracking and managing the water-food-environment-ecosystem (WFEE) nexus in groundwater irrigation districts using system dynamics modelling. Science of The Total Environment, 947:174705. (Online first) [doi: https://doi.org/10.1016/j.scitotenv.2024.174705]
(Location: IWMI HQ Call no: e-copy only Record No: H053014)
(7.10 MB)
Groundwater irrigation districts, which play a crucial role in the Earth's critical zone, are confronted with numerous challenges, including water scarcity, pollution, and ecological degradation. These issues come from multiple systems and are linked to a groundwater-dominated water-food-environment-ecosystem nexus problem related to agricultural activities (WFEE). There is a pressing need for the scientific characterization and evaluation of the WFEE nexus in groundwater irrigation districts to assure high-quality, sustainable development. Furthermore, it is critical to provide practical and efficient regulations at the farmer level to uphold the health of this nexus. This paper presents a mapping network that focuses on groundwater irrigation districts. The network aims to convert the restriction indicators utilized to maintain the health of the WFEE nexus (at the irrigation district scale) into the targets employed to manage farmers' living and agricultural activities (at the farmer scale). Additionally, a system dynamics model is created to track and manage the interacting relationships between the WFEE nexus and farmers' living and agricultural activities. This proposed model employs a structured parameter system comprising targets, state parameters, regulatory parameters, and evaluation parameters. This system can get insight into the status of the WFEE nexus at the farmer level using state parameters, induce tailored management and regulation measures using regulatory parameters, assess the effectiveness of various measures using the evaluation parameters, and finally provide decision support to enhance the health of the WFEE nexus. The findings from the research conducted in the Yong'an groundwater irrigation district demonstrated that the model accurately described the relationship between the WFEE nexus and farmers' activities in groundwater irrigation districts. Furthermore, the model responded strongly to a variety of improvement strategies, including adjustments in planting area, optimization of planting pattern, improvement of irrigation method, and implementation of agronomic measures. As a result, it provided farmers with decision support for applying agricultural management methods and addressing the WFEE nexus problem in groundwater irrigation areas.
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