Whether the land carries an agricultural or wildlife valuation can change your annual cost dramatically, often re-valuing qualifying acreage from market value down to a productivity value a fraction as large.
The trap is on the other side. If ag land is converted to non-agricultural use, Texas recaptures the tax savings through a rollback assessment covering prior years plus interest. If you buy ag-valued land and stop the qualifying use, that bill lands on you, not the seller.
Ag valuation also does not transfer automatically on sale. A new owner generally has to apply, and continuous qualifying use has to be maintained at a real degree of intensity set by the county.
Ask this: Does the property currently carry ag or wildlife valuation, what use qualifies it, and what does the county appraisal district require to keep it? If I intend to build or subdivide, what would the rollback exposure be?