The Scot was beaten 6-4, 6-7, 6-3, 6-2 by the world No.6 from Spain, falling one round earlier than last year when he lost to Rafa Nadal.
"I believe I lost to a better clay court player here," said Murray.
"I was playing some good tennis towards the end but I made a few more mistakes than I would have liked.
"I'll need to work on some things in my clay court game for next year.
"However, it's not the first time he's won against me on clay. It was going to be a tough match and it proved that way.
"I had a lot of chances in the last couple of sets on his serve and lost a lot of really long games on my serve, which didn't help.
"He is so consistent that if you're not converting your opportunities, it turns to many long games, and then the pressure can build on your serve.
"He broke me a lot in the last couple of sets. I had chances to break him and didn't convert them like he did."
Murray said he would head straight to London today to begin preparations for Wimbledon.
He is due to defend the title in the Aegon Championships at Queen's Club next week and said he believed his form was good, especially after the back spasms he suffered before his second-round match with Jarkko Nieminen.
"I'm not disappointed," he said. "It was a decent tournament. Coming in, I didn't feel as good as last year but after the match in the second round, if I'm looking at the positives, it was good to get into this position.
The world No.4 was aggressive throughout but was made to pay for an inability to take chances, breaking five times only to immediately drop his own serve.
"You need to be patient but make sure there is enough on your ball so that you're not letting a guy like Ferrer dictate on big points.
"Tonight I feel like I went for my shots. If I hadn't done, I would have got criticised. If I do go for my shots, I get criticised for mistakes.
"I played the way I thought was best to win the match. I don't think it was down to a psychological thing that I lost. It was down to poor execution of the shots."
Murray said he had not decided when he will begin practising on grass.