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　　Floating Farm Docks in New Yordson River学案
　　An urban farm may seem out of place on a pier in the Hudson River, with the Manhattan skyline towering a mere half-kilometer to the east. But environmental engineer Ted Caplow looite at home standing on the deck of the science barge he designed, then built, with a small group of plant scientists, energy specialists and fellow environmentalists.
　　Kape Caplow stands on the deck of a barge that’s like no other on the New York Waterfront.Part high-tech farm, part laboratory, and part floating classroom, the New Yorn Works Science Barge sports solar panels, wind turbines, a couple of greenhouses and other gear aimed at demonstrating sustainable agriculture in one of the world’s most densely-packed cities.
　　The Science Barge project, which is set to launch next month, aims to show how urban areas like New Yorpport agriculture using recycled water and renewable energy.
　　“And the prupose of this project is to demonstrate that growing food in the city is good for the environment in a number of ways. When we grow food out in the country, we use a tremendous amount of land and water and fertilizers, and all these things have a large impact on the environment in the countryside. By moving food production into the city, we save a lot of land, and at the same time, we bring the food closer to the consumer.So we avoid the environmental and monetary cost of trucking food,often thousands of miles from the field to the dinner plate.”
　　There is not a lot of vacant land in Manhattan that would be suitable for farming. But Caplow says the farms don’t have to be on ground level.
　　“There is a lot of space in the city up on the roof. In New York City, for example, we have approximately 5000 hectares of available space just on existing rooftops. That is space that is open to the sky so there is plenty of sunlight where we can grow vegetables, but we can’t grow vegetable in the city in the same way that we grow them in the country.”
　　On a traditional farm, there is one horizontal surface where plants are grown. It’s the surface of the Earth itself. But the Science Barge folks say that many crops can be grown in containers stacked one atop the other, somewhat like a high-rise apartment building.
　　Sun Works’ greenhouse director Jenn Nelkin says this is a good way to grow certain plants. “So instead of having, list a horizontal row of plants, here I have 40 plants instead of one that might tap that same square of space if we were growing everything horizontally. So that’s [how] we get some vertical space out of short crops.”
　　An abundance of other crops, including tomatoes, lettuce, cucumbers, and other vegetables are flourishing in the New Yorn Works greenhouses. They’re grown using hydroponios technology where the roots are immersed in trays of nutrient rich water, not soil.
　　The water itself comes either from rainwater stored in an onboard tank, or from the Hudson River itself. New Yorn Works staff member Viraj Puri demonstrates that the river water is purified and desalinated by a “reverse osmosis” machine.
　　“You pump water up, a lot of pressure builds up and it is passed through a membrane. It separates the salt from the water and the brine goes back into the water.”
　　This machinery and sophisticated environmental control devices and computers,