Dynamic study on water diffusivity of soil with super-absorbent polymer application

Han, Yanni; Yu, Xinxiao; Yang, Peiling; Li, Bo; Xu, Lei; Wang, Chengzhi

doi:10.1007/s12665-012-1956-9

Cited by 49 publications

(46 citation statements)

References 30 publications

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“…In this study, if a unique time‐dependent effect was not considered in the calculation method, the numerical experimental results indicated a pronounced error when the soil hydraulic parameters were decreased by 50–90%. As reported in previous studies, compared with the treatment without SAP application, significant decreases in the soil hydraulic parameters were observed, that is, up to 71.6% in the experiment carried by Han, Yu, et al () and 70–76% in the test performed by Liao et al (). Therefore, the time‐dependent effect of SAPs on soil hydraulic parameters should be fully considered when using the proposed calculation method to estimate RWU in response to SAPs.…”

Section: Discussionsupporting

confidence: 69%

“…However, it does not mean the multiphase functional equations no longer satisfied the basic equations of soil hydraulics such as the Richards and van Genuchten equations. We assumed that the soil still had a rigid condition after SAP application; subsequently, at a specific time, irrespective of the presence or absence of a SAP, the soil hydraulic functions would remain a function of only θ , and for a continuous time period, the multiphase functions D ( θ , t ) and K ( θ , t ) can be obtained through a comprehensive regression analysis of D n ( θ ) and K n ( θ ) at different specific times, which is supported by Han, Yu, et al () and Han, Wu, et al (). Here, the independent variable t was used for describing the ‘performance attenuation characteristic,’ which refers to the condition where the water retention capacity decreases over time as the SAP structure is destroyed (Liao et al, ; Zhou et al, ).…”

Section: Discussionmentioning

confidence: 77%

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Establishing and validating a root water uptake model under the effects of superabsorbent polymers

Liao

Yang

et al. 2018

Land Degrad Dev

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In‐depth understanding of the patterns of root water uptake (RWU) is the key to improving the water‐use efficiency of plants. Superabsorbent polymers (SAPs) can repeatedly absorb and then release water to plants when needed, which substantially increases the water‐use efficiency of plants in arid and semiarid farming. However, it also creates a challenge in modeling RWU due to unstable soil hydraulic parameters and the unclear response of root growth to SAP application. A controlled soil column experiment was conducted to investigate the response of two important root indexes, that is, root length density (RLD) and root nitrogen mass density (RND), to SAP application, as well as their relationships with RWU. The results showed that the use of the SAP caused a steady increase in RND, and it also substantially increased the RLD in the early stage, but the rate of increase gradually slowed over time. The effect of unstable soil hydraulic parameters on RWU was analyzed in a numerical experiment, which indicated that the time‐dependent effect of SAP on soil hydraulic parameters should be considered to avoid errors in calculating RWU. A specific method for calculating the RWU source/sink term in the Richards equation was proposed and ultimately used as the theoretical value of RWU to verify the RWU models based on RLD and RND to ensure the best one was selected. The results showed that RND was better able to be used for development of the RWU model to simulate the patterns of RWU under SAP application.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 77%

Establishing and validating a root water uptake model under the effects of superabsorbent polymers

Liao

Yang

et al. 2018

Land Degrad Dev

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“…A 10 cm soil–SAP mixture layer was designed 20 cm below the soil surface. The ratio of SAP is 0.6% (Han et al ., ; Liu et al ., ). In the course of loading the soil sample, three‐rod TDR (time domain reflectometry) probes were equidistantly immersed at different depths in the soil.…”

Section: Methodsmentioning

confidence: 99%

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

Han

Yang

et al. 2015

Irrigation and Drainage

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The application of superabsorbent polymers (SAPs) in agriculture can enhance water use efficiency and ease water shortage in agriculture. In this study, by applying SAPs to the middle layer of the soil root zone, the effects of SAPs on moisture distribution during infiltration and evaporation under the condition of point source irrigation were investigated. The results show that during infiltration, the wetting front formed an accident change zone in the horizontal direction; in the bottom layer, the horizontal infiltration rate is greater than the vertical infiltration rate due to the effect of SAPs from the middle layer; the soil water content in the middle layer increased remarkably by 23.6%, higher than that in the surface and bottom layers; during evaporation, the soil water content changed significantly in the surface layer due to strong evaporation on the surface, it was largest and quite even in the SAP-soil mixture layer, and decreased the least in the bottom layer due to water storage in the mixture layer. Therefore, SAP application in the crop root layer is helpful to conserve soil water content in the crop root zone, inhibit evaporation of soil water in the lower layer and facilitate moisture conservation. RÉSUMÉ L'application de polymères super-absorbants (SAP) dans l'agriculture peut améliorer l'utilisation de l'eau et faciliter la gestion de la pénurie d'eau dans l'agriculture. Nous avons étudié les incidences d'un SAP appliqué sur la couche médiane de la zone racinaire d'un sol sur l'évaporation et l'infiltration au droit d'un goutteur d'irrigation. Les résultats montrent que lors de l'infiltration, le front d'humectation subit un accident dans le sens horizontal; dans la couche inférieure, le taux d'infiltration horizontal est supérieur à la vitesse d'infiltration verticale sous l'effet du SAP de la couche centrale; la teneur en eau du sol dans la couche intermédiaire a augmenté de 23.6%, supérieure à celle de la surface et des couches inférieures; au cours de l'évaporation, la teneur en eau du sol a changé de manière significative dans la couche de surface en raison d' une forte évaporation; la variation a été la plus importante dans la couche de mélange SAP-sol, et la diminution de teneur en eau a été la plus petite dans la couche inférieure en raison du stockage d'eau dans la couche avec SAP. Par conséquent, l'application de SAP dans la zone racinaire est utile à y conserver l'humidité du sol et à inhiber l'évaporation de l'eau dans la couche inférieure.

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“…They also indicated that these SH are potential candidates to be applied as an alternative to combat of global climate change because they can improve the soil properties, mainly in conditions of reduced moisture availability. Other authors investigated the applicability of the polymers, common hydrogels and SH as strategies to improve the soil properties [184][185][186][187][188][189][190][191][192][193][194][195][196][197][198][199][200][201].…”

Section: Application As Soil Conditionersmentioning

confidence: 99%

Superabsorbent hydrogels based on polysaccharides for application in agriculture as soil conditioner and nutrient carrier: A review

Guilherme

Aouada

Fajardo

et al. 2015

European Polymer Journal

603

325

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a b s t r a c t Superabsorbent hydrogels (SH) continue being a very important issue in both academic and industrial fields due to their applications in several technologies. This is proved by the impressive number of publications, through papers and patents as well, dealing with SH. This review is targeted to update and discuss some important aspects of synthesis, characterization and application of SH in agriculture, mainly those based on polysaccharides, as soil conditioners and as polymer carriers for nutrient release. Basic properties of SH and some methods for chemically modifying polysaccharides are given and some directions for hydrogels preparation are highlighted as well. Mechanisms associated with water transport into the 3D matrix, taking into account the transference of mass from hydrogelsoil system to plant, are discussed in the light of some mathematical models. Release of nutrients either from granules coated by hydrophilic polymer or from SH, targeting applications in agriculture, is also discussed on the basis of often used mathematical models (the swelling-based kinetic models) and on a diffusion-based kinetic model with a partition activity coefficient. Examples of recent applications in agriculture as soil conditioners and carriers for nutrient release (fertilizers, etc.) are given. At the final, future trends and perspectives are considered. More than two hundreds references are cited in the whole text.

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Dynamic study on water diffusivity of soil with super-absorbent polymer application

Cited by 49 publications

References 30 publications

Establishing and validating a root water uptake model under the effects of superabsorbent polymers

Establishing and validating a root water uptake model under the effects of superabsorbent polymers

Effects of Superabsorbent Polymers on Infiltration and Evaporation of Soil Moisture Under Point Source Drip Irrigation

Superabsorbent hydrogels based on polysaccharides for application in agriculture as soil conditioner and nutrient carrier: A review

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