My people were farmers. There was a story I was told as a kid.
A farmer went on a long journey. When he came back, he had a new corn seed. He planted it and had yields 50 bushels per acre higher he had last year and it was much higher than all his neighbors. His neighbors wanted to buy seed from the farmer. He refused to sell it to him.
The next year, the farmer's yield was only 35 bushels per acre better than his neighbors. Every year it decreased, until his yield per acre was back at the original amount.
The moral of the story is twofold. First, crops germinate.
Second, a rising tide raises all boats if you let it. Just because your neighbors also have more grain doesn't mean you'll have less. With more grain, you can raise more head of cattle, have more chickens, reduce the amount of grain and begin raising vegetables. Even if the price of grain declines, the amount you can do with that grain should offset the decline.