Response to Zinc in Maize Crops in the Argentinian Pampas

Grain crops of the Pampas region of Argentina, mainly maize, have shown Zn deficiencies. However, research on Zn responses in maize is scarce. The objectives of this research project are to: 1) quantify maize response to Zn in the Pampas region, 2) determine the optimum Zn rate for corn, and 3) validate local Zn analyses and critical levels. Eight field experiments were carried out in the 2009/10 season at different locations of the Pampas regions, including: A. Ledesma, Guatimozin, and Chaján in Cordoba; San Justo and M. Teresa in Santa Fe; and Pergamino, 9 de Julio, and Balcarce in Buenos Aires. Treatments include different Zn rates (0, 0.5, 1, 1.5, and 2 kg Zn/ha) under NPS fertilization. Zinc sources included chemical blends of P+S+Zn as MicroEssentials (MESZ)^®.

Visual deficiency symptoms were observed in most locations. Results in this first season of experimentation showed significant grain yield responses in six of the eight sites. Average grain yields for the six experiments with significant response were 11,968, 12,078, 12,500, 12,312, and 12,665 kg/ha for the 0, 0.5, 1, 1.5, and 2 kg Zn/ha rates, respectively. Optimum Zn rates varied between 0.5 and 1.5 kg Zn/ha, depending on the location. New experiments will be established at different locations in the 2010/11 growing season. Argentina-29