Hydrogels are substances designed to retain significant quantities of water and slowly release it to support plant growth. This study produced and evaluated the use of a test hydrogel (TH), a natural polymer derived from cashew gum (Anacardium occidentale), on the growth, chemical composition, and mineral content of cactus pear genotypes. The TH was compared to a negative control (no hydrogel; NH), and to a positive control or commercial hydrogel (CH). The CH was a synthetic polyacrylamide-based hydrogel. The study was carried out in a completely randomized design with a 3 × 3 factorial arrangement (n = 36), involving three hydrogel types × three cactus pear genotypes [Elephant Ear (Opuntia stricta); Giant (Opuntia ficus-indica); and Sweet (Nopalea cochenillifera)]. There was a significant effect of interaction (p ≤ 0.05) between genotypes and hydrogel types on cladode area, plant height, dry biomass of cladodes, and macro- and micromineral content. The use of TH promoted greater growth and improved chemical and mineral composition (p ≤ 0.05) to cactus genotypes. The Sweet genotype hydrated with TH presented the highest crude protein accumulation (p ≤ 0.05). Cashew gum-based hydrogel improved both growth and chemical composition of the cactus genotypes, and it is an eco-friendly alternative to synthetic polymers.

Hydrogels are water-absorbing polymers that can hydrate forage plants in the soil. The objective was to evaluate the replacement of synthetic hydrogels derived from petroleum with biodegradable hydrogels in Mombaça grass pastures (Megathyrsus maximum). The experimental treatments consisted of no hydrogel (NH); synthetic commercial hydrogel (CH), made from a synthetic polyacrylamide product; and biodegradable test hydrogel (TH), obtained from cashew gum (Anacardium occidentale). The experimental design consisted of randomized blocks with five replications and three treatments. The morphogenesis, production, chemical, and mineral composition of the Mombaça grass pasture were assessed. The data were subjected to analysis of variance and mean comparison using the Scott–Knott test at 5% probability. The leaf elongation rate showed 42.3 mm day⁻¹ in the treatment TH, which was higher (p < 0.05) than NH (35.0 mm day⁻¹). The green leaf mass yield was higher in TH than in NH and CH. On the other hand, hydration had no effect on the chemical composition. The mineral composition of Mombaça grass showed more Zn when TH was used. It can be concluded that biodegradable hydrogels can replace synthetic commercial hydrogels in pastures.

The development of natural hydrogels as water carrying components for controlled release is considered promising in agriculture. The objective of this study was to evaluate the use of a test hydrogel from cashew gum (Anacardium occidentale), on forage grass genotypes, in comparison to the commercial hydrogel composed of polyacrylamide. The completely randomized design was applied in a factorial scheme (4 × 3) with four grass genotypes, which were two grass genotypes Megathyrsus maximum: Mombaça and Massai and two grass genotypes Urochloa brizantha: Marandu and Paiaguás, associated with three forms of hydration: no hydrogel, test hydrogel and commercial hydrogel in four replications. Some morphogenetic, structural and production characteristics of the grass had significant effect of the forms of hydration, and there was effect also on the different grasses for production characteristics, showing greater growth with the use of hydrogel. The contents of crude protein and fiber were influenced by the form of hydration in the studied grasses, obtaining higher values with the use of hydrogel. The use of hydrogel improves agronomic characteristics, chemical and mineral composition of the grass genotypes. In addition, the cashew gum hydrogel showed similar or better results than polyacrylamide hydrogel on the growth and production of the grasses. Graphical Abstract

Hydrogels are water-absorbing polymers that can hydrate forage plants in the soil. The objec-tive was to evaluate the replacement of synthetic hydrogels derived from petroleum by biode-gradable hydrogels in Mombaça grass pastures (Megathyrsus maximum). The experimental treat-ments consisted of: No hydrogel (NH); Synthetic commercial hydrogel (CH), made from a syn-thetic polyacrylamide product; and Biodegradable test hydrogel (TH), obtained from cashew gum (Anacardium occidentale). The experimental design was randomized blocks with five replica-tions and three treatments. Morphogenesis, production, chemical and mineral composition of the Mombaça grass pasture were assessed. The data was subjected to analysis of variance and mean comparison by the Snott-Knott test at 5% probability. Leaf elongation rate was 42.3 mm day-1 in the TH treatment, which was higher (P<0.05) than NH (35.0 mm day-1). Green leaf mass yield was higher in TH in comparison to NH and CH. On the other hand, there was no effect of hydration on chemical composition. The mineral composition of Mombaça grass showed more Zn when TH was used. It can be concluded that biodegradable hydrogels can replace synthetic commercial hydrogels in pastures.