The high yielding spring wheats grown in Arizona usually require applications of fertilizer nitrogen (N) to achieve optimum grain yields and acceptable quality. The University of Arizona's currently recommended procedure (preplant soil plus periodic stem tissue analysis for NO₃-N to predict the N needs of wheat) is not widely used by Graham County growers for various reasons. A nitrogen fertility trial was conducted at the Safford Agricultural Center during the 1986-87 crop year to: 1) examine the relationships between basal stem nitrate-N levels, grain yields of durum wheat, and N fertilizer rates; and 2) to test the accuracy of the recommended procedure for predicting the N needs of durum wheat. Five rates of N from O to 419 lbs N /acre were applied in three split applications. One additional N treatment was made as indicated by the current University of Arizona procedure. Maximum grain yields of 5500 to 6200 lbs /a and protein levels in excess of 14.5% were attained with the application of at least 186 lbs NIA. An untimely early season irrigation induced a temporary N deficiency condition for all plots, which may have kept grain yields below the maximum yield possibility for this site. In spite of this, the amount of N predicted by the University of Arizona procedure (197 lbsN/acre) did attain an adjusted economic return which was not significantly different from the maximum numerical yield that was achieved for any of the other N treatments.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/203767 |
| Date | 09 1900 |
| Creators | Doerge, Thomas, Knowles, Tim, Ottman, Mike, Clark, Lee |
| Contributors | Ottman, Mike |
| Publisher | College of Agriculture, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Relation | 370071, Series P-71 |
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