High Yield Corn Response to Micronutrient-Enhanced Potassium Fertilizer Under Intensive Management.

Corn high yield management systems including improved stack hybrids and production practices especially planting at high populations has increased the need for balanced crop nutrition. Micronutrients such as boron (B) are crucial for cell growth, reproductive development, and to increase yield. Role of B in high stressed situations has shown to be beneficial in various studies. We investigated the effect of Murate of Potash (MOP) and Aspire™ (MOP+B) on Corn (Zea mays) yield under high yield management systems. The high yield management practices included hybrid with triple stack technology, planting population of more than 40,000 plants/ac, fungicide application at R1 and higher N (269 kg N/ha), P (112 kg P₂O₅/ha) and K (84 kg K₂O/ha) rates. Small plot field experiments were established at 31 locations across United States in 2011-14. Experiments were conducted in a randomized complete block design with four replications. In another study conducted at 5 locations in United States, MOP and Aspire were tested at different populations (64 K, 79K, 94K and 109 K plants/ha) in a factorial treatments structure.  P and K fertilizers were applied as pre-plant broadcast and incorporated; N was split as 60% at planting and 40% as side dress. Results showed that over 4 years of study Aspire improved corn yield by 551 kg/ha with a 71% win rate for total 31 sites. The response to Aspire ranged from 282 kg/ha to 627 kg/ha and was very consistent across 4 years.  For varying populations study conducted in 2014, response to Aspire™ increased with increasing plant populations.  At population of 64 K plants/ha there was no response to Aspire and applied Boron, however, the response to Aspire increased at 79 K (52 kg/ha), 94 K (290 kg/ha) and 109K (668 kg/ha) plants/ha.  Increased response to Aspire with increasing populations indicates the importance of B and balanced crop nutrition to meet the needs of a dense population in corn high yield management systems.