Why is this important? Because irrigation for food production is about 70% (!) of water use in the U.S., and even more in some other countries. This is a gigantic amount of water, and while it is not destroyed (unlike fossil fuels), it could be used much more efficiently and we could keep many aquifers, rivers, and lakes in much better condition.
NASA researchers have developed a computer program to help farmers better manage irrigation systems in real time. The software uses data from NASA satellites, local weather observations, and wireless sensor networks installed in agricultural fields to calculate water balance across a field and provide farmers with information on crop water needs and forecasts that can be accessed from computers or handheld devices. (source)
This system is being beta-tested by farmers and vineyard managers in the San Joaquin Valley in California as part of an 18-month research project to optimize irrigation management. The project is the first to combine satellite and surface observations to estimate irrigation needs at the scale of an individual field or vineyard, and distribute the information to farmers in near real time.
We're still in the early stages of this technology, but the trend is obvious, especially in countries where agriculture is still very inefficient (uses lots of water, chemicals, fertilizer, etc).