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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

Distribution of canal system in Qingyuan Irrigation District.
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pone.0139839.g006: Distribution of canal system in Qingyuan Irrigation District.

Mentions: Generally, catchment can be divided into a number of sub-catchments based on terrain characteristics in the SWAT model. However, the area of Qingyuan Irrigation District is small. The terrain inclines downward from southwest to northeast and there is no watershed in the irrigation district. Besides, the water systems are artificial canal systems which have a great impact on the natural hydrological processes. Therefore, the irrigation district which is divided based on terrain characteristics by the function of SWAT cannot reflect the real situation of the study area. As irrigation system is the main factor that influences hydrological cycle, the irrigation district was divided mainly based on the canal systems. Then, taking into account the factors of DEM, land use and soil type, the whole irrigation district was divided into 39 subdivisions and 145 HRUs. The distribution of canal system and subdivision of Qingyuan Irrigation District is shown as Fig 6 and Fig 7.


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)

Distribution of canal system in Qingyuan Irrigation District.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0139839.g006: Distribution of canal system in Qingyuan Irrigation District.
Mentions: Generally, catchment can be divided into a number of sub-catchments based on terrain characteristics in the SWAT model. However, the area of Qingyuan Irrigation District is small. The terrain inclines downward from southwest to northeast and there is no watershed in the irrigation district. Besides, the water systems are artificial canal systems which have a great impact on the natural hydrological processes. Therefore, the irrigation district which is divided based on terrain characteristics by the function of SWAT cannot reflect the real situation of the study area. As irrigation system is the main factor that influences hydrological cycle, the irrigation district was divided mainly based on the canal systems. Then, taking into account the factors of DEM, land use and soil type, the whole irrigation district was divided into 39 subdivisions and 145 HRUs. The distribution of canal system and subdivision of Qingyuan Irrigation District is shown as Fig 6 and Fig 7.

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