Agricultural Applications of Superabsorbent Polymer Hydrogels

Abstract

This review presents data from the past five years on the use of polymeric superabsorbent hydrogels in agriculture as water and nutrient storage and retention materials, as well as additives that improve soil properties. The use of synthetic and natural polymeric hydrogels for these purposes is considered. Although natural polymers, such as various polysaccharides, have undoubted advantages related to their biocompatibility, biodegradability, and low cost, they are inferior to synthetic polymers in terms of water absorption and water retention properties. In this regard, the most promising are semi-synthetic polymeric superabsorbents based on natural polymers modified with additives or grafted chains of synthetic polymers, which can combine the advantages of natural and synthetic polymeric hydrogels without their disadvantages. Such semi-synthetic polymers are of great interest for agricultural applications, especially in dry regions, also because they can be used to create systems for the slow release of nutrients into the soil, which are necessary to increase crop yields using environmentally friendly technologies.

Preparation and characterization of PA/P(AA-co-AM) composite hydrogels via photopolymerization

“…In the agricultural sector, hydrogels can be added to soil to increase soil water retention and improve the water utilization efficiency in plant growth. 4 In the medical eld, hydrogels can be used as a drug carrier to deliver drugs to specic locations in the human body, improving drug safety and efficacy. [5][6][7] In the eld of environmental protection, hydrogels can be used to absorb organic matter and heavy metal ions in wastewater, improving water quality.…”

Modified corn stalk carboxymethyl cellulose, acrylic acid and SBA‐15 based composite hydrogel used for agricultural water retention

“…[15][16][17] Usually through chemical and physical cross-linking, it can absorb and retain considerable amounts of water or biofluids compared to conventional absorbents (e.g., sponge, cotton, wood pulp, and colloidal silica, etc. [18][19][20] ). Due to their superior properties, highly absorbent hydrogels are used in a wide range of applications, such as agriculture, cosmetics, wastewater treatment, drug delivery, tissue engineering, biosensors, and adsorbents for heavy metals and dyes.…”

“…Due to their superior properties, highly absorbent hydrogels are used in a wide range of applications, such as agriculture, cosmetics, wastewater treatment, drug delivery, tissue engineering, biosensors, and adsorbents for heavy metals and dyes. 18,21,22 Hydrogels with characteristic responses to external stimuli such as temperature, pH, light, electricity, salt concentration, and ionic strength are often called "smart" hydro-gels and have great potential for applications in various fields. 23 After the introduction of natural polymers such as cellulose, 24 starch, 25 chitosan, 26 sodium alginate, 27 collagen, 28 and their derivatives, the spatial structure of the water retention agent will not change significantly, but still has a porous three-dimensional spatial network-like structure, which can physically enclose water molecules in the resin to achieve the purpose of water retention, and high hydrophilicity, good biocompatibility, low toxicity, and good biodegradability, so it has attracted a lot of attention.…”

“…The water retention agent uses a superabsorbent hydrogel, which is a functional three‐dimensional network of hydrophilic polymers with a particularly highly water absorption capacity 15–17 . Usually through chemical and physical cross‐linking, it can absorb and retain considerable amounts of water or biofluids compared to conventional absorbents (e.g., sponge, cotton, wood pulp, and colloidal silica, etc 18–20 …”

“…). Due to their superior properties, highly absorbent hydrogels are used in a wide range of applications, such as agriculture, cosmetics, wastewater treatment, drug delivery, tissue engineering, biosensors, and adsorbents for heavy metals and dyes 18,21,22 . Hydrogels with characteristic responses to external stimuli such as temperature, pH, light, electricity, salt concentration, and ionic strength are often called “smart” hydro‐gels and have great potential for applications in various fields 23 .…”