Maybe I don't get your point but a tariff is a tax, and US consumers pay for a lot of that tax. So this is effectively a super inefficient redistribution of wealth to farmers from everyone else in the country.
So American farmers are losing export sales due to Chinese tariffs, the sting of which Trump is trying to reduce by paying the farmers. Those payments probably aren't funded by tariff revenue collected by the US. So they'll probably be paid for through borrowing. Which may mean borrowing from China.