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2022 ◽  
Vol 25 (1) ◽  
pp. 21-35
Author(s):  
Esam Mahmoud Mohammed ◽  
Salahaldeen Abid-Alziz AL-Qassab ◽  
Faris Akram Salih AL-Wazan

The objective of this research was to assess the use of unsaturated water flow in terms of soil water evaporation, which was determined by evaluating some soil hydraulic parameters in different soil textures. The results show that the predicted values of these parameters, which were obtained through inverse modeling with the HYDRUS-1D software and depend on the change of the volumetric water content, exhibited a significant agreement with the measured values from laboratory or field simulation data for soil water evaporation at 5. 10. 20. and 45 days of measurement. At the same time, inverse simulation was conducted on soil hydraulic parameters obtained from a 5-day laboratory soil evaporation period to predict field infiltration values and water retention curve, which showed a significant agreement with measured values for all soil textures.


2022 ◽  
Vol 259 ◽  
pp. 107234
Author(s):  
Bruno Patias Lena ◽  
Luca Bondesan ◽  
Everton Alves Rodrigues Pinheiro ◽  
Brenda V. Ortiz ◽  
Guilherme Trimer Morata ◽  
...  

2021 ◽  
Author(s):  
Alice Künzel
Keyword(s):  

<p>Winterweizen ist die wichtigste Kulturpflanze in Deutschland, weshalb in der vorliegenden Arbeit eine statistisch-klimatologische Analyse der Evapotranspiration von Winterweizen mittels Lysimeterdaten und Modellergebnissen in Groß Lüsewitz, Brandis und Potsdam erfolgte. Die ausgewählten Standorte unterscheiden sich hinsichtlich der klimatischen und edaphischen Verhältnisse. In Groß Lüsewitz und in Brandis wird die aktuelle Evapotranspiration (AET) mittels Lysimetern gemessen. Diese Messdaten wurden mit der modellierten AET der Bodenwasserhaushaltsmodelle METVER und HYDRUS-1D verglichen, wobei nur Anbaujahre des Winterweizens am jeweiligen Lysimeterstandort berücksichtigt wurden. Für Potsdam erfolgte für vier Klimaperioden nur eine modellbasierte Auswertung der AET. Die Analyse beschränkt sich an allen Standorten auf die Vegetationsperiode des Winterweizens, welche die Monate März bis August umfasst.</p> <p>Die für das Wachstum des Winterweizens entscheidenden Monate sind April bis Juni. In dieser Hauptwachstumszeit ist der Wasserverbrauch des Winterweizens am größten, weshalb eine kontinuierliche Wasserversorgung gewährleistet sein muss. Die Analyse ergab, dass die Variabilität der gemessenen AET mittels beider Bodenwasserhaushaltsmodelle an den Lysimeterstandorten, wenn auch unterschiedlich gut im Vergleich zur gemessenen AET auf den Lysimetern, simuliert werden konnte.</p> <p>Die potentielle Evapotranspiration (ETP) wird in METVER mit einem modifizierten Berechnungsansatz nach Turc-Wendling und in HYDRUS-1D nach dem Ansatz von Penman-Monteith modelliert. In Groß Lüsewitz und in Potsdam wurden trotz der unterschiedlichen Berechnungsansätze ähnliche Ergebnisse erzielt. Für Brandis dagegen ergaben sich deutlich unterschiedliche Ergebnisse.</p> <p>Wenn sehr trockene Bedingungen in einzelnen Monaten der jeweiligen Anbaujahre vorlagen, war die Differenz zwischen der modellierten ETP des jeweiligen Bodenwasserhaushaltsmodells und der gemessenen AET auf den Lysimetern deutlich ausgeprägt. Anhand des verwendeten Ariditätsindexes konnte festgestellt werden, dass in Groß Lüsewitz die Vegetationsperiode des Winterweizens bei METVER in vier und bei HYDRUS in einem von insgesamt 26 Anbaujahren durchweg sehr trocken war. In Brandis waren es bei METVER drei und bei HYDRUS zwei von insgesamt 12 Anbaujahren.</p> <p>Mittels einer modellbasierten Trendanalyse der ETP und der AET am jeweiligen Standort konnte für Groß Lüsewitz im Zeitraum 1975-2020, für Brandis (1981-2020) und für Potsdam (1901-2020) eine zunehmende Trockenheit festgestellt werden, sodass die Bewässerung von Winterweizen hier zukünftig an Bedeutung gewinnen wird.</p>


Author(s):  
Marco Aurélio Calixto Ribeiro De Holanda ◽  
Diogo Botelho Correa De Oliveira ◽  
Willames de Albuquerque Soares

Propose a specific method (Junction Between Arya and Heitman and Haverkamp - JAHH), similar to BEST, to obtain the hydrodynamic parameters of soils in Pernambuco, Brazil. Sample: Department of Civil Engineering, Polytechnic School of Pernambuco – POLI, between March 2019 and February 2021. For this, BEST and JAHH were used to obtain the hydrodynamic characteristics of the collected materials, and the results of both methods were compared with simulations performed in Hydrus-1D. Sorptivity and Ks, acquired using both methods, presented differences reached 68.38% regarding Ks. The characteristic radius of the pores (λm) and capillary length (λc) obtained with BEST are not coherent, and this can be explained because during the evaluation of one sandy soil, λm values were the highest and λc were the lowest, when the opposite was expected. The use of JAHH to estimate soil parameters could generate more coherent estimates than BEST-slope, even though both of them have presented results of the same proportion, such as sorptivity and saturated hydraulic conductivity, for exemple. Therefore, the proposed method presented more pertinent results when compared to BEST regarding the studied soils.


Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3492
Author(s):  
Ioannis Argyrokastritis ◽  
Maria Psychogiou ◽  
Paraskevi A. Londra

Ponded infiltration processes occur in agricultural lands irrigated by flooding of their soil surface or under insufficient drainage conditions. The existing equations describing the phenomenon of vertical infiltration under ponded conditions have not considered the actual contribution of the pressure head gradient to the flow. In this study, simple equations are proposed to describe the horizontal and vertical infiltration under various ponding heads incorporating the actual contribution of the pressure head gradient to the flow. Six soils with known hydraulic properties, covering a wide range of soil textures, were used. Horizontal and vertical infiltration data are obtained by numerical simulation for all soils studied using the Hydrus-1D code. To validate the accuracy of the proposed equations, the solutions of horizontal and vertical infiltrations provided by the proposed equations were compared with numerically simulated ones provided by the Hydrus 1-D. The analysis of the results showed a very good agreement in all soils studied. The proposed vertical infiltration equation was also compared to a simple and accurate equation which does not incorporate the actual contribution of the pressure head gradient to the flow and differences between them were observed in all soils studied.


2021 ◽  
Vol 27 ◽  
pp. 47-58
Author(s):  
Erik Zimmermann
Keyword(s):  

Se propone un esquema numérico explícito de 4 celdas (4C) para la integración de las ecuaciones de flujo en la zona no saturada diseñado para áreas de llanura con niveles freáticos someros. El esquema contempla un coeficiente de ponderación para definir la conductividad hidráulica no saturada representativa entre celdas adyacentes y considera la heterogeneidad de cada horizonte edáfico. El esquema 4C es comparado con estimaciones realizadas por el HYDRUS-1D en dos grupos de ensayos modelados, uno con saturación de superficie durante 10 días y otro con series de precipitaciones durante 96 días. Los ensayos numéricos se hicieron para 14 tipos de asociaciones de suelos características de la zona de estudio (A° del Azul, Bs. As.) y 6 profundidades freáticas (entre 300 y 50 cm). Para el primer ensayo, la respuesta del esquema se considera aceptable con diferencias porcentuales del orden al 19%. En el segundo, el esquema propuesto estimó satisfactoriamente las recargas freáticas con diferencias porcentuales del 1% entre ambos esquemas. Complementariamente, mostró un muy buen ajuste en las evoluciones de contenidos de humedad de cada estrato. Estos resultados validan el esquema simplificado propuesto permitiendo una respuesta rápida en términos de tiempo computacional.


2021 ◽  
Author(s):  
Emeka Ndulue ◽  
Afua Adobea Mante ◽  
Ramanathan Sri Ran

Abstract Soil water content (SWC) plays a critical role in crop yield, irrigation scheduling, and water resources management. In the Canadian Prairies, the water content in the rootzone replenished by rainfall is rarely sufficient to satisfy crop water requirements. Thus, the need for robust and effective water management. Hydrologic modelling provides the opportunity to understand the underlying processes controlling and affecting soil water movement and distribution. Evapotranspiration (ET) is an important input of hydrologic models; thus, the estimation of ET could have significant consequences on modelling outcome and inference. The FAO Penman-Monteith (PM) is the recommended model for estimating the reference crop evapotranspiration (ETo). However, it is limited by requiring too many weather variables that are not readily available. Simple empirical ETo models have been developed as an alternative. In this study, six ETo models with different inputs were used to simulate soil water dynamics in a rainfed potato farm in Winkler, Manitoba, using the HYDRUS-1D model. The results showed that when used to simulate SWC, all the models followed a similar pattern, although a significant difference was observed at shallow depth (20 cm). Specifically, a significant difference (p < 0.05) was observed between observed and simulated SWC from Hargreaves Samani, Romanenko, Penman, and FAO-PM (missing) models. When used to simulate the crop evapotranspiration (ETc), there was no significant difference (p > 0.05) between observed and simulated ETc from FAO PM, Irmak, and Priestly – Taylor models. Hence, ETo models with fewer data inputs such as Irmak and Priestly – Taylor models can provide accurate and reliable results for water management in southern Manitoba.


2021 ◽  
Vol 13 (19) ◽  
pp. 10967
Author(s):  
Muhammad Mohiuddin ◽  
Jawad Ali ◽  
Megersa Kebede Leta ◽  
Muhammad Waseem ◽  
Muhammad Irshad ◽  
...  

This study investigated the ability of a HYDRUS 1D model for predicting the vertical distribution of potassium iodine (200 ppm) in soil columns after amendment with five different common remediation materials (gypsum, lime, fly ash, charcoal, and sawdust) at a rate of 2.5% (w/w), relative to an unamended control soil. Results showed that relative to the unamended soil, iodine leaching was decreased by all amendments but that the magnitude of the decreases varied with the soil amendment applied. Iodine content was highest in the upper layer of the soil columns and decreased progressively with soil depth. The model was evaluated via comparison of the model simulated values with measured values from the soil column studies. The results showed that the HYDRUS 1D model efficiency was near to 1, indicating the stimulated results near to the measured values. Therefore, this study showed that iodine leaching through a soil could be ascertained well using a HYDRUS 1D model. The model over predicted iodine leaching, results in a weak correspondence between the simulated and the measured results for iodine leaching. This suggests that the HYDRUS-1D model does not explain accurately different organic and inorganic amended soil and the preferential flow that occurs in these columns. This may be due to the fact that Freundlich isotherm, which is part of the transport equations, does not sufficiently describe the mechanism of iodine adsorption onto the soil particles. This study would help to select an amendment for an effective management strategy to reduce exogenous iodine losses from agro-ecosystems. This would also improve scientific understanding of iodine transport in soil profile.


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