Respuesta del cultivo de trigo al agregado de cinc y cobre en suelos del sudeste Bonaerense

HERNÁN R SAINZ ROZAS, HERNÁN E ECHEVERRÍA, CALVIÑO PABLO A, PABLO A. BARBIERI, REDOLATTI MIGUEL.

Ciencia del Suelo

Asociación Argentina de la Ciencia del Suelo

Lugar: Bs As; Año: 2003 p. 52 - 58

0326-3169

In the southeast of the Buenos Aires Province (Argentina) agricultural soils have been intensively used and wheat productivity increased in the last two decades. Therefore, nitrogen and phosphorus fertilization is an usual practice in wheat production. However, some micronutrients like zinc (Zn) or copper (Cu) considered not restrictive can be limiting for more intensive management practices. The objective of this work was to evaluate wheat yield response to zinc and copper fertilization during two years (2000-2001) in 19 farmer fields. In each field a randomized completely block design with three replications was carried out. Experiments were conducted without deficiencies of nitrogen (N), phosphorus (P) and sulfur (S). In 2000, treatments were: NPS and NPS plus 7.2 kg ha-1 of Zn and 7.0 kg ha-1 of Cu (NPS+Zn+Cu). In 2001, treatments were: NPS, NPS plus 7.2 kg ha-1 of Zn (NPS+Zn) and NPS plus 7.0 kg ha-1 of Cu (NPS+Cu) and NPS plus 7.2 kg ha-1 of Zn and 7.0 kg ha-1 of Cu (NPS+Zn+Cu). Grain yield was increased by micronutrient addition only in 4 sites (between 246 and 890 kg ha-1), and negative responses in one site. In both years, a significant and linear relationship between yield response to micronutrient and soil Zn concentration (Melhich-3) determined at sowing (ZnMh-3) was observed (y= 899.2 – 157.8 x ZnMh-3; r2= 0.39). No relationship was found between yield response and soil Cu content (Melhich-3) at sowing. Therefore, the Zn availability would have limited wheat grain yield. When soil pH was included as a variable to ZnMh-3, grain yield response was better explained (y=  -977.7 – 158.1 x ZnMh-3 + 313.9 x pH; r2= 0.51). The results indicate that Zn availability and soil pH must be used like diagnostics to estimate wheat Zn fertilization needs in soils of southeast of Buenos Aires. Key words: Zinc, copper, fertilization, Triticum aestivum.