A comparison of two nitrogen credit methods: traditional vs. difference
Cereals and other nonlegumes typically require less fertilizer N when grown following a legume. Nitrogen credits for a previous legume crop often are used to reduce fertilizer N recommendations in combination with other site-specific information. Researchers continue to use two methods of determinin...
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Published in | Agronomy journal Vol. 87; no. 4 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
01.07.1995
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Subjects | |
Online Access | Get more information |
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Summary: | Cereals and other nonlegumes typically require less fertilizer N when grown following a legume. Nitrogen credits for a previous legume crop often are used to reduce fertilizer N recommendations in combination with other site-specific information. Researchers continue to use two methods of determining N credits, the traditional and difference techniques, which often produce unequal estimates. Our objective was to clarify when each method provides accurate N credit estimates. The traditional method compares yield of a nonfertilized nonlegume crop grown in rotation to the fertilizer N response curve of the continuously cropped nonlegume. This approach assumes that fertilizer N compensates for all benefits of rotation. The difference method compares the economic N rate of the nonlegume crop grown in rotation with that of the continuously cropped nonlegume. We use examples from the literature to demonstrate that when non-N rotation effects are present, N credit estimates from the two methods will differ. The difference method is more accurate and should be used unless it has been demonstrated that non-N rotation effects are not present |
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Bibliography: | 9562780 F04 F08 |
ISSN: | 0002-1962 1435-0645 |
DOI: | 10.2134/agronj1995.00021962008700040007x |