22-27 September 2019
Trade Fairs and Congress Center (FYCMA)
Europe/Madrid timezone

The parametric uncertainty analysis of water and nitrogen transport simulation in vadose zone for irrigation districts in western Jilin province,china.

24 Sep 2019, 16:00
1h
Trade Fairs and Congress Center (FYCMA)

Trade Fairs and Congress Center (FYCMA)

Av. de José Ortega y Gasset, 201 29006 Malaga, Spain
Poster Topic 5 - Tools, methods and models to study groundwater Poster with refreshments

Speaker

Prof. jianmin bian (College of New Energy and Environment Institute, Jilin University, Changchun 130021,China.)

Description

The saline soil area in western Jilin is affected by water conservancy projects and agricultural activities, the leaching loss of nitrogen is serious in the unsaturated zone of the irrigation area, causing groundwater pollution.The numerical simulation of soil water and nitrogen transport is an effective technical means to understand the process and mechanism of complex nitrogen infiltration at farmland scale. However, soil water and nitrogen transport parameters under farmland scale have strong spatial variability, which leads to random uncertainty of model parameters in the simulation calculation and prediction process. Therefore, this paper takes the unsaturated zone of the saline soil area in Da'an city as the research object, designs the field experiment,construct a unsaturated zone of water and nitrogen transport model in Hydrus and verify it, considering soil spatial variability,based on the GLUE method, the uncertainty of the water and nitrogen transport reaction parameters of the model was identified, and predict the range of water and nitrogen parameters and its effect on the cumulative leaching amount of nitrate nitrogen were predicted under the uncertain parameters. The results are as follows: (1) The RMSE values of soil water content, nitrate nitrogen and ammonium nitrogen are all small, the n-RMSE values are in the acceptable range,and the index of coincidence(d) and correlation coefficient (R2) is close to 1, indicating that the simulation effect of the Hydrous model is better; (2) Soil saturated water content, dispersivity and adsorption coefficient have better identification, and the range of values is reduced to 0.42-0.45 cm3/cm3, 0.26-0.29 cm and 0.141-0.158 L/mg, respectively, denitrification rate and saturated hydraulic conductivity have great influence on the uncertainty of model results; (3) Under different schemes, the predicted range of soil nitrate-nitrogen accumulation leaching from 0-100 cm is 10.34-13.63 kg/ha, 9.47-12.71 kg/ha, respectively, and the range of prediction interval can be narrowed considering the parameter uncertainty, it can reduce the uncertainty of the results, improve the simulation accuracy of water and nitrogen transport in the unsaturated zone, and increasing the result accuracy when quantitative assessment of cumulative nitrate leaching risk.

Primary authors

Prof. jianmin bian (College of New Energy and Environment Institute, Jilin University, Changchun 130021,China.) Ms juanjuan wu (College of New Energy and Environment Institute, Jilin University, Changchun 130021,China.) Ms siyu nie (Changchun Institute of Technology, Changchun 130021,China.)

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