Water retention in different types of protective gel compositions for plant rhizosphere

Abstract

The research investigates thermodynamic characteristics of water-retention capacity in different types of high swelling polymer hydrogels mixed with mineral soil substrates. The use of a combination of methods of equilibrium centrifugation and thermodesorption of soil moisture allowed for the first time to estimate the water-retaining curves and dispersion of gel compositions in the range of absolute values of thermodynamic potentials from 0 to 1 million J/kg. The introduction of hydrogels in concentrations of 0.1-0.3% total weight of the enclosing mineral material leads to a 5-15 fold increase in the total energy of water retention, 3-8 fold increase in water capacity and available moisture range, bringing investigated hydrophysical characteristics of the original sandy substrate at the level of the fertile loamy soils. The new types of acrylic hydrogels with amphiphilic fillers obtained by the author's technology had a greater water-holding capacity and a better structuring effect in comparison with the "Aquasorb" European trade mark. The incorporation of the electrolyte additives in the form of trace elements and ionic silver into the polymer matrix practically does not change the swelling capacity, allowing adding elicitor and antimicrobial properties to these compositions without compromising the effect of water retention.