Corn, soy, wheat prices up
The reasons include China buying more because the country is rebuilding its hog herd after major losses in 2019 and last winter (African Swine Fever); draught in Brazil and ongoing dry conditions in the U.S (two major suppliers); and traders trying to hedge inflationary risks.
The robust Chinese demand is expected to continue for 2-4 years. Additionally, rising incomes in developing countries could keep food prices moving upward.
There isn't much alternative (such as rice and wheat) to feeding livestock good grains (corn and soy beans) when a livestock economy is focused on maximizing gains and quality, as China's is.
Offsetting factors to inflation in food prices have started to be seen in more elastic demand factors, such as Chinese animal protein demand, where indications are consumers are starting to pull back due to prices. Also, the supply side, if robust enough, could put downward pressure on prices. We'll see how robust U.S. production turns out to be this year in the June Acerage Report, as the U.S. is still planting this years crops.
Rice prices aren't up in the same way because stocks have been built up over the past few years.
USDA Acreage Reports