Hydrogel composed of potassium acrylate, acrylamide, and mineral as soil conditioner under saline conditions
Costa, Mirian Cristina GomesFreire, Alcione GuimarãesLourenço, Diego VasconcelosSousa, Rayane Rodrigues deFeitosa, Judith Pessoa de AndradeMota, Jaedson Cláudio Anunciato
ABSTRACT Hydrogels have potential as soil conditioners due to their high capacity to retain water and mitigate soil salinity. However, investigations under saline conditions are necessary because there are losses in both water absorption and salinity mitigation depending on the composition of hydrogel and ions involved in salinity. In this work, we studied a commercial hydrogel in two experiments. The first experiment was conducted in the laboratory to evaluate the absorption by the hydrogel of water with electrical conductivity (EC) of 0.5, 1.5, 3.0, and 4.5 dS m1, promoted by NaCl. The second experiment was conducted in a greenhouse in a 2 × 4 factorial scheme (with and without hydrogel × EC of the first experiment). Although salinity reduced water absorption by hydrogel by 84 %, the polymer applied in a sandy soil under saline conditions reduced water losses by 58 %. However, hydrogel did not increase the final soil moisture (~ 0.10 g g1). The polymer reduced Na+ concentration in leachate from 1,499 to 1,219 mg L1 at the highest salinity level (4.5 dS m1), but it increased Na+ soil availability by 0.1 mg kg1 in comparison with polymer absence. Hydrogel application increased Na+ content in plants from 9 to 13 mg kg1 at the highest salinity, while K+ content was 10 to 16 mg kg1 lower than that observed without a polymer. Hydrogel 0.07 % (w/w) reduced maize biomass, indicating damage by monovalent ions, compromising the polymer potential under salinity.
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