Agricultural products are seasonal, and the contract after the new crop is listed is a new contract.

Take soybeans as an example. Domestic soybeans were harvested in September and put on the market -65438+ 10. So the old contract was before September, and the new contract was after 165438+ 10. Corn and cotton are seasonal.

Wheat is different, it is harvested in June-July, but the reason is the same.