Furrow or Corrugation
A small sloping channel is scraped out of or pressed into soil surface. For high uniformity of wetting, the irrigation stream should reach the end of the channel in about one fourth of the time allotted for the irrigation; but the stream is not shut off until the root zone soil at the lower end of the furrow is adequately irrigated. Water in the soil moves both laterally and downward from the channel. Water is lost chiefly by deep percolation and runoff.
Any or numerous devices for spraying water over the soil surface are called sprinklers. Water discharged from a sprinkler into the air should infiltrate the soil where it falls but it should not saturate the soil surface. For high uniformity of wetting, the. spray patterns from adjacent sprinklers must be properly overlapped. Evaporation, wind drift, and deep percolation are the chief causes of loss of water.
Drip (or Trickle)
A device used in trickle (or drip) irrigation for discharging water at some very low rate (less than 12 Ips) through small holes in tubing placed near the soil surface. Water moves through the soil both sideways and downward away from the point of application to form a bulb of wet soil. Typically, only a portion of the soil mass is kept quite moist by very frequent or continuous application. Water loss is mainly by deep percolation.