Wheat and barley use about 2 ft of water in Arizona, but 3 to 3.5 ft of applied water is often required with surface flood irrigation due inefficiencies in the irrigation system. Less irrigation water is required with more efficient irriga- tion systems such as sprinkler or drip. If 6 inches of water is applied per irrigation, then six or seven irrigations are required during the season. The first post-emergence irri- gation is generally needed by the 5 leaf stage and the last irrigation by soft dough. An example irrigation schedule is presented in Table 1. For an explanation of small grain growth stages and heat units to attain these stages see Ottman (2004)
Small grains can be produced successfully with a variety of irrigation systems. Drip and sprinkler irrigation sys- tems can apply smaller amounts of water than surface flood systems, and therefore, less applied water moves past the root zone. Surface flood systems are more efficient at leaching salts, which is a consideration if salts are a problem. Small grains can be grown equally well on beds or flat ground. Beds have an advantage if infiltration is a problem, the field has substantial sidefall, or a sufficient head of water can not be delivered. Growing small grain plants in furrows in a bed system can slow the advance of surface irrigation water, increase water infiltration, but result in less efficient irrigation.