scholarly journals Super Absorbent polymers and their Composites for Application in Agriculture

2021 ◽  
Vol 9 (9) ◽  
pp. 665-672
Author(s):  
Aryan Dwivedi
Keyword(s):  
Mechanical Property ◽  
Water Absorption ◽  
Soil Water ◽  
Water Retention ◽  
Hydraulic Parameters ◽  
Dryland Agriculture ◽  
Superabsorbent Polymers ◽  
Over Time

Abstract: In dryland agriculture, Superabsorbent Polymers (SAPs) are popular. However, the mechanical property, repetitive soil water absorption and release, regularly affects the water retention and hydraulic parameters of the soil, and since this property decreases progressively over time, the results of the property appear to be unpredictable. Polymers use to in agriculture field.

scholarly journals Effects of Superabsorbent Polymers on the Hydraulic Parameters and Water Retention Properties of Soil

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Renkuan Liao ◽  
Wenyong Wu ◽  
Shumei Ren ◽  
Peiling Yang
Keyword(s):  
Soil Water ◽  
High Speed ◽  
Water Retention ◽  
Soil Column ◽  
Future Research ◽  
Hydraulic Parameters ◽  
Superabsorbent Polymers ◽  
Treated Soil ◽  
Water Retention Properties ◽  
Properties Of Soil

Superabsorbent polymers (SAPs) are widely applied in dryland agriculture. However, their functional property of repeated absorption and release of soil water exerts periodic effects on the hydraulic parameters and water-retention properties of soil, and as this property gradually diminishes with time, its effects tend to be unstable. During the 120-day continuous soil cultivation experiment described in this paper, horizontal soil column infiltration and high-speed centrifugation tests were conducted on SAP-treated soil to measure unsaturated diffusivityDand soil water characteristic curves. The experimental results suggest that the SAP increased the water retaining capacity of soil sections where the suction pressure was between 0 and 3,000 cm. The SAP significantly obstructed water diffusion in the soil in the early days of the experiment, but the effect gradually decreased in the later period. The average decrease in water diffusivity in the treatment groups fell from 76.6% at 0 days to 1.2% at 120 days. This research also provided parameters of time-varying functions that describe the unsaturated diffusivityDand unsaturated hydraulic conductivityKof soils under the effects of SAPs; in future research, these functions can be used to construct water movement models applicable to SAP-treated soil.

Reducing non-uniqueness of inverting bimodal soil Kosugi hydraulic parameters

2021 ◽  
Author(s):  
Jesús Fernández-Gálvez ◽  
Joseph Pollacco ◽  
Stephen McNeill ◽  
Sam Carrick ◽  
Linda Lilburne ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Unsaturated Soils ◽  
Water Retention ◽  
Water Pressure ◽  
Full Range ◽  
Inverse Modelling ◽  
Residual Soil ◽  
Hydraulic Parameters ◽  
The Matrix

<p>Hydrological models use soil hydraulic parameters to describe the storage and transmission of water in soils. Hydraulic parameters define the water retention, <em>θ(ψ)</em>, and the hydraulic conductivity, <em>K(θ)</em>, functions. These functions are usually obtained by fitting experimental data to the corresponding θ(ψ) and K(θ) functions. The drawback of deriving the hydraulic parameters by inverse modelling is that they suffer from equifinality or non-uniqueness, and the optimal hydraulic parameters are non-physical (Pollacco <em>et al.</em>, 2008). To reduce the non-uniqueness, it is necessary to invert the hydraulic parameters simultaneously from observations of both<em> θ(ψ)</em> and <em>K(θ</em>), and ensure the measurements cover the full range of <em>θ</em> from fully saturated to oven dry, which requires expensive, labour-intensive measurements.  </p><p>We present a novel procedure to derive a unique, physical set of bimodal or dual permeabilityKosugi hydraulic functions,<em> θ(ψ)</em> and <em>K(θ)</em>, from inverse modelling. The Kosugi model was chosen given its parameters have direct physical meaning to the soil pore-size distribution. The challenge of using bimodal functions is they require double the number of parameters (Pollacco <em>et al.</em>, 2017), exacerbating the problem of non-uniqueness. To address this shortcoming, we<strong> (1) </strong>derive residual soil water content from the matrix Kosugi standard deviation, <strong>(2) </strong>derive macropore hydraulic parameters from the soil water pressure boundary between macropore and matrix, and <strong>(3)</strong> dynamically constraint the matrix Kosugi hydraulic parameters. We successfully reduce the number of hydraulic parameters to optimize and constrain the hydraulic parameters without compromising the fit of the <em>θ(ψ)</em> and <em>K(θ)</em> functions.</p><p>The robustness of the methodology is demonstrated by deriving the hydraulic parameters exclusively from<em> θ(ψ)</em> and <em>K<sub>s</sub></em>data, enabling satisfactory prediction of <em>K(θ)</em> without having measured K(θ) data. Moreover, having a reduced number of hydraulic parameters that are physical allows an improved characterization of hydraulic properties of soils prone to preferential flow, which is a fundamental issue regarding the understanding of hydrological processes.</p><p> </p><p><strong>References</strong></p><p>Pollacco, J.A.P., Ugalde, J.M.S., Angulo-Jaramillo, R., Braud, I., Saugier, B., 2008. A linking test to reduce the number of hydraulic parameters necessary to simulate groundwater recharge in unsaturated soils. Adv Water Resour 31, 355–369. https://doi.org/10.1016/j.advwatres.2007.09.002</p><p>Pollacco, J.A.P., Webb, T., McNeill, S., Hu, W., Carrick, S., Hewitt, A., Lilburne, L., 2017. Saturated hydraulic conductivity model computed from bimodal water retention curves for a range of New Zealand soils. Hydrol. Earth Syst. Sci. 21, 2725–2737. https://doi.org/10.5194/hess-21-2725-2017</p>

A New Approach to Estimate Soil Hydraulic Parameters Using Only Soil Water Retention Data

2008 ◽  
Vol 72 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Navin K. C. Twarakavi ◽  
Hirotaka Saito ◽  
Jirka Šimunek ◽  
M. Th. van Genuchten
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Retention Data ◽  
Hydraulic Parameters ◽  
Soil Water Retention ◽  
New Approach ◽  
Soil Hydraulic Parameters ◽  
Soil Hydraulic

INFLUENCE OF SOIL MATRIX ON SOIL-WATER RETENTION CURVE AND HYDRAULIC CHARACTERISTICS

2017 ◽  
Vol 16 (4) ◽  
pp. 869-877
Author(s):  
Vasile Lucian Pavel ◽  
Florian Statescu ◽  
Dorin Cotiu.ca-Zauca ◽  
Gabriela Biali ◽  
Paula Cojocaru
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Hydraulic Characteristics ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Soil Matrix ◽  
Retention Curve

scholarly journals Carboxylated nanocellulose superabsorbent: Biodegradation and soil water retention properties

2021 ◽  
pp. 51495
Author(s):  
Ruth M. Barajas‐Ledesma ◽  
Vanessa N. L. Wong ◽  
Karen Little ◽  
Antonio F. Patti ◽  
Gil Garnier
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Soil Water Retention ◽  
Water Retention Properties

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.

Gastric emptying, absorption, and carbohydrate oxidation during prolonged exercise

1992 ◽  
Vol 72 (2) ◽  
pp. 468-475 ◽  
Author(s):  
N. J. Rehrer ◽  
A. J. Wagenmakers ◽  
E. J. Beckers ◽  
D. Halliday ◽  
J. B. Leiper ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Crossover Study ◽  
Water Absorption ◽  
Water Uptake ◽  
Prolonged Exercise ◽  
Carbohydrate Oxidation ◽  
O2 Consumption ◽  
Digestive Function ◽  
Jejunal Perfusion ◽  
Over Time

This study was designed to examine aspects of digestive function that may limit assimilation of water and oxidation of orally ingested carbohydrate (CHO) during exercise. Eight males completed a crossover study in which each cycled on four occasions for 80 min at 70% maximal O2 consumption. Beverage was consumed at 0, 20, 40, and 60 min. Beverages were water, 4.5% glucose (4.5G), 17% glucose (17G), and 17% maltodextrin (17MD). CHO beverages contained 20 meq/l NaCl and were 13C enriched to measure exogenous CHO oxidation. Gastric (beverage) volume was measured at 80 min. Water uptake was estimated by including 2H2O in the beverage and measuring 2H accumulation in blood. Jejunal perfusion tests were conducted at rest with the same subjects and beverages. In 60 min, 1,294 +/- 31 (SE) ml were ingested; at 80 min, volumes emptied with H2O (1,257 +/- 32 ml) and 4.5G (1,223 +/- 32 ml) were greater than with 17G (781 +/- 56 ml) and 17MD (864 +/- 71 ml; P less than 0.05). Total CHO oxidized was similar with all beverages, but there was a greater increase in exogenous CHO oxidation over time with 17G and 17MD than with 4.5G; 54, 19, and 18% of the CHO ingested with 4.5G, 17G, and 17MD, respectively, was oxidized. This represents 57, 32, and 27%, respectively, of the CHO emptied from the stomach. 2H accumulation in the blood was more rapid with H2O and 4.5G than with 17G or 17MD. Net jejunal water absorption was greater from 4.5G than from water. Net water absorption was also observed from 17MD, whereas net secretion was observed with 17G.(ABSTRACT TRUNCATED AT 250 WORDS)

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