The intensified use of pesticides and chemical fertilizers has resulted in threats to the environment. Thus it is crucial to the implementation of sustainable alternatives in order to mitigate the negative effects. The biofertilizer brings this proposal, as it improves soil fertility and minimize environmental risks. The ametryne herbicide is used for weed control, very soluble in water, bringing risks to terrestrial and aquatic ecosystem. Thus, the objective of this work was to study the degradation of ametryne in soil with the addition of liquid biofertilizers. After application of biofertilizer in soil with ametryne, the microbial activity increased in 39.149%, in CO2 generation.In the assay for quantification of ametryne by HPLC-MS/MS there was reduction of concentration of the molecule in the presence soil sample contaminated with the herbicide. Thus, the biofertilizer was able to assist in soil fertility, increasing metabolic activity, resulting in degradation of the herbicide.