Pre Tassel Nitrogen in Corn

Author: Angela McClure, Extension Corn and Soybean Specialist Comments Off on Pre Tassel Nitrogen in Corn

Our corn planting window was pretty strung out this year, ranging from end of March until close to the end of May.  Just wanted to include a few comments on nitrogen for those still needing to put out adequate amounts and those thinking about pre-tassel applications.

We have had an abundance of rain so far, and crop yield potential is looking decent at this point.  Our nitrogen recommendation has always been yield based where a rate is selected to support the yield potential of each field.  Most nitrogen goes on as a split timing with a portion being delayed until before V-6 stage.  Applying nitrogen pre tassel is new to many folks, but has been shown to create a yield bump of about 10 bushels in irrigated corn in research plots in west TN (2 years data).  In our research, we did not apply extra N as a pre tassel, we simply delayed the last 40 units until the pre tassel timing.  Where UAN can be applied through an irrigation system, this can be a cost effective way to increase yield by delaying some N of your planned rate.  Unfortunately, because of the higher costs involved in flying pre tassel N on, growers may end up swapping dollars, since the increased yield revenue is pretty much used up to cover aerial application cost and the cost of granular fertilizer.  (Note: Obviously, aerial application would make sense in rescue situations in fields that were not fertilized at planting or where the layby was missed due to weather and corn is too tall for a ground rig.)

As a general rule of thumb, corn will tassel about 60 days after emergence.  In years where we have had a lot of cloudy, cooler weather, Growing Degree units have not accumulated as quickly in early planted corn, so tassel emergence may be delayed by an additional week or more.


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