Evaluation of nitrogen-fertilizer recommendation for annual crops in soils of volcanic origin using a simulation model

Erick Zagal V.1*, Juan Hirzel C.2 e Iván Vidal P.1

Fertilizer recommendation systems used to optimize nitrogen fertilization can be divided into three groups: systems based principally on soil analysis, systems based on plant analysis, and systems based on simulation models. One of the available models that describes N flows in plant and soil systems applicable to agricultural ecosystems is the "Rothamsted Model" (Rothamsted Nitrogen Turnover Model). This experiment used the SUNDIAL model, a PC-based version of the Rothamsted Model, to evaluate N-fertilization recommendations made by the technological transfer groups (GTTs) of Mulchén (37º42’ S lat and 72º14’ W long) and of El Carmen (36º51’ S lat and 72º01’ W long), considering the respective agricultural management systems. Nitrate leaching estimates were also determined for normal rainfall conditions. The results obtained indicate that the SUNDIAL model is sensitive to the agricultural management performed in foothill conditions for the crop rotations considered. Nitrogen dose rates and fertilization strategy used by the farmers coincide to those calculated by the model, showing acceptable yields and moderate nitrogen losses. The usefulness of the SUNDIAL computational model as a tool to generate nitrogen fertilization recommendations is discussed.

Keywords: crop rotation, nitrogen turnover, SUNDIAL model.
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. E-mail: jhirzel@inia.cl