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.

Solum is a barley bred for reduced water use that tends to have low test weight. An experiment was conducted at the Maricopa Agricultural Center to determine the effect of the number of irrigations and their timing on test weight and grain yield of Solum barley. Applying an irrigation at planting and a second irrigation at jointing resulted in the lowest test weight (44.4 lbs/bu) and nearly the highest grain yield (4315 lbs/acre) recorded in the test. All other irrigation treatments resulted in acceptable test weights above 48 lbs/bu except for irrigating at planting plus tillering, which resulted in 47.0 lb/bu test weight. Irrigating at planting and then delaying the second irrigation until boot or later resulted in acceptable test weight but decreased grain yield by 9% or more compared to applying the second irrigation at jointing. Grain yields similar to that obtained by applying a second irrigation at jointing was obtained by delaying the second irrigation until boot and applying a third irrigation at milk or soft dough. This experiment will be conducted a second year before conclusions are drawn.

This research represents the second year of a project to determine when to irrigate wheat 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 wheat at 35, 50, 65, and 80% depletion of plant available water in the soil for two durum varieties, Kronos and Westbred 881. Grain yields averaged over the two varieties were 6787, 6494, 5460, and 3067 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate irrigating at 50% soil water depletion or less is optimal for wheat grain yield.

Small grain varieties are evaluated each year by University of Arizona personnel and industry cooperators. 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. The results contained in this report will be combined with results from previous years in a summary available from Arizona Cooperative Extension.

Small plot replicate trials were established to test thirteen durum wheat varieties, seven varieties of bread/feed wheat and nine varieties of barley. Platinum was the leading durum wheat variety with a yield of 4550 pounds per acre and Experimental BR 4836 from World Wide Wheat the highest yielding bread/feed wheat variety with 5893 pounds per acre. Patti was the highest yielding barley variety with a yield of 4724 pounds per acre.

Small plot replicate trials were established to test thirteen durum wheat varieties, nine varieties of bread/feed wheat, and five varieties of barley. Trump was the leading durum wheat variety with a yield of 3470 pounds per acre. Stander, a variety from Resources Seeds Intl in California, was the top producing wheat variety with a yield of 5780 pounds per acre and Max produced the highest barley yield with 5792 pounds per acre. Except for the durum varieties, most varieties in the study produced reasonable yields in 1999.

Research has not been conducted in Arizona to determine when to irrigate wheat 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 wheat at 35, 50, 65, and 80% depletion of plant available water in the soil for two durum varieties, Kronos and Westbred 881. Grain yields averaged over the two varieties were 6479, 5099, 4283, and 4145 lbs/acre for the 35, 50, 65, and 80% depletion levels, respectively. The results of this study indicate that more frequent irrigations may be required than is typically practiced to optimize wheat grain yields in Arizona. This work will be repeated during the 1999-2000 growing season and the results from both years will be evaluated before general conclusions are drawn.

Small grain varieties are evaluated each year by industry and 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. The results contained in this report will be combined with results from previous years in a summary available from Arizona Cooperative Extension.

Solum is a barley bred for reduced water use that tends to have low test weight. This is the second year of an experiment conducted at the Maricopa Agricultural Center to determine the effect of the number of irrigations and their timing on test weight and grain yield of Solum barley. A single irrigation resulted in low yield (2043 lbs/acre) and unacceptable test weight (45.2 lbs/acre). Two or three irrigations increased yield and test weight in most cases. Applying a second irrigation at the 1 node, 2-3 node, or boot stages resulted in yield of 2694, 2877, and 2670 lbs/acre and test weight of 48.5, 49.0, and 49.5 lbs/bu, respectively. Applying a second irrigation at boot and a third irrigation between flowering and soft dough resulted in an average yield of 3008 lbs/acre and an average test weight of 50.0 lbs/bu. Delaying the second irrigation of Solum barley until boot reduces the risk of lodging and low test weight, and results in high yields.

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. The results contained in this report will be combined with results from previous years in a summary available from University of Arizona Cooperative Extension.