Let's say the RoboWater(tm) rolls down a row of trees in the orchard, water hose unreeling behind it. At each tree, it dumps the calculated dose of water into a clay pot that is sunken into the ground near the trunk (from which the water slowly soaks into the soil). When the row is done - it reverses direction, reeling the hose back up in the process. Then some side-shuffling, and it's soon rolling down the next row of trees in the orchard, again dumping the calculated dose of water...