1. Effect of Time of N Application for Corn

The economic benefit associated with the application of N fertilizers for corn has been known for over 5 decades. As a result, over 99 % of the farmers in Illinois apply N fertilizers when corn is grown. Unlike phosphorus and potassium, there is no good soil test to predict the amount of N needed, instead, farmers use a factor times yield potential with appropriate credits for legume and other N sources to set N rates. While this works well over a number of years, there are years when less N wil...