I would just say the farmable (or agricultural) land was converted to residential/commercial/industrial use. Now if the land is reverted back to its natural state the we would say the farm land was reclaimed.

In the United States we would call this "development," short for "real estate development." Here, "development" means "to increase the monetary value of a piece land," and land with house or commercial businesses on it is (usually) worth more money than farmland. Many places in the United States have restrictions on development. In my community, for example, development has to be approved by the Conservation Commission. Laws controlling land use are called "zoning ordinances" and "environmental laws." They are mostly state and local laws. There is a conflict in U.S. law between the rights of ownership and the rights of communities to control land use. The Fifth Amendment to the Constitution says that "private property [shall not] be taken for public use without just compensation." There have been legal battles over whether laws restricting land use represent a "taking." A Supreme Court decision in 1922 said that laws can restrict and control land use if they don't go too far, but if the are "excessive" they constitute a "taking."

Dear Mohamed, as far as I can see from public sources there is no term for what you describe, except 'Change of use' which requires a planning application: any such application, intending to build an industrial/residential development on agricultural land, will be assessed by the local authority for environmental impact and any significant change to the wider community (including neighbouring farms). One of the issues is drainage, since rainwater on open fields sinks into the ground but hard covering (e.g. concrete) stops this from happening and puts increased pressure on ditches, with the result that these may be unable to cope and cause flooding: this can affect neighbouring farms too, so there is an issue of drainage that has to be considered. Letting land 'lie fallow' is a term used in crop rotation, but in this case there is no preparation other than drainage for the purpose of laying the foundations of a building. . . Other than digging out existing crops, or removing tree roots or other unwanted debris. there does not seem to be a word as such... Perhaps someone else may find one where I did not...