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Developing Sap Nitrate Tests for Wheat and Barley, Maricopa, 1998

The standard procedure for determining nitrogen (N) status in small grains is to sample lower stem tissue for nitrate (NO₃) analysis. The tissues are then submitted to a laboratory for analysis. Sap nitrate (NO₃) can be analyzed in the field, immediately after collecting the sample, using a Cardy meter. Guidelines for sap analysis have not yet been determined. The objectives of this study were to: (i) correlate NO₃-N in dried stem tissue with sap NO₃-N, and (ii) develop sap NO₃ test guidelines for N management in durum and feed barley. In November 1997 one variety of durum (Kronos) and one variety of feed barley (Gustoe) were planted at the Maricopa Agricultural Center. Three N rates (80, 200, and 400 lbs N/acre) were applied in four split applications. Each treatment was replicated five times in a randomized complete block design. Samples were collected from lower stems at the 3-4 leaf 2 node, flag leaf visible, and heading growth stages. Grain yields ranged from 5185 lbs/A to 7156 lbs/A for Kronos and 6314 lbs/A to 7517 lbs/A for Gustoe. Maximum yields were achieved at 200 lbs N/A for both varieties. Correlation coefficients between stem NO₃-N and sap NO₃-N were 0.79 for Kronos and 0.84 for Gustoe. Sap NO₃-N analysis can be used to determine N status during the season for both Kronos and Gustoe.

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/208252
Date10 1900
CreatorsRiley, E. A., Thompson, T. L., White, S. A., Ottman, M. J.
ContributorsOttman, Michael J.
PublisherCollege of Agriculture, University of Arizona (Tucson, AZ)
Source SetsUniversity of Arizona
Languageen_US
Detected LanguageEnglish
Typetext, Article
RelationAZ1059, Series P-114

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