No. Our editors have solid academic backgrounds and years of experience, which allows them to spot and fix the most various factual errors while improving your paper's flow and style. However, performing additional research isn't what they are required to do. If you want someone to check your piece for factual errors and point out places that require deeper research, you might want to try peer editing. Keep in mind that in such a case, you need to make sure peer editors have respective qualifications (for example, your farming paper is checked by people relevant to agriculture, not art or math).