So Marx opposed mechanisation because it replaced live labour?

No, Marx merely pointed out that, under capitalism, dead labor does not make the live stuff obsolete; it merely increases the laborer's productivity out of all proportion to the amount he/ she is paid.

You know, all of Marx is online, and I'm not really telling you anything that isn't available in a standard guide to the topic.

Oh, and is land productive? And is a wind turbine productive?

No.  Look at the other planets of the solar system.  They've got plenty of land, and what do they produce?

A wind turbine is productive because it is the product of living labor.  More dead labor at work.

"Imagine all the people/ Sharing all the world" -- John Lennon