scholarly journals TESTING SOME PEDO-TRANSFER FUNCTIONS (PTFS) IN APULIA REGION

2009 ◽  
Vol 40 (1) ◽  
pp. 19
Author(s):  
Floriano Buccigrossi ◽  
Angelo Caliandro ◽  
Pietro Rubino ◽  
Mario Alberto Mastro
Keyword(s):  
Soil Moisture ◽  
Soil Properties ◽  
Soil Water ◽  
Water Retention ◽  
Transfer Functions ◽  
Organic Matter Content ◽  
Soil Water Storage ◽  
Mean Deviation ◽  
Matric Potential ◽  
Apulia Region

The knowledge of soil water retention vs. soil water matric potential is used to study irrigation and drainage schedules, soil water storage capacity (plant available water), solute movement, plant growth and water stress. The hydraulic soil properties measuring is expensive, laborious and takes too long time, so, frequently, matemathic models, called pedo-transfer functions (PTFs) are utilized to estimate hydraulic soil properties through soil chimical and phisical characteristics. Six pedo-transfer functions have been evaluated (Gupta & Larson, 1979; Rawls et al., 1982; De Jong et al., 1983; Rawls & Brakensiek, 1985; Saxton et al., 1986; Vereecken et al., 1989) by comparing estimated with measured soil moisture values at soil water matric potential of –33 and –1500 kPa of 361 soil samples collected from 185 pedons of Apulia Region (South Italy), having various combinations of particle-size distribution, soil organic matter content and bulk density. Accuracy of the soil moisture predictions have been evaluated by statistic indexes such as Weighted stantard error (WSEE), Mean Deviation (MD), Root Mean Squared Deviation (RMSD) and the determination coefficient (R2) between estimated and measured water retention values. The Rawls PTF model demostrated to have the lowest values of WSEE, MD and RMSD indexes (0.044, -0.007 and 0.059 m3 H2O m-3 soil, respectively) at –33 Kpa soil water matric potential (Field Capacity), while for estimating soil moisture at the Wilting Point (-1500 kPa) Rawls & Brakensiek model is adequate (WSEE, MD and RMSD of 0.034, -0.016 and 0.046 m3 H2O m-3 soil). De Jong, Saxton and Rawls & Brakensiek models, at –33 kPa soil water matric potential and Gupta & Larson and De Jong models at –1500 kPa soil water matric potential, showed the highest statistic errors.

scholarly journals The Influence of a Water Absorbing Geocomposite on Soil Water Retention and Soil Matric Potential

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1731 ◽  
Author(s):  
Michał Śpitalniak ◽  
Krzysztof Lejcuś ◽  
Jolanta Dąbrowska ◽  
Daniel Garlikowski ◽  
Adam Bogacz
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Water ◽  
Water Retention ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Soil Matric Potential ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Control Samples

Climate change induces droughts that are becoming more intensive and more frequent than ever before. Most of the available forecast tools predict a further significant increase in the risk of drought, which indicates the need to prepare solutions to mitigate its effects. Growing water scarcity is now one of the world’s leading challenges. In agriculture and environmental engineering, in order to increase soil water retention, soil additives are used. In this study, the influence of a newly developed water absorbing geocomposite (WAG) on soil water retention and soil matric potential was analyzed. WAG is a special element made from geotextile which is wrapped around a synthetic skeleton with a superabsorbent polymer placed inside. To describe WAG’s influence on soil water retention and soil matric potential, coarse sand, loamy sand, and sandy loam soils were used. WAG in the form of a mat was used in the study as a treatment. Three kinds of samples were prepared for every soil type. Control samples and samples with WAG treatment placed at depths of 10 cm and 20 cm were examined in a test container of 105 × 70 × 50 cm dimensions. The samples had been watered and drained, and afterwards, the soil surface was heated by lamps of 1100 W total power constantly for 72 h. Soil matric potential was measured by Irrometer field tensiometers at three depths. Soil moisture content was recorded at six depths: of 5, 9, 15, 19, 25, and 30 cm under the top of the soil surface with time-domain reflectometry (TDR) measurement devices. The values of soil moisture content and soil matric potential were collected in one-minute steps, and analyzed in 24-h-long time steps: 24, 48, and 72 h. The samples with the WAG treatment lost more water than the control samples. Similarly, lower soil matric potential was noted in the samples with the WAG than in the control samples. However, after taking into account the water retained in the WAG, it appeared that the samples with the WAG had more water easily available for plants than the control samples. It was found that the mechanism of a capillary barrier affected higher water loss from soil layers above those where the WAG had been placed. The obtained results of water loss depend on the soil type used in the profile.

scholarly journals Estimated soil water storage within a historical bunker during the growth period of vegetation

2018 ◽  
Vol 39 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Łukasz Pardela ◽  
Tomasz Kowalczyk
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Retention ◽  
Growth Period ◽  
Vegetation Period ◽  
Soil Water Storage ◽  
Soil Profiles ◽  
Soil Water Retention ◽  
Average Value ◽  
Volumetric Soil Moisture

AbstractThe objective of the study was to estimate the variation of soil water retention on the site of a historical bunker, an element of the former Wrocław Fortress in Poland. Measurements of soil moisture in the study area were taken in the period from March to September, 2017. Measurements of volumetric soil moisture were taken by means of a hand-held gauge, type FOM/mts with an FP/mts probe, operating on the basis of the reflectometric technique TDR. Soil moisture measurements realized in the vegetation period demonstrated that soil moisture resources in profiles situated in the section of the bunker varied within the range of 37–135 mm in the layer of 50 cm, and 66–203 mm in the layer of 100 cm. The maximum differences of the average value of soil moisture of the soil profiles studied in the period covered by the measurements were 31 mm and 56 mm, respectively. This indicates a significant differentiation of the retention properties of soils used for the construction of individual shelter areas.

scholarly journals Impacts of Wildfire Frequency On Plant Recovery, Soil Properties And Water Storage In Pine Woodlands of North-Central Portugal

2021 ◽  
Author(s):  
Oscar González-Pelayo ◽  
Sergio Prats ◽  
Erik van den Elsen ◽  
Maruxa Malvar ◽  
Coen Ritsema ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Organic Matter Content ◽  
Water Dynamics ◽  
North Central ◽  
Plant Recovery ◽  
Central Portugal

Abstract PurposeIncreasing wildfire frequency in Mediterranean-basin together with drought periods expansion could affect plant-soil-water dynamics processes. The goal is to assess the effects of wildfire frequency on plant recovery, soil properties, soil moisture content (SMC; %) and effective soil water content (ESWC; %) during the first hydrological year after a 2012 moderate-severity-wildfire.MethodsThis study was conducted in pine woodlands of North-central Portugal affected by 1-, 4-wildfires and unburnt (1975-2012). Soil samples were gathered from plant/bare microsites at top-mid-bottom hillslope positions to determine bulk density, soil texture, soil moisture, soil organic matter content-SOM, pF-curves (available water content-AWC, field capacity-FC, permanent wilting point-PWP) (n=54) during four dry/wet periods. Soil cover, plant recovery and soil water repellency were measured. On the burnt areas 72 sensors daily/seasonal monitored SMC and ESWC at two depths (2.5/7.5 cm) and two microsites (plant/bare). ResultsThe 1 fire hillslopes showed higher plant recovery than the 4 fires hillslopes. SOM was higher in the burnt soils (17-20%) than in the unburnt ones (12-14%). Wildfire frequency: i) increased the water stress for plants and led to both maximum and minimum values of SMC/ESWC, respectively, for the wet-/dry-seasons; ii) reduced the capacity of the soils to retain water (decreased FC/AWC, increased PWP), being more accentuated in bare microsites. ConclusionThe increasing wildfire frequency and the predicted expansion of drought periods promotes lower water availability for plants in the more frequent bare soil patches. The water-stress window of the dry season happened sooner and extended for longer as increasing wildfire frequency.

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.

Method for Quick Prediction of Hydraulic Conductivity and Soil-Water Retention of Unsaturated Soils

2018 ◽  
Vol 2672 (52) ◽  
pp. 108-117 ◽  
Author(s):  
Shaoyang Dong ◽  
Yuan Guo ◽  
Xiong (Bill) Yu
Keyword(s):  
Finite Element ◽  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Characteristic Curve ◽  
Soil Water Retention

Hydraulic conductivity and soil-water retention are two critical soil properties describing the fluid flow in unsaturated soils. Existing experimental procedures tend to be time consuming and labor intensive. This paper describes a heuristic approach that combines a limited number of experimental measurements with a computational model with random finite element to significantly accelerate the process. A microstructure-based model is established to describe unsaturated soils with distribution of phases based on their respective volumetric contents. The model is converted into a finite element model, in which the intrinsic hydraulic properties of each phase (soil particle, water, and air) are applied based on the microscopic structures. The bulk hydraulic properties are then determined based on discharge rate using Darcy’s law. The intrinsic permeability of each phase of soil is first calibrated from soil measured under dry and saturated conditions, which is then used to predict the hydraulic conductivities at different extents of saturation. The results match the experimental data closely. Mualem’s equation is applied to fit the pore size parameter based on the hydraulic conductivity. From these, the soil-water characteristic curve is predicted from van Genuchten’s equation. The simulation results are compared with the experimental results from documented studies, and excellent agreements were observed. Overall, this study provides a new modeling-based approach to predict the hydraulic conductivity function and soil-water characteristic curve of unsaturated soils based on measurement at complete dry or completely saturated conditions. An efficient way to measure these critical unsaturated soil properties will be of benefit in introducing unsaturated soil mechanics into engineering practice.

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 The influence of stony soil properties on water dynamics modeled by the HYDRUS model

2018 ◽  
Vol 66 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Hana Hlaváčiková ◽  
Viliam Novák ◽  
Zdeněk Kostka ◽  
Michal Danko ◽  
Jozef Hlavčo
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Water Storage ◽  
Water Dynamics ◽  
Soil Water Storage ◽  
Rock Fragments ◽  
Soil Fraction ◽  
Fine Soil ◽  
Stony Soil ◽  
Water Retention Properties

AbstractStony soils are composed of two fractions (rock fragments and fine soil) with different hydrophysical characteristics. Although stony soils are abundant in many catchments, their properties are still not well understood. This manuscript presents an application of the simple methodology for deriving water retention properties of stony soils, taking into account a correction for the soil stoniness. Variations in the water retention of the fine soil fraction and its impact on both the soil water storage and the bottom boundary fluxes are studied as well. The deterministic water flow model HYDRUS-1D is used in the study. The results indicate that the presence of rock fragments in a moderate-to-high stony soil can decrease the soil water storage by 23% or more and affect the soil water dynamics. Simulated bottom fluxes increased or decreased faster, and their maxima during the wet period were larger in the stony soil compared to the non-stony one.

scholarly journals Effect of Osmotic and Matric Potentials on the Availability of Water for Seed Germination

1971 ◽  
Vol 24 (3) ◽  
pp. 423 ◽  
Author(s):  
JR Mcwilliam ◽  
PJ Phlllips
Keyword(s):  
Soil Moisture ◽  
Seed Germination ◽  
Osmotic Stress ◽  
Soil Water ◽  
Seed Coat ◽  
Moisture Diffusivity ◽  
Matric Potential ◽  
Water Potentials ◽  
Germination Behaviour ◽  
Dry Soil

Under special conditions where soil-moisture diffusivity and seed-soil contact are non-limiting, the osmotic and matric potentials of the substrate were found to be equivalent in their effect on the germination of seeds of ryegrass and dehulled phalaris over a range of water potentials from 0 to -15 bars. However, with intact phalaris seeds it appears that the seed coat constitutes a large resistance to the absorption of soil water, and under these conditions the equivalence between osmotic and matric potential no longer holds, and results of germination under osmotic stress must be used with caution in predicting the germination behaviour of seeds in dry soil.

The effects of biochar on the physical properties of bare soil

2012 ◽  
Vol 103 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Francesca Ventura ◽  
Fiorenzo Salvatorelli ◽  
Stefano Piana ◽  
Linda Pieri ◽  
Paola Rossi Pisa
Keyword(s):  
Soil Moisture ◽  
Bulk Density ◽  
Soil Water ◽  
Agricultural Soil ◽  
Water Retention ◽  
Bare Soil ◽  
Soil Water Retention ◽  
Experimental Scheme ◽  
Dark Colour ◽  
Key Factor

ABSTRACTThe pyrolysis conversion of vegetable residues into energy and biochar, and its incorporation in agricultural soil, reduces CO2emission and provides a longterm soil carbon sequestration. Moreover, biochar application in soil seems to increase nutrient stocks in the rooting layer, improving crop yield. Compared with the numerous studies assessing the positive effect of biochar on yield, however, little research has been published elucidating the mechanisms responsible for the reported benefits. Few studies cited soil moisture as the key factor, attributing the increased yield to the higher soil water availability.The aim of this study was to investigate the effect of biochar on the physical and hydraulic properties of a bare Padana Plain (Cadriano, Bologna) agricultural soil. A preliminary plot experiment in 2009 explored the influence of 10 and 30 kg ha–1of biochar on soil moisture, without effects from plants. Results of the first experiment suggested using higher biochar rates in a similar experimental scheme. During the second experiment, 30 and 60 t ha–1doses were investigated. Soil water content, bulk density, electrical conductivity and soil water retention were measured. The comparison between treated soils and the control indicates that the biochar rate is directly correlated to electrical conductibility and inversely correlated with bulk density. The effect on the density of soil can be very positive in case of heavy soils. The dark colour of the char increased the surface temperature with respect to the control, while no differences were detected at 7·5 cm depth. No influences were found on other soil characteristics, including soil pH, moisture and water retention.

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