ABSTRACT
Nitrogen use efficiency and dynamics in a rotation with and without use of residues

Erick Zagal1*, Nicasio Rodríguez2, Iván Vidal1 y Glenn Hofmann3
 

With the objective of studying N use efficiency and dynamics in a rotation with and without management of residues, a labeled-N (15N) experiment was established, in a volcanic soil (Typic Melanoxerand), under irrigation. 15N-labeled micro-plots were installed on a 4-year rotation. 15N was applied only once, as labeled fertilizer or residue, to later follow its fate in the rotation. Treatments applied were as follows: i) T1, rotation with incorporation of residues and inorganic labeled-N; ii) T2, rotation with incorporation of residues and organic labeled-N; iii) T3, rotation without incorporation of residues and inorganic labeled-N. The DM yields of T1 and T3 after two growing seasons, maize (Zea mays) - wheat (Triticum aestivum) was 32.0 and 30.7 t ha-1, respectively, and no significant differences were observed. In this study, maize residues were not a significant source of N for the next crops in the rotation. Incorporation of residues (additional C input) did not lead to higher N retention in the crop system studied for the period considered.

Keywords: 15N, crop rotation, irrigation, maize, wheat, volcanic soil.
1 Universidad de Concepción, Facultad de Agronomía, Casilla 537, Chillán, Chile. E-mail: ezagal@udec.cl *Autor para correspondencia.
2 Instituto de Investigaciones Agropecuarias, Centro Regional de Investigación Quilamapu, Casilla 426, Chillán, Chile.
3 Universidad de Concepción, Facultad de Ciencias Físicas y Matemáticas, Casilla 160-C, Concepción, Chile