scholarly journals Soil Water Stable Isotopes Reveal Surface Soil Evaporation Loss Dynamics in a Subtropical Forest Plantation

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1648
Author(s):  
Sidan Lyu ◽  
Jing Wang
Keyword(s):  
Soil Water ◽  
Soil Layer ◽  
Subtropical Forest ◽  
Soil Evaporation ◽  
Forest Plantation ◽  
Evaporation Loss ◽  
Event Based ◽  
Δd And Δ18o ◽  
The Relationship ◽  
Loss Estimate

Line-conditioned excess (lc-excess), the deviation of the relationship between δD and δ18O in soil water from that of precipitation, is often used to indicate soil evaporation loss, but the conditions of using lc-excess under the influences of precipitation infiltration or percolation had not been identified. The interaction effects of climate, soil and vegetation on soil evaporation in forests are not well known. We collected soil water at 0–5, 15–20 and 40–45 cm depths and event-based precipitation from 2011 to 2015 in a subtropical forest plantation and calculated the lc-excess. Precipitation on the sampling day and percolation of upper soil water with low lc-excess affected the capacity of the lc-excess to indicate the soil evaporation fractionation signals. Lc-excess of soil water at 0–5 cm depth indicated a reliable soil evaporation loss estimate over 30 days prior to the sampling day. Soil evaporation loss was dominated by the cumulative soil temperature (Tss) during drought periods and was dominated by the relative soil water content (RSWC) during non-drought periods. High Tss decreased soil evaporation loss by increasing transpiration and relative humidity. Our results emphasize the importance of sampling the upper-most soil layer when there is no rain and vegetation during drought periods in forests when studying soil evaporation loss dynamics.

scholarly journals Characteristics of Soil Moisture and Evaporation under the Activities of Earthworms in Typical Anthrosols in China

2020 ◽  
Vol 12 (16) ◽  
pp. 6603
Author(s):  
Li Ma ◽  
Ming’an Shao ◽  
Tongchuan Li
Keyword(s):  
Soil Temperature ◽  
Soil Water ◽  
Agricultural Development ◽  
Soil Layer ◽  
Soil Surface ◽  
Soil Evaporation ◽  
Water Evaporation ◽  
Soil Columns ◽  
Soil Surface Temperature ◽  
Water Holding

Earthworms have an important influence on the terrestrial ecological environment. This study assesses the effect of different earthworm densities on soil water content (SWC) and evaporation in a laboratory experiment. Four earthworm densities (0 no-earthworm, control [C]; 207 earthworms m−2, low density [LDE]; 345 earthworms m−2, medium density [MDE]; and 690 earthworms m−2, high density [HDE]) are tested in soil columns. Results show that cumulative evaporation occurs in the decreasing order of densities: C (98.6 mm) > LDE (115.8 mm) > MDE (118.4 mm) > HDE (124.6 mm). Compared with the control, earthworm activity decreases cumulative soil evaporation by 5.0–20.9%, increases soil temperature to 0.46 °C–0.63 °C at 8:00, and decreases soil temperature to 0.21 °C–0.52 °C at 14:00 on the soil surface. Temperature fluctuations reduce with increasing earthworm densities. A negative correlation is found between cumulative soil evaporation and earthworm density (R2 = 0.969, p < 0.001). Earthworms significantly (p < 0.05) decrease the surface SWC loss (0–20 cm) soil layer but increase the subsoil SWC loss (60–100 cm) by adjusting the soil temperature and reducing soil water evaporation. Earthworm activities (burrows, casts…) improve the soil water holding ability by adjusting soil temperature and reducing soil water evaporation. Thus, the population quantity of earthworms may provide valuable ecosystem services in soil water and heat cycles to save water resources and realize sustainable agricultural development.

Modelling the seasonal dynamics of the soil water balance of vineyards

2003 ◽  
Vol 30 (6) ◽  
pp. 699 ◽  
Author(s):  
Eric Lebon ◽  
Vincent Dumas ◽  
Philippe Pieri ◽  
Hans R. Schultz
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Soil Layer ◽  
Water Storage ◽  
Soil Evaporation ◽  
Water Dynamics ◽  
Soil Water Balance ◽  
Sensitivity Analyses ◽  
Rooting Depth ◽  
Top Soil

A geometrical canopy model describing radiation absorption (Riou et al. 1989, Agronomie 9, 441–450) and partitioning between grapevines (Vitis vinifera L.) and soil was coupled to a soil water balance routine describing a bilinear change in relative transpiration rate as a function of the fraction of soil transpirable water (FTSW). The model was amended to account for changes in soil evaporation after precipitation events and subsequent dry-down of the top soil layer. It was tested on two experimental vineyards in the Alsace region, France, varying in soil type, water-holding capacity and rooting depth. Simulations were run over four seasons (1992–1993, 1995–1996) and compared with measurements of FTSW conducted with a neutron probe. For three out of four years, the model simulated the dynamics in seasonal soil water balance adequately. For the 1996 season soil water content was overestimated for one vineyard and underestimated for the other. Sensitivity analyses revealed that the model responded strongly to changes in canopy parameters, and that soil evaporation was particularly sensitive to water storage of the top soil layer after rainfall. We found a close relationship between field-average soil water storage and pre-dawn water potential, a relationship which could be used to couple physiological models of growth and / or photosynthesis to the soil water dynamics.

scholarly journals Soil Water Dynamics Under Different Land Uses in Loess Hilly Region in China by Stable Isotopic Tracing

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 242
Author(s):  
Kang Du ◽  
Beiying Zhang ◽  
Linjuan Li
Keyword(s):  
Land Use ◽  
Soil Water ◽  
Preferential Flow ◽  
Soil Evaporation ◽  
Water Dynamics ◽  
Soil Water Dynamics ◽  
Land Use Types ◽  
Hilly Region ◽  
The Difference ◽  
Δd And Δ18o

Exploring soil water dynamics under different land use types is important for water resource management and vegetation restoration in the Loess Plateau. In this study, we investigated the hydrogen and oxygen isotopic compositions of soil water from four different land use types to explore the mechanism of soil water movement and transformation and analyse the influence of land use. The results show that the range of stable isotopes (δD and δ18O) in soil water was smaller than that in precipitation. Values for δD and δ18O in soil water showed relatively similar temporal variation, heavy isotopes were enriched in the soil water in July and depleted in October. Stable isotope values in shallow (<100 cm depth) soil water and deep (>200 cm depth) soil water were low. The δD and δ18O values in woodlands decreased gradually with increasing depth. Across the four land use types, the maximum variation in δD and δ18O was in the shallow depth of the soil profile. Groundwater was recharged mainly from precipitation and then from soil water. The ratio of groundwater recharge by soil water under different land use types followed this rank order: woodland (35.70%) > grassland (31.14%) > shrubland (29.47%) > cropland (29.18%). Matrix flow and preferential flow coexisted during infiltration, and the occurrence of preferential flow was related to the land use type. The main reason for the variation in isotopic composition in soil water is the difference in soil evaporation, which is influenced by different vegetation cover. Owing to the difference in soil evaporation and fractionation, precipitation on cropland, shrubland, and grassland can recharge more soil water than on woodland.

scholarly journals Stem-root flow effect on soil–atmosphere interactions and uncertainty assessments

2015 ◽  
Vol 12 (11) ◽  
pp. 11783-11816
Author(s):  
T.-H. Kuo ◽  
J.-P. Chen ◽  
Y. Xue
Keyword(s):  
Heat Flux ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Sensible Heat Flux ◽  
Soil Layer ◽  
Soil Evaporation ◽  
Soil Layers ◽  
Flow Effect ◽  
Top Soil

Abstract. Soil water can rapidly enter deeper layers via vertical redistribution of soil water through the stem–root flow mechanism. This study develops the stem–root flow parameterization scheme and coupled this scheme with the Simplified Simple Biosphere model (SSiB) to analyze its effects on land–atmospheric interactions. The SSiB model was tested in a single column mode using the Lien Hua Chih (LHC) measurements conducted in Taiwan and HAPEX-Mobilhy (HAPEX) measurements in France. The results show that stem–root flow generally caused a decrease in the moisture content at the top soil layer and moistened the deeper soil layers. Such soil moisture redistribution results in significant changes in heat flux exchange between land and atmosphere. In the humid environment at LHC, the stem–root flow effect on transpiration was minimal, and the main influence on energy flux was through reduced soil evaporation that led to higher soil temperature and greater sensible heat flux. In the Mediterranean environment of HAPEX, the stem–root flow significantly affected plant transpiration and soil evaporation, as well as associated changes in canopy and soil temperatures. However, the effect on transpiration could either be positive or negative depending on the relative changes in the moisture content of the top soil vs. deeper soil layers due to stem–root flow and soil moisture diffusion processes.

scholarly journals Regression Models for Soil Water Storage Estimation Using the ESA CCI Satellite Soil Moisture Product: A Case Study in Northeast Portugal

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Tomás de Figueiredo ◽  
Ana Caroline Royer ◽  
Felícia Fonseca ◽  
Fabiana Costa de Araújo Schütz ◽  
Zulimar Hernández
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Regression Models ◽  
Meteorological Data ◽  
Water Storage ◽  
Model Performance ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
The Relationship

The European Space Agency Climate Change Initiative Soil Moisture (ESA CCI SM) product provides soil moisture estimates from radar satellite data with a daily temporal resolution. Despite validation exercises with ground data that have been performed since the product’s launch, SM has not yet been consistently related to soil water storage, which is a key step for its application for prediction purposes. This study aimed to analyse the relationship between soil water storage (S), which was obtained from soil water balance computations with ground meteorological data, and soil moisture, which was obtained from radar data, as affected by soil water storage capacity (Smax). As a case study, a 14-year monthly series of soil water storage, produced via soil water balance computations using ground meteorological data from northeast Portugal and Smax from 25 mm to 150 mm, were matched with the corresponding monthly averaged SM product. Linear (I) and logistic (II) regression models relating S with SM were compared. Model performance (r2 in the 0.8–0.9 range) varied non-monotonically with Smax, with it being the highest at an Smax of 50 mm. The logistic model (II) performed better than the linear model (I) in the lower range of Smax. Improvements in model performance obtained with segregation of the data series in two subsets, representing soil water recharge and depletion phases throughout the year, outlined the hysteresis in the relationship between S and SM.

scholarly journals Changes in soil water holding capacity and water availability following vegetation restoration on the Chinese Loess Plateau

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong-wang Zhang ◽  
Kai-bo Wang ◽  
Jun Wang ◽  
Changhai Liu ◽  
Zhou-ping Shangguan
Keyword(s):  
Land Use ◽  
Soil Water ◽  
Loess Plateau ◽  
Soil Layer ◽  
Soil Physical Properties ◽  
Chinese Loess Plateau ◽  
Land Use Type ◽  
Chinese Loess ◽  
Water Holding ◽  
The Chinese Loess Plateau

AbstractChanges in land use type can lead to variations in soil water characteristics. The objective of this study was to identify the responses of soil water holding capacity (SWHC) and soil water availability (SWA) to land use type (grassland, shrubland and forestland). The soil water characteristic curve describes the relationship between gravimetric water content and soil suction. We measured the soil water characteristic parameters representing SWHC and SWA, which we derived from soil water characteristic curves, in the 0–50 cm soil layer at sites representing three land use types in the Ziwuling forest region, located in the central part of the Loess Plateau, China. Our results showed that the SWHC was higher at the woodland site than the grassland and shrubland, and there was no significant difference between the latter two sites, the trend of SWA was similar to the SWHC. From grassland to woodland, the soil physical properties in the 0–50 cm soil layer partially improved, BD was significantly higher at the grassland site than at the shrubland and woodland sites, the clay and silt contents decreased significantly from grassland to shrubland to woodland and sand content showed the opposite pattern, the soil porosity was higher in the shrubland and woodland than that in the grassland, the soil physical properties across the 0–50 cm soil layer improved. Soil texture, porosity and bulk density were the key factors affecting SWHC and SWA. The results of this study provide insight into the effects of vegetation restoration on local hydrological resources and can inform soil water management and land use planning on the Chinese Loess Plateau.

scholarly journals Root Response to Soil Water Status via Interaction of Crop Genotype and Environment

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 708
Author(s):  
Phanthasin Khanthavong ◽  
Shin Yabuta ◽  
Hidetoshi Asai ◽  
Md. Amzad Hossain ◽  
Isao Akagi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Root Distribution ◽  
Water Status ◽  
Soil Layer ◽  
Shoot Biomass ◽  
Soil Conditions ◽  
Crop Adaptation ◽  
Soil Moisture Status ◽  
Root Distributions

Flooding and drought are major causes of reductions in crop productivity. Root distribution indicates crop adaptation to water stress. Therefore, we aimed to identify crop roots response based on root distribution under various soil conditions. The root distribution of four crops—maize, millet, sorghum, and rice—was evaluated under continuous soil waterlogging (CSW), moderate soil moisture (MSM), and gradual soil drying (GSD) conditions. Roots extended largely to the shallow soil layer in CSW and grew longer to the deeper soil layer in GSD in maize and sorghum. GSD tended to promote the root and shoot biomass across soil moisture status regardless of the crop species. The change of specific root density in rice and millet was small compared with maize and sorghum between different soil moisture statuses. Crop response in shoot and root biomass to various soil moisture status was highest in maize and lowest in rice among the tested crops as per the regression coefficient. Thus, we describe different root distributions associated with crop plasticity, which signify root spread changes, depending on soil water conditions in different crop genotypes as well as root distributions that vary depending on crop adaptation from anaerobic to aerobic conditions.

scholarly journals Persistent Activist Communication in Occupy Gezi

Sociology ◽  
2017 ◽  
Vol 52 (5) ◽  
pp. 915-933 ◽  
Author(s):  
Dan Mercea ◽  
Duygu Karatas ◽  
Marco T Bastos
Keyword(s):  
Survey Data ◽  
Early Summer ◽  
Online Activity ◽  
Clear Cut ◽  
Twitter Data ◽  
Organisational Structures ◽  
Biographical Availability ◽  
Event Based ◽  
The Relationship ◽  
Depth Interviews

We revisit the notion of activist persistence against the backdrop of protest communication on Twitter. We take an event-based approach and examine Occupy Gezi, a series of protests that occurred in Turkey in the early summer of 2013. By cross-referencing survey data with longitudinal Twitter data and in-depth interviews, we investigate the relationship between biographical availability, relational and organisational ties, and social and personal costs to persistent activism online and on location. Contrary to expectations, we find no clear-cut relationship between those factors and sustained commitment to participation in the occupation. We show that persistent activist communication did not feed into enduring organisational structures despite the continuous online activity observed during and beyond the peak of the Gezi occupation. The article concludes with reflections on the organisational ramifications of persistent communication and its significance in a political context posing high risks to participation in dissident politics.

A descriptive model of the relationship between rainfall and soil water table

1980 ◽  
Vol 47 (1-2) ◽  
pp. 103-114 ◽  
Author(s):  
K. Rennolls ◽  
R. Carnell ◽  
V. Tee
Keyword(s):  
Soil Water ◽  
Water Table ◽  
Descriptive Model ◽  
The Relationship
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