scholarly journals A novel regional irrigation water productivity model coupling irrigation- and drainage-driven soil hydrology and salinity dynamics and shallow groundwater movement in arid regions in China

2020 ◽  
Vol 24 (5) ◽  
pp. 2399-2418
Author(s):  
Jingyuan Xue ◽  
Zailin Huo ◽  
Shuai Wang ◽  
Chaozi Wang ◽  
Ian White ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Water Productivity ◽  
Shallow Groundwater ◽  
Groundwater Table ◽  
Spatial Distributions ◽  
Cropping Patterns ◽  
Groundwater Movement ◽  
Land Use Types ◽  
Temporal And Spatial ◽  
Irrigation Water Productivity

Abstract. The temporal and spatial distributions of regional irrigation water productivity (RIWP) are crucial for making decisions related to agriculture, especially in arid irrigated areas with complex cropping patterns. Thus, in this study, we developed a new RIWP model for an irrigated agricultural area with complex cropping patterns. The model couples the irrigation- and drainage-driven soil water and salinity dynamics and shallow groundwater movement in order to quantify the temporal and spatial distributions of the target hydrological and biophysical variables. We divided the study area into 1 km × 1 km hydrological response units (HRUs). In each HRU, we considered four land use types: sunflower fields, wheat fields, maize fields, and uncultivated lands (bare soil). We coupled the regional soil hydrological processes and groundwater flow by taking a weighted average of the water exchange between unsaturated soil and groundwater under different land use types. The RIWP model was calibrated and validated using 8 years of hydrological variables obtained from regional observation sites in a typical arid irrigation area in North China, the Hetao Irrigation District. The model simulated soil moisture and salinity reasonably well as well as groundwater table depths and salinity. However, overestimations of groundwater discharge were detected in both the calibration and validation due to the assumption of well-operated drainage ditch conditions; regional evapotranspiration (ET) was reasonably estimated, whereas ET in the uncultivated area was slightly underestimated in the RIWP model. A sensitivity analysis indicated that the soil evaporation coefficient and the specific yield were the key parameters for the RIWP simulation. The results showed that the RIWP decreased from maize to sunflower to wheat from 2006 to 2013. It was also found that the maximum RIWP was reached when the groundwater table depth was between 2 and 4 m, regardless of the irrigation water depth applied. This implies the importance of groundwater table control on the RIWP. Overall, our distributed RIWP model can effectively simulate the temporal and spatial distribution of the RIWP and provide critical water allocation suggestions for decision-makers.

scholarly journals A novel regional irrigation water productivity model for complex cropping patterns in arid regions coupling soil water and salinity dynamics, irrigation and drainage, and shallow groundwater movement

2019 ◽  
Author(s):  
Jingyuan Xue ◽  
Zailin Huo ◽  
Ian White ◽  
Isaya Kisekka ◽  
Zhuping Sheng ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Water Productivity ◽  
Shallow Groundwater ◽  
Groundwater Table ◽  
Temporal And Spatial Distribution ◽  
Cropping Patterns ◽  
Groundwater Movement ◽  
Land Use Types ◽  
Temporal And Spatial ◽  
Irrigation Water Productivity

Abstract. The temporal and spatial distribution of regional irrigation water productivity (RIWP) is crucial for making agricultural related decisions, especially in arid irrigated areas with complex cropping patterns. Thus, we developed a new RIWP model for an irrigated agricultural area with complex cropping patterns. The model couples the irrigation and drainage driven soil water and salinity dynamics and shallow groundwater movement, to quantify the temporal and spatial distributions of the target hydrological and biophysical variables. We divided the study area into 1 km×1 km hydrological response units (HRUs). In each HRU, we considered four land-use types: sunflower fields, wheat fields, maize fields and uncultivated lands. And we coupled the regional soil hydrological processes and groundwater flow by taking a weighted average of the water exchange between unsaturated soil and groundwater under different land-use types. The RIWP model was calibrated and validated using eight years of hydrological variables obtained from regional observation sites in a typical arid irrigation area of North China, Hetao Irrigation District. The model reasonably well simulated soil moisture and salinity, groundwater table depths, salinity, and discharge, and regional evapotranspiration. Sensitivity analysis indicates that soil evaporation coefficient and specific yield are the key parameters for RIWP simulation. The results showed that, from 2006 to 2013, RIWP decreased from maize to sunflower to wheat. It was found that the maximum RIWP can be reached when groundwater table depth is in the range of 2 m to 4 m, regardless of irrigation water depths. This implies the importance of groundwater table control on RIWP. Overall, our distributed RIWP model can effectively simulate the temporal and spatial distribution of RIWP and provide critical water allocation suggestions for decision makers.

scholarly journals A unique vadose zone model for shallow aquifers: the Hetao irrigation district, China

2019 ◽  
Vol 23 (7) ◽  
pp. 3097-3115 ◽  
Author(s):  
Zhongyi Liu ◽  
Xingwang Wang ◽  
Zailin Huo ◽  
Tammo Siert Steenhuis
Keyword(s):  
Field Experiment ◽  
Irrigation Water ◽  
Yellow River ◽  
Shallow Groundwater ◽  
Groundwater Table ◽  
Irrigation District ◽  
Zone Model ◽  
Calibration And Validation ◽  
Irrigation Water Use ◽  
Hetao Irrigation District

Abstract. Rapid population growth is increasing pressure on the world water resources. Agriculture will require crops to be grown with less water. This is especially the case for the closed Yellow River basin, necessitating a better understanding of the fate of irrigation water in the soil. In this paper, we report on a field experiment and develop a physically based model for the shallow groundwater in the Hetao irrigation district in Inner Mongolia, in the arid middle reaches of the Yellow River. Unlike other approaches, this model recognizes that field capacity is reached when the matric potential is equal to the height above the groundwater table and not by a limiting soil conductivity. The field experiment was carried out in 2016 and 2017. Daily moisture contents at five depths in the top 90 cm and groundwater table depths were measured in two fields with a corn crop. The data collected were used for model calibration and validation. The calibration and validation results show that the model-simulated soil moisture and groundwater depth fitted well. The model can be used in areas with shallow groundwater to optimize irrigation water use and minimize tailwater losses.

Development and Evaluation of a Variable-Rate Irrigation Management Method in the Mississippi Delta

2021 ◽  
Vol 64 (1) ◽  
pp. 287-298
Author(s):  
Ruixiu Sui ◽  
Jonnie Baggard
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Water Use ◽  
Irrigation Water ◽  
Mississippi Delta ◽  
Water Productivity ◽  
Variable Rate ◽  
Irrigation Water Use ◽  
Irrigation Water Productivity ◽  
Variable Rate Irrigation

HighlightsWe developed and evaluated a variable-rate irrigation (VRI) management method for five crop years in the Mississippi Delta.VRI management significantly reduced irrigation water use in comparison with uniform-rate irrigation (URI). There was no significant difference in grain yield and irrigation water productivity between VRI and URI management.Soil apparent electrical conductivity (ECa) was used to delineate irrigation management zones and generate VRI prescriptions.Sensor-measured soil water content was used in irrigation scheduling.Abstract. Variable-rate irrigation (VRI) allows producers to site-specifically apply irrigation water at variable rates within a field to account for the temporal and spatial variability in soil and plant characteristics. Developing practical VRI methods and documenting the benefits of VRI application are critical to accelerate the adoption of VRI technologies. Using apparent soil electrical conductivity (ECa) and soil moisture sensors, a VRI method was developed and evaluated with corn and soybean for five crop years in the Mississippi Delta. Soil ECa of the study fields was mapped and used to delineate VRI management zones and create VRI prescriptions. Irrigation was scheduled using soil volumetric water content measured by soil moisture sensors. A center pivot VRI system was employed to deliver irrigation water according to the VRI prescription. Grain yield, irrigation water use, and irrigation water productivity in the VRI treatment were determined and compared with that in a uniform-rate irrigation (URI) treatment. Results showed that the grain yield and irrigation water productivity between the VRI and URI treatments were not statistically different with both corn and soybean crops. The VRI management significantly reduced the amount of irrigation water by 22% in corn and by 11% in soybean (p = 0.05). Adoption of VRI management could improve irrigation water use efficiency in the Mississippi Delta. Keywords: Soil electrical conductivity, Soil moisture sensor, Variable rate irrigation, Water management.

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