Your ignorance is almost as big as that fucking goitre currently masquerading as your brain.
The UK contribution towards the EU CAP is around £3 billions. The thing is, this is more or less the same the UK paid into the UK agriculture industry in 1971/2 to finance the various intervention boards and subsidy schemes preventing bankruptcies leading to the disastrous cycles of feast or famine. The Ministry of Agriculture received £700 million in 1971/2 which allowing for inflation equates to the current £3 billions or thereabouts.
When/if a hard Brexit takes place, the industry is going to have to accept that subsidy will continue but this time they will have to export to their 500 million EU customers in the knowledge they could be paying 30% more in added tariffs. Don't quite think the punters are going to swallow that, har har.
Just as 130,000 British businesses have now understood that they will be paying VAT etc up front on all their EU imports when we leave the single market, the British farmer is going to face the awful fact his only significant viable customer is going to be the British consumer.
But I daresay those crazy mofos such as Mogg, Gove, Johnson, Fox and Davis will probably believe riches beyond the dreams of Croesus will lie in the sub-continent markets where the British farmer will sell his pork products to the Pakis and the Banglas, and beef to the Hindu wobble heads.
Har, har.