The increasing use of herbicides in recent years for improved crop yields requires a risk assessment. To assess their impact on soil, the use of an indicator named the synthetic biological indicator (ISB%) is proposed, which includes a range of biotic and enzymatic parameters derived from previous experiments. Three sulfonylurea herbicides were evaluated, named chlorsulfuron, amidosulfuron, and tifensulfuron. The biotic and enzymatic parameters were monitored using different herbicide doses in field and laboratory experiments. Calculating this indicator for all experimental variants in the field and laboratory showed that the impact of the analyzed herbicides was insignificant, but there were statistically significant differences between the experimental conditions. The registration of an herbicide based on the legislation of different countries requires several toxicity tests of the active substance’s effects against soil microorganisms and some of the soil functions performed by microorganisms, parameters which are also included in the synthetic biological indicator (ISB). This indicator has the capacity to provide important information for sustainable soil management, including a minimum set of parameters, which can provide global information regarding the environment, showing changes in multiple areas of interest, including parameters that can be applied at minimal cost worldwide. In conclusion, we can say that the use of the indicator highlights all the changes caused by various soil chemical treatments because it follows the variation in a large number of parameters, unlike other indicators that follow only one, providing useful information for sustainable farming practices.

Aclonifen is an herbicide with a global market that is expected to grow in the period 2021–2027. This study focuses on revealing the effects of both aclonifen and of its soil metabolites on aqueous and soil environments. The soil’s physicochemical parameters and activities of enzymes found in the soil (urease, dehydrogenase, catalase, alkaline phosphatase) were evaluated in laboratory conditions for soil treated with various doses of aclonifen (from half of a normal dose, 2.1 g/ha, to three times the normal dose) every 7 days for a period of 28 days. A computational approach was used to calculate the acute toxicity of aclonifen and of its soil metabolites on aqueous organisms and to evaluate the possible interactions of these compounds with soil enzymes. The results obtained in the experimental study showed a significant inhibitory effect of the herbicide aclonifen on the investigated enzymes; those activities were not recovered after 28 days in the presence of high doses of aclonifen. Statistically significant effects of the herbicide dose and exposure duration on enzymes’ activities were observed using post hoc analysis at the p < 0.001 level. Pearson’s correlations revealed that the investigated enzyme activities were usually strongly (p < 0.001) influenced by the organic matter, available phosphorus content, and nitrogen level. The outcomes of the computational study revealed moderate acute aqueous toxicity of aclonifen and of its metabolites. All metabolites were also able to bind to the investigated enzymes and may have an inhibitory effect on their activities.