Obtaining optimal yields of spring wheat in Arizona normally requires applications of fertilizer nitrogen (N), and occasionally phosphorus (P). The University of Arizona currently recommends preplant soil tests for NO₃-N and P, plus periodic stem tissue NO₃-N analyses to predict the N and P needs of wheat. Preplant application of P within the root zone of growing plants is suggested due to the immobility of P in soils. Split applications of N broadcast to dry soil preceding irrigations are generally recommended. Collecting additional data to calibrate and refine current guidelines for interpreting soil and plant test values is an ongoing need in Arizona. An experiment was conducted at the Safford Agricultural Center during the 1986-87 crop year to evaluate the response of "Aldura" durum wheat to banded and broadcast N and P, and split applications of N on a clay loam soil testing low in NO₃-N and available P. Maximum grain yields of over 4,500 lbs./A were obtained by banding of 40 lbs. P₂O₅ /A and 32 lbs. N/A as 16-20-0 at planting and broadcasting 118 lbs. urea-N/A prior to seeding. Stem tissue NO₃-N analyses revealed that N deficient conditions prevailed throughout the growing season in all fertilizer treatments. Treatments in which the preassigned rate of N was split into three applications produced the lowest yields due to serious N deficiency early in the season. The stem NO₃-N tissue test proved accurate in predicting N status and a stem. PO₄-P tissue test seemed reliable in monitoring P nutrition of durum wheat.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/203805 |
| Date | 09 1900 |
| Creators | Knowles, Tim, Doerge, Thomas, 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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