Special Issue "Study of the Soil Water Movement in Irrigated Agriculture"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Water, Agriculture and Aquaculture".

Deadline for manuscript submissions: 30 September 2020.

Special Issue Editors

Prof. Dr. George Kargas
Website
Guest Editor
Department of Natural Resources Management and Agricultural Engineering Agricultural University of Athens; Greece
Interests: Soil physics; flow and transport in soils; dielectric sensors; salinity; irrigation and drainage
Emeritus Prof. Dr. Petros Kerkides

Guest Editor
Department of Natural Resources Management and Agricultural Engineering, Agricultural University of Athens; Greece
Interests: Soil physics; agricultural meteorology; irrigation and drainage; salt transport in soils.
Dr. Paraskevi Londra
Website
Guest Editor
Department of Natural Resources Management and Agricultural Engineering, Agricultural University of Athens; Greece
Interests: Soil physics; plant soil-water interaction; flow and transport in soils; horticultural substrates; vadose zone hydrology, water resources management

Special Issue Information

Dear Colleagues,

In irrigated agriculture, the study of the various ways water infiltrates into the soils is necessary. In this respect, soil hydraulic properties, such as moisture retention curve (SMRC), diffusivity, and hydraulic conductivity functions, play a crucial role, as they control the infiltration process and the soil water and solute movement.

Modeling and flow simulation of soil water movement depends on the appropriate description of the hydraulic properties and their measurements (in situ and in the laboratory), upon which these are provided. A comprehensive review of the recent developments in the various aspects of soil water movement in irrigated agriculture is welcome.

The above may be presented in a number of research topics that tackle one or more of the following challenges:

  • Irrigation systems and one-, two-, and three-dimensional soil water movement.
  • One- and three-dimensional infiltration analysis from a disc infiltrometer.
  • Dielectric devices for monitoring soil water content and methods for assessment of soil water pressure head.
  • Soil hydraulic properties and their temporal and spatial variability under the irrigation situations.
  • Saturated–unsaturated flow model in irrigated soils.
  • Soil water redistribution and the role of hysteresis.
  • Soil water movement and drainage in irrigated agriculture.
  • Salt accumulation, soil salinization, and soil salinity assessment.
  • Effect of salts on hydraulic conductivity.
  • Soil conditioners and mulches which change the upper soil hydraulic properties and their effect on soil water movement.

Prof. Dr. George Kargas
Emeritus Prof. Dr. Petros Kerkides
Dr. Paraskevi Londra
Guest Editors

Manuscript Submission Information

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Keywords

  • Infiltration process
  • hydraulic properties
  • water and salt transport in irrigated soils
  • modeling water flow
  • disc infiltrometer
  • dielectric sensors

Published Papers (8 papers)

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Research

Open AccessFeature PaperArticle
Comparison of Soil EC Values from Methods Based on 1:1 and 1:5 Soil to Water Ratios and ECe from Saturated Paste Extract Based Method
Water 2020, 12(4), 1010; https://doi.org/10.3390/w12041010 - 02 Apr 2020
Abstract
The present study investigates the effect of three different methods of obtaining 1:1 and 1:5 soil-over-water mass ratios (soil:water) extracts for soil electrical conductivity (EC) measurements (EC1:1, EC1:5). On the same soil samples, also the electrical conductivity of the [...] Read more.
The present study investigates the effect of three different methods of obtaining 1:1 and 1:5 soil-over-water mass ratios (soil:water) extracts for soil electrical conductivity (EC) measurements (EC1:1, EC1:5). On the same soil samples, also the electrical conductivity of the saturated paste extract (ECe) was determined and the relationships between ECe and each of the three of EC1:1 and EC1:5 values were examined. The soil samples used were collected from three areas over Greece (Laconia, Argolida and Kos) and had ECe values ranging from 0.611 to 25.9 dS m−1. From the results, it was shown that for soils with ECe < 3 dS m−1 the higher EC values were obtained by the method where the suspension remained at rest for 23 hours and then shaken mechanically for 1 h. On the contrary, no differences were observed among the three methods for soils with ECe > 3 dS m−1. Also, in the case of EC1:5, the optimal times for equilibration were much longer when ECe < 3 dS m−1. Across all soils, the relationships between ECe and each of three methods of obtaining EC1:1 and EC1:5 were strongly linear (0.953 < R2 < 0.991 and 0.63 < RMSE < 1.27 dS m−1). Taking into account the threshold of ECe = 3 dS m−1, different ECe = f(EC1:5) linear relationships were obtained. Although the linear model gave high values of R2 and RMSE for ECe < 3 dS m−1, the quadratic model resulted in better R2 and RMSE values for all methods examined. Correspondingly, in the 1:1 method, two of the three methods used exhibited similar slope values of the linear relationships independent of ECe value (ECe < 3 or ECe > 3 dS m−1), while one method (23 h rest and then shaken mechanically for 1 hour) showed significant differences in the slopes of the linear relationships between the two ranges of ECe. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessArticle
The Effect of Irrigation Treatment on the Growth of Lavender Species in an Extensive Green Roof System
Water 2020, 12(3), 863; https://doi.org/10.3390/w12030863 - 19 Mar 2020
Abstract
In green roofs, the use of plant species that withstand dry arid environmental conditions and have reduced water requirements is recommended. The current study presents the effect of irrigation amount on the growth of four different species of lavender; Lavandula angustifolia, Lavandula [...] Read more.
In green roofs, the use of plant species that withstand dry arid environmental conditions and have reduced water requirements is recommended. The current study presents the effect of irrigation amount on the growth of four different species of lavender; Lavandula angustifolia, Lavandula dentata var. candicans, Lavandula dentata var. dentata, and Lavandula stoechas established on an extensive green roof system and used in urban agriculture. Two irrigation treatments (high and low) determined by the substrate hydraulic properties were applied. Plant growth studied at regular intervals included measurements of plant height, shoot canopy diameter, plant growth index, shoot dry weight and stomatal conductance. The results were consistent and showed that low irrigation reduced plant growth. With the exception of L. stoechas, the appearance of plants watered with the low irrigation treatment was satisfactory, and their use under low water amount irrigation is supported. Interspecies differences among lavender species were present in both irrigation treatments. Overall, L. dentata var. candicans showed the greatest growth, followed in descending order by L. dentata var. dentata and L. angustifolia. In parallel, for stomatal conductance, L. dentata var. candicans showed the lowest value, similar to L. dentata var. dentata, and L. angustifolia the largest. Differences in plant characteristics and size among the latter three species can be considered in the design of extensive green roof systems. The use of substrate hydraulic properties was shown to be important for irrigation management on extensive green roof systems. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessArticle
The Effect of Salinity on the Growth of Lavender Species
Water 2020, 12(3), 618; https://doi.org/10.3390/w12030618 - 25 Feb 2020
Abstract
Long term degradation of water quality from natural resources has led to the use of alternative water resources for irrigation that are saline. Saline water irrigation in floriculture for the production of nursery crops requires an understanding of plant response. The pot growth [...] Read more.
Long term degradation of water quality from natural resources has led to the use of alternative water resources for irrigation that are saline. Saline water irrigation in floriculture for the production of nursery crops requires an understanding of plant response. The pot growth of four lavender species (Lavandula angustifolia, Lavandula dentata var. dentata, Lavandula dentata var. candicans and Lavandula stoechas) irrigated with water containing different concentrations of NaCl (0, 25, 50, 100 and 200 mM) was investigated under greenhouse conditions. Overall results of different plant growth variables were consistent, showing a significant decrease at 100 and 200 mM NaCl. All lavender species showed signs of salinity stress that included chlorosis, followed by leaf and stem necrosis at NaCl concentrations greater than 50 mM. L. dentata var. dentata showed the greatest plant growth followed in descending order by L. dentata var. candicans, L. stoechas and L. angustifolia. Despite greater growth of L. dentata var. dentata, the appearance of L. dentata var. candicans was “healthier”. In areas with saline irrigation water, L. dentata var. dentata and L. dentata var. candicans are proposed for the production of lavender nursery crops. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessFeature PaperArticle
The Effect of Soil Iron on the Estimation of Soil Water Content Using Dielectric Sensors
Water 2020, 12(2), 598; https://doi.org/10.3390/w12020598 - 22 Feb 2020
Abstract
Nowadays, the estimation of volumetric soil water content (θ) through apparent dielectric permittivity (εa) is the most widely used method. The purpose of this study is to investigate the effect of the high iron content of two sandy loam soils on [...] Read more.
Nowadays, the estimation of volumetric soil water content (θ) through apparent dielectric permittivity (εa) is the most widely used method. The purpose of this study is to investigate the effect of the high iron content of two sandy loam soils on estimating their water content using two dielectric sensors. These sensors are the WET sensor operating at 20 MHz and the ML2 sensor operating at 100 MHz. Experiments on specific soil columns, in the laboratory, by mixing different amounts of water in the soils to obtain a range of θ values under constant temperature conditions were conducted. Analysis of the results showed that both sensors, based on manufacturer calibration, led to overestimation of θ. This overestimation is due to the high measured values of εa by both sensors used. The WET sensor, operating at a lower frequency and being strongly affected by soil characteristics, showed the greatest overestimation. The difference of εa values between the two sensors ranged from 14 to 19 units at the maximum actual soil water content (θm). Compared to the Topp equation, the WET sensor measures 2.3 to 2.8 fold higher value of εa. From the results, it was shown that the relationship θma0.5 remained linear even in the case of these soils with high iron content and the multi-point calibration (CALALL) is a good option where individual calibration is needed. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessArticle
Optimization of Spring Wheat Irrigation Schedule in Shallow Groundwater Area of Jiefangzha Region in Hetao Irrigation District
Water 2019, 11(12), 2627; https://doi.org/10.3390/w11122627 - 13 Dec 2019
Abstract
Due to the large spatial variation of groundwater depth, it is very difficult to determine suitable irrigation schedules for crops in shallow groundwater area. A zoning optimization method of irrigation schedule is proposed here, which can solve the problem of the connection between [...] Read more.
Due to the large spatial variation of groundwater depth, it is very difficult to determine suitable irrigation schedules for crops in shallow groundwater area. A zoning optimization method of irrigation schedule is proposed here, which can solve the problem of the connection between suitable irrigation schedules and different groundwater depths in shallow groundwater areas. The main results include: (1) Taking the annual mean groundwater depth 2.5 m as the dividing line, the shallow groundwater areas were categorized into two irrigation schedule zones. (2) On the principle of maximizing the yield, the optimized irrigation schedule for spring wheat in each zone was obtained. When the groundwater depth was greater than 2.5 m, two rounds of irrigation were chosen at the tillering–shooting stage and the shooting–heading stage with the irrigation quota at 300 mm. When the groundwater depth was less than 2.5 m, two rounds of irrigation were chosen at the tillering–shooting stage, and one round at the shooting–heading stage, with the irrigation quota at 240 mm. The main water-saving effect of the optimized irrigation schedule is that the yield, the soil water use rate, and the water use productivity increased, while the irrigation amount and the ineffective seepage decreased. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessArticle
Investigation of the Flux–Concentration Relation for Horizontal Flow in Soils
Water 2019, 11(12), 2442; https://doi.org/10.3390/w11122442 - 21 Nov 2019
Abstract
The objective of the present work is to investigate the flux–concentration (F(Θ)) relation, where Θ is the normalized soil volumetric water content for the case of one-dimensional horizontal flow, subject to constant concentration conditions. More specifically, the possibility of describing F [...] Read more.
The objective of the present work is to investigate the flux–concentration (F(Θ)) relation, where Θ is the normalized soil volumetric water content for the case of one-dimensional horizontal flow, subject to constant concentration conditions. More specifically, the possibility of describing F(Θ) by an equation of the form F(Θ) = 1 − (1 − Θ)p+1 is examined. Parameter p is estimated from curve-fitting of the experimentally obtained λ(Θ) data to an analytic expression of the form (1 − Θ)p where λ is the well-known Boltzmann transformation λ = xt−0.5 (x = distance, t = time). The results show that the equation of (1 − Θ)p form can satisfactorily describe the λ(Θ) relation for the four porous media tested. The proposed F(Θ) function was compared with the limiting F(Θ) function for linear and Green–Ampt soils and to the actual F(Θ) function. From the results, it was shown that the proposed F(Θ) function gave reasonably accurate results in all cases. Moreover, the analytical expression of the soil water diffusivity (D(Θ)) function, as it was obtained by using the equation for λ(Θ) of the form (1 − Θ)p, appears to be very close to the experimental D(Θ) data (root mean square error (RMSE) = 0.593 m2min−1). Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessArticle
Dynamics and Distribution of Soil Salinity under Long-Term Mulched Drip Irrigation in an Arid Area of Northwestern China
Water 2019, 11(6), 1225; https://doi.org/10.3390/w11061225 - 12 Jun 2019
Cited by 1
Abstract
Mulched drip irrigation has been widely used in agricultural planting in arid and semi-arid regions. The dynamics and distribution of soil salinity under mulched drip irrigation greatly affect crop growth and yield. However, there are still different views on the distribution and dynamics [...] Read more.
Mulched drip irrigation has been widely used in agricultural planting in arid and semi-arid regions. The dynamics and distribution of soil salinity under mulched drip irrigation greatly affect crop growth and yield. However, there are still different views on the distribution and dynamics of soil salinity under long-term mulched drip irrigation due to complex factors (climate, groundwater, irrigation, and soil). Therefore, the soil salinity of newly reclaimed salt wasteland was monitored for 9 years (2008–2016), and the effects of soil water on soil salinity distribution under mulched drip irrigation have also been explored. The results indicated that the soil salinity decreased sharply in 3–4 years of implementation of mulched drip irrigation, and then began to fluctuate to different degrees and showed slight re-accumulation. During the growth period, soil salinity was relatively high at pre-sowing, and after a period of decline soil salinity tends to increase in the late harvest period. The vertical distribution of soil texture had a significant effect on the distribution of soil salinity. Salt accumulated near the soil layer transiting from coarse soil to fine soil. After a single irrigation, the soil water content in the 30–70 cm layer under the cotton plant undergoes a ‘high–low–high’ change pattern, and the soil salt firstly moved to the deep layer (below 70 cm), and then showed upward migration tendency with the weakening of irrigation water infiltration. The results may contribute to the scientific extension of mulched drip irrigation and the farmland management under long-term mulched drip irrigation. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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Open AccessArticle
Modeling of Fertilizer Transport for Various Fertigation Scenarios under Drip Irrigation
Water 2019, 11(5), 893; https://doi.org/10.3390/w11050893 - 28 Apr 2019
Cited by 4
Abstract
Frequent application of nitrogen fertilizers through irrigation is likely to increase the concentration of nitrate in groundwater. In this study, the HYDRUS-2D/3D model was used to simulate fertilizer movement through the soil under surface (DI) and subsurface drip irrigation (SDI) with 10 and [...] Read more.
Frequent application of nitrogen fertilizers through irrigation is likely to increase the concentration of nitrate in groundwater. In this study, the HYDRUS-2D/3D model was used to simulate fertilizer movement through the soil under surface (DI) and subsurface drip irrigation (SDI) with 10 and 20 cm emitter depths for tomato growing in three different typical and representative Egyptian soil types, namely sand, loamy sand, and sandy loam. Ammonium, nitrate, phosphorus, and potassium fertilizers were considered during simulation. Laboratory experiments were conducted to estimate the soils’ adsorption behavior. The impact of soil hydraulic properties and fertigation strategies on fertilizer distribution and use efficiency were investigated. Results showed that for DI, the percentage of nitrogen accumulated below the zone of maximum root density was 33%, 28%, and 24% for sand, loamy sand, and sandy loam soil, respectively. For SDI with 10 and 20 cm emitter depths, it was 34%, 29%, and 26%, and 44%, 37%, and 35%, respectively. Results showed that shallow emitter depth produced maximum nitrogen use efficiency varying from 27 to 37%, regardless of fertigation strategy. Therefore, subsurface drip irrigation with a shallow emitter depth is recommended for medium-textured soils. Moreover, the study showed that to reduce potential fertilizer leaching, fertilizers should be added at the beginning of irrigation events for SDI and at the end of irrigation events for DI. As nitrate uptake rate and leaching are affected by soil’s adsorption, it is important to determine the adsorption coefficient for nitrate before planting, as it will help to precisely assign application rates. This will lead to improve nutrient uptake and minimize potential leaching. Full article
(This article belongs to the Special Issue Study of the Soil Water Movement in Irrigated Agriculture)
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