An Introduction to the Use of Reference Strips for Nitrogen Management in Durum Wheat

Although nitrogen (N) fertilizer input is high in durum wheat, growers in Arizona often find it difficult to apply an adequate amount of N at the right time to produce desirable grain yield and protein content. Many growers use fixed N fertilizer programs to manage durum wheat crops. In these programs, N fertilizer can be under- or over-applied in the field due to differential crop growth and N demand from year to year. For example, durum wheat planted following alfalfa, cotton, or grain sorghum can have very different N requirements. When crop yield is high due to favorable growing conditions, N fertilizer applications from fixed programs are often not sufficient for the crop to attain the desirable 13% protein content. When crop yield is low, N fertilizer is often over-applied in fixed programs, resulting in protein contents higher than 13%. In either case, growers’ profitability is reduced.