Contribución de la capacidad de mineralización del suelo al diagnóstico de requerimiento de nitrógeno en maíz

• PABLO CALVIÑO; HERNÁN ECHEVERRÍA; HERNÁN SAÍNZ ROZAS; REDOLATTI M. Y PABLO BARBIERI

Rosario, Santa Fe

Congreso; VIII Congreso Nacional de Maíz. Rosario; 2005

AIANBA

The objective of this paper was to evaluate if soil nitrogen mineralization capacity improves diagnostic methods used in the southeast of Buenos Aires province. The study was carried out in Azul, Tandil and Balcarce (Bs. As.) in 24 fields (on typical Argiudoll soils), under no-tillage with high residue cover. The treatments were a control (0-N) and three N rates that were determined adding to soil NO3--N content at planting the necessary quantity of N as urea to increase total soil N content up to 120, 160 and 200 kg N ha-1. The nitrogen mineralization capacity (Nan) was determined by a seven day anaerobic soil incubation. The grain yield ranged from 6.6 to 14.5 t ha-1. Using soil NO3--N content at planting, 95% of maximum yield was achieved with 131 and 162 kg N ha-1 for soils with high (Nan>48 mg kg-1) and low (Nan<48 mg kg-1) Nan, respectively. Using soil NO3--N content at six-leaf stage, 95% of maximum yield was achieved with 92 and 122 kg N ha-1, for the soils with high and low Nan, respectively. These results indicate that soils identification with high and low Nan would allow to quantify differences in the N rates to be applied. The quantity of N saved was approximately 30 kg N ha-1, which would justify the quantification of Nan.   Palabras clave: maíz, nitrógeno, capacidad de mineralización, métodos de diagnóstico. Key words: maize, nitrogen, mineralization capacity, diagnostic methods.