Falmer was selected for Brighton and Hove Albion's new stadium because it was easy to acquire and cheap to develop, Sussex's oldest conservation group has claimed.
The Society of Sussex Downsmen said the club's site assessment had not been a genuine attempt to find the best place for the proposed 22,000-seat ground.
Graham Fuller, giving evidence for the society at the public inquiry into the scheme, said the document was "inadequate and flawed".
He said: "The club decided Falmer was the best site for their new stadium because they believed the site was easy to acquire and would be cheap to develop."
The society said building at Falmer would cause huge environmental harm and would set an "appalling precedent" for development in the Sussex Downs area of outstanding natural beauty.
Mr Fuller said there were at least two brownfield sites in Brighton and Hove which could be used for a stadium and their potential had been dismissed too easily.
He told the hearing, taking place at Hove Town Hall, Brighton station would be suitable for the ground and difficulties in developing Shoreham harbour had been exaggerated.
He said problems at the latter site could be overcome and the transport improvements needed would be no greater than those required at Falmer.
Jonathan Clay, representing the club, said planning guidance did not specify brownfield sites had to be developed before greenfield ones, or that town centre sites were suitable for football stadiums.
Major road works and land reclamation would be needed at Shoreham harbour and the port authority did not want to release the land.
He said: "It would be irresponsible to put a stadium for 22,000 people there if one had to be sure the infrastructure was there in a short period.
"It would be disastrous to grant permission and then find the scheme did not take place."
The society was the final objecting group to give evidence on Friday. The inquiry has now adjourned for eight weeks.
The Council for the Protection of Rural England and individual objectors and supporters will speak when the hearing reconvenes for two weeks on June 3.
Planning inspector John Collyer will send his report and recommendations to Deputy Prime Minister John Prescott later in the summer.
A final decision is not expected until the autumn.
Follow all the latest developments at thisisbrightonandhove.co.uk/issues
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