Preparing the soil is the most likely meaning of "cultivating" in the context of weed prevention in a nursery.
Based on the document, cultivating means preparing the soil. While sowing seeds and eradicating weeds are also mentioned in the document, they don't directly imply the meaning of "cultivating."
Installing a barrier and neglecting the soil are clearly not related to cultivation. Therefore, preparing the soil is the most likely meaning of "cultivating" in the context of weed prevention in a nursery.