Durum wheat (Triticum turgidum L. var. durum ) is grown as a winter annual crop, normally in rotation with cotton, and in 1989, comprised 121,500 acres in Arizona. Winter rainfall is insignificant, therefore water is supplied totally through surface irrigation. The relationship between the timing and amount of irrigation water applied and grain yields have not been well -defined Field plot studies were conducted in 1986 and 1987 to test the feasibility of using the Crop Water Stress Index (CWSI) to time wheat irrigations and also to determine the relationship among the CWSI, grain production, and water applied The study was repeated at the commercial production level with a grower cooperator in 1989 to determine the usefulness of CWSI scheduling on large farms. Highest grain production was attained when irrigations were scheduled when the CWSI averaged 0.37 and 0.30 units on small plots for 1986 and 1987, respectively. At the grower production level, highest yields were attained when irrigations were scheduled when the CWSI averaged 0.17 units. In 1986 and 1987 scheduling irrigations at lower CWSI values did not significantly increase grain production while requiring more applied water than the optimum CWSI values. Scheduling irrigations at CWSI's exceeding the optimum values did significantly reduce grain production from the optimum, but required less applied water in all three years.

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Labeled nitrogen fertilizer (N-15) was applied to wheat to determine fertilizer nitrogen movement in the soil at harvest. Most of the labeled fertilizer recovered in the soil was found in the surface few feet. The amount of nitrogen fertilizer detected below S feet was minimal.

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Durum wheat was grown with deficient, adequate, and excessive rates of ¹⁵N-labeled nitrogen fertilizer in order to document fertilizer nitrogen movement in the soil with differing nitrogen management. Crop water use increased with nitrogen rate due to increased vegetative growth. The amount of excess water applied increased with a decrease in nitrogen rate. Soil bromide concentrations at harvest suggest that the maximum potential depth of leaching was 3 to 6 feet. Most of the fertilizer applied in this study was recovered in the top 2 to 3 feet of soil. Fertilizer nitrogen rate and timing resulted in some differences in recovery of labeled fertilizer in the soil and plant, but did not contribute significantly to the depth of fertilizer nitrogen leaching.

Ten varieties of barley were tested at the Safford Agricultural Center in 1994. Gustoe, the standard variety for the area, was the highest yielding variety in the trial.