scholarly journals Understanding the Role of Shallow Groundwater in Improving Field Water Productivity in Arid Areas

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3519
Author(s):  
Xiaoyu Gao ◽  
Zhongyi Qu ◽  
Zailin Huo ◽  
Pengcheng Tang ◽  
Shuaishuai Qiao
Keyword(s):  
Soil Water ◽  
Soil Salinity ◽  
Water Productivity ◽  
Shallow Groundwater ◽  
Irrigation Scheduling ◽  
Crop Growth ◽  
Groundwater Depth ◽  
Groundwater Salinity ◽  
Arid Areas ◽  
Soil Water And Salt

Soil water and salt transport in soil profiles and capillary rise from shallow groundwater are significant seasonal responses that help determine irrigation schedules and agricultural development in arid areas. In this study the Agricultural Water Productivity Model for Shallow Groundwater (AWPM-SG) was modified by adding a soil salinity simulation to precisely describe the soil water and salt cycle, calculating capillary fluxes from shallow groundwater using readily available data, and simulating the effect of soil salinity on crop growth. The model combines an analytical solution of upward flux from groundwater using the Environmental Policy Integrated Climate (EPIC) crop growth model. The modified AWPM-SG was calibrated and validated with a maize field experiment run in 2016 in which predicted soil moisture, soil salinity, groundwater depth, and leaf area index were in agreement with the observations. To investigate the response of the model, various scenarios with varying groundwater depth and groundwater salinity were run. The inhibition of groundwater salinity on crop yield was slightly less than that on crop water use, while the water consumption of maize with a groundwater depth of 1 m is 3% less than that of 2 m, and the yield of maize with groundwater depth of 1 m is only 1% less than that of 2 m, under the groundwater salinity of 2.0 g/L. At the same groundwater depth, the higher the salinity, the greater the corn water productivity, and the smaller the corn irrigation water productivity. Consequently, using modified AWPM-SG in irrigation scheduling will be beneficial to save more water in areas with shallow groundwater.

scholarly journals The Ecological Relationship of Groundwater–Soil–Vegetation in the Oasis–Desert Transition Zone of the Shiyang River Basin

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1642
Author(s):  
Le Cao ◽  
Zhenlong Nie ◽  
Min Liu ◽  
Lifang Wang ◽  
Jinzhe Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Soil Salinity ◽  
Shallow Groundwater ◽  
Water Source ◽  
Northwest China ◽  
Soil Salinization ◽  
Arid Areas ◽  
Important Indicator ◽  
Vegetation Growth

Groundwater is an important ecological water source in arid areas. Groundwater depth (GWD) is an important indicator that affects vegetation growth and soil salinization. Clarifying the coupling relationship between vegetation, groundwater, and soil in arid areas is beneficial to the prevention of environmental problems such as desertification and salinization. Existing studies lack research on the water–soil–vegetation relationship in typical areas, especially in shallow groundwater areas. In this study, the shallow groundwater area in Minqin, northwest China, was taken as study area, and vegetation surveys and soil samples collection were conducted. The relationships between vegetation fractional coverage (VFC) and GWD, soil salinity, soil moisture, and precipitation were comprehensively analyzed. The results showed low soil salinity in the riparian zone and high soil salinity in other shallow-buried areas with salinization problems. Soil salinity was negatively correlated with VFC (R = −0.4). When soil salinity >3 g/kg, VFC was less than 20%. Meanwhile, when GWD >10 m, VFC was usually less than 15%. In the areas with soil salinity <3 g/kg, when GWD was in the range of 4–10 m, VFC was positively correlated with soil moisture content (R = 0.99), and vegetation growth mainly depended on surface soil water, which was significantly affected by precipitation. When GWD was less than 4 m, VFC was negatively correlated with GWD (R = −0.78), and vegetation growth mainly relied on groundwater and soil water. There are obvious ecological differences in the shallow-buried areas in Minqin. Hence, it is reasonable to consider zoning and grading policies for ecological protection.

Improving Irrigation Scheduling of Wheat to Increase Water Productivity in Shallow Groundwater Conditions Using Aquacrop

2018 ◽  
Vol 67 (5) ◽  
pp. 738-754 ◽  
Author(s):  
Mohiaddin Goosheh ◽  
Ebrahim Pazira ◽  
Ali Gholami ◽  
Bahram Andarzian ◽  
Ebrahim Panahpour
Keyword(s):  
Water Productivity ◽  
Shallow Groundwater ◽  
Irrigation Scheduling

scholarly journals A field validated surrogate model for optimum performance of irrigated crops in regions with shallow salty groundwater

2020 ◽  
Author(s):  
Zhongyi Liu ◽  
Zailin Huo ◽  
Chaozi Wang ◽  
Limin Zhang ◽  
Xianghao Wang ◽  
...  
Keyword(s):  
Field Experiment ◽  
Irrigation Water ◽  
Surrogate Model ◽  
Shallow Groundwater ◽  
Crop Growth ◽  
Groundwater Depth ◽  
Upward Movement ◽  
Optimum Performance ◽  
Calibration And Validation ◽  
Irrigated Crops

Abstract. Optimum performance of irrigated crops in regions with shallow saline groundwater requires a careful balance between application of irrigation water and upward movement of salinity from the groundwater. Few field validated surrogate models are available to aid in the management of irrigation water under shallow groundwater conditions. The objective of this research is to develop a model that can aid in the management using a minimum of input data that is field validated. In this paper a 2-year field experiment was carried out in the Hetao irrigation district in Inner Mongolia, China and a physically based integrated surrogate model for arid irrigated areas with shallow groundwater was developed and validated with the collected field data. The integrated model that links crop growth with available water and salinity in the vadose zone is called Evaluation of the Performance of Irrigated Crops and Soils (EPICS). EPICS recognizes that field capacity is reached when the matric potential is equal to the height above the groundwater table and thus not by a limiting hydraulic conductivity. In the field experiment, soil moisture contents and soil salt conductivity at 5 depths in the top 100 cm, groundwater depth, crop height, and leaf area index were measured in 2017 and 2018. The field results were used for calibration and validation of EPICS. Simulated and observed data fitted generally well during both calibration and validation. The EPICS model that can predict crop growth, soil water, groundwater depth and soil salinity can aid in optimizing water management in irrigation districts with shallow aquifers.

scholarly journals Estimate Cotton Water Consumption from Shallow Groundwater under Different Irrigation Schedules

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 213
Author(s):  
Guohua Zhang ◽  
Xinhu Li
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Consumption ◽  
Meteorological Factors ◽  
Shallow Groundwater ◽  
Soil Evaporation ◽  
Groundwater Depth ◽  
Crop Water ◽  
Crop Water Consumption

Shallow groundwater is considered an important water resource to meet crop irrigation demands. However, limited information is available on the application of models to investigate the impact of irrigation schedules on shallow groundwater depth and estimate evaporation while considering the interaction between meteorological factors and the surface soil water content (SWC). Based on the Richards equation, we develop a model to simultaneously estimate crop water consumption of shallow groundwater and determine the optimal irrigation schedule in association with a shallow groundwater depth. A new soil evaporation function was established, and the control factors were calculated by using only the days after sowing. In this study, two irrigation scheduling methods were considered. In Method A, irrigation was managed based on the soil water content; in Method B, irrigation was based on the crop water demand. In comparison with Method B, Method A was more rational because it could use more groundwater, and the ratio of soil evaporation to total evapotranspiration was low. In this model, the interaction between meteorological factors and the SWC was considered to better reflect the real condition; therefore, the model provided a better way to estimate the crop water consumption.

Using short-term ensemble weather forecast to evaluate outcomes of irrigation

2021 ◽  
Author(s):  
Danlu Guo ◽  
Andrew Western ◽  
Quan Wang ◽  
Dongryeol Ryu ◽  
Peter Moller ◽  
...  
Keyword(s):  
Soil Water ◽  
Root Zone ◽  
Water Status ◽  
Water Productivity ◽  
Limited Resource ◽  
Weather Forecast ◽  
Irrigation Scheduling ◽  
Irrigation Event ◽  
Optimal Timing ◽  
Short Term

&lt;p&gt;Irrigation water is an expensive and limited resource. Previous studies show that irrigation scheduling can boost efficiency by 20-60%, while improving water productivity by at least 10%. In practice, scheduling decisions are often needed several days prior to an irrigation event, so a key aspect of irrigation scheduling is the accurate prediction of crop water use and soil water status ahead of time. This prediction relies on several key inputs such as soil water, weather and crop conditions. Since each input can be subject to its own uncertainty, it is important to understand how these uncertainties impact soil water prediction and subsequent irrigation scheduling decisions.&lt;/p&gt;&lt;p&gt;This study aims to evaluate the outcomes of alternative irrigation scheduling decisions under uncertainty, with a focus on the uncertainties arising from short-term weather forecast. To achieve this, we performed a model-based study to simulate crop root-zone soil water content, in which we comprehensively explored different combinations of ensemble short-term rainfall forecast and alternative decisions of irrigation scheduling. This modelling produced an ensemble of soil water contents to enable quantification of risks of over- and under-irrigation; these ensemble estimates were summarized to inform optimal timing of next irrigation event to minimize both the risks of stressing crop and wasting water. With inclusion of other sources of uncertainty (e.g. soil water observation, crop factor), this approach shows good potential to be extended to a comprehensive framework to support practical irrigation decision-making for farmers.&lt;/p&gt;

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