Farmers will only get payouts if they agree to protect the environment and enhance rural life, he will say.
The move is part of what he calls his vision for a “green Brexit”.
Farmers’ leaders want the current £3bn total to be spent on the environment, more infrastructure to develop farm businesses, and promoting British food.
The government has promised to keep overall payments at the same level until 2022.
The Tenant Farmers’ Association – which represents tenant farmers in England and Wales – has called for the same amount of money to remain after that time.