Fast- and Slow-Release Boron Co-Granulated with Potash: An Improved Method for B Application.

Greater yields associated with enhanced agronomic management and superior genetic performance has accelerated the rate of nutrient accumulation, especially for micronutrients such as boron (B). Approximately 40% of total B accumulation in maize (Zea mays L.) occurs after the onset of seed-fill. Common granular B nutrient sources are often blended with other macronutrients and realize limited effectiveness due to poor nutrient distribution. The need for season-long B availability and uptake through plant roots led to the development of a fast (i.e., sodium borate) and slow (i.e., calcium borate) release B source co-granulated with potash (Aspire_EXP, 0-0-58-0.5B). The objective of this research was to understand how different B sources and soil characteristics influence maize responsiveness to improved B management. Aspire_EXP outperformed MOP+B treatments in fall trials (n=6) by 75 kg ha^-1 and spring trials (n=25) by 69 kg ha^-1. Correlation matrices between soil characteristics and yield responses continue to demonstrate that prediction of B response is difficult, although low soil test B, low CEC, or high rainfall environments may enhance the probability of a response. Initial findings suggest that the distribution properties and multiple B sources in Aspire_EXP may serve as a viable agronomic solution for B management on maize, while follow-up research will improve understanding across more B-responsive crops such as alfalfa, potato, canola, and soybean.