Maize (Zea mays L.) potassium uptake, yield and root growth as affected by potassium rate, management and land slope

Potassium application at rates greater than that recommended by the Ontario Soil Management Research and Services Committee (OSMRSC) did not increase corn grain yield at either the Hart site in 2002 and 2003 nor at the Woodstock site in 2003. Importantly greater ear-leaf potassium concentration was found with higher potassium rates in all the three experiments. Deep-placed potassium did not show any advantage over broadcast application of potassium fertilizer in regard to corn grain yield or ear-leaf potassium concentration. High-input management (High N and P and higher plant population) increased corn grain yield at the Hart site only in 2002, but it did not affect ear-leaf, grain and stover potassium concentration compared to standard practice either in 2002 or 2003. Gross margins received with different potassium rates, potassium placement or management practices were found to be statistically identical. (Abstract shortened by UMI.)...