What is Surge Irrigation?
Surge irrigation is the intermittent application of water used to improve distribution uniformity along a furrow. It works on the principle that dry soil infiltrates water faster than wet soil. When soil is wet is seals because the soil particles at the surface consolidate. When water is re-introduced in a furrow that has been wet, the wetting front moves quickly past the wetting zone to dry soil. At the wetting interface, dry soil slows the advance. This phenomena allows for a faster advance through the field with less deep percolation and better application uniformity. The end result, therefore, is a more even distribution of water in the rooting zone from the poly-tubing to the tail ditch, and reduced nutrient loss from deep percolation near the poly-tubing.

Surge irrigation is performed through a program of cycle times that account for the advance of the furrow, they must be set by the user. Some tail water is necessary with surge irrigation for it to be effective. The intermittent application reduces the tail water volume because the water is moving as a pulse over the sealed furrow to the end of the furrow. Its velocity decreases as it moves along the furrow and has more time to infiltrate before it leaves the furrow. Link to Complete Article