scholarly journals Thermodynamic Concept of Water Retention and Physical Quality of the Soil

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1686
Author(s):  
Andrey V. Smagin
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Practical Interest ◽  
Interfacial Interactions ◽  
Physical Quality ◽  
Thermodynamic Potentials ◽  
Physically Based ◽  
Retention Characteristics

The physical quality of the soil is determined by its interfacial interactions in conditions of variable water content. In this regard, water retention characteristics in the form of functions of water content and its thermodynamic potentials are used as indicators of physical quality and its dynamics in the soil. The combination of centrifugation and thermodesorption methods allowed for the first time the assessment of soil water potentials in the entire range of variation from 0 to 106 J/kg for a representative database (more than 400 samples) of the main genetic types of Eurasian soils, grouped into 5 FAO/USDA soil texture classes. The main fundamental achievement of the research is a physically based diagnosis of the critical values of water content and its thermodynamic potentials that separate the areas of dominance of various forms of soil water, physical forces, and mechanisms of interfacial interactions on the WRC-diagrams of the physical quality of the soil. Theoretical and experimental results of the study are of practical interest of sustainable agronomy for determining the optimal ranges of water content in the soil during plant cultivation, water saving, and salt protection in irrigation, mechanical tillage, and other technological operations.

scholarly journals Responses of Soil Infiltration to Water Retention Characteristics, Initial Conditions, and Boundary Conditions

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 361
Author(s):  
Lesheng An ◽  
Kaihua Liao ◽  
Chun Liu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Constant Pressure ◽  
Pressure Head ◽  
Estimation Methods ◽  
Initial Water Content ◽  
Initial Water ◽  
Cumulative Infiltration ◽  
Retention Characteristics

(1) Background: Simulation of soil water infiltration process and analysis of its influencing factors are important for water resources management. (2) Methods: In this study, the relative contributions of the soil water retention characteristics (SWRC) estimation, initial water content, and constant pressure head at upper boundary to the cumulative infiltration under various soil conditions were quantified based on the 1-D Richards’ equation and 900 scenarios. Scenario simulations were performed for two SWRC estimation methods (Jensen method and Rosetta); three different initial water contents (0.15, 0.20, and 0.25 cm3/cm3); five different constant pressure heads (0.5, 1, 2, 4, and 8 cm); and thirty soil samples with varying texture and bulk density. (3) Results: Rosetta representing the drying branch of the SWRC yielded higher simulated cumulative infiltration compared with the Jensen method representing the wetting branch of the SWRC. However, the Jensen method–predicted cumulative infiltration fluxes matched well with the measured values with a low RMSE of 0.80 cm. (4) Conclusions: The relative contribution of the SWRC estimation method to cumulative infiltration (19.1–72.2%) was compared to that of constant pressure head (14.0–65.5%), and generally greater than that of initial water content (2.2–29.9%). Findings of this study have practical significance for investigating the transport of water, nutrients, and contaminants in the unsaturated zone.

scholarly journals The Mechanical Impact of Water Affected the Soil Physical Quality of a Loam Soil under Minimum Tillage and No-Tillage: An Assessment Using Beerkan Multi-Height Runs and BEST-Procedure

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Mirko Castellini ◽  
Anna Maria Stellacci ◽  
Danilo Sisto ◽  
Massimo Iovino
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Management Practices ◽  
Soil Management ◽  
Soil Water Retention ◽  
Physical Quality ◽  
Soil Physical Quality ◽  
Loam Soil ◽  
The Impact

The multi-height (low, L = 3 cm; intermediate, M = 100 cm; high, H = 200 cm) Beerkan run methodology was applied on both a minimum tilled (MT) (i.e., up to a depth of 30 cm) and a no-tilled (NT) bare loam soil, and the soil water retention curve was estimated by the BEST-steady algorithm. Three indicators of soil physical quality (SPQ), i.e., macroporosity (Pmac), air capacity (AC) and relative field capacity (RFC) were calculated to assess the impact of water pouring height under alternative soil management practices. Results showed that, compared to the reference low run, M and H runs affected both the estimated soil water retention curves and derived SPQ indicators. Generally, M–H runs significantly reduced the mean values of Pmac and AC and increased RFC for both MT and NT soil management practices. According to the guidelines for assessment of SPQ, the M and H runs: (i) worsened Pmac classification of both MT and NT soils; (ii) did not worsen AC classification, regardless of soil management parameters; (iii) worsened RFC classification of only NT soil, as a consequence of insufficient soil aeration. For both soil management techniques, a strong negative correlation was found between the Pmac and AC values and the gravitational potential energy, Ep, of the water used for the infiltration runs. A positive correlation was detected between RFC and Ep. The relationships were plausible from a soil physics point of view. NT soil has proven to be more resilient than MT. This study contributes toward testing simple and robust methods capable of quantifying soil degradation effects, due to intense rainfall events, under different soil management practices in the Mediterranean environment.

Analysis of soil water retention characteristics (SWRC) models using R computer program

2021 ◽  
Author(s):  
Vitalis Kibiwott Too ◽  
Christian Thine Omuto ◽  
Elijah Kipngetich Biamah ◽  
John Paul Obiero
Keyword(s):  
Computer Program ◽  
Soil Water ◽  
Water Retention ◽  
Soil Water Retention ◽  
Retention Characteristics

scholarly journals Investigating soil water retention characteristics at high suctions using relative humidity control

2016 ◽  
Vol 9 ◽  
pp. 10007 ◽  
Author(s):  
Vasileios Mantikos ◽  
Steven Ackerley ◽  
Andrew Kirkham ◽  
Aikaterini Tsiampousi ◽  
David M.G. Taborda ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Soil Water ◽  
Water Retention ◽  
Soil Water Retention ◽  
Humidity Control ◽  
Retention Characteristics

scholarly journals Effect of Nano-Carbon on Water Holding Capacity in a Sandy Soil of the Loess Plateau

2017 ◽  
Vol 21 (4) ◽  
pp. 189-195 ◽  
Author(s):  
Beibei Zhou ◽  
Xiaopeng Chen
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Loess Plateau ◽  
Sandy Soil ◽  
Water Retention ◽  
Soil Mixture ◽  
Cumulative Infiltration ◽  
Nano Carbon ◽  
Water Contents ◽  
Soil Water Contents

The poor water retention capacity of sandy soils commonly aggregate soil erosion and ecological environment on the Chinese Loess Plateau. Due to its strong capacity for absorption and large specific surface area, the use of nanocarbon made of coconut shell as a soil amendment that could improve water retention was investigated. Soil column experiments were conducted in which a layer of nanocarbon mixed well with the soil was formed at a depth of 20 cm below the soil surface. Four different nanocarbon contents by weight (0%, 0.1%, 0.5%, and 1%) and five thicknesses of the nanocarbon- soil mixture layer ranging from 1 to 5 cm were considered. Cumulative infiltration and soil water content distributions were determined when water was added to soil columns. Soil Water Characteristic Curves (SWCC) were obtained using the centrifuge method. The principal results showed that the infiltration rate and cumulative infiltration increased with the increases of nanocarbon contents, to the thicknesses of the nano carbon-soil mixture layer. Soil water contents that below the soil-nano carbon layer decreased sharply. Both the Brooks-Corey and van Genuchten models could describe well the SWCC of the disturbed sandy soil with various nano carbon contents. Both the saturated water content (θs), residual water content (θr) and empirical parameter (α) increased with increasing nano carbon content, while the pore-size distribution parameter (n) decreased. The available soil water contents were efficiently increased with the increase in nanocarbon contents.

scholarly journals Environmentally Friendly Soil Water Conservation Techniques

2019 ◽  
Vol 9 (1) ◽  
pp. 5513-5520
Keyword(s):  
Plant Growth ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Use ◽  
Water Scarcity ◽  
Water Retention ◽  
Direct Method ◽  
Environmentally Friendly ◽  
Cultivated Plants

The conservation of water resources through their optimal use is a compulsory for countries with water shortages in the arid and semi-arid regions, and it should be in an environmentally friendly manner to avoid the serious consequences of the use of environmentally harmful substances, the implications of which are currently evident from climate change, pollution of water bodies, soils, etc. Since Egypt is one of those countries suffering from water scarcity and uses about 82.5 percent of its water consumption in agriculture, according to data of the Ministry of Irrigation in 2010, so this research is focusing on the use of new methods to increase the efficiency of irrigation water, to achieve high productivity of agricultural crops with less water use that will certainly help to alleviate or solve the water scarcity issue. The study used a physical based model, to simulate the methods used to increase sand soil properties to ensure larger water retention index. Within this work, soil have been sampled from different areas, to simulate the behavior of arid lands, under different water retention techniques. Soil was exposed to different techniques, as it was mixed with soil additives in different quantities and different types. Physical barriers of cohesive soil and polyethylene sheets were used in addition to studying the effect of mulch on water storage capacity in noncohesive soil. Water retention have been measured using the direct method of determination soil water content by oven drying and the volumetric water content (𝞱v ) with time graphs have been plotted in groups, as well as the cultivated plants have been monitored as to measure the influence on plants growing and irrigation efficiency. And the experiment showed that the use of rice straw (RS) and wheat straw (WS) in the powder condition have a significant effect in increasing in the soil water content and even to the plant growth, the WS obtained 𝞱v values approaching the loam soil at times and slightly less in the case of RS, when the percentage of RC and WS was 30% to the sandy soil volume/volume (v/v). Also the use of mulch of RS showed a noticeable increase in 𝞱v and significant improvement of plant growth to that without mulch. These proven technologies can be used in sandy land targeted for reclamation to reduce water use in agriculture.

scholarly journals Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique

2009 ◽  
Vol 6 (3) ◽  
pp. 4265-4306 ◽  
Author(s):  
K. Verbist ◽  
W. M. Cornelis ◽  
D. Gabriels ◽  
K. Alaerts ◽  
G. Soto
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Retention ◽  
Measurement Techniques ◽  
Inverse Modelling ◽  
Model Parameters ◽  
Arid Zones ◽  
Water Harvesting ◽  
Data Set

Abstract. In arid and semi-arid zones runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Nevertheless, few efforts were observed to quantify the water harvesting processes of these techniques and to evaluate their efficiency. In this study a combination of detailed field measurements and modelling with the HYDRUS-2D software package was used to visualize the effect of an infiltration trench on the soil water content of a bare slope in Northern Chile. Rainfall simulations were combined with high spatial and temporal resolution water content monitoring in order to construct a useful dataset for inverse modelling purposes. Initial estimates of model parameters were provided by detailed infiltration and soil water retention measurements. Four different measurement techniques were used to determine the saturated hydraulic conductivity (Ksat) independently. Tension infiltrometer measurements proved a good estimator of the Ksat value and a proxy for those measured under simulated rainfall, whereas the pressure and constant head well infiltrometer measurements showed larger variability. Six different parameter optimization functions were tested as a combination of soil-water content, water retention and cumulative infiltration data. Infiltration data alone proved insufficient to obtain high model accuracy, due to large scatter on the data set, and water content data were needed to obtain optimized effective parameter sets with small confidence intervals. Correlation between observed soil water content and simulated values was as high as R2=0.93 for ten selected observation points used in the model calibration phase, with overall correlation for the 22 observation points equal to 0.85. Model results indicate that the infiltration trench has a significant effect on soil water storage, especially at the base of the trench.

scholarly journals Investigating the Proper Application Rate of Nitrogen under Mulched Drip Irrigation to Improve the Yield and Quality of Tomato in Saline Soil

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 293
Author(s):  
Jifeng Zhang ◽  
Zhenhua Wang ◽  
Bihang Fan ◽  
Yusheng Hou ◽  
Yunqing Dou ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Drip Irrigation ◽  
N Application ◽  
Tomato Yield ◽  
Yield And Quality ◽  
Application Rates ◽  
Mulched Drip Irrigation

Xinjiang is one of the most prolific tomato-planting areas in China. Here, we carried out a two-year (2017–2018) field experiment in Xinjiang to study the effects of different nitrogen (N) application rates on the spatial distribution of water and salt in the root zone, as well as their impacts on the yield and quality of tomatoes under mulched drip irrigation. The ideal ranges of N application rates for tomato yield and quality were examined under different salinity levels. Results indicated that soil water content and salinity increased with soil depth. Soil water content was closely related to soil salinity but not to N. Among the tested application rates, tomato yield was highest under the medium-high N (225–300 kg/ha) and low salt (4 g/kg) treatment. Under the highest salt level (10 g/kg), the low nitrogen treatment (150 kg/ha) was better than the high N treatment (300 kg/ha) at boosting tomato yield. Moreover, we found that salinity had a stronger effect on tomato quality than N. Based on these results, we were able to recommend ideal ranges for N (155–201 kg/ha) and salt (3.56–5.59 g/kg) while both are present in the soil.

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