China has encouraged farmers to expand corn planting and abandon soybeans in recent years by paying them inflated prices for corn. The policy, abandoned earlier this year, has left China with huge reserves of corn.
The government is now attempting to reverse that trend while also seeking ways to use up its huge stocks of grain.
The corn acreage is set to fall by 0.7 percent each year over the next five years, to reach 500 million mu (33.3 million hectares) by 2020, showed the five-year plan.
Soybean area will rise to 140 million mu by 2020, up from 98 million mu in 2015.
The government also wants to promote "deep processing" of agricultural products such as corn and accelerate consumption of the grain, cotton and oil stockpiles, it said.
It did not give details on how such goals would be achieved but the market is expecting further stockpile sales and government subsidies for processing.
Meat output is also set to grow slightly, with promotion of large-scale farming of pigs and beef cattle, while dairy production should jump from 38.7 million tonnes to 41 million tonnes by 2020.