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Simulating Crop Evapotranspiration Response under Different Planting Scenarios by Modified SWAT Model in an Irrigation District, Northwest China.

Liu X, Wang S, Xue H, Singh VP - PLoS ONE (2015)

Bottom Line: On the basis of model calibration and verification, the improved model showed better simulation efficiency than did the original model.Results indicated that crop evapotranspiration decreased by 2.94% and 6.01% under the scenarios of reducing the planting proportion of spring wheat (scenario 1) and summer maize (scenario 2) by keeping the total cultivated area unchanged.The values decreased by 3.28% under scenario 1, while it increased by 7.79% under scenario 2, compared with the current situation.

View Article: PubMed Central - PubMed

Affiliation: Department of Water Resources and Civil Engineering, China Agricultural University, Beijing, China.

ABSTRACT
Modelling crop evapotranspiration (ET) response to different planting scenarios in an irrigation district plays a significant role in optimizing crop planting patterns, resolving agricultural water scarcity and facilitating the sustainable use of water resources. In this study, the SWAT model was improved by transforming the evapotranspiration module. Then, the improved model was applied in Qingyuan Irrigation District of northwest China as a case study. Land use, soil, meteorology, irrigation scheduling and crop coefficient were considered as input data, and the irrigation district was divided into subdivisions based on the DEM and local canal systems. On the basis of model calibration and verification, the improved model showed better simulation efficiency than did the original model. Therefore, the improved model was used to simulate the crop evapotranspiration response under different planting scenarios in the irrigation district. Results indicated that crop evapotranspiration decreased by 2.94% and 6.01% under the scenarios of reducing the planting proportion of spring wheat (scenario 1) and summer maize (scenario 2) by keeping the total cultivated area unchanged. However, the total net output values presented an opposite trend under different scenarios. The values decreased by 3.28% under scenario 1, while it increased by 7.79% under scenario 2, compared with the current situation. This study presents a novel method to estimate crop evapotranspiration response under different planting scenarios using the SWAT model, and makes recommendations for strategic agricultural water management planning for the rational utilization of water resources and development of local economy by studying the impact of planting scenario changes on crop evapotranspiration and output values in the irrigation district of northwest China.

No MeSH data available.


Related in: MedlinePlus

Simulated and measured values scatter diagram of summer maize monthly evapotranspiration in the verification period.
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pone.0139839.g011: Simulated and measured values scatter diagram of summer maize monthly evapotranspiration in the verification period.

Mentions: The simulation results in the verification period are presented as Table 7, and Figs 10 and 11. During the verification period (2006–2011), the RE values of summer maize annual evapotranspiration varied from -37.55% to -9.57% before model modification, while the RE values were between -11.83% and 1.79% after improving the evapotranspiration module. The relative errors which were relatively large in the year 2008, 2009 and 2010 decreased by 74.51%, 69.05% and 47.00%, respectively, after model modification. The R2 and Ens values of summer maize monthly evapotranspiration were 0.75 and 0.45 in the original model. By contrast, the R2 and Ens values were 0.88 and 0.71 in the modified model, which increased by 17.33% and 57.78%, respectively. In the verification period, only the modified model met the evaluation requirements of the SWAT model and showed higher simulation efficiency. Therefore, the modified model is more suitable for evapotranspiration simulation in Qingyuan Irrigation District of arid area of northwest China.


Simulating Crop Evapotranspiration Response under Different Planting Scenarios by Modified SWAT Model in an Irrigation District, Northwest China.

Liu X, Wang S, Xue H, Singh VP - PLoS ONE (2015)

Simulated and measured values scatter diagram of summer maize monthly evapotranspiration in the verification period.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595335&req=5

pone.0139839.g011: Simulated and measured values scatter diagram of summer maize monthly evapotranspiration in the verification period.
Mentions: The simulation results in the verification period are presented as Table 7, and Figs 10 and 11. During the verification period (2006–2011), the RE values of summer maize annual evapotranspiration varied from -37.55% to -9.57% before model modification, while the RE values were between -11.83% and 1.79% after improving the evapotranspiration module. The relative errors which were relatively large in the year 2008, 2009 and 2010 decreased by 74.51%, 69.05% and 47.00%, respectively, after model modification. The R2 and Ens values of summer maize monthly evapotranspiration were 0.75 and 0.45 in the original model. By contrast, the R2 and Ens values were 0.88 and 0.71 in the modified model, which increased by 17.33% and 57.78%, respectively. In the verification period, only the modified model met the evaluation requirements of the SWAT model and showed higher simulation efficiency. Therefore, the modified model is more suitable for evapotranspiration simulation in Qingyuan Irrigation District of arid area of northwest China.

Bottom Line: On the basis of model calibration and verification, the improved model showed better simulation efficiency than did the original model.Results indicated that crop evapotranspiration decreased by 2.94% and 6.01% under the scenarios of reducing the planting proportion of spring wheat (scenario 1) and summer maize (scenario 2) by keeping the total cultivated area unchanged.The values decreased by 3.28% under scenario 1, while it increased by 7.79% under scenario 2, compared with the current situation.

View Article: PubMed Central - PubMed

Affiliation: Department of Water Resources and Civil Engineering, China Agricultural University, Beijing, China.

ABSTRACT
Modelling crop evapotranspiration (ET) response to different planting scenarios in an irrigation district plays a significant role in optimizing crop planting patterns, resolving agricultural water scarcity and facilitating the sustainable use of water resources. In this study, the SWAT model was improved by transforming the evapotranspiration module. Then, the improved model was applied in Qingyuan Irrigation District of northwest China as a case study. Land use, soil, meteorology, irrigation scheduling and crop coefficient were considered as input data, and the irrigation district was divided into subdivisions based on the DEM and local canal systems. On the basis of model calibration and verification, the improved model showed better simulation efficiency than did the original model. Therefore, the improved model was used to simulate the crop evapotranspiration response under different planting scenarios in the irrigation district. Results indicated that crop evapotranspiration decreased by 2.94% and 6.01% under the scenarios of reducing the planting proportion of spring wheat (scenario 1) and summer maize (scenario 2) by keeping the total cultivated area unchanged. However, the total net output values presented an opposite trend under different scenarios. The values decreased by 3.28% under scenario 1, while it increased by 7.79% under scenario 2, compared with the current situation. This study presents a novel method to estimate crop evapotranspiration response under different planting scenarios using the SWAT model, and makes recommendations for strategic agricultural water management planning for the rational utilization of water resources and development of local economy by studying the impact of planting scenario changes on crop evapotranspiration and output values in the irrigation district of northwest China.

No MeSH data available.


Related in: MedlinePlus