I have a few additional questions before I can properly answer your question: 

Was this agricultural land previously? How long ago? 

What is growing there currently? 

About how large of a parcel is this?

Thank you for the additional details! Do you know how long ago the tree was removed? Are the neighbors who removed it still around so you can ask what they did? If it's been a couple of years, it's likely that plants will grow there again and the chemicals used are likely broken down. If plants don't grow, they may have used salts to break down the stump, which will leave the soil contaminated with salt. If you are concerned about any residues or salts, you could remove the top 6 inches of soil in the 2 x 2 area and replace with topsoil or a mix of topsoil and compost. You can test for pesticide residues, but that is pretty expensive, and the lab needs to have a pretty good idea of what they are looking for or they can miss the product used. For example, if they are looking for herbicide residue, they may not detect high salinity. 

If you would like to test the soil for nutrients, you can use our Home Lawn & Garden Soil Test Mailer.

For more information on soil testing: https://www.canr.msu.edu/news/soil-testing-returns-through-msu-extension

For soil testing for contaminants, including labs that do testing: https://www.canr.msu.edu/news/testing-for-contaminants-in-soil-water-and-plants