Evaluation of nitrogen sources (15N) on three wheat varieties in an andisol and an ultisol in the IX Region. II. Isotopic parameters and fertilizer use efficiency

Inés Pino N.1, Amelia Peyrelongue C.2 y Mirta Buneder B.1

A field study was carried out in order to evaluate different N fertilizers sources in three wheat varieties, considering an Andisol and an Ultisol soils, in the IX Region of the country. The dilution isotopic techniques was used, with AS, 10% at. exc., at rates of 20 kg ha-1 of N. The isotopic parameters such us N in the plant derived from the nitrogen sources, the N in the plant derived from the soil, the fertilizer use efficiencies and the agronomic evaluation between them were determined. The Nddfu (%) was associated to the varieties and to the soils. In the Ultisol, Dalcahue variety had a better behaviour with SS and, in the Andisol, Laurel variety showed an special affinity with U. In the three varieties, the higher % of N derived from the sources it was in the grain, showing Dalcahue variety a better translocation. The fertilizer use efficiency (FUE) and the physiological efficiency, determined according the isotopic parameters, were higher than the values determined according the convencional methodology.

Keywords: N-fertilizers, isotope dilution, whea1.
1 Comisión Chilena de Energía Nuclear. Casilla 188-0, Santiago, Chile.
2 Centro Regional de Investigación Carillanca (INIA), Casilla 58-O, Temuco, Chile.