scholarly journals Soil Hydrothermal Characteristics among Three Typical Vegetation Types: An Eco-Hydrological Analysis in the Qilian Mountains, China

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1277
Author(s):  
Jian Hu ◽  
Da Lü ◽  
Feixiang Sun ◽  
Yihe Lü ◽  
Youjun Chen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Water ◽  
Water Loss ◽  
Soil Profile ◽  
Surface Soil ◽  
Vegetation Pattern ◽  
Spruce Forest ◽  
Vegetation Types ◽  
Daily Average

Soil moisture is a central theme in eco-hydrology. Topography, soil characteristics, and vegetation types are significant factors impacting soil moisture dynamics. However, water loss (evapotranspiration and leakage) and its factors of the self-organized vegetation pattern are not clear, which has significant ecologic functions and contributes to different hydrological ecosystem services. From an eco-hydrological point of view, we relied on the observation of rainfall, soil moisture, and soil temperature in the growing season of a drought year to compare soil moisture and temperature dynamics in terms of frequency/probability distribution and water loss among three typical vegetation types in the Qilian Mountains, China. The results indicated that shrubland (the semi-shaded slope) had the highest average soil moisture at the surface soil (0–40 cm) and soil profile during the growing season, while grassland (the south-facing slope) had the lowest daily average soil moisture and highest daily average soil temperature at the surface soil and soil profile. Spruce forest (the shaded slope) had the lowest daily average soil temperature at the surface soil and soil profile (p < 0.001). Water loss among the three vegetation types has a clear positive relationship with soil water content and a negative relationship with soil temperature. The values of water loss between values of water loss at the wilting point and maximum evapotranspiration point tend to occur in wetter soil moisture under the spruce forest and shrubland, whereas that of grassland emerges in drier soil moisture. The spruce forest and shrubland experienced higher water loss than the grassland. Although the spruce forest and shrubland had a better capacity to retain soil water, they also consumed more soil water than the grassland. Soil moisture may be the main factor controlling the difference in water loss among the three vegetation types. These findings may contribute to improving our understanding of the relationship between the soil moisture dynamics and vegetation pattern, and may offer basic insights for ecosystem management for upstream water-controlled mountainous areas.

scholarly journals From near-surface to root-zone soil moisture using an exponential filter: an assessment of the method based on in-situ observations and model simulations

2008 ◽  
Vol 12 (6) ◽  
pp. 1323-1337 ◽  
Author(s):  
C. Albergel ◽  
C. Rüdiger ◽  
T. Pellarin ◽  
J.-C. Calvet ◽  
N. Fritz ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Surface Soil ◽  
Root Zone ◽  
Synthetic Data ◽  
Surface Soil Moisture ◽  
Data Set ◽  
Water Index ◽  
In Situ Observations

Abstract. A long term data acquisition effort of profile soil moisture is under way in southwestern France at 13 automated weather stations. This ground network was developed in order to validate remote sensing and model soil moisture estimates. In this paper, both those in situ observations and a synthetic data set covering continental France are used to test a simple method to retrieve root zone soil moisture from a time series of surface soil moisture information. A recursive exponential filter equation using a time constant, T, is used to compute a soil water index. The Nash and Sutcliff coefficient is used as a criterion to optimise the T parameter for each ground station and for each model pixel of the synthetic data set. In general, the soil water indices derived from the surface soil moisture observations and simulations agree well with the reference root-zone soil moisture. Overall, the results show the potential of the exponential filter equation and of its recursive formulation to derive a soil water index from surface soil moisture estimates. This paper further investigates the correlation of the time scale parameter T with soil properties and climate conditions. While no significant relationship could be determined between T and the main soil properties (clay and sand fractions, bulk density and organic matter content), the modelled spatial variability and the observed inter-annual variability of T suggest that a weak climate effect may exist.

Adjoint retrieval of prognostic land surface model variables for an NWP model: Assimilation of ground surface temperature

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Diandong Ren
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Land Surface ◽  
Surface Soil ◽  
Land Surface Model ◽  
Initial Guess ◽  
Surface Model ◽  
Soil Moisture Condition ◽  
Wide Range ◽  
Surface Soil Temperature

AbstractBased on a 2-layer land surface model, a rather general variational data assimilation framework for estimating model state variables is developed. The method minimizes the error of surface soil temperature predictions subject to constraints imposed by the prediction model. Retrieval experiments for soil prognostic variables are performed and the results verified against model simulated data as well as real observations for the Oklahoma Atmospheric Surface layer Instrumentation System (OASIS). The optimization scheme is robust with respect to a wide range of initial guess errors in surface soil temperature (as large as 30 K) and deep soil moisture (within the range between wilting point and saturation). When assimilating OASIS data, the scheme can reduce the initial guess error by more than 90%, while for Observing Simulation System Experiments (OSSEs), the initial guess error is usually reduced by over four orders of magnitude.Using synthetic data, the robustness of the retrieval scheme as related to information content of the data and the physical meaning of the adjoint variables and their use in sensitivity studies are investigated. Through sensitivity analysis, it is confirmed that the vegetation coverage and growth condition determine whether or not the optimally estimated initial soil moisture condition leads to an optimal estimation of the surface fluxes. This reconciles two recent studies.With the real data experiments, it is shown that observations during the daytime period are the most effective for the retrieval. Longer assimilation windows result in more accurate initial condition retrieval, underlining the importance of information quantity, especially for schemes assimilating noisy observations.

scholarly journals Establishing an Empirical Model for Surface Soil Moisture Retrieval at the U.S. Climate Reference Network Using Sentinel-1 Backscatter and Ancillary Data

2020 ◽  
Vol 12 (8) ◽  
pp. 1242 ◽  
Author(s):  
Sumanta Chatterjee ◽  
Jingyi Huang ◽  
Alfred E. Hartemink
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Soil Properties ◽  
Soil Water ◽  
Surface Soil ◽  
Reference Network ◽  
Surface Soil Moisture ◽  
Ancillary Data ◽  
Terrain Parameters ◽  
The U.S

Progress in sensor technologies has allowed real-time monitoring of soil water. It is a challenge to model soil water content based on remote sensing data. Here, we retrieved and modeled surface soil moisture (SSM) at the U.S. Climate Reference Network (USCRN) stations using Sentinel-1 backscatter data from 2016 to 2018 and ancillary data. Empirical machine learning models were established between soil water content measured at the USCRN stations with Sentinel-1 data from 2016 to 2017, the National Land Cover Dataset, terrain parameters, and Polaris soil data, and were evaluated in 2018 at the same USCRN stations. The Cubist model performed better than the multiple linear regression (MLR) and Random Forest (RF) model (R2 = 0.68 and RMSE = 0.06 m3 m-3 for validation). The Cubist model performed best in Shrub/Scrub, followed by Herbaceous and Cultivated Crops but poorly in Hay/Pasture. The success of SSM retrieval was mostly attributed to soil properties, followed by Sentinel-1 backscatter data, terrain parameters, and land cover. The approach shows the potential for retrieving SSM using Sentinel-1 data in a combination of high-resolution ancillary data across the conterminous United States (CONUS). Future work is required to improve the model performance by including more SSM network measurements, assimilating Sentinel-1 data with other microwave, optical and thermal remote sensing products. There is also a need to improve the spatial resolution and accuracy of land surface parameter products (e.g., soil properties and terrain parameters) at the regional and global scales.

scholarly journals Water Regulation in Cyanobacterial Biocrusts from Drylands: Negative Impacts of Anthropogenic Disturbance

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 720 ◽  
Author(s):  
Yolanda Cantón ◽  
Sonia Chamizo ◽  
Emilio Rodriguez-Caballero ◽  
Roberto Lázaro ◽  
Beatriz Roncero-Ramos ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Soil Water ◽  
Water Loss ◽  
Spatial Scales ◽  
Arid Ecosystems ◽  
Rainfall Simulation ◽  
Water Regulation ◽  
Natural Rainfall ◽  
Bare Soils

Arid and semi-arid ecosystems are characterized by patchy vegetation and variable resource availability. The interplant spaces of these ecosystems are very often covered by cyanobacteria-dominated biocrusts, which are the primary colonizers of terrestrial ecosystems and key in facilitating the succession of other biocrust organisms and plants. Cyanobacterial biocrusts regulate the horizontal and vertical fluxes of water, carbon and nutrients into and from the soil and play crucial hydrological, geomorphological and ecological roles in these ecosystems. In this paper, we analyze the influence of cyanobacterial biocrusts on water balance components (infiltration-runoff, evaporation, soil moisture and non-rainfall water inputs (NRWIs)) in representative semiarid ecosystems in southeastern Spain. The influence of cyanobacterial biocrusts, in two stages of their development, on runoff-infiltration was studied by rainfall simulation and in field plots under natural rainfall at different spatial scales. Results showed that cover, exopolysaccharide content, roughness, organic carbon, total nitrogen, available water holding capacity, aggregate stability, and other properties increased with the development of the cyanobacterial biocrust. Due to the effects on these soil properties, runoff generation was lower in well-developed than in incipient-cyanobacterial biocrusts under both simulated and natural rainfall and on different spatial scales. Runoff yield decreased at coarser spatial scales due to re-infiltration along the hillslope, thus decreasing hydrological connectivity. Soil moisture monitoring at 0.03 m depth revealed higher moisture content and slower soil water loss in plots covered by cyanobacterial biocrusts compared to bare soils. Non-rainfall water inputs were also higher under well-developed cyanobacterial biocrusts than in bare soils. Disturbance of cyanobacterial biocrusts seriously affected the water balance by increasing runoff, decreasing soil moisture and accelerating soil water loss, at the same time that led to a very significant increase in sediment yield. The recovery of biocrust cover after disturbance can be relatively fast, but its growth rate is strongly conditioned by microclimate. The results of this paper show the important influence of cyanobacterial biocrust in modulating the different processes supporting the capacity of these ecosystems to provide key services such as water regulation or erosion control, and also the important impacts of their anthropic disturbance.

Rooting depth and plant water relations explain species distribution patterns within a sandplain landscape

2004 ◽  
Vol 31 (5) ◽  
pp. 423 ◽  
Author(s):  
Philip K. Groom
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Loss ◽  
Rooting Depth ◽  
Summer Drought ◽  
Tissue Water ◽  
Shrub Species ◽  
Water Deficits ◽  
Groundwater Levels ◽  
Water Potentials

Tree and shrub species of the Banksia woodlands on the sandplains of northern Swan Coastal Plain, Western Australia possess a range of strategies to avoid or tolerate soil water deficits during the annual summer drought. Shallow-rooted shrub species (< 1 m rooting depth) inhabit a range of locations in the landscape, from top of dune crests to wetland embankments. These are the most drought-tolerant of all sandplain species, surviving extremely low summer soil water potentials (< –7 MPa) and tissue water deficits by significantly reducing their transpirational water loss (< 0.2 mmol m–2 s–1). This is in contrast to the few shallow-rooted species restricted to low-lying or seasonally waterlogged areas which are reliant on subsurface soil moisture or groundwater to maintain their relatively high summer water use. Recent studies of water source usage of selected Banksia tree species have shown that these deep-rooted species access groundwater up to a maximum depth of 9 m depth during the summer months, or soil moisture at depth when groundwater was greater than maximum rooting depths, depending on the species. Medium- and deep-rooted (1–2 m and > 2 m, respectively) shrub species cope with the summer soil drying phase and related decrease in groundwater levels by conserving leaf water loss and incurring predawn water potentials between –1 and –4 MPa, enabling them to occur over a range of topographic positions within the sandplain landscape.

COMPARISON OF LIGHTLY GRAZED AND UNGRAZED RANGE IN THE FESCUE GRASSLAND OF SOUTHWESTERN ALBERTA

1961 ◽  
Vol 41 (3) ◽  
pp. 615-622 ◽  
Author(s):  
Alexander Johnston
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Field Study ◽  
Water Intake ◽  
Soil Profile ◽  
Basal Area ◽  
The Other ◽  
Intake Rate ◽  
Vegetative Cover ◽  
Harmful Effects

The influence of grazing on the vegetative cover of fescue grassland in southwestern Alberta was assessed by studying two adjoining sites, one lightly grazed, the other ungrazed. Percentage basal area, yield, water-intake rate, soil temperature, soil moisture, and amount of root material were compared on a paired plot basis.The data showed that light grazing resulted in the development of a richer flora dominated by Danthonia parryi. Protection from grazing appeared to simplify the flora with a trend toward a cover consisting largely of Festuca scabrella. There was little evidence of difference in productivity between the two sites. Cooler and moister conditions prevailed in the upper 12 inches of the soil profile of the ungrazed site as a result of heavy accumulation of mulch. Considerably more root material to a depth of 54 inches was present on the lightly grazed site. The harmful effects of herbage removal, shown by clipping studies, were not apparent in the field study under a light rate of grazing.

scholarly journals Soil Moisture Sensor Test with Mississippi Delta Soils

2019 ◽  
Vol 62 (2) ◽  
pp. 363-370
Author(s):  
Ruixiu Sui ◽  
Horace C. Pringle ◽  
Edward M. Barnes
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Measurement Accuracy ◽  
Mississippi Delta ◽  
Soil Water Potential ◽  
Gravimetric Method ◽  
Irrigation Scheduling

Abstract. One of the methods for irrigation scheduling is to use sensors to measure the soil moisture level in the plant root zone and apply water if there is a water shortage for the plants. The measurement accuracy and reliability of the soil moisture sensors are critical for sensor-based irrigation management. This study evaluated the measurement accuracy and repeatability of the EC-5 and 5TM soil volumetric water content (SVWC) sensors, the MPS-2 and 200SS soil water potential (SWP) sensors, and the 200TS soil temperature sensor. Six 183 cm × 183 cm × 71 cm wooden compartments were built inside a greenhouse, and each compartment was filled with one type of soil from the Mississippi Delta. A total of 66 sensors with 18 data loggers were installed in the soil compartments to measure SVWC, SWP, and soil temperature. Soil samples were periodically collected from the compartments to determine SVWC using the gravimetric method. SVWC measured by the sensors was compared with that determined by the gravimetric method. The SVWC readings from the sensors had a linear regression relationship with the gravimetric SVWC (r2 = 0.82). This relationship was used to calibrate the sensor readings. The SVWC and SWP sensors could detect the general trend of soil moisture changes. However, their measurements varied significantly among the sensors. To obtain accurate absolute soil moisture measurements, the sensors require individual and soil-specific calibration. The 5TM, MPS-2, and 200TS sensors performed well in soil temperature measurement tests. Individual temperature readings from these sensors were very close to the mean of all sensor readings. Keywords: Irrigation, Sensors, Soil types, Soil water content, Soil water potential.

VARIATION OF SUNFLOWER GROWTH, SOIL MOISTURE AND SOIL TEMPERATURE IN RELATION TO PLANTING PATTERNS AT A HIGH LATITUDE SITE

2001 ◽  
Vol 49 (3) ◽  
pp. 273-282 ◽  
Author(s):  
M. Long ◽  
H. Eiszner
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Water ◽  
High Latitude ◽  
Dry Matter ◽  
Field Experiments ◽  
Hyperbolic Model ◽  
Row Spacing ◽  
Dry Matter Accumulation ◽  
Deep Soil

HALLE-WITTENBERG, HALLE(SAALE), GERMANY Received: 13 June, 2001; accepted: 6 August, 2001 Field experiments were conducted at a high latitude site for sunflower (Helianthus annuus L.) production in central Germany (51 o 24' N, 11 o 53' E) in 1996, 1997 and 1998. The responses of sunflower development to various planting patterns differed in the duration from emergence to the middle of the linear growth period as calculated via a tangent hyperbolic model F(t)=(. +ß)×tanh[. ×(t–.)]. Final dry matter accumulation showed few differences among the planting patterns: 12 plants m –2 at 50 cm row spacing at 75 cm row spacing (RS2PD2) and 4 plants m –2 at 100 cm row spacing (RS3PD1). The actual and simulated values for final dry matter were close to 1200 g m –2 . The responses of soil moisture and temperature to planting patterns changed from the upper to the deep soil layers. In a normal year, e.g. 1997, the soil water to 150 cm depth was sufficient for sunflower growth. In a drought year, e.g. 1998, soil water deeper than 150 cm was used by sunflower crops. The soil temperature was mostly lower in RS1PD3 and RS2PD2 than in RS3PD1, particularly in the upper soil, at depths of 5 and 20 cm. The most important factor defining the responses of soil moisture and temperature to planting patterns seems to be the amount of radiation penetrating the ground, which may depend on latitude, wind and row orientation.

Water balance and irrigation planning in a forest tree nursery

1989 ◽  
Vol 19 (5) ◽  
pp. 575-579
Author(s):  
Marcel Prévost ◽  
Jean Stein ◽  
André P. Plamondon
Keyword(s):  
Soil Water ◽  
Water Loss ◽  
Soil Profile ◽  
Root Zone ◽  
Potential Evapotranspiration ◽  
Forest Tree ◽  
Irrigation Planning ◽  
Tree Nursery ◽  
Soil Water Tension ◽  
Water Tension

A soil water budget was established to estimate the water loss from the 0- to 60-cm layer as a result of evapotranspiration in a forest tree nursery. Estimated evapotranspiration totaled 69% of potential evapotranspiration (as estimated by the Penman equation) for 36 selected periods from May 15 to July 30, 1975. The root zone (0- to 15-cm layer) supplied 58% of the total evapotranspired water from the soil profile. Evapotranspiration from this layer was found to be a good predictor of total water loss. Evapotranspiration from the root zone, expressed as a percentage of potential evapotranspiration, was related to soil water tension at 3 cm depth. This relationship, combined with a knowledge of soil hydrodynamic properties, can be used to estimate evapotranspiration from the 0- to 60-cm soil profile, which in turn can be used to predict irrigation needs. For practical purposes, a relationship using net radiation instead of potential evapotranspiration can also be used. Depending on the available information, either of these two relationships may be used for irrigation planning.

scholarly journals PERANAN EKOLOGI DUSUNG DAN NON DUSUNG DAN KONTRIBUSINYA PADA KONSERVASI LINGKUNGAN DI DESA URENG KECAMATAN LEIHITU KABUPATEN MALUKU TENGAH

2018 ◽  
Vol 2 (1) ◽  
pp. 28-48
Author(s):  
Napsiah Heluth ◽  
J. Matinahoru ◽  
Fransina Latumahina
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Air Temperature ◽  
Organic Content ◽  
Environmental Conservation ◽  
Soil Macrofauna ◽  
Organic C

The research study aims to determine the ecological conditions of dusung and non dusung, and the role of the contribution to environmental conservation in Ureng Village. The research method used was purposive sampling with observation parameters were microclimate (CO2 content, air temperature, humidity), vegetation conditions and soil conditions (soil temperature, soil moisture, soil pH, soil moisture content, soil macrofauna and organic C) . The results of  Paired of each parameter measured mostly show a smaller calculated t value compared to the t0.05 table value (1.8595) which means that the parameter is not a real difference, ie for the air humidity, t count = 0.27,; soil pH, t count = 0.6; soil macrofauna, t count = -0.66 and vegetation, t count = 1.01. As for the parameters of CO2; air temperature, soil temperature, , soil water content and organic C, t value of CO2 gives the value t count = - 16.06; air temperature = -5.11; soil temperature = -3.62; soil moisture, t count = 2,16; soil water content = 8.47, and C-Organic = 8.53; t count value which is greater than t table value which shows that there is a significant difference between CO2, air temperature, soil temperature, soil moisture, soil water content and C-Organic content in the dusung area which is greater than in the non-dusung area. From the results of the analysis it is known that dusung has a better role in environmental conservation when compared to non dusung which is indicated by the value of CO2 air temperature, soil temperature, soil moisture, soil water content and C-organic content.

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