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.

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.

Soil Organic Matter Content and Volumetric Water Content Affect Indaziflam–Soil Bioavailability

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 757-765 ◽  
Author(s):  
Matthew D. Jeffries ◽  
Travis W. Gannon
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Water Content ◽  
Perennial Ryegrass ◽  
Soil Depth ◽  
Organic Matter Content ◽  
Matter Content ◽  
Volumetric Water Content ◽  
Growth Data ◽  
Soil Organic Matter Content

Indaziflam is a cellulose biosynthesis-inhibiting herbicide for annual weed control in various agricultural systems. Sporadic cases of unacceptable injury to desirable plants have been reported after indaziflam application, which may have been due to conditions favoring increased indaziflam–soil bioavailability. Research was conducted from 2013 to 2015 on a sandy soil to elucidate the effects of soil organic matter content (SOMC) and soil volumetric water content (SVWC) on indaziflam–soil bioavailability. Indaziflam was applied (50 or 100 g ha–1) at fall only, fall plus spring, and spring only timings to plots in a factorial arrangement of SOMC, pre–indaziflam application (PrIA) SVWC, and post–indaziflam application (PoIA) SVWC. After application, field soil cores were collected for a subsequent greenhouse bioassay experiment, where foliage mass reduction of perennial ryegrass seeded from 0 to 15 cm soil depth was used as an indicator of indaziflam–soil bioavailability throughout the profile. Significant edaphic effects were observed at 0 to 2.5, 2.5 to 5, and 5 to 7.5 cm depths, with increased bioavailability at low compared with high SOMC. Pre–indaziflam application SVWC did not affect bioavailability, whereas PoIA high SVWC increased indaziflam–soil bioavailability at 2.5 to 7.5 cm depth compared with PoIA low SVWC. Low SOMC–PoIA high SVWC decreased perennial ryegrass foliage mass 40 and 37% at 5 to 7.5 cm depth from cores collected 10 and 14 wk after treatment, respectively, whereas reductions from all other SOMC–PoIA SVWC combinations were < 12% and did not vary from each other. Pearson's correlation coefficients showed a moderate, positive relationship between perennial ryegrass mass reductions at 0 to 2.5, 2.5 to 5, 0 to 5, and 0 to 10 cm depths and hybrid bermudagrass cover reduction, which suggests conditions favoring increased indaziflam–soil bioavailability can adversely affect plant growth. Data from this research will aid land managers to use indaziflam effectively without adversely affecting growth of desirable species.

scholarly journals Parameter identification and analysis of soluble chemical transfer from soil to surface runoff

2012 ◽  
Vol 9 (3) ◽  
pp. 3901-3931
Author(s):  
J. X. Tong ◽  
J. Z. Yang ◽  
B. X. Hu
Keyword(s):  
Analytical Solution ◽  
Water Content ◽  
Surface Runoff ◽  
Soil Depth ◽  
Volumetric Water Content ◽  
Related Parameter ◽  
Chemical Transfer ◽  
Study Results ◽  
The Moment ◽  
Experimental Soil

Abstract. A two-layer mathematical model is used to predict the chemical transfer from the soil into the surface runoff with ponding water. There are two incomplete infiltration-related parameter γ and runoff-related parameter α in the analytical solution to the model, which were assumed to be constant in previous studies (Tong et al., 2010). In this study, experimental data are used to identify the variable γ and α based on the analytical solution. The soil depth of the mixing zone is kept to be constant in different experiments, and the values of γ and α before the surface runoff occurs are constant and equal to their values at the moment the runoff starts. From the study results, it is found that γ will decrease with the increase of the surface runoff time, the increase of the ponding-water depth, hp, or with the decrease of the initial volumetric water content. The variability of γ will decrease with the increase of the initial volumetric water content. Similarly, α will decrease with time for the initially unsaturated experimental soils, but will increase with time for the initially saturated experimental soils. The larger the infiltration, the less chemical concentration in the surface runoff is. The analytical solution is not valid for experimental soil without any infiltration if α is expected to be less or equal to 1. The results will help to quantify chemical transfer from soil into runoff, a significant problem in agricultural pollution management.

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