scholarly journals Comparison of Soil Moisture Dynamics in Fixed Dune and Sandy Grassland on Korqin Sandy Land

2021 ◽  
Vol 293 ◽  
pp. 01013
Author(s):  
Shuxia Yao ◽  
Chuancheng Zhao
Keyword(s):  
Soil Moisture ◽  
Soil Depth ◽  
Spatial Dynamics ◽  
Growing Season ◽  
Observation Data ◽  
Sandy Land ◽  
Soil Layers ◽  
Semi Arid Region ◽  
Moisture Dynamics ◽  
Sandy Grassland

Based on the fixed-point observation data of soil moisture in different soil layers (0~150 cm) of fixed dunes and sandy grassland in the semi-arid region of Horqin Sandy Land, in the growing season (May to September) from 2005 to 2014, we conducted a comparative study on the seasonal, inter-annual, and spatial dynamics of soil moisture in the two types of sandy land. The results revealed that: (1) in the growing season, the soil moisture in sandy grassland was significantly higher than that in fixed dunes, and the multi-year average soil moisture in both types of sandy land was higher in July than in other months; (2) from 2005 to 2014, the average soil moisture in both types of sandy land was relatively high in 2010, and the average soil moisture in sandy grassland increased gradually with each year; specifically, there was a significant increase in soil moisture in June, while the average soil moisture in fixed dunes did not show an obvious increase; (3) the soil moisture in fixed dunes and sandy grassland generally showed a trend of “first increase, then decrease, and finally increase again”, with the increase in soil depth, and this change was more obvious for sandy grassland.

scholarly journals Application of Time Series Analysis in Soil Moisture of Fixed Dune on Korqin Sandy Land, Northern China

2020 ◽  
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Time Series Analysis ◽  
Soil Depth ◽  
Time Lag ◽  
Soil Layer ◽  
Growing Season ◽  
Northern China ◽  
Sandy Land ◽  
Series Analysis

<p>Time series analysis is a very effective method to analyze the dynamic characteristics of soil moisture at long-term scale. In this study, we have used the time series to analyze the relationship between precipitation and soil moisture on fixed dune at different soil depths (from 0 to 120 cm) during the growing season (from May to September) of 2006-2010 in Korqin Sandy Land, northern China. The results indicate that: (1) The precipitation is a relatively independent time series and has no obvious autocorrelation. Precipitation in an earlier stage has no obvious effect on the later stage in the growing season. (2) Soil moisture in different soil layers has higher autocorrelation; and the autocorrelation of soil moisture in each soil layer is significantly weakened with the increase in time lag interval. (3) The correlation coefficient between soil moisture and precipitation in each soil layer is higher at the time lag interval of k = 0; with the increase in soil depth, the correlation is gradually weakened. (4) The maximum correlation coefficients of soil moisture series and precipitation series in different soil depths were obtained at the time lag interval of k = 0.</p>

Soil moisture dynamics under Caragana korshinskii shrubs of different ages in Wuzhai County on the Loess Plateau, China

2018 ◽  
Vol 109 (3-4) ◽  
pp. 387-396 ◽  
Author(s):  
Haibin LIANG ◽  
Yayong XUE ◽  
Jianwei SHI ◽  
Zongshan LI ◽  
Guohua LIU ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Growing Season ◽  
Deep Soil ◽  
Soil Moisture Dynamics ◽  
Soil Layers ◽  
Caragana Korshinskii ◽  
Hilly Region ◽  
Different Ages ◽  
Moisture Dynamics

ABSTRACTSoil moisture is a key factor affecting vegetation growth and survival in arid and semi-arid regions. Knowledge of deep soil moisture dynamics is very important for guiding vegetation restoration and for improving land management practices on the water-limited Loess Plateau. Temporal changes and vertical variations in deep soil moisture (at soil depths of 0–600cm) combined with soil moisture availability were monitored in situ under Caragana korshinskii shrubs of different ages (named CK-10a, CK-20a and CK-35a) in the Loess hilly region during the growing season of 2013. The soil moisture content (SMC) under C. korshinskii shrubs of different ages was highly consistent with the seasonal precipitation variations and generally decreased as follows: CK-10a>CK-20a>abandoned land>CK-35a. The SMC varied greatly over time during the growing season (P<0.01), decreasing from April to May and then slowly increasing with some fluctuation from June to October. The SMC drastically decreased with depth from 0–300cm and then gradually increased with some fluctuation from 300–600cm. A critical turning point and transition zone connecting the shallow and deep soil moisture occurred at 200–300cm. Therefore, the soil profile was divided into active, secondary active and relatively steady soil layers in terms of soil moisture. The SMC fluctuated at depths of 0–100cm and 300–400cm and was relatively stable in the deeper soil layers. The amount of available soil moisture gradually decreased as the forest stand age increased, especially at CK-35a, where most of the soil moisture was unavailable for plant use. In addition, our study indicates that a large-scale restoration strategy with pure shrubland or woodland may not be suitable for soil moisture recovery in arid environments.

Soil moisture dynamics under Caragana korshinskii shrubs of different ages in Wuzhai County on the Loess Plateau, China

2020 ◽  
Author(s):  
Zongshan Li ◽  
Haibin Liang
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Growing Season ◽  
Deep Soil ◽  
Soil Moisture Dynamics ◽  
Soil Layers ◽  
Caragana Korshinskii ◽  
Hilly Region ◽  
Different Ages ◽  
Moisture Dynamics

&lt;p&gt;Soil moisture is a key factor affecting vegetation growth and survival in arid and semi-arid regions. Knowledge of deep soil moisture dynamics is very important for guiding vegetation restoration and for improving land management practices on the water-limited Loess Plateau. Temporal changes and vertical variations in deep soil moisture (at soil depths of 0&amp;#8211;600 cm) combined with soil moisture availability were monitored in situ under &lt;em&gt;Caragana korshinskii&lt;/em&gt; shrubs of different ages (named CK-10a, CK-20a and CK-35a) in the Loess hilly region during the growing season of 2013. The soil moisture content (SMC) under &lt;em&gt;C. korshinskii&lt;/em&gt; shrubs of different ages was highly consistent with the seasonal precipitation variations and generally decreased as follows: CK-10a &gt; CK-20a &gt; abandoned land &gt; CK-35a. The SMC varied greatly over time during the growing season (P &lt; 0.01), decreasing from April to May and then slowly increasing with some fluctuation from June to October. The SMC drastically decreased with depth from 0&amp;#8211;300 cm and then gradually increased with some fluctuation from 300&amp;#8211;600 cm. A critical turning point and transition zone connecting the shallow and deep soil moisture occurred at 200&amp;#8211;300 cm. Therefore, the soil profile was divided into active, secondary active and relatively steady soil layers in terms of soil moisture. The SMC fluctuated at depths of 0&amp;#8211;100 cm and 300&amp;#8211;400 cm and was relatively stable in the deeper soil layers. The amount of available soil moisture gradually decreased as the forest stand age increased, especially at CK-35a, where most of the soil moisture was unavailable for plant use. In addition, our study indicates that a large-scale restoration strategy with pure shrubland or woodland may not be suitable for soil moisture recovery in arid environments.&lt;/p&gt;

scholarly journals A Multilayer Soil Moisture Dataset Based on the Gravimetric Method in China and Its Characteristics

2019 ◽  
Vol 20 (8) ◽  
pp. 1721-1736 ◽  
Author(s):  
Aihui Wang ◽  
Xueli Shi
Keyword(s):  
Soil Moisture ◽  
Soil Depth ◽  
Linear Trend ◽  
Standardized Precipitation Index ◽  
Gravimetric Method ◽  
Northwest China ◽  
Soil Layers ◽  
Significance Level ◽  
The Mean ◽  
The Standardized Precipitation Index

Abstract Based on the gravimetric-technique-measured soil relative wetness and the observed soil characteristic parameters from 1992 to 2013 in China, this study derives a user-convenient monthly volumetric soil moisture (SM) dataset from 732 stations for five soil layers (10, 20, 50, 70, and 100 cm). The temporal–spatial variations in SM and its relationship with precipitation (Pr) in different subregions are then explored. The magnitude of SM is relatively large in south China and is low in northwest China, and it generally increases with soil depth in each region. The maximum SM appears in spring and/or autumn and the minimum in summer, and the SM seasonality does not vary as distinctly as that of Pr. For the top three soil layers (10-, 20-, and 50-cm levels), the linear trend analysis indicates an overall increasing SM tendency, and the mean trends (averaged across stations with trends passing a 95% significance level test) are 9.35 × 10−7, 7.37 × 10−3, and 2.45 × 10−3 cm3 cm−3 yr−1, respectively. SM memory depends on the soil depth and regions, and it has longer retention time in the deeper layers. Furthermore, the correlation between SM and antecedent Pr varies with soil depth and lag time. The antecedent Pr anomaly (1 or 2 months in advance) can be used to some extent as a surrogate SM anomaly in most regions except for in arid regions. This result is further demonstrated by the relationships between the SM anomaly and the standardized precipitation index. The current SM dataset can be used in various applications, such as validating satellite-retrieved products and model outputs.

Extension of the regional climate model REMO by a 5-layer soil scheme

2020 ◽  
Author(s):  
Daniel Abel ◽  
Felix Pollinger ◽  
Katrin Ziegler ◽  
Heiko Paeth
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Soil Depth ◽  
Regional Climate ◽  
Capillary Rise ◽  
Rooting Depth ◽  
Climate Projections ◽  
Observation Data ◽  
Soil Hydrology ◽  
Spatiotemporal Resolution

&lt;p&gt;The EFRE-Project BigData@Geo, founded by the European Union, aims to create highly resolved climate projections for the model region of Lower Franconia in Bavaria, Germany. These projections are analyzed and made available to local stakeholders of agriculture, forestry, and viniculture as well as the public. As recent regional climate models are not dealing with the necessary spatiotemporal resolution the model REMO will be developed in the project&amp;#8216;s frame in cooperation with the Climate Service Center Germany (GERICS).&lt;/p&gt;&lt;p&gt;For these very high resolutions, besides improvements like the non-hydrostatic atmosphere, higher resolved static land surface parameters, and land use land cover changes, etc., realistic modeling of the soil hydrology becomes absolutely necessary. Therefore, REMO is extended by a 5-layer soil scheme which is a first step to overcome restrictions of the recently used soil hydrology scheme due to the included vertical water flow. Furthermore, the current work also aims to implement lateral water flows between grid cells because this is the only way to model the soil hydrology appropriate to the project&amp;#8216;s question.&lt;/p&gt;&lt;p&gt;The current model version of REMO includes a bucket scheme that treats the soil hydrology as a single layer. The soil depth is equal to the rooting depth and, thus, depends on the overlying vegetation class. Consequently, the whole soil moisture of the soil is available for transpiration. Evaporation only occurs if the soil moisture reaches at least 90 % of the field capacity.&lt;/p&gt;&lt;p&gt;The 5-layer scheme has 5 layers with increasing thicknesses for deeper layers. The maximum depth of the soil is at approximately 10&amp;#160;m or the depth of the bedrock. Due to the existence of water below the rooting zone and the processes of capillary rise and percolation more water becomes available for transpiration compared to the bucket scheme. Furthermore, evaporation only occurs if the uppermost layer contains soil moisture which is a more realistic process representation as well.&lt;/p&gt;&lt;p&gt;First results of the comparison of the two schemes and with observation data in the EURO-CORDEX region and a german subregion are presented. We also show some sensitivity studies of the current improvements to the parameterizations of the 5-layer scheme which are necessary for the goal of incorporation of the lateral flow.&lt;/p&gt;

scholarly journals Recharge estimation and soil moisture dynamics in a Mediterranean karst aquifer

2014 ◽  
Vol 11 (7) ◽  
pp. 8803-8844 ◽  
Author(s):  
F. Ries ◽  
J. Lange ◽  
S. Schmidt ◽  
H. Puhlmann ◽  
M. Sauter
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Unsaturated Soil ◽  
Soil Depth ◽  
Climatic Gradient ◽  
Soil Moisture Dynamics ◽  
Soil Zone ◽  
Moisture Dynamics ◽  
Hydrus 1D

Abstract. Knowledge of soil moisture dynamics in the unsaturated soil zone provides valuable information on the temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region, where a substantial fraction of long-term groundwater recharge is expected to occur during high magnitude precipitation events of above-average wet winters. To elucidate process understanding of infiltration processes during these extreme events, a monitoring network of precipitation gauges, meteorological stations, and soil moisture plots was installed in an area with a steep climatic gradient in the Jordan Valley region. In three soil moisture plots, Hydrus-1D was used to simulate water movement in the unsaturated soil zone with soil hydraulic parameters estimated by the Shuffled Complex Evolution Metropolis algorithm. To generalize our results, we modified soil depth and rainfall input to simulate the effect of the pronounced climatic gradient and soil depth variability on percolation fluxes and applied the calibrated model to a time series with 62 years of meteorological data. Soil moisture measurements showed a pronounced seasonality and suggested rapid infiltration during heavy rainstorms. Hydrus-1D successfully simulated short and long-term soil moisture patterns, with the majority of simulated deep percolation occurring during a few intensive rainfall events. Temperature drops in a nearby groundwater well were observed synchronously with simulated percolation pulses, indicating rapid groundwater recharge mechanisms. The 62 year model run yielded annual percolation fluxes of up to 66% of precipitation depths during wet years and of 0% during dry years. Furthermore, a dependence of recharge on the temporal rainfall distribution could be shown. Strong correlations between depth of recharge and soil depth were also observed.

scholarly journals Recharge estimation and soil moisture dynamics in a Mediterranean, semi-arid karst region

2015 ◽  
Vol 19 (3) ◽  
pp. 1439-1456 ◽  
Author(s):  
F. Ries ◽  
J. Lange ◽  
S. Schmidt ◽  
H. Puhlmann ◽  
M. Sauter
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Unsaturated Soil ◽  
Soil Depth ◽  
Climatic Gradient ◽  
Soil Moisture Dynamics ◽  
Soil Zone ◽  
Moisture Dynamics ◽  
Hydrus 1D

Abstract. Knowledge of soil moisture dynamics in the unsaturated soil zone provides valuable information on the temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region, where a substantial fraction of long-term groundwater recharge is expected to occur during high magnitude precipitation events of above-average wet winters. To elucidate process understanding of infiltration processes during these extreme events, a monitoring network of precipitation gauges, meteorological stations, and soil moisture plots was installed in an area with a steep climatic gradient in the Jordan Valley region. In three soil moisture plots, Hydrus-1D was used to simulate water movement in the unsaturated soil zone with soil hydraulic parameters estimated by the Shuffled Complex Evolution Metropolis algorithm. To generalize our results, we modified soil depth and rainfall input to simulate the effect of the pronounced climatic gradient and soil depth variability on percolation fluxes and applied the calibrated model to a time series with 62 years of meteorological data. Soil moisture measurements showed a pronounced seasonality and suggested rapid infiltration during heavy rainstorms. Hydrus-1D successfully simulated short and long-term soil moisture patterns, with the majority of simulated deep percolation occurring during a few intensive rainfall events. Temperature drops in a nearby groundwater well were observed synchronously with simulated percolation pulses, indicating rapid groundwater recharge mechanisms. The 62-year model run yielded annual percolation fluxes of up to 66% of precipitation depths during wet years and of 0% during dry years. Furthermore, a dependence of recharge on the temporal rainfall distribution could be shown. Strong correlations between depth of recharge and soil depth were also observed.

scholarly journals The effects of stemflow on redistributing precipitation and infiltration around shrubs

2018 ◽  
Vol 66 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Dong Li ◽  
Deng Wang ◽  
Zening Wu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
Soil Depth ◽  
Rainfall Threshold ◽  
Chinese Loess Plateau ◽  
Wetting Front ◽  
Deep Soil ◽  
Soil Layers ◽  
Chinese Loess ◽  
Caragana Korshinskii

Abstract The experiments of stemflow of two semiarid shrubs (Caragana korshinskii and Hippophae rhamnoides) and its effect on soil water enhancement were conducted from 1st May to 30th September of 2009-2013 in the Chinese Loess Plateau. Stemflow values in C. korshinskii and H. rhamnoides averaged 6.7% and 2.4% of total rainfall. The rainfall threshold for stemflow generation was 0.5 and 2.5 mm for C. korshinskii and H. rhamnoides. When rainfall was less than 17.0 mm, the funnelling ratios were highly variable, however, stable funnelling ratios were found for rainfall greater than 17.0 mm for C. korshinskii. The funnelling ratios of H. rhamnoides first increased until a threshold value of 10.0 mm and then the funnelling ratios begin stabilize. The wetting front depths in the area around stem was 1.4-6.7 and 1.3-2.9 times deeper than area outside the canopy for C. korshinskii and H. rhamnoides. Soil moisture at soil depth 0-200 cm was 25.6% and 23.4% higher in soil around stem than that outside canopy for C. korshinskii and H. rhamnoides. The wetting front advanced to depths of 120 and 100 cm in the area around stem and to depths of 50 cm in the area outside the canopy for C. korshinskii and H. rhamnoides suggested that more rain water can be conserved into the deep soil layers through shrub stemflow. Soil moisture was enhanced in the area outside the shrub canopy, only when rainfall depth is > 4.7 and 5.1 mm, which is an effective rainfall for the area for C. korshinskii and H. rhamnoides. While for the area around stem of C. korshinskii and H. rhamnoides, the corresponding threshold values are 3.2 and 4.3 mm. These results confirmed that stemflow has a positive effect on soil moisture balance of the root zone and the enhancement in soil moisture of deeper soil layers.

The Effect of Tied Ridge Cultivation on the Yield of Maize and a Maize/Cowpea Relay in the Gambia

1991 ◽  
Vol 27 (3) ◽  
pp. 269-279 ◽  
Author(s):  
J. P. Wright ◽  
J. L. Posner ◽  
J. D. Doll
Keyword(s):  
Soil Moisture ◽  
Cropping System ◽  
Growing Season ◽  
The Gambia ◽  
Residual Soil ◽  
Tillage Practices ◽  
Growing Seasons ◽  
Average Rainfall ◽  
Semi Arid Region ◽  
Semi Arid

SummaryThe growing season in the semi-arid region of West Africa is drought prone and of irregular duration. Two experiments were conducted in 1986 and 1987 to test the effects of flat cultivation and tied ridge cultivation (TRC) on the yields of maize and the component crops of a maize and cowpea relay cropping system. The two research sites, with slopes of 0.05% and 3%, were near Sapu, The Gambia, on an Aridic Kandiustalf in the 700 mm rainfall zone.Both growing seasons had above average rainfall. In both years, maize on level sites showed no response to tillage practices. On the sloped site in 1987, soil moisture 10 and 15 days after the last rain was greater with TRC than with flat cultivation and yields of sole cowpea and maize were 25% and 18% greater, respectively. On the level site, TRC had no effect on residual soil moisture or grain yield. When rainfall was well distributed, tied ridging did not appear to be a viable tillage alternative for maize-based systems on flat land in central Gambia but with modest slopes, tied ridges markedly increased soil water reserves in the 0.15 to 0.60 m depth after maize harvest.

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