The effect of split applications of nitrogen on corn yield under ridge and no-till conditions

Trials were carried out on two farms in Huron County to examine the relative merits of splitting the timing of the application of nitrogen fertilizer between planting and sidedress applications. Current findings have been that in southwestern Ontario sidedress applications of nitrogen have a yield advantage over preplant applications. Thus more nitrogen must be applied if the total season application is applied on or before the date of planting, relative to where a large portion of the nitrogen is applied later in the season, closer to the time of consumption by corn. The experiments involved applications of 0, 20 and 40% of the seasonal application of nitrogen at the time of planting, with the remainder of the nitrogen sidedressed. Trials were carried out in each of a no-till and ridge-till system. There was no evidence from these trials to support the practice of splitting nitrogen applications or for the application of the entire season's nitrogen at sidedressing. However, in light of this study having been limited to one year's data collection, further testing may be warranted to more thoroughly examine the relationship of nitrogen timing and crop nutrition and grain yields.