Variation of dry and pre-soaked super absorbent polymer (SAP) on the rheology, strength and drying shrinkage of mortar

Water scarcity is increasingly challenging greenhouse tomato production, particularly in Mediterranean and semi-arid regions where irrigation water availability is becoming progressively limited. This study evaluated whether a superabsorbent polymer (SAP) can support water-saving irrigation in tomato grown in coconut fibre. Plants were cultivated in pots under four irrigation amounts (100, 75, 50, and 25% of crop water requirement—WC) combined with two SAP levels (0 and 2 g L−1). Irrigation was managed by a lysimetric control system. Reducing irrigation decreased total fruit yield (averaged across SAP treatments) from 100% WC (1212 g plant−1) to 50–25% WC (914 and 624 g plant−1, respectively), while non-marketable fruit number was unchanged (15.4 fruit plant−1, on average). SAP increased total yield, averaged across irrigation treatments (from 925 to 1022 g plant−1), and marketable fruit number (from 26.3 to 32.3 fruit plant−1), without affecting unitary fruit weight (20.4 g fruit−1, on average). SAP also increased net photosynthesis (from 16.0 to 17.4 µmol CO2 m−2 s−1), while stomatal conductance (0.14–0.15 mol H2O m−2 s−1) and WUE (4.0 µmol CO2 mmol−1 H2O) were not affected by SAP. Total soluble solids increased under severe deficit (7.8 °Brix at 25% WC) and were enhanced by SAP (from 6.9 to 7.6 °Brix), while colour parameters were mainly driven by irrigation. Overall, the irrigation amount was the primary driver of performance. Moderate deficit irrigation (75% WC) maintained a marketable fruit number and total fruit weight comparable to full irrigation (100% WC). SAP amendment acted as a complementary tool to improve marketable production and net photosynthesis across irrigation levels, providing an additive benefit to crop productivity.

Enhancing the long-term water immersion stability of ultra-low water-cement ratio cement-based materials: Controlling the rehydration stage with superabsorbent polymers

The growing accumulation of inedible abnormal eggs and environmental concerns regarding petroleum-based superabsorbent polymers (SAPs) in food packaging underscore the need for sustainable, food-derived alternatives. In this study, biodegradable egg-white hydrogels were developed through controlled acylation and crosslinking to enhance absorbency and structural stability. Processing optimization of lyophilization, heating, and grinding reduced production time from 4 to 1.5 days and significantly improved water uptake (p < 0.05). Among protein concentrations tested, a 4% (w/w) egg-white solution achieved the optimal balance between gel stability and water uptake, exhibiting significantly higher swelling capacity than lower or higher concentrations (p < 0.05). Chemical modification using succinic anhydride (SA) or ethylenediaminetetraacetic dianhydride (EDTAD), combined with glycerol (G) or N,N'-methylenebisacrylamide (MBA), produced five hydrogel formulations. Although SG (SA + G) and EG (EDTAD + G) showed lower initial swelling capacity than EM (EDTAD + MBA), both SG and EG exhibited significantly higher water-holding and reswelling capacities compared with EM (p < 0.05). Rheological analysis indicated that SG possessed the highest storage modulus (G') and lowest tan δ, characteristic of a predominantly elastic network, whereas EG displayed increased viscosity and plasticity due to enhanced hydrophilicity. In contrast, MBA-crosslinked hydrogels showed weaker network formation and limited swelling performance. Soil burial tests demonstrated that SG and EG hydrogels degraded more rapidly than commercial water beads and promoted greater microbial growth within 7 days (p < 0.05). Overall, controlled chemical modification of egg-white proteins enables the production of sustainable, biodegradable hydrogels as promising alternatives to petroleum-based absorbent materials.

We evaluated a novel closed-loop evaporative system designed to concentrate alkalised human urine while simultaneously recovering water using regenerable superabsorbent polymers (SAPs). This architecture recirculates air and physically isolates urine from atmospheric CO₂, thereby maintaining high alkalinity and preventing enzymatic urea hydrolysis. The system was operated at ∼30 °C using sodium polyacrylate, potassium polyacrylate, or a 1:1 ( w /w) blend of both SAPs across eight absorption–desorption cycles. All treatments exhibited high initial water uptake (>1.4 kg m −2 day −1 ) and gravimetric absorption (>0.8 g g −1 ), with performance declining due to polymer fatigue after repeated use. FT-IR spectra revealed the depolymerisation of the acrylate backbone leading to the formation of acrylic acid residues, confirming chemical deterioration during the thermal regeneration of the SAPs. Notably, the closed-loop design eliminated the need for supersaturating urine with Ca(OH)₂, which is required in open evaporative systems to buffer against CO₂-induced acidification. Colorimetric and targeted metabolomic analyses confirmed complete nitrogen retention and > 99 % recovery of the 30 most abundant endogenous organic solutes in urine, including urea, creatinine, and hippuric acid. These results demonstrate that low-temperature evaporation can preserve the full biochemical complexity of urine, producing a dry, sanitised fertiliser as well as water with extremely low organic content. • Closed-loop air recirculation system for low-temperature urine dehydration • Regenerable SAP-based desiccants enable cyclic air–vapour moisture absorption. • Eliminates CO₂-driven acidification and nitrogen loss without excess Ca(OH)₂ • >99 % retention of major endogenous organics confirmed by targeted metabolomics • Produces a dry fertiliser and clean water suitable for various reuse applications

Soil desiccation cracking is ubiquitous in arid and semi-arid environments, and its evolution directly affects foundation stability and ecosystem functions. To improve the operability of superabsorbent polymer (SAP) incorporation and the crack-control performance, this study proposes a “liquid–solid mixing” in situ polymerization strategy, enabling SAP to form a three-dimensional network within the soil matrix, and systematically evaluates the effects of SAP content on water processes and crack evolution. The in situ generated SAP was characterized in terms of structure and morphology using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and ultra-depth-of-field microscopic imaging (EDOF). Combined with laboratory drying tests and quantitative image analysis, the temporal variations in Water content decay, evaporation kinetics, Crack ratio, and crack geometric parameters were tracked. The results indicate that SAP can be successfully polymerized in situ within soil and can significantly slow water loss and suppress crack propagation. At a dosage of 12%, compared with the blank sample (CK), the average Evaporation rate decreased by approximately 20.6% and the total drying time increased by approximately 38.4%; crack development was effectively controlled, with the final Crack ratio approaching 0%. With increasing SAP dosage, Total crack length, Average crack width, and crack morphological complexity all decreased markedly. Under high-dosage conditions, crack openings exhibited a closure tendency during continued drying, suggesting a certain potential for crack self-healing. These findings demonstrate that the proposed in situ polymerization strategy not only expands a convenient route for SAP incorporation into geotechnical media, but also provides a feasible technical pathway and mechanistic basis for the coupled regulation of “water retention–crack suppression” in soils under drying conditions. Preparation of the SAP precursor solution and schematic illustration of the SAP water absorption mechanism, Mechanism of SAP in regulating moisture dynamics and crack evolution during soil drying, Mechanism of soil desiccation cracking and SAP-induced crack suppression/healing • A novel in situ polymerization strategy was proposed for synthesizing superabsorbent polymers (SAPs) directly within the soil matrix using a liquid–solid mixing approach. • The incorporation of SAP significantly delayed soil moisture loss and reduced average evaporation rate, showing a clear dosage-dependent water-retention effect. • SAP-treated soils exhibited substantial reductions in crack ratio, total crack length, average crack width, and fractal dimension, with improved crack suppression and self-healing behavior at higher dosages. • A positive feedback mechanism of “slow release–crack suppression–water retention” was identified, linking moisture regulation with structural stabilization during desiccation. • This work proposes a promising soil enhancement approach for arid regions, offering new perspectives on the interaction mechanisms between SAP and soil and broadening its potential for practical engineering and environmental applications.

Effects of superabsorbent polymer on water transport property of concrete: Experimental study and modelling

Root and tuber crops (RTCs) such as cassava, sweet potato, and taro are vital for food and nutrition security, particularly in developing countries. Despite their adaptability and relative drought tolerance, these often-neglected crops suffer substantial yield losses under prolonged water stress. This review examines the potential of superabsorbent polymers (SAPs) as a drought mitigation tool for RTCs to enhance water-use efficiency and irrigation sustainability. SAPs, as a subclass of high water-absorbing hydrogels, refer to three-dimensional cross-linked polymer networks capable of absorbing and retaining hundreds of times their own weight in water. While evidence demonstrates SAP efficacy in staple cereals and legumes, research focused on RTCs remains limited. This review identifies critical knowledge gaps, including optimal SAP formulations, application rates, and their interaction with root system architecture and soil hydrology. We propose integrating SAPs with practices like mulching and deficit irrigation may synergistically boost RTC productivity under variable climates. Future research priorities should include multi-location field trials and long-term studies to validate SAPs use for RTCs. Furthermore, investigations integrating root phenotyping, hydrotropic responses, and polymer-soil characterization are needed to optimize the use of SAPs in RTCs. This review is the first to systematically evaluate the application potential of SAPs specifically in underutilized RTCs such as cassava, sweet potato, and taro, with a particular focus on the critical knowledge gaps regarding their interactions with root system architecture and hydraulic properties. By bridging this knowledge gap, SAPs can be positioned as a key innovation to stabilize yields, enhance climate resilience, and safeguard food security in vulnerable farming systems. • Underutilized root and tuber crops (RTCs) support food security in dry regions. • Cassava, sweet potato, and taro face major yield losses under prolonged drought. • Hydrogels enhance soil moisture, reduce irrigation, and boost drought tolerance. • There are limited superabsorbent polymers (SAPs) studies on underutilized RTCs. • Optimizing SAPs for RTCs can improve resilience and productivity.

The formation of cracks in concrete is inevitable and often accelerated by inadequate curing. In many regions, the availability of potable water for external curing is limited, leading to improper curing practices and the development of shrinkage cracks. Resolving this issue is essential to enhancing concrete structures' long-term performance. In the present study, an alternative approach has been explored to reduce reliance on external curing while enhancing the mechanical and durability properties of concrete. Superabsorbent polymer (SAP) was used as an internal curing agent, and a bacterial self-healing mechanism was employed to mitigate cracks and refine the pore structure of concrete. Four different mixes were prepared for investigation: a control mix, a mix containing SAP, a bacterial concrete mix, and a mix incorporating both superabsorbent polymer and bacteria. A series of tests, including shrinkage, compressive strength, flexural strength, and electrical resistivity, were conducted to evaluate the performance of these mixes. The experimental results confirmed that the inclusion of superabsorbent polymer significantly reduced shrinkage, while the combined use of superabsorbent polymer and bacteria further enhanced the properties of concrete. The combination of superabsorbent polymer and healing agent exhibits a 15.1% and 26.4% improvement in compressive strength in comparison with the control mix at an age of 7 and 28days. A strong correlation was observed between compressive strength and shrinkage, indicating that reduced shrinkage contributes to improved concrete performance. This study shows that combining superabsorbent polymer and bacterial self-healing offers an effective way to overcome curing challenges and enhance the strength and durability of concrete, especially in water-scarce regions.

Enhancement of Saline Absorbency in CMC/Starch-Based Superabsorbent Polymers by Incorporation of Sodium Bicarbonate

In drip-irrigated maize of arid Xinjiang, seedling hardening (withholding irrigation) is used to induce deep rooting, but the conventional practice of banding phosphorus (P) fertilizer without basal application creates a spatial mismatch—roots are forced downward while P remains trapped in drying topsoil. We hypothesized that co-applying superabsorbent polymer (SAP) with banded P fertilizer can form a localized, persistently hydrated P-enriched patch that synchronizes root–resource distribution. A two-year field experiment (2024–2025) was conducted with three treatments: no P (P0), banded monoammonium phosphate (B-MAP, 120 kg P2O5 ha−1), and B-MAP + SAP (15 kg ha−1). Soil properties, root growth, canopy physiology, dry matter accumulation, nutrient uptake, and grain yield were measured. Results: At the V4 stage, B-MAP + SAP increased available P and soil water content in the 0–10 cm layer by 9.4% and 16.1%, respectively, relative to B-MAP. This patch triggered vigorous root proliferation: topsoil root length at V4 rose by 23.9%, and root length density in the 30–40 cm subsoil at V9 and R1 increased by 59.0% and 36.5%. Consequently, B-MAP + SAP sustained the highest leaf area index, net photosynthetic rate, and biomass accumulation. Two-year average grain yield reached 18.2 t ha−1, 9.7% and 20.7% higher than B-MAP and P0. Crucially, P use efficiency (PUE) and water productivity (WP) under B-MAP + SAP improved by 76.2% and 9.8% over B-MAP. Co-applying SAP with banded P fertilizer resolves the spatial mismatch in hardening systems, optimizes root architecture, and synergistically boosts yield, PUE, and WP. This one-time amendment offers a simple, scalable strategy for efficient P management in arid drip-irrigated maize.

Menstruation, a biological phenomenon experienced by more than half of the global population, remains stigmatized and poorly addressed in the context of research and public discourse. One overlooked issue is that of “period pollution,” the waste generated by millions of feminine hygiene pads (menstrual pads) that end up in landfills or the environment. Simultaneously, Japanese knotweed (Reynoutria japonica), a non-native invasive plant which disrupts native species, leads to the disruption of ecological systems. This experimental study assesses the Japanese knotweed plant for its potential to serve as the absorbent core in a sustainable menstrual pad, helping to address both environmental challenges in tandem. As control groups, commercial pads (Natracare and Saathi) were tested for their performance as absorbent materials, as defined by the absorbency ratio (AR) test. All preliminary studies were done using normal saline solutions dyed with red food coloring. Saathi pads demonstrated significantly higher levels of AR compared to Natracare and knotweed pads due to the presence of superabsorbent polymers, making it an unreliable benchmark. Because Japanese knotweed is composed of cellulosic fibers that absorb water through hydrogen bonding to hydroxyl groups and capillary imbibition within porous fiber networks, lignin removal via alkaline processing was employed to enhance absorbency prior to experimental testing. The inner lumen of the knotweed was selected and delignified using a sodium hydroxide bath, later being shaped into an absorbent core akin to the measurements of the commercial pads and inserted into Natracare shells for proof-of-concept testing. Although knotweed-based pads exhibited lower AR values than Natracare, the testing places the knotweed prototype at approximately 40% of the fluid capacity, indicating a strong starting point for a natural fiber. To further evaluate the processing feasibility of Japanese knotweed beyond laboratory-scale pad prototyping, Japanese knotweed biomass was subjected to conventional Kraft pulping, which helps to remove lignin and increase absorbency. The Kraft pulping produced a moderately delignified brown pulp with a Kappa number of 20. Due to limiting factors, the absorbency of the pulp was not tested. However, the pulp’s fiber dimensions were comparable to hardwood pulps that are commonly used in absorbent applications, suggesting feasibility for future development into bleached fluff pulp and sustainable menstrual hygiene products.

Plastic shrinkage and self-desiccation, along with the associated early-age cracking, are still among the most important factors that influence long-term performance of concrete structures, including durability. Superabsorbent polymers (SAPs) have been widely researched for application in concrete to mitigate shrinkage through facilitating effective internal curing by releasing water into the mixture to promote continuous hydration of cement. The acoustic emission (AE) monitoring technique, due to its high sensitivity, has proven very effective in tracking the process of water release by SAPs in concrete during early-stage curing. Typically, AE parameters such as cumulative activity, amplitude and energy are utilized to characterize the kinetics of curing processes. While these parameters indicate well the internal activity of SAPs in time, they do not offer information on the precise location of the active sources within the material's volume, leaving a crucial gap in the understanding of the ongoing microstructural changes caused by internal water distribution and cement hydration. In this sense, AE event source localization can offer information about the active zones of water hydration activity in the material 3D domain, allowing detection of their evolution during concrete curing. Meanwhile, Acoustic Emission Tomography (AET) computes ultrasonic velocity distributions in different periods of monitoring, which are governed by acoustic characteristics of the concrete mixtures, to visualize material stiffness development spatially and temporally. This level of insight is particularly important for SAP concrete, where uniformity of internal water curing is essential for ensuring long-term durability and material soundness. By visualizing how the hydration sources evolve in real time, these methods offer an effective, non-destructive, and cost-effective solution for early-age concrete quality control, which would be challenging to achieve through other techniques.

Drought stress is a major constraint on rapeseed (Brassica napus L.) production, particularly during germination and early seedling development, and its impact is intensifying with climate change. Superabsorbent polymers (SAPs) have emerged as a promising strategy to mitigate water limitation by enhancing moisture availability. This study conducted a comparative analysis of three SAP types, two fossil-based (MERCK, SWT) and one natural-based (ABG), applied via seed coating to evaluate their effects on germination, sodium uptake, total phenol content mitigation, and transcriptomic profiles under drought stress. While all SAPs increased seedling sodium content, the MERCK treatment produced the highest rate of normal germination, the lowest Na+ accumulation, and reduced oxidative stress, closely resembling the well-watered control (CN). Transcriptome sequencing revealed distinct expression profiles across treatments. MERCK seedlings showed expression of key stress-responsive genes (PER45, ABI1, STM) most similar to CN. In contrast, ABG seedlings exhibited significant downregulation of important genes (especially transcription factor (TF) genes) such as WRKY33, MYB77, CIPK17, and STZ, consistent with their poor performance. Functional enrichment analysis indicated the induction of phenylpropanoid biosynthesis, antioxidant activity, and hormonal signaling pathways, with MERCK and ABG showing contrasting signatures. These findings demonstrate that SAP composition influences drought adaptation in rapeseed by modulating molecular stress-response pathways. The integration of physiological and transcriptomic analyses not only identifies effective SAP formulations for seed coating but also provides candidate genes to support breeding programs aimed at developing stress-resilient cultivars.

This study evaluates the application of superabsorbent polymers for reducing free moisture in iron ore sinter feed through bench-scale tests and initial characterization analyses. Two commercial polymers were investigated at different dosages, with moisture reduction monitored over time. Samples were analyzed by X-ray diffraction and particle size distribution to verify possible structural changes. Results indicated significant moisture reduction without relevant mineralogical modifications, demonstrating the initial technical feasibility of the application.

Drought stress severely impairs maize germination and early seedling growth, posing a significant threat to global food security. To address this, superabsorbent polymers (SAPs) are being explored as an effective seed-coating method to improve water availability during the crucial germination phase. However, their comparative efficacy and underlying molecular mechanisms remain insufficiently understood. In this study, we evaluated the effects of three distinct SAPs, two fossil-based (MERCK, SWT) and one natural-based (ABG), on maize germination and seedling development under controlled drought conditions. We integrated physiological (germination rate and NA+), biochemical (total phenol content), and transcriptomic (mRNA-seq) analyses to provide a comprehensive multi-level assessment. Physiologically, among all SAPs, the MERCK was the most effective, resulting in the highest proportion of normal seedlings and the fewest abnormal seedlings. In contrast, the SWT treatment was detrimental, increasing the proportion of abnormal seedlings, suggesting phytotoxic effects. Biochemically, all SAP treatments resulted in elevated seedling sodium (Na+) content, indicating potential secondary ionic stress. Transcriptomic analysis further elucidated these observations, revealing a set of differentially expressed genes, including those involved in stress response (BADH, FACT, XCP2), SAP-specific response (DRB5, RAF35, EDR1), and combined salt/drought stress (WRKY47, DTX20), as promising candidate biomarkers for stress assessment and breeding. Our research highlights the nuanced efficacy of SAPs; specifically, the MERCK SAP yielded more favorable outcomes, while other formulations occasionally caused unexpected phytotoxicity. The identified gene expression patterns not only mechanistically explain the observed physiological responses but also offer a valuable panel of molecular biomarkers. These markers can be used to screen novel SAP applications, such as seed coatings, and to breed stress-resilient maize cultivars.

To address the limitations of conventional superabsorbent polymers in complex aqueous environments, a novel ternary composite gel (BT-SAP) based on xanthan gum, poly(acrylic acid-co-acrylamide), and bentonite was synthesized via a facile one-pot polymerization. Characterization confirmed the formation of a stable organic-inorganic hybrid three-dimensional network. The gel demonstrated outstanding comprehensive performance: a maximum water absorption capacity of 378.6 g/g; good adaptability to various pH levels, salt ions, and real water bodies; and rapid absorption kinetics and reusable potential over multiple cycles. Simultaneously, it exhibited a high adsorption capacity of 181.3 mg/g for methylene blue. The adsorption isotherm followed the Freundlich model, indicating adsorption on a heterogeneous surface. Kinetic studies revealed that the process was best described by the pseudo-second-order model, suggesting chemisorption as the rate-controlling step. XPS analysis further elucidated that the adsorption primarily occurred through the synergistic effect of electrostatic attraction from carboxyl groups and hydrogen bonding from amide/hydroxyl groups within the gel. This work provides a new strategy for developing smart materials integrating efficient water absorption and dye removal functionalities.

Low emergence and poor vigor in canola (Brassica napus L.) are common challenges for growers, and seed pelleting is an effective approach to address them. This study aimed to identify the optimal combination of nano-superabsorbent materials for seed pelleting, thereby enhancing water absorption and improving the emergence of canola seeds. The treatments included four levels of seed pelleting: control (seed-free pelleting), nanoparticles of TiO2-rutile (0.05 mM), and Aquazorb superabsorbent polymer enriched (KNO3) (0.5%), and a combination of TiO2 rutile (0.05 mM) and AQ (KNO3) (0.5%), and water deficit at four levels (100%, 75%, 50%, and 25% of FC). The results demonstrated that emergence percentage, seedling traits, and biochemical traits were significantly affected by the interaction of moisture regime and pellet materials (TiO2-rutile (0.05 mM) and AQ (KNO3) (0.5%). The highest emergence rate (0.228), number of leaves (10), root dry weight (0.133 g), shoot dry weight (0.133 g), chlorophylla (2.33 mg/g), and chlorophyllb (0.96 mg/g) were achieved with seeds pelleted using a combination of TiO2-rutile (0.05 mM) and AQ (KNO3) (5%) under severe water stress (25% FC). These compounds significantly improved pellet sphericity and dissolution time. Seed pelleting reduced water stress treatment effects during germination and accelerated seedling establishment by aiding in seed water absorption, enhancing the seedling's ability to utilize phosphorus, potassium, iron, and zinc. Therefore, a combination of TiO2-NP rutile (0.05 mM) and AQ (KNO3) (0.5%) is recommended for rapeseed pelleting. Planted seeds reduce damage from drought stress and lead to increased yield and reduced annual costs for farmers.

The accidental ingestion of radioactive iodine is known to increase the risk of thyroid cancer and thyroid dysfunction; hence, strict radiation safety measures are required when handling it. In a previous study, we demonstrated that absorbing radioactive-iodine-containing wastewater using a water-absorbent polymer with cyclic oligosaccharides that selectively capture iodine, followed by natural drying, effectively separates at least 80% of the iodine from the wastewater. However, because natural drying requires approximately 2 wk, faster processing is essential to improve the efficiency of this wastewater treatment. Hence, we propose a method for quickly separating iodine from wastewater via heat drying. This study aimed to compare radioactive iodine volatilization levels between samples subjected to heat-drying- and natural-drying-based iodine and water separation. Na 125 I was added to purified water and artificial urine to prepare simulated waste liquids containing iodine at concentrations equivalent to those in the urine of patients undergoing radioactive iodine treatment. The prepared simulated waste liquids were poured into containers containing a superabsorbent polymer, dried in a thermostatic dryer set at 100 °C for 9 h, and subsequently stored for 90 d. The iodine residual rate in the simulated waste liquids was determined by measuring 125 I radioactivity. At the end of the heat-drying process, the iodine residual rates in the simulated waste liquids prepared with purified water and artificial urine were 0.452 and 0.783, respectively. When absorbed in 1 g of superabsorbent polymer, the residual rates increased to 0.956 and 0.952, respectively. Over the following 82 d, the residual rates decreased by approximately 10%. Thus, by absorbing radioactive-iodine-containing wastewater into a highly water-absorbent polymer and then applying heat drying, iodine can be effectively separated from the wastewater while limiting its volatilization to less than 15%.

Superabsorbent polymers (SAPs) are materials that can absorb and retain water solutions with a mass of several hundred times greater than their own. This work aimed to synthesise and evaluate the effects of highly absorbent starch phosphate-g-poly(acrylic acid) copolymers on the microbiological activity of soils previously used for agriculture. The biopolymers studied were obtained by thermal and chemical oxidation of starch phosphates and copolymerized with potassium salts of acrylic acid. Basic physicochemical parameters were determined in the applied soil. Following SAP application, the basal respiration rate was measured at 22 °C with a constant soil moisture content of 60% WHC. The incubation time in constant temperature and moisture conditions was 78 days. After this period, their microbiological activity (microbial and organic phosphorus fractions) was assessed, thereby enabling the determination of the direction of change in the soil environment. The addition of SAP increases the soil’s water-holding capacity and respiration. The SP-g-PAA polymers serve as slow-release sources of potassium and phosphorus ions. These elements were bound to the polymer network by ionic and covalent bonds. Analysis of the results shows that within two weeks, 47–80% of the starch hydrogel undergoes microbial degradation. No differences were found in the content of labile forms of phosphorus in soils with SAP additions compared to soils without polymer additions. The use of modified starch reduces the consumption of vinyl monomers, while the resulting product is characterised by high absorbency and low water content, which reduces the amount of energy needed to obtain the finished product, thus contributing to sustainable development.