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Sunflower Nitrogen Requirement and N Fertilizer
Recovery in Western Pampas, Argentina |
Autores: Javier D. Scheiner, Flavio H. Gutiérrez Boem, Raúl S. Lavado
Cátedra de Fertilidad y Fertilizantes, Facultad de Agronomía, Universidad de
Buenos Aires
Trabajo presentado en: European Journal Agronomy 17 (2002) 73-79
In order to avoid nitrogen overfertilization, fertilizer rates must be adjusted to meet crop requirements. Two field
experiments with sunflower (Helianthus annuus L.) were performed in the western part of the Pampas, Argentina, to:
(i) assess nitrogen fertilization effects on seed yield, grain oil content, and plant lodging, (ii) determine N requirement
per unit of yield, crop recovery of fertilizer N, and whether these two parameters were affected by N and other
nutrient additions. Nitrogen fertilization increased the seed yield only by 17% at one site. Crop nitrogen requirement
per unit yield (b-value) increased from 37 to 42 kg Mg−1 due to nitrogen fertilization only at the site where there was
not a yield response. Therefore, if a yield response is expected, it is not necessary to use different b-values for non
fertilized or fertilized crop. Reduction of seed oil content due to N addition was relatively small (2–5%), and was
overcompensated by the seed yield increase at the responsive site. Recovery of fertilizer 15N was of 51%. This
efficiency of absorption should be considered for making fertilizer recommendations. Application of further nutrients
including P and K had no influence on seed yield. © 2002 Elsevier Science B.V. All rights reserved.
Keywords : Sunflower; b-Value; Nitrogen fertilization; 15N recovery
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