A field experiment was conducted on a Trix clay loam at the Maricopa Agricultural Center to 1) determine the optimum rates of late season N needed to achieve optimum yield and quality of irrigated durum wheat in conjunction with varying rates of early season N, and 2) to evaluate the usefulness of stem NO₃⁻N analysis in predicting the late season N rates which optimize grain production but minimize the potential for nitrate pollution of groundwater. The application of 75, 150 and 300 lbs. N/a during vegetative growth resulted in wheat with highly deficient, slightly deficient and excessive N status at the boot stage as indicated by stem NO₃⁻N analysis. The application of 60 lbs. N/a at heading to highly N-deficient and slightly N-deficient wheat resulted in grain protein levels of 12.7 and 14.3 % respectively but had little effect on grain yield. Applications from 0 to 60 lbs. N /acre at heading to wheat which had previously received excessive N did not affect grain yield but did increase grain protein levels from 15.2 to 17.4 %. The use of stem NO₃⁻N analysis appears to be a useful tool in predicting the minimum N rate to be applied during the early reproductive period to insure acceptable levels of grain protein at harvest in cases where N status during the vegetative period was not highly deficient.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/201382 |
| Date | 09 1900 |
| Creators | Doerge, T. A., Ottman, M. J. |
| Contributors | Ottman, Michael |
| Publisher | College of Agriculture, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Relation | 370090, Series P-90 |
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