The Role of Sodium Alginate Hydrogel in Maintaining Soil Homeostasis Exposed to Sulcotrione

Herbicides are the most widely used agrochemicals in crop protection, which has led to serious environmental pollution around the world, including soil ecosystems. It is important to look for new solutions that lead to an improvement in soil quality, even if only through the use of hydrogels. The aim of this study was therefore to determine the effect of sodium alginate on the microbiological and biochemical properties of sulcotrione-treated soil. It was found that both the herbicide and the sodium alginate had a significant effect on the soil environment. An amount of 10 g kg−1 of sodium alginate was applied to the soil, while sulcotrione was applied to the soil in the following amounts: 0.00 (C), 0.200 (R), 0.999 (5R), and 9.999 mg kg−1 (50R). Sulcotrione stimulated the activity of dehydrogenases, catalase, arylsulfatase, and β-glucosidase and inhibited the activities of alkaline phosphatase, acid phosphatase, and urease as well as the proliferation of organotrophic bacteria, actinobacteria, and fungi. This caused an increase in the colony development index (CD) of organotrophic bacteria and fungi and decreased the colony development index value of actinobacteria. It also increased the value of the ecophysiological diversity index (EP) of fungi. The addition of sodium alginate to the soil increased the numbers of organotrophic bacteria, actinobacteria, and fungi as well as the activities of dehydrogenases, catalase, urease, alkaline phosphatase, and arylsulfatase. The hydrogel had different effects on β-glucosidase activity. Acid phosphatase showed a significant decrease in activity after the addition of sodium alginate to the soil. Under the influence of sodium alginate, there was an increase in the index of colony development of actinobacteria and fungi, while there were decreases in organotrophic bacteria and the index of ecophysiological diversity of actinobacteria and fungi. The proliferation of microorganisms and the enzymatic activity of the soil changed over time both in soil enriched with sodium alginate and without its addition. This study may be useful for evaluating the effects of sulcotrione on the microbiological and biochemical properties of soil and the effectiveness of sodium alginate in improving the quality of soil exposed to sulcotrione.