This research represents the second year of a project to determine when to irrigate barley based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of barley at 35, 50, 65, and 80% depletion of plant available water in the soil for two barley varieties, Baretta and Max. Grain yields for the 35, 50, 65, and 80% depletion levels were 8319, 7296, 5606, and 3404 lbs/acre for Baretta and 9164, 8403, 6463, and 3416 lbs/acre for Max, respectively. The yield increase averaged across varieties from irrigating at 35% rather than 50% depletion is 893 lbs/acre, which has a value of $45.54/acre assuming a grain price of $5.10/cwt. However, the cost of producing this grain is $54.33/acre due the cost of two additional irrigations ($44/acre), 30 lbs additional nitrogen per acre ($8.10/acre), and increased hauling cost ($2.23/acre). The profitability of irrigating at 35% rather than 50% depletion is improved with an increase in grain price or decrease in water cost.

This research was conducted to test the effect of soil water depletion levels on durum productivity. An experiment was conducted at a commercial farm in Stanfield where irrigations were applied at 35, 50, or 65% depletion of plant available soil water. These soil water depletion levels were estimated from soil texture and weather data. The grain yields obtained with 35, 50, and 65% depletion were 6718, 6324, and 4752 lbs/acre, respectively. Grain protein decreased and HVAC increased by irrigating more frequently at lower depletion levels. Irrigating at 50% depletion was the most economical in this study considering irrigation costs and grain quality discounts.

Bacterial blight of barley, caused by the bacterium Xanthomonas translucens, occurs sporadically in Arizona in sprinkler-irrigated barley. The pathogen is seed borne, and there are no resistant varieties of barley. Bacterial blight has been severe when contaminated seed is planted and favorable weather conditions, including spring rains and late frosts, occur in March and April. Methods for detection of the bacteria on seed have been established at The University of Arizona using both standard pathogenicity trials on barley seedlings and immunoassay techniques.

Small grain varieties are evaluated each year by University of Arizona personnel at one or more locations. The purpose of these tests is to characterize varieties in terms of yield and other attributes. Variety performance varies greatly from year to year and several site-years are necessary to adequately characterize the yield potential of a variety. A summary of small grain variety trials from previous years can be found online at http://ag.arizona.edu/pubs/crops/az1265.pdf.

Small plot replicate trials were established to test nineteen durum wheat varieties, three varieties of bread/feed wheat and six varieties of barley. D1856, an experimental, was the leading durum wheat variety, Cavalier from World Wide Wheat the highest yielding bread/feed wheat variety and Commander was the highest yielding barley. All three varieties were entries from World Wide Wheat. A three year summary is also provided in this paper.

The AZSCHED irrigation scheduling software was developed in the early 1990's to be used in a DOS environment on computers (1) and has been used extensively for irrigation scheduling on the Safford Agricultural Center since its development. The new Windows version of AZSCHED (2) was first tested for barley and wheat in 2003. This is a follow-up verification to the first test using a wider range of irrigation depletion levels.

Four herbicides and combinations of these herbicides with MCPA were evaluated for the control of Littleseed canarygrass in durum wheat. The currently registered herbicides, Achieve and Puma (not registered in Arizona) produced control levels of 80 to 95 percent with good crop safety. The new herbicides being developed, Osprey and Olympus produced higher and more consistent levels of control of 95 to 99 percent but caused slight to moderate crop injury. Combinations of Achieve and Puma with MCPA, a broadleaf herbicide, resulted in decreased control. When Osprey was tank mixed with MCPA, crop injury was increased.

Small grain varieties are evaluated each year by University of Arizona personnel. The purpose of these tests is to characterize varieties in terms of yield and other attributes. Variety performance varies greatly from year to year and several site-years are necessary to adequately characterize the yield potential of a variety. A summary of small grain variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1265.pdf.

Small plot replicate trials were established to test fifteen durum wheat varieties and thirteen varieties of barley (including six malting varieties from Colorado). Duraking from World Wide Wheat was the leading durum wheat variety with a yield just over two tons per acre. Max barley variety from World Wide Wheat was the highest yielding barley variety with a yield over two and three quarters tons per acre. A multi-year summary is also provided in this paper.

This research represents the first year of a project to determine when to irrigate barley based on soil water depletion levels. The purpose of this work is to establish the optimum irrigation timing based on depletion of plant available water in the soil. A field experiment was conducted at the Maricopa Agricultural Center testing irrigation of barley at 35, 50, 65, and 80% depletion of plant available water in the soil for two barley varieties, Baretta and Max. Grain yields averaged over the two varieties were 8415, 7735, 7512, and 4553 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate irrigating at 35% soil water depletion is optimal for barley grain yield.