Evaluation of nitrogen sources (15N) in three wheat varieties in an andisol and an ultisol in the IX Region. I. Effect on yield, N absorption and N efficiency

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

During 1988/1989 the effect of nitrate and ammoniacal fertilization was studied on yield. yield components, absorption and efficiency of N according to the conventional methods in two wheat varieties in an Ultisol and one variety in an Andisol of the IX Region of Chile.
In the three trials the statistical design used was completely randomized blocks where the sources ofNwere the treatments: sodium nitrate. urea and ammonium nitrate. In the Andisol the wheat variety used was Laurel and in the Ultisol Dalcahue and Perquenco varieties were used. The rate of N was 160 kg N ha-1.
The application of N had a significant effect on yield in the three environments. For Dalcahue this effect was obtained with sodium nitrate and for Perquenco and Laurel there were not significant differences between nitrogen sources.
The results in the Ultisol show different behavíor between varieties, with a better response of Perquenco according to N application but a lower yield in relation to Dalcahue. The higher yield was obtained with Laurel in the Andisol. and also the higher total N absorption, AE and AFE, in accordance with the yield obtained.

Keywords: agronomic efficiency (AE), fisiological efficiency (EF). apparent fertilizer efficiency (AFE), wheat. N-fertilizers, harvest index (IC).
1 Centro Regional de Investigación Carillanca (INIA), Casilla 58-D, Temuco, Chile.