121. HYDROPONICS

Hydroponics is the science of growing plants without soil by bathing their roots in a nutrient solution. It holds great promise of increasing the carrying capacity of the earth, and reducing the footprint of human agriculture. This is because:

1. Hydroponics eliminates the need for soil and the labor involved in soil building and care.
2. It greatly reduces the need for pesticides since many pests can simply be quarantined out of the structure.
3. It requires extremely low levels of water and fertilizer use compared to conventional agriculture.
4. It enables massive increases in yield per acre.

Today, tomatoes are at the leading edge in hydroponic agriculture:
Average U.S. yields for greenhouse tomatoes (which includes both hydroponics and soil-based forms of controlled environment agriculture) are 484 metric tons/hectare. Average U.S. yields for field tomatoes, on the other hand, are 32 metric tons/hectare (Source(pdf, P. 4)). "By providing all the plant's nutrients via hydroponics and regulating the environment, yields can be very high, as much as 15 times greater than field production per year"(Source: same as above, P. 69).

This is not a hypothetical technology. Greenhouse tomatoes are a real-world industry:

In 2003, in the United States and Mexico, the greenhouse shares of total fresh tomato production were 9 and 8 percent, respectively, but are likely higher now. In Canada, greenhouse tomatoes now completely dominate fresh tomato production, with an 89-percent share.(Source: same as above, P. v)

California has even gone so far as to legally define a greenhouse tomato as hydroponically-grown:

In September 2004, the State of California adopted a definition requiring tomatoes labeled as greenhouse to be grown in "a fixed steel structure using irrigation and climate control, in an artificial medium that substitutes for soil" This means that any tomatoes labeled as greenhouse and marketed in California must be grown hydroponically.(Source: same as above P. 6)