Furrow torpedoes improve irrigation water advance

To increase irrigation uniformity and to reduce drainage volumes, some San Joaquin Valley growers drag weighted steel cylinders (torpedoes) in furrows before irrigation to speed the advance of water across the field. The effectiveness of this practice and the reasons it works have been investigated.

At one site, torpedoing reduced the furrow's steady-state water infiltration rate. A similar phenomenon was not observed at the other two sites investigated. An increase in the irrigation advance rate of torpedoed furrows, ranging from 15 to 30%, was noted at each site evaluated. Torpedoed, nonwheel furrows had water advance characteristics similar to wheel furrows. Torpedoing nonwheel furrows therefore resulted in more equal water advance rates among furrows.