One isolated market, flat uniform land. Each crop bids for land based on its value and transport cost; the highest bidder at each distance wins. The result is concentric rings. Raise transport cost and watch the farmed area shrink toward the market.
Bid-rent: rent each use will pay falls with distance (transport eats profit). The upper envelope (heavy line) = the winning use, and where it crosses sets a ring boundary.
Try: push t to 2.5× — the bid-rent lines steepen, every crossing slides toward the market, and the outer ranching ring is squeezed out: high transport cost makes distant farming unprofitable. Drop t to 0.5× to expand cultivation outward.