Soil Water Retention Properties Research Articles

Effect of volumetric deformation on saturation of unsaturated soils under constant suction

The soil–water retention curve (SWRC) represents a fundamental relationship in the study of unsaturated soils, where volumetric deformation plays a crucial role in shaping the water retention characteristics by impacting the pore size distribution. This study conducted a thermodynamic analysis to derive a relationship between the effective stress parameter and the water retention properties of unsaturated soils. Consequently, a streamlined formula was introduced to forecast the impact of volumetric deformation on saturation at constant suction. This formula, incorporating a singular parameter from the effective stress parameters equations, can be seamlessly integrated with any prevailing SWRC model to characterize the influence of volume deformation on the SWRC. The effectiveness of the proposed model was corroborated through seven sets of experimental data spanning various soils, affirming its capability to precisely describe the water retention behavior of deformable soils under deformation.

POTENTIAL OF NO-TILL TECHNOLOGY FOR ENVIRONMENTAL PROTECTION

Reducing the negative impact of agricultural practices on the environment is essential. There is a growing need for the use and adoption of environmentally friendly and environmentally sound technologies in agriculture. Encouraging the adoption of agri-environmental practices will increase crop productivity, minimise labour time, improve biological control, reduce erosion, improve soil structure, increase infiltration and water retention properties and achieve environmental sustainability. The wide range of conditions under which the minimum tillage system works successfully worldwide are its economic, social and environmental advantages. No-till technology is often characterised as a means of tilling the soil and growing different crop species with positive environmental externalities. The purpose of this paper is to describe the importance of using the agroecological practice of no-till and its impact on land resources as well as its secondary environmental impacts. A literature review of the author's views related to the definitions of No-till technology is conducted. It is most commonly defined as no-till, minimum tillage or a technology such as planting in soil without prior preparation. The palette of benefits that agroecological practice brings to the soil, the environment, agriculture and farmers is rich, namely: ➢ does not disturb soil composition; ➢ improves the functions that occur in ecosystems; ➢ increases the availability of crop residues. Increased availability of crop residues and cover crops on cropland increases biomass production, with the maximized yield serving to store more C in the soil; ➢ improves water conveyance functions, moisture retention, and reduction of surface runoff and erosion, increases heat throughout the soil world; ➢ production quantities obtained are comparable to those of intensive tillage; ➢ reduces both labor time and the use of fuels and pesticides; ➢ minimizes depreciation of the equipment used; ➢ reduce investment in purchasing attachments; ➢ smaller capacity of the machinery and equipment used; ➢ reduce and simplify labour requirements; ➢ easy matching with crop rotation and improved nutrient cycling. Key words: JEL: Q00, Q01, O13

Influence of Date Palm-Based Biochar and Compost on Water Retention Properties of Soils with Different Sand Contents

Generally, soils of arid and semi-arid regions have low water retention properties due to high sand and low organic carbon contents. This study aimed at quantifying the effect of date palm-based organic amendments (OAs) on the water retention properties of two soils (sandy loam and silty loam), as well as the influence of sand supplementation (0.5–2 mm) on the magnitude of the effect of OAs. Different grain size distributions were obtained by adding sand to natural soils. For this purpose, sand was added to the two soils (1/3 and 2/3) and different soil-OA combinations were tested at a dose of 3% by mass: compost alone, biochar alone and a mixture of biochar and compost (50:50 in mass), in addition to unamended control soils. Soil water contents were measured at nine matric potentials ranging from the saturation to the permanent wilting point. Biochar was more efficient than compost at improving soil water retention. The effect of organic amendments on water retention increased with sand content. In most cases, soil water content values were significantly higher for biochar-amended soils than for unamended or compost-amended soils. The weakness of the effect of compost addition (if alone) was probably due to its properties and notably its high mineral content and electrical conductivity. Soil sand supplementation led to higher differences between the OA-amended soils and unamended soils. Changes in available water capacity reached +26% and +80% in a sandy loamy soil enriched with 2/3 sand and amended with compost and with biochar, respectively, compared to the unamended soil. These results show that sand content (and more generally, soil texture) influences the effect of OA application. Thus, the application of biochar from date palm residues in soil seems to be an effective solution to improve the water retention properties of coarse textured soils and contribute to optimizing the use of water resources in irrigated areas.

Exploring soil water retention hysteresis in the entire suction range and microstructure evolution of loess: The influence of sediment depths

Sediment depths can influence both soil structure and hydraulic processes, resulting in diverse soil-water retention properties. This study aimed to investigate the impact of sediment depths on soil-water retention hysteresis across the entire suction range, as well as the microstructure evolution of loess during the drying-wetting cycle. Laboratory tests were conducted to achieve this objective. The test results demonstrated that the water retention properties of the natural loess were significantly affected by sediment depths over the entire suction range. And the tested samples shrank considerably due to drying, while the swelling curves were almost linear induced by the wetting. Besides, the commonly used four water retention models were adopted to fit the test data, and Zhou's model showed the best-fitting performance. Furthermore, the local degree of hysteresis in the low suction range was generally larger than that in the high suction range for all samples, and the minimum local degree of hysteresis corresponded to the in-situ suction of tested samples. The average degree of hysteresis of JY-5 m, JY-15 m, and JY-30 m samples were 0.12, 0.14, and 0.13 respectively. Regarding microstructure change, the void ratios (which were smaller than the actual void ratios of soil samples) measured by the mercury intrusion porosimetry (MIP) tests became larger after undergoing the drying-wetting cycle, and most of the increased pores were primarily attributed to the formation of small mesopores in the vicinity of the main capillary pores. The results of this study contribute valuable insights into the dynamics of soil-water retention hysteresis and the associated microstructure evolution of loess.

Short-term impact of different doses of spent coffee grounds, salt, and sand on soil chemical and hydrological properties in an urban soil

Natural and human activities have deteriorated urban soil’s health and ecological functions as compared to forest soils. Therefore, we hypothesized that any intervention in poor quality soil in urban area will change their chemical and water retention properties. The experiment was conducted in Krakow (Poland) in completely randomized design (CRD). The soil amendments used in this experiment consisted of control, spent coffee grounds (SCGs), salt, and sand (1 and 2 t ha−1) in order to evaluate the impact of these soil amendments on the urban soil chemical and hydrological properties. Soil samples were collected after 3 months of soil application. The soil pH, soil acidity (me/100 g), electrical conductivity (mS/cm), total carbon (%), CO2 emission (g m−2 day−1), and total nitrogen (%) were measured in laboratory condition. The soil hydrological properties like volumetric water content (VWC), water drop penetration time (WDPT), current water storage capacity (Sa), water storage capacity after 4 and 24 h (S4 and S24), and capillary water Pk (mm) were also determined. We noted variations in soil chemical and water retention properties in urban soil after the application of SCGs, sand, and salt. It was observed that SCGs (2 t ha−1) has reduced soil pH and nitrogen (%) by 14 and 9%, while the incorporation of salt resulted in maximum soil EC, total acidity, and soil pH. The soil carbon (%) and CO2 emission (g m−2 day−1) were enhanced and declined by SCGs amendment. Furthermore, the soil hydrological properties were significantly influenced by the soil amendment (spent coffee grounds, salt, and sand) application. Our results showed that spent coffee grounds mixing in urban soil has considerably enhanced the soil VWC, Sa, S4, S24, and Pk, whereas it decreased the water drop penetration time. The analysis showed that the single dose of soil amendments had not improved soil chemical properties very well. Therefore, it is suggested that SCGs should be applied more than single dose. This is a good direction to look for ways to improve the retention properties of urban soil and you can consider combining SCGs with other organic materials like compost, farmyard manure, or biochar.

Mechanical behaviour of soil under drying–wetting cycles and vertical confining pressures

A system for preparing soil specimens subjected to drying–wetting cycles while under vertical confining pressures was introduced with clayey soil specimens subjected to different drying–wetting histories, and then the relative performance was tested using consolidated undrained triaxial shear tests. Meanwhile, their soil water retention properties were also measured. The experimental results indicated that drying–wetting cycles lead to a rise in the matric suction for soil with a high moisture content and a decrease in matric suction for soil with a low moisture content. Partly owing to the higher pore water pressure, peak shear strength reduces gradually during drying–wetting cycles. The impacts of drying–wetting cycles on the hydromechanical properties of soil specimens during the first cycle are greater than those during the second and third cycles, as the highest matric suction of soil occurs during the first cycle. The vertical confining pressure is shown to limit the impact of drying–wetting cycles on the hydromechanical properties of soil effectively because of its restricting effects on the volumetric deformation of soil during the cycles.

A Trans-Scale Study on the Influence of Water Content and Particle Size on Matric Suction

Exploring the water retention properties of unsaturated soil from the perspective of a liquid bridge has been a popular issue in recent years. This study first measures the soil–water characteristic curves (SWCCs) of granular specimens to determine the influence of particle size on matric suction from a macroscopic perspective. Then, the internal mechanism of the influence of particle size and volumetric water content on matric suction is analyzed from the mesoscopic perspective by using the Young–Laplace (Y–L) equation to calculate matric suction between two equal spheres. The macroscopic and mesoscopic experiments both show that matric suction decreases with an increase in particle radius. Moreover, identifying the internal mechanism of SWCC from the liquid bridge perspective is only applicable when the influence of gravity can be disregarded or is in the transitional stage. The influence of volumetric water content and sphere radius on matric suction is mostly caused by the variation in the outer radius of the liquid bridge ( r 1 ) and the neck radius of the liquid bridge ( r 2 ). With an increase in volumetric water content and sphere diameter, the increasing rate of r 1 is much higher than r 2 , and the macroscopical matric suction gradually decreases.

Developing an environmental friendly approach for enhancing water retention with the amendment of water-absorbing polymer and fertilizers

The effect of climate/environmental change has resulted in adverse water stress conditions which necessitates the sustainable approaches for improving the water use efficiency to boost agricultural production in Central Asia. Water-absorbing polymer (WAP) has emerged as one of the amendments for soil water stress management. WAP are chemically cross-linked structure capable of absorbing and storing a large amount of water. The agricultural land has different levels of fertilizers which can influence the performance of WAP because of its sensitivity due to external ionic medium. Therefore, the combined or hybrid use of WAP and organic/ inorganic fertilizers may inhibit the functionality of WAP, which needs to be thoroughly investigated. This study demonstrates the performance of two different WAPs (a commercially WAP (crosslinked potassium polyacrylate) and a laboratory synthesized WAP (crosslinked fly ash-polyacrylate superabsorbent composite)) with varying combinations of fertilizers in silt loam (agrarian soil). The combined use of fertilizers and WAP have improved the water retention properties of soils due to modification in the soil pore volume for both the WAPs. Quantification from water retention properties revealed a significant increase in plant wilting time (PWT) and plant available water content (PAWC) under the combined influence of fertilizers and WAP amended soils, indicating the possibility of high-water availability to plant roots. The study suggests the potential of WAPs as an efficient soil conditioner even in the presence of fertilizer for countering the negative impacts of water stress conditions. WAPs might minimize the requirement for chemical fertilizers, which helps to enhance the climate/environmental change and agriculture sector in the Central Asian region.

Changes in Soil Water Retention and Micromorphological Properties Induced by Wetting and Drying Cycles

Wetting and drying (W-D) cycles are responsible for significant changes in soil structure. Soil often undergoes irreversible changes affecting infiltration and solute retention through W-D cycles. Thus, it becomes essential to evaluate how soils under natural conditions are altered by W-D cycles. This study analyzed two non-cultivated (from grassland and secondary forest) Oxisols (Typic Hapludox and Rhodic Hapludox) of different textures under 0 and 6 W-D cycles. The main results obtained showed that soil water retention was mainly affected in the driest regions (smaller pore sizes). The contribution of residual pores to total porosity increased with 6 W-D and transmission pores decreased in both soils. The Rhodic Hapludox presented differences in water content at field capacity (increase), while the Typic Hapludox showed alterations at the permanent wilting point (increase), affecting the amount of free water (Rhodic Hapludox) and water available to plants (Typic Hapludox). Both soils showed increases in imaged porosity with 6 W-D. Variations in the contribution of small and medium rounded pores, mainly large and irregular (with an increase in both soils not significant in the Rhodic Hapludox), could explain the results observed. The micromorphological properties were mainly influenced by changes in the number of pores, in which smaller pores joined, forming larger ones, increasing the areas occupied by larger pores. Overall, this study showed that the investigated soils presented pore systems with adequate water infiltration and retention capacities before and after continuous W-D cycles.

Prediction of water retention properties of French soils using the in situ volumetric water content at field capacity as single input data

The objective of this study was to investigate the relevance of using the in situ volumetric water content at field capacity (θFC) as a predictor of the water retention properties by comparing the performances of pedotransfer functions (PTFs) established using artificial neural networks (ANN-PTFs) and support vector machines (SVM-PTFs) with much simpler PTFs in the form of simple linear regressions (SLR-PTFs). A dataset comprising 456 horizons collected in soils located in France was used. The available data were: the silt and clay contents (SC), the organic carbon content (OC), the bulk density at field capacity (BDFCm), the in situ gravimetric water content at field capacity (WFCm) related to θFC by using BDFCm, and the volumetric water content at –1, –3.3, –10, –33, –100, –330 and –1500 kPa matric potential. The performances of the PTFs studied were compared by using the root mean squared error (RMSE) and the coefficient of determination (R²). Our results showed the relevance of using θFC, which was proved to be close to the volumetric water content at –10 kPa matric potential, as a predictor of the water retention properties. With ANN-PTFs, the best performances were recorded when both θFC and SC were used as input data (RMSE = 0.027 cm3 cm-3 and R2 = 0.92). With SVM-PTFs, the smallest RMSE was recorded when θFC was used as single input data (RMSE = 0.026 cm3 cm-3). As for R2 of SVM-PTFs, it was the highest with θFC and SC as input data (R2 = 0.84). The SLR-PTFs using θFCas single predictor after stratification by texture performed better (RMSE = 0.031 cm3 cm-3 and R2 = 0.88) than the ANN-PTFs using one or two soil characteristics as input data. Comparison of SLR-PTFs with SVM-PTFs showed that the latter performed slightly better than SLR-PTFs after stratification by texture but R2 was smaller when θFCwas used as the single predictor. Use of a predicted value of the bulk density at field capacity to obtain a value of in situ volumetric water content at field capacity led to poorer performances of the SLR-PTFs but after stratification by texture they remained close to those recorded with ANN-PTFs or SVM-PTFs when they used a single soil characteristic as input data. Finally, our results showed that associating OC to the input data did not increase the perfomances of the ANN-PTFs and SVM-PTFs.

Effect of Bamboo biochar on strength and water retention properties of low plastic clay and silty sand

Biochar is a carbon-rich stable product derived from the thermochemical decomposition of biomass. The properties of biochar vary with types of feedstock, heating rate, pyrolysis temperature, etc. Consequently, the mechanical and hydrological properties of biochar amended soil (BAS) also differ with types of biochar and soils. However, the effect of bamboo biochar (BB) amendment on soil strength and water retention properties is missing in the previous literature. Bamboo biomass was pyrolysed at 600 °C to produce biochar. BB and soils (low plastic clay (CL) and silty sand (SM)) were mixed to prepare BAS. The samples were prepared by mixing BB in five ratios, i.e., 0%, 1%, 2%, 3.5% and 5% of dry soil weight. The biochar application has increased optimum moisture content, alkalinity (pH) and Atterberg limits, whereas, reduced maximum dry density and specific gravity of both the soils (CL and SM). The unconfined compressive strength (UCS) of CL soil was noted to increase by 10.5% with 2% biochar content and decreased after that, whereas the UCS of SM soil was found to decrease continuously with the biochar content increment. Therefore, the unconfined compressive strength (UCS) result showed that biochar application has contrary effects on both soils. The measured gravimetric water content (GWC) of BAS was increased with biochar increment in both soils. However, GWC increased more in CL than in SM soil at the same biochar content. The microstructural analysis showed that the biochar amendment filled the pore space of the soil matrix, resulting in an increase in UCS and GWC values. The increased water retention capacity and strength (UCS) of biochar amended CL soil provides evidence that it could be used as a landfill cover material.

Water-retention properties of xanthan-gum-biopolymer-treated soils

This study aimed to estimate the effects of the xanthan gum biopolymer on the wetting and drying processes of soils. Xanthan gum with different contents by the mass of dried soil was used to treat Jumunjin sand and sand-clay mixtures. The wetting and drying soil-water characteristics of xanthan-gum-biopolymer-treated sand were investigated using capillary rise open tubes and a Fredlund-type soil-water characteristic curve device, respectively. The results show that xanthan gum has a significant effect on controlling the movement of water in soil. The xanthan gum biopolymer shapes the drying soil-water characteristics of soil, and there is a non-linear relationship between the xanthan gum content and the soil-water characteristic parameters of the treated soils. Xanthan gum significantly reduces the capillary conductivity of soil down to 10−7–10−8 m/s for soil treated with 1.0% xanthan gum. Xanthan gum affects the capillary equilibrium process of water differently in wetting tests as well. Furthermore, the wetting results show the role of clay particles in the flow-controlling performance of xanthan gum.

Effect of the Application of Sunflower Biochar and Leafy Trees Biochar on Soil Hydrological Properties of Fallow Soils and under Soybean Cultivation.

Soils enriched with biochar are recommended as a cultivation grounds, especially in case they contain significant amount of sand. However, the interactions between biochar and plants, as well as the influence of the biochar on water retention, cultivation and air properties of soils, are still not obvious. The present study aimed to determine the impact of various biochar doses on soils used for soya cultivation, in comparison to soils maintained as black fallow soil, on their water retention and productivity, for the period of two years. Sunflower husk biochar (BC1) and biochar of leafy trees (BC2), in doses of 0, 40, 60, 80 t·ha-1, were used for field experiments. The water retention was investigated with porous boards in pressure chambers by a drying method. No differences in the hydrological properties of the soils that were differently managed (black fallow soil, crop) were observed following biochar application. Addition of BC1, in the amounts of 40, 60, and 80 t·ha-1, caused an increase in the plant available water capacity (AWC) by 15.3%, 18.7%, and 13.3%, respectively, whereas the field capacity (FC) increased by 7.4%, 9.4%, and 8.6% for soils without biochar. Application of BC2 analogously resulted in higher AWC, by 8.97, 17.2%, and 33.1%, respectively, and higher FC by 3.75, 7.5%, and 18.3%, respectively. Increasing the doses of BC1 and BC2, both on black fallow soils and soils enriched with soya, caused a rise in total porosity (TP) and drainage porosity (DP), and a decrease in soil bulk density (SBD). Biochar with a higher total area and higher porosity (BC1) applied to soils with soya cultivation resulted in lower reductions in AW and FC than BC2 in the second year of investigation.

Multiscale pore network construction for two phase flow simulations in granular soils

Characterizing and modeling the pore structure is the key to simulating single and multiphase flow through granular soils. Modeling the grain-based packing and predicting the multiphase flow properties of granular soils with a wide grain size distribution (GSD) spanning over several orders of magnitude is still a challenging task. This work presents a novel numerical framework for constructing the pore network of granular soils with a wide grain size variation. The present work focuses on using basic properties of granular soils like GSD and porosity to generate pore network properties that are further utilized to simulate the water retention properties of granular soils along drying and wetting paths. A topologically equivalent network of pores and throats is extracted from modeled soil packing at different length scales. By integrating the pore networks extracted from individual length scales in the main simulating domain, a multiscale pore network that represents the pore structure of the soil to be modeled is obtained. The pore-scale phenomena like piston-like advance, corner flow (wetting layers), pore body filling, and snap-off are used to model fluid displacements at the pore scale. The estimated soil water retention curves for various granular soils are in good agreement with experimental data from the literature, and the hysteretic wetting-drying response is also accurately predicted.

A simple model for the water retention curve of compressible biocemented sands using MIP results

Biocementation treatment consists in using bacteria or other biological agents to promote the precipitation of calcium carbonate (biocement) in the soil pores. When used in slopes for protection against surface erosion, this treatment creates a stiff and strong pervious cover, allowing infiltration necessary to reduce water runoff. The knowledge of the water retention properties of biocemented soils is fundamental knowledge for modelling infiltration but it may not be easy. In this paper the water retention curves of two different treated sands were estimated using a simple model obtained from pores size distribution measured using mercury intrusion porosimetry (MIP) tests. The model proposed considers volume changes of the soil during the MIP test due to the compression of air trapped in the voids. The WRC derived from the MIP tests fits well the points measured using a water dewpoint psychrometer, however it is not possible to check curve fitting below the residual water content due to lack of experimental data.

Effects of microstructure on THM behaviour of geomaterials

In this paper, we discuss the thermo-hydro-mechanical behaviour of geomaterials at the light of their microstructure and its changes induced by multiphysics loading. After recalling the strong links between the microstructure and the water retention properties of unsaturated soils, the relation between themicrostructure and the physical properties ruling heat and mass transfers are discussed. The mechanical behaviour of unsaturated soils is then discussed focussing on the definition of an effective stress based on a microstructure description. The experimental determination of this microstructurally-based effective stressis presented, including recent advances to identify the stress coefficient from Mercury Intrusion Porosimetry data. Opening remarks towards macroscopic modelling of unsaturated geomaterials accounting for their microstructure and its changes is finally discussed.

Experimental study on the water retention properties of sulfate saline soils during the cooling process

The water retention properties of sulfate saline soils during cooling were investigated by theoretical derivation as well as by nuclear magnetic resonance (NMR) tests and matrix suction determination tests by the contact filter paper method. The equations for calculating the free water content of sulfate saline soils during the cooling process and the amount of salt crystallization were derived based on the law of conservation of mass. The free water content of sulfate saline soil during the cooling process was determined by the NMR test. The reliability of the derived calculation equation was verified, which laid the foundation for the subsequent processing of the test data for matrix suction determination. The study showed that when the soil pore solution is saturated with sodium sulfate, the free water content in the soil decreases as the temperature decreases, accompanied by the crystallization process, and that the matrix suction of the soil increases as the temperature decreases. For silty clay without salt, the effect of temperature on its matrix suction is small. Use of either the serial filter paper method or the parallel filter paper method to measure the matrix suction has no effect on the matrix suction soil-water characteristic curve. The parallel filter paper method can exponentially reduce the test time compared with the serial filter paper method. Salt crystallization has no effect on the matrix suction soil-water characteristic curves (SWCCs) of sulfate saline soils. The matrix suction SWCCs of silty clay soils without salt can be employed to calculate the matrix suction of sulfate saline soils during the cooling process.

Water Retention Potential in Novel Terrestrial Ecosystems Restored on Post-Mine Sites: A Review

Many activities are conducted with the view of reducing CO2 emission from fossil fuels, but mining extraction will continue to be important for energy sources, mineral and metal ores, and the general economy. This activity has negative environmental consequences such as habitat loss, water scarcity, and soil degradation in novel ecosystems. Additionally, climate change, drought, and desertification accelerate important problems with water retention. From one point of view, identifying and conserving critical regions for ecological sustainability are issues of fundamental importance, but on the other hand, post-mine sites could provide additional carbon sinks and improve regional water retention (WR). This review paper analyses different studies focusing on the impact of the reclamation of mining sites on the water retention properties of soil. Water retention in reclaimed mining soil (RMS) increased considerably after various restoration efforts were implemented. The amount of water holding capacity in RMS was mostly affected by reclamation methods, soil properties, soil biota, restoration duration, and vegetation type. The major conclusions from the analysis were that (i) the bulk density of reclaimed mining soil ranges from 1.35 to 1.50 g/cm3 and decreases with restoration duration; (ii) Soil fauna increases soil water storage capacity and plant litter and earthworms convert litter to fecal pellets, which increases water field capacity; and (iii) water holding capacity increases with duration of reclaimed sites and type of plants, i.e., afforestation and tree communities have higher WR than younger grasslands. Therefore, identification of the suitable reclamation method, restoration duration, vegetation type, and soil fauna are important factors for increasing water retention capacity at a regional scale.

Facile Access to Gleditsia microphylla Galactomannan Hydrogel with Rapid Self-Repair Capacity and Multicyclic Water-Retaining Performance of Sandy Soil.

Sandy soil has poor water-holding performance, making it difficult for plants to survive, which worsens the deterioration of the ecological environment. Therefore, borax cross-linked Gleditsia microphylla galactomannan hydrogel (GMGH) was prepared, and its practicability as a water-retaining agent was analyzed. GMGH exhibited fast self-healing performance (150 s, ≈100%) and a high swelling index (88.70 g/g in pH 9). The feasibility of improving the water absorption and retention properties of sandy soil was explored by mixing different proportions (0.1, 0.3, 0.5 wt % sandy soil) of GMGH and sandy soil. The results showed that sandy soil had a more porous structure after adding 0.5 wt % GMGH, and its water absorption index increased from 15.68 to 38.12%. In an artificial climate box, the water-holding time of the sandy soil was extended from 3 to 23.5 days, and the cycles of water absorption and retention were more than 10 times. Therefore, GMGH has broad application prospects as a potential water-retaining agent for desertification control.

Synthesis and Characterization of Okara-Poly(acrylic acid) Superabsorbent Hydrogels for Enhancing Vegetable Growth through Improving Water Holding and Retention Properties of Soils

Synthesis and Characterization of Okara-Poly(acrylic acid) Superabsorbent Hydrogels for Enhancing Vegetable Growth through Improving Water Holding and Retention Properties of Soils