scholarly journals Simulation of Soil Volumetric Water Content by HYDRUS-2D under Line Source with Different Salinities of Irrigation Water and Comparison with Field Observations

2016 ◽  
Vol 20 (75) ◽  
pp. 129-140
Author(s):  
F. Javadzadeh Shakhali ◽  
M. Khaledian ◽  
M. Navabian ◽  
P. Shahinrokhsar ◽  
◽  
...  
Keyword(s):  
Water Content ◽  
Irrigation Water ◽  
Line Source ◽  
Volumetric Water Content ◽  
Field Observations ◽  
Soil Volumetric Water Content

scholarly journals Water-Use Characteristics and Physiological Response of Moso Bamboo to Flash Droughts

2019 ◽  
Vol 16 (12) ◽  
pp. 2174 ◽  
Author(s):  
Minxia Zhang ◽  
Shulin Chen ◽  
Hong Jiang ◽  
Yong Lin ◽  
Jinmeng Zhang ◽  
...  
Keyword(s):  
Water Content ◽  
Water Use ◽  
Forest Canopy ◽  
Stand Density ◽  
Water Shortage ◽  
Volumetric Water Content ◽  
Moso Bamboo ◽  
Extreme Drought ◽  
Soil Volumetric Water Content ◽  
The Stability

Frequent flash droughts can rapidly lead to water shortage, which affects the stability of ecosystems. This study determines the water-use characteristics and physiological mechanisms underlying Moso bamboo response to flash-drought events, and estimates changes to water budgets caused by extreme drought. We analyzed the variability in forest canopy transpiration versus precipitation from 2011–2013. Evapotranspiration reached 730 mm during flash drought years. When the vapor pressure deficit > 2 kPa and evapotranspiration > 4.27 mm·day−1, evapotranspiration was mainly controlled through stomatal opening and closing to reduce water loss. However, water exchange mainly occurred in the upper 0–50 cm of the soil. When soil volumetric water content of 50 cm was lower than 0.17 m3·m−3, physiological dehydration occurred in Moso bamboo to reduce transpiration by defoliation, which leads to water-use efficiency decrease. When mean stand density was <3500 trees·ha−1, the bamboo forest can safely survive the flash drought. Therefore, we recommend thinning Moso bamboo as a management strategy to reduce transpiration in response to future extreme drought events. Additionally, the response function of soil volumetric water content should be used to better simulate evapotranspiration, especially when soil water is limited.

scholarly journals RELATIONSHIPS OF IRRIGATION AND MEDIUM COMPOSITION TO TEMPERATURE DYNAMICS IN CONTAINER MEDIA

HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 849e-849
Author(s):  
Chris A. Martin ◽  
Dewayne L. Ingram
Keyword(s):  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Water Content ◽  
High Temperatures ◽  
Irrigation Water ◽  
Medium Composition ◽  
Volumetric Water Content ◽  
Pine Bark ◽  
Sand Content ◽  
Temperature Dynamics

Thermal properties of pine bark: sand container media as a function of volumetric water content and effectiveness of irrigation as a tool for modulating high temperatures in container media were studied. Volumetric water and sand content interacted to affect container medium thermal diffusivity. Adding sand to a pine bark container medium decreased thermal diffusivity if volumetric water content was less than 10 percent and increased thermal diffusivity if volumetric water content was between 10 and 70 percent. Thermal diffusivity was greatest for a 3 pine bark : 2 sand container medium if volumetric water content was between 30 and 70 percent. Irrigation was used to decrease temperatures in 10-liter container media. Irrigation water at 26°C was more effective if 1) volumes equaled or exceeded 3000 ml, 2) applications were made during mid-day, and 3) sand was present in the container medium compared to pine bark alone. However, due to the volume of water required to lower container media temperatures, nursery operators should first consider reducing incoming irradiance via overhead shade or container spacing.

scholarly journals Field Monitoring-Based and Theoretical Analysis of Baota Mountain Landslide Stability

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yaming Tang ◽  
Heping Shu ◽  
Qiang Xue ◽  
Jiayun Wang ◽  
Wei Feng ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Depth ◽  
Limit Equilibrium ◽  
Stable State ◽  
Field Monitoring ◽  
Volumetric Water Content ◽  
Soil Volumetric Water Content ◽  
Limit Equilibrium Methods ◽  
Landslide Stability ◽  
Different Depths

Landslide is one of the most widely distributed surface morphological landscapes, and it can cause a series of major economic and human losses. Field monitoring and limit equilibrium methods were applied to investigate Baota Mountain landslide stability, and soil volumetric water content, different scales of rainfall data, and landslide displacements were monitored using various equipment. The theoretical factor of safety was also calculated for the landslide. Finally, the theoretical results were validated by monitoring data in the field. The results demonstrate that soil volumetric water content experienced the greatest change with time at a depth of 0.2 m and then 1 m; however, the change in soil volumetric water content was relatively small with time at a soil depth ranging from 2.0 m to 4.0 m. Soil volumetric water content also did not change with time at a soil depth of 5.0 m and below. In addition, the retardation effect was found in different depths of volumetric water content for continuous rainfall. The safety factors were 2.713 and 1.133 for landslide No. 1 and landslide No. 2, respectively. These results indicate that landslide No. 1 is relatively stable, but there is a probability of the occurrence of movement in landslide No. 2. The monitoring displacement data indicate that landslide No.1 was in a relatively stable state between 2008 and 2013, and this result was in accordance with the value of theoretical calculation. This study provided relevant parameters for numerical simulation of landslides in loess areas.

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