Corn Response to Zinc and Fertilizer Source.

The objective of this study was to determine if zinc (Zn) limits corn yield in the Argentine Pampas and to compare nitrogen, phosphorus, and sulfur (NPS) sources. The experiments were conducted at nine sites during the 2007/08 and 2008/09 corn growing seasons. Treatments consisted on an unfertilized control, a NPS physical blend, a compound NPS fertilizer (MES10) at the same PS rate as the blend, and a NPS compound fertilizer with 1% Zn (MESZ) applied at the same PS rate. Fertilizer was banded at planting. Soil samples were collected before planting and analyzed for nutrient concentration. On average across locations, MES10 significantly (p<0.05) increased corn yield over the NPS treatment by 440 kg/ha (4.1%). Corn grain yield was significantly higher (p<0.1) for MESZ than MES10 at four sites, indicating a response to Zn. Three of these sites had soil available Zn lower than 0.8 ppm and one higher than 1 ppm. These results are the first evidence of corn yield response to zinc fertilization in the Pampas and indicate that this micronutrient is becoming a yield limiting factor in Argentina.