Normally, I would be sounding the wheat topdress alarm in early January. When you have 5.5 million acres to cover, it is important to start early. However, this year we have mostly kept the topdress rigs in neutral with a wait and see approach due to the drought. The recent rain brought life to portions of the Oklahoma wheat belt and it is time to make a decision regarding topdress nitrogen. I have posted three slide presentations with audio regarding topdressing wheat at my YouTube channel available by clicking here or by searching YouTube for OSU Small Grains. I have listed some additional facts and items to consider below.
- In order to have full benefit, nitrogen must be in the rooting zone by the time wheat is jointing. Jointing occurs around the first of March in southern OK and around the second week of March in northern OK.
- On average it takes about 2 lbs/ac of N for every bushel of wheat yield. In addition, dual-purpose wheat requires 30 lbs/ac of N for every 100 lbs/ac of beef removed. You can subtract your soil test NO3-N from these total requirements.
- It is okay to adjust topdress N plans based on your current yield potential. When you submitted your soil test, you might have stated a 50 bu/ac yield goal which would require 100 lbs/ac of nitrogen; however, it is important to take a hard look and determine if this yield goal is still realistic based on your current crop status. I am not suggesting to adjust based on what you think the weather might do, but it is okay to take inventory and adjust your topdress N up or down based on current field conditions.
- Don’t have an N-rich strip? It would be a lot cooler if you did. An N-rich strip would take the guess work out of adjusting your topdress N up or down based on your current crop conditions. Your county extension educator can provide more information on N-rich strips and you can find more information on the web at www.npk.okstate.edu