CERLIANI C, BOSSIO N, NAVILLE R, ROMANINI I, BALBOA G, ESPOSITO G.
Departamento de Producción Vegetal, Facultad de Agronomía y Veterinaria, Universidad Nacional de Río
Cuarto.
ccerliani@ayv.unrc.edu.ar
Presentado en: 7th World Congress on Conservation Agriculture. 2017.
In Rio Cuarto region (Cordoba, Argentina) corn is the most sown crop. Most of the crop is
grown in no tillage systems that improves soil structure and rise the organic matter as
consequence of the less mineralization and the stubble. As consequence of this more nitrogen
(N) fertilization is needed. There are different method to estimate N rates but none of them
takes in account the interaction with N and seeding rate (SD). The aim of this research was to
evaluate the interaction between dose of N and seeding rate. Four experiments were stablished
during 2016/17 growing season in Rio Cuarto Region. A combination of four N rates
(between 0 to 300 kg ha-1) and four seeding rates (between 30000 to 130000 seed ha-1) were
tested. The Agronomical Optimum N Rate (AONR) was determined for each seeding rate.
The criteria for the field selection included soybean as predecessor crop and at least 10 years
of no tillage system. The experiments were harvested with yield monitor connected to a GPS.
The data was analyzed with general models with spatial correlation. The results shown that
there was significate interaction between N and SD (p<0.0001). The response to N and the
AONR varied with SD in all sites. In site I AORN ranged from 115 to 147 kg N ha-1 for
40.000 and 90.000 seed ha-1, in site II the rage of rates were 159 and 187 kg N ha-1 for the
mentioned rates. In sites III and IV the AORN ranged from 0 to 300 kg N ha-1 for the low
and the high seeding rate evaluated respectively. N requirements increase while increasing
seeding rate and the magnitude of the increase was related to the site productivity.

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