One of the most important among the numerous applications of superabsorbent polymers (SAPs), also known as hydrogels, is soil improvement and supporting plant vegetation in agriculture and environmental engineering. Currently, when water scarcity involves water stress, they are becoming still more commonly used for water retention in soil. As it turns out, one of the major factors influencing the superabsorbent polymers water retention capacity (WRC) is the load of soil. The study presents test results of absorbency under load (AUL) of SAPs. The object of the analysis was cross-linked copolymer of acrylamide and potassium acrylate, of a granulation of 0.50–3.15 mm. The authors analysed the water absorption capacity of the superabsorbent polymers under loads characteristic for 3 different densities of soil (1.3 g∙cm⁻³, 0.9 g∙cm⁻³, 0.5 g∙cm⁻³) and three different depths of application (10 cm, 20 cm, and 30 cm). Soil load and bulk densities were simulated by using weights. The experiments were conducted with a Mecmesin Multitest 2.5-xt apparatus. The obtained results demonstrate a very significant reduction in water absorption capacity by SAP under load. For a 30 cm deep layer of soil of bulk density of 1.3 g∙cm⁻³, after 1 h, this value amounted to 5.0 g∙g⁻¹, and for the control sample without load, this value amounted to more than 200 g∙g⁻¹. For the lowest load in the experiment, which was 0.49 kPa (10 cm deep layer of soil of a bulk density of 0.5 g∙cm⁻³), this value was 33.0 g∙g⁻¹ after 60 min. Loads do not only limit the volume of the swelling superabsorbent polymer but they also prolong the swelling time. The soil load caused a decrease in the absorption capacity from 338.5 g∙g⁻¹ to 19.3 g∙g⁻¹, as well as a prolongation of the swelling time. The rate parameter (time required to reach 63% of maximum absorption capacity) increased from 63 min for the control sample to more than 300 min for the largest analysed load of 3.83 kPa. The implications of soil load on superabsorbent polymer swelling are crucial for its usage and thus for the soil system. This knowledge might be employed for the more effective usage of superabsorbent polymers in agriculture and environmental engineering, in which they are commonly used to retain water and to support plant growth.

Heavy metal (HM) contamination poses a major threat to environmental health, agriculture and human well-being, requiring effective and sustainable remediation strategies. Phytoremediation, an eco-friendly and cost-effective approach, is widely used for the remediation of HM-contaminated soils. Although phytoremediation holds considerable potential in the extraction, stabilisation and degradation of HMs, its effectiveness is often constrained by limited metal bioavailability, plant stress under toxic conditions and slow metal uptake rates. To address these limitations, this review examines the integration of various soil amendments—the application of biochar, compost, plant exudates, microbial agents and chelating agents—to enhance phytoremediation efficiency. This review critically evaluates empirical evidence on the effectiveness, scalability, economic feasibility and environmental impact of these amendments. By synthesising recent studies, this review advances the understanding of amendment-assisted phytoremediation as a viable solution for treating HM-contaminated soils. In addition, this review identifies practical applications, discusses limitations and explores the potential synergies of these amendments to optimise phytoremediation strategies, ultimately contributing to more effective and sustainable environmental cleanup efforts.

Various applications of superabsorbent polymers (SAP) include the use of these materials in agriculture and environmental engineering to increase soil water retention. Under such conditions, there is water absorption of the SAP in soil under load. This paper presents the results of absorbency under load (AUL) of a cross-linked copolymer of acrylamide and potassium acrylate mixed at ratios of 0.3%, 0.5% and 1.0% with coarse sand and sandy loam. The mixtures were subjected to loads equivalent to 10, 20 and 40 cm of soil. The highest differences in AUL values for both soils, compared to the control sample, were obtained after 24 hours and at a maximum load of 5.9 kPa, which corresponds to a load of a 40 cm thick topsoil layer. The AUL was 71.4 g∙g⁻¹ for coarse sand and 52.7 g∙g⁻¹ for sandy loam with a 1.0% SAP addition, which corresponded to 24.0% and 18.0%, respectively, of the absorption in the control sample. All the conducted tests revealed a significantly low rate of water absorbency, which is especially important for capturing the water that infiltrates into the soil profile. The results demonstrate that water absorption by SAPs decreased with the increase in SAP addition.

Human activity is accompanied by the introduction of excessive amounts of artificial materials, including geosynthetics, into the environment, causing global environmental pollution. Moreover, climate change continues to negatively affect global water resources. With the intensification of environmental problems, material reusability and water consumption limitations have been proposed. This study replaced synthetic soil additives with biodegradable materials and analysed the potential and sustainable processing of natural fibrous materials, which form problematic waste. Waste fibres are the basis of innovative soil water storage technologies in the form of biodegradable and water-absorbing geocomposites (BioWAG). We analysed the influence of BioWAGs on plant vegetation and the environment through a three-year field experiment. Furthermore, biomass increases, drought effect reductions, and biodegradation mechanisms were analysed. Natural waste fibres had a positive influence, as they released easily accessible nutrients into the soil during biodegradation. BioWAGs had a positive influence on the biometric parameters of grass, increasing biomass growth by 430 %. Our results indicated that this is an effective method of waste fibre management that offers the possibility to manufacture innovative, environmentally friendly materials in compliance with the objectives of circular economy and the expectations of users.