Similarity of the temporal pattern of soil moisture across soil profile in karst catchments of southwestern China

In this paper we study a mathematical model of soil moisture transport with variable porosity. The problem is set for the case of highly concentrated solute spilled onto soil surface. We investigate the way solute transfer, adsorption of contaminant by soil particles and variable porosity influence infiltration of solute into the soil profile. For that purpose, two models are used: a classical one and the one with consideration of mentioned factors. By comparing the results of both models, we established that high concentration of solute causes moisture transport to transpire more slowly, and the pollutant to remain on the soil surface for longer time. Numerical results indicate that porosity can vary considerably under the conditions of intensive contamination with salts.

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Towards an operationally capable satellite-based 0-100 cm soil moisture dataset from C3S

10.5194/egusphere-egu21-12268 ◽

2021 ◽

Author(s):

Adam Pasik ◽

Wolfgang Preimesberger ◽

Bernhard Bauer-Marschallinger ◽

Wouter Dorigo

Keyword(s):

Soil Moisture ◽

Soil Profile ◽

Land Surface ◽

Root Zone ◽

Soil Layer ◽

Land Surface Model ◽

In Situ Measurements ◽

Surface Model ◽

T Values

Multiple satellite-based global surface soil moisture (SSM) datasets are presently available, these however, address exclusively the top layer of the soil (0-5cm). Meanwhile, root-zone soil moisture cannot be directly quantified with remote sensing but can be estimated from SSM using a land surface model. Alternatively, soil water index (SWI; calculated from SSM as a function of time needed for infiltration) can be used as a simple approximation of root-zone conditions. SWI is a proxy for deeper layers of the soil profile which control evapotranspiration, and is hence especially important for studying hydrological processes over vegetation-covered areas and meteorological modelling.Here we introduce the advances in our work on the first operationally capable SWI-based root-zone soil moisture dataset from C3S Soil Moisture v201912 COMBINED product, spanning the period 2002-2020. The uniqueness of this dataset lies in the fact that T-values (temporal lengths ruling the infiltration) characteristic of SWI were translated into particular soil depths making it much more intuitive, user-friendly and easily applicable. Available are volumetric soil moisture values for the top 1 m of the soil profile at 10 cm intervals, where the optimal T-value (T-best) for each soil layer is selected based on a range of correlation metrics with in situ measurements from the International Soil Moisture Network (ISMN) and the relevant soil and climatic parameters. Additionally we present the results of an extensive global validation against in situ measurements (ISMN) as well as the results of investigations into the relationship between a range of soil and climate characteristics and the optimal T-values for particular soil depths.

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Development of calibration algorithms for selected water content reflectometry probes for burned and non-burned organic soils of Alaska

International Journal of Wildland Fire ◽

10.1071/wf07175 ◽

2010 ◽

Vol 19 (7) ◽

pp. 961 ◽

Cited By ~ 8

Author(s):

Laura L. Bourgeau-Chavez ◽

Gordon C. Garwood ◽

Kevin Riordan ◽

Benjamin W. Koziol ◽

James Slawski

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Water Content ◽

Soil Profile ◽

Soil Moisture Content ◽

Mineral Soil ◽

Organic Soil ◽

Organic Content ◽

Organic Soils ◽

Probe Type

Water content reflectometry is a method used by many commercial manufacturers of affordable sensors to electronically estimate soil moisture content. Field‐deployable and handheld water content reflectometry probes were used in a variety of organic soil‐profile types in Alaska. These probes were calibrated using 65 organic soil samples harvested from these burned and unburned, primarily moss‐dominated sites in the boreal forest. Probe output was compared with gravimetrically measured volumetric moisture content, to produce calibration algorithms for surface‐down‐inserted handheld probes in specific soil‐profile types, as well as field‐deployable horizontally inserted probes in specific organic soil horizons. General organic algorithms for each probe type were also developed. Calibrations are statistically compared to determine their suitability. The resulting calibrations showed good agreement with in situ validation and varied from the default mineral‐soil‐based calibrations by 20% or more. These results are of particular interest to researchers measuring soil moisture content with water content reflectometry probes in soils with high organic content.

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

Canadian Journal of Plant Science ◽

10.4141/cjps61-090 ◽

1961 ◽

Vol 41 (3) ◽

pp. 615-622 ◽

Cited By ~ 19

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.

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The Effect of Human Activity on the Distribution of Soil Nitrate Nitrogen in Unsaturated Zone

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.790.202 ◽

2013 ◽

Vol 790 ◽

pp. 202-205

Author(s):

Hui Yan Gao ◽

Lu Hua Yang ◽

Tian Li ◽

Zi Peng Guo

Keyword(s):

Soil Moisture ◽

Nitrogen Content ◽

Human Activity ◽

Soil Profile ◽

Nitrate Nitrogen ◽

Root Zone ◽

Deep Layer ◽

Soil Layer ◽

Growth Period ◽

Soil Nitrate

Soil moisture and nitrate nitrogen were measured respectively in planting area and non-planting area in RANZHUANG experiment station from 2011 to 2012. The effect of human activity on soil moisture and nitrate nitrogen was analyzed. The results show that soil moisture content varies from 8.61% to 30.09% within 0~250cm depth and is tended to be stable below 250cm deep layer in non-planting area. The distribution of soil nitrate nitrogen is a single peak curve, the peak moves downward at a speed of 0.81cm/d in percolation of rainfall. Soil moisture varies form 21.23% to 41.67% within 0~400cm depth and is tended to be stable below 400cm deep layer in planting area. Nitrate nitrogen is mainly accumulated at 0~100cm deep soil layer in the wheat growth period. In the maize growth period, the distribution of nitrate nitrogen is double peak curve in 0~500cm soil profile. The upper peak occurs at 40~100cm soil layer, the peak of nitrate nitrogen content is between 26.7~54.6mg/kg; the lower emerges at 150~260cm soil profile, the value is between 36.7~106.36mg/kg. Deep percolation of the nitrate nitrogen is obvious due to unreasonable irrigation and fertilization. The nitrate nitrogen content accounts for 52.3% of the total nitrate nitrogen below the root zone soil, which is a potential contamination source of groundwater.

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Desert shrub stemflow and its significance in soil moisture replenishment

Hydrology and Earth System Sciences ◽

10.5194/hess-15-561-2011 ◽

2011 ◽

Vol 15 (2) ◽

pp. 561-567 ◽

Cited By ~ 49

Author(s):

X.-P. Wang ◽

Z.-N. Wang ◽

R. Berndtsson ◽

Y.-F. Zhang ◽

Y.-X. Pan

Keyword(s):

Soil Moisture ◽

Soil Profile ◽

Root Zone ◽

Sand Dunes ◽

Aluminum Foil ◽

Time Domain Reflectometry ◽

Desert Ecosystem ◽

Desert Ecosystems ◽

Caragana Korshinskii ◽

Moisture Variation

Abstract. Stemflow of xerophytic shrubs represents a significant component of water replenishment to the soil-root system influencing water utilization of plant roots at the stand scale, especially in water scarce desert ecosystems. In this study, stemflow of Caragana korshinskii was quantified by an aluminum foil collar collection method on re-vegetated sand dunes of the Shapotou restored desert ecosystem in northwestern China. Time domain reflectometry probes were inserted horizontally at 20 different soil profile depths under the C. korshinskii shrub to monitor soil moisture variation at hourly intervals. Results indicated that 2.2 mm precipitation was necessary for the generation of stemflow for C. korshinskii. Stemflow averaged 8% of the gross precipitation and the average funnelling ratio was as high as 90. The soil moisture in the uppermost soil profile was strongly correlated with individual rainfall and the stemflow strengthened this relationship. Therefore, it is favourable for the infiltrated water redistribution in the deeper soil profile of the root zone. Consequently, stemflow contributes significantly to a positive soil moisture balance in the root zone and the replenishment of soil moisture at deeper soil layers. This plays an important role in plant survival and the general ecology of arid desert environments.

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Performance analysis of regional landslide early warning based on soil moisture simulations

10.5194/egusphere-egu2020-3362 ◽

2020 ◽

Author(s):

Adrian Wicki ◽

Manfred Stähli

Keyword(s):

Time Series ◽

Soil Moisture ◽

Performance Analysis ◽

Early Warning ◽

Soil Profile ◽

Forecast Skill ◽

Soil Moisture Dynamics ◽

Landslide Early Warning ◽

Moisture Dynamics

In mountainous regions, rainfall-triggered landslides pose a serious risk to people and infrastructure, particularly due to the short time interval between activation and failure and their widespread occurrence. Landslide early warning systems (LEWS) have demonstrated to be a valuable tool to inform decision makers about the imminent landslide danger and to move people or goods at risk to safety. While most operational LEWS are based on empirically derived rainfall exceedance thresholds, recent studies have demonstrated an improvement of the forecast quality after the inclusion of in-situ soil moisture measurements.The use of in-situ soil moisture sensors bears specific limitations, such as the sensitivity to local conditions, the disturbance of the soil profile during installation, and potential data quality issues and inhomogeneity of long-term measurements. Further, the installation and operation of monitoring networks is laborious and costly. In this respect, making use of modelled soil moisture could efficiently increase information density, and it would further allow to forecast soil moisture dynamics. On the other hand, numerical simulations are restricted by assumptions and simplifications related to the soil hydraulic properties and the water transfer in the soil profile. Ultimately, the question arises how reliable and representative landslide early warnings based on soil moisture simulations are compared to warnings based on measurements.To answer this, we applied a state-of-the-art one-dimensional heat and mass transfer model (CoupModel, Jansson 2012) to generate time series of soil water content at 35 sites in Switzerland. The same sites and time period (2008-2018) were used in a previous study to compare the temporal variability of in-situ measured soil moisture to the regional landslide activity (currently under review in Landslides). The same statistical framework for soil moisture dynamics analysis, landslide probability modelling and landslide early warning performance analysis was applied to the modelled and the measured soil moisture time series. This allowed to directly compare the forecast skill of modelling-based with measurements-based landslide early warning.In this contribution, we will highlight three steps of model applications: First, a straight-forward simulation to all 35 sites without site-specific calibration and using reference soil layering only, to assess the forecast skill as if no prior measurements were available. Second, a model simulation after calibration at each site using the existing soil moisture time series and information on the soil texture to assess the benefit of a thorough calibration process on the forecast skill. Finally, an application of the model to additional sites in Switzerland where no soil moisture measurements are available to assess the effect of increasing the soil moisture information density on the overall forecast skill.

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Distribution of rainfall and soil moisture content in the soil profile under citrus tree canopy and at the dripline

Irrigation Science ◽

10.1007/s002710050051 ◽

1999 ◽

Vol 18 (3) ◽

pp. 109-115 ◽

Cited By ~ 15

Author(s):

A. K. Alva ◽

O. Prakash ◽

Ali Fares ◽

Arthur G. Hornsby

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Profile ◽

Soil Moisture Content ◽

Tree Canopy ◽

Citrus Tree

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PATTERNS OF WATER UPTAKE AND ROOT DISTRIBUTION OF CHILLI PEPPERS GROWN IN SOIL COLUMNS

Canadian Journal of Plant Science ◽

10.4141/cjps87-075 ◽

1987 ◽

Vol 67 (2) ◽

pp. 531-535 ◽

Cited By ~ 7

Author(s):

N. R. HULUGALLE ◽

S. T. WILLATT

Keyword(s):

Soil Moisture ◽

Root Growth ◽

Water Uptake ◽

Water Availability ◽

Soil Profile ◽

Root Distribution ◽

Soil Columns ◽

Chilli Pepper ◽

Pepper Plants ◽

Water Uptake Patterns

Root distribution and water uptake patterns of individual chilli pepper (Capsicum annuum L. ’Long Slim Cayenne’) plants growth in 1-m-high soil columns in plastic cylinders were examined under irrigated and nonirrigated conditions. Roots were able to grow through the soil profile and consequently extract water from a soil which was conducive to root growth. Water uptake occurred both in the irrigated and in the nonirrigated treatment throughout the soil profile. Uptake was highest in the top 0.50 m of the former and was a result of greater water availability rather than lack of root growth at greater depths. Chilli pepper plants can, under droughty conditions, extract subsoil moisture.Key words: Chilli pepper, soil moisture, water uptake, root growth

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DEVELOPMENT OF A PROTOTYPE SELF-WATERING RAISED SOIL BED SUITABLE FOR URBAN AGRICULTURE

UMUDIKE JOURNAL OF ENGINEERING AND TECHNOLOGY ◽

10.33922/j.ujet_v5i1_4 ◽

2019 ◽

pp. 22-29

Keyword(s):

Soil Moisture ◽

Urban Agriculture ◽

Soil Profile ◽

Irrigation System ◽

Arable Soils ◽

Palm Fruit ◽

Vegetable Growth ◽

Application Efficiency ◽

Different Depths ◽

Overall Efficiency

A portable raised soil bed integrated with a self-regulated irrigation system was designed, developed and evaluated. The system is most suited to urban settings where arable soils are scarce to locate and most times too expensive to purchase. The system was evaluated with Palm fruit fibre. Palm fruit fibre filled to thickness of 0.15m when saturated was observed to release moisture throughout the entire 0.20cm thickness of the overlaying soil at an application efficiency of 65%, fibre efficiency of 18% and overall efficiency of 12%. It was established from the soil moisture data recorded at different depths in the soil profile that the system provided subsurface irrigation sufficient for vegetable growth and is also efficiently self-regulated as no case of moisture overflow or flooding at the surface of the soil profile was recorded.

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