1.2 Europe and North America
there is no such steep expansion of protected cultivation area in Europe and North America as in Asia, but the total area is not small, and a stable situation exists. A close look at protected cultivation in Europe shows that new system are gradually being installed. Climate control by digital computers, hydroponic system, and inter-transportation system(which can be called agri-robot systems) are spreading in northwestern European countries, in Mediterranean countries simple plastic houses are predominant. in eastern European countries, large-scale glasshouses with energy supplied from nearby power plants are very common, they are normally operated cooperatively, although levels of mechanization are not high. in the United States, greenhouses are used for long-term farming, and row covers and floating mulches are becoming popular in small framing, as shown in table 1.2