Harris: Red Rain, Sidedress Nitrogen and Foliar Feeding

I have a friend, who is not involved in agriculture per se, who told me he thinks it’s interesting when farmers talk about getting a “red rain”. “You know, when they look at the radar and you got green and yellow and then that heavy red rain”.  Seems like we have gotten a lot of “red rains” across the Georgia cotton belt already in this 2023 growing season. This reminds me of 2021 or maybe more like 2013. In those years we got severely delayed with our sidedress nitrogen (N) applications with some cotton not seeing any nitrogen until well into bloom. Right now, in late June 2023, a lot of  Georgia cotton is between first square and first bloom which is the prime timing window to sidedress nitrogen. I don’t think it is time to panic. We may still dry off enough to get most of our sidedress nitrogen out by first bloom or soon after. If we keep getting rain, especially “red rains”, we will have more of a challenge.  But we have  more time on later planted cotton and we can always foliar feed some nitrogen if we have too. The good news is that overall we made a pretty good cotton crop in Georgia in 2021, and 2013 too.  I always say we have a better chance of making a good crop in a wet years than a dry or drought year.

So let’s talk about timing some more.  If you are familiar with the “4R’s of Fertilization”, you know that the right time, in addition to the right rate, right source and right placement is key to successfully fertilizing any crop. The official UGA Extension recommendation is to apply ¼ to 1/3 of your total N rate at planting, followed by sidedressing N between first square and first bloom.  We (UGA Extension) also recommend switching over to foliar feeding N after the 3rd week of bloom. Or in other words, no more soil applied nitrogen (by ground rig or through a center pivot) after this point.

So did you plant cotton on May 1 or June 1? Did you apply any preplant or at-planting N? Did you already sidedress your N? When did you sidedress?, more toward first square or first bloom?  All of these questions are important to consider.  For example, say you planted May 1, you applied 30 lb N/a preplant, and you have been squaring for two weeks. You haven’t been able to get in the field to sidedress with N yet. You should still have another week until bloom so as long as it dries out some then you still have time. And, since you applied some preplant N you can sidedress more toward first bloom than first square.

If you have already applied your sidedress N and have gotten some of these “red rains” you could consider replacing around 30 lb N/a if it dries out enough to get in the field before the third week of bloom. If you get to the third week of bloom and still can’t get in the field with a ground rig you could consider foliar feeding N. It may take a few doses of a decent rate (10 lb N/a each time you foliar) but it can be done (with a ground rig).

And are there any magical products that you can fertilized when the crop is waterlogged and not growing? I think you know how I am going to answer that one.  There are just some things you can’t fertilize your way out of. Nematodes is one. Waterlogging is another.

And now for the worst case scenario… what if it keeps raining and I can’t get into the field and its 3rd week of bloom and I still haven’t gotten any sidedress N out? This situation occurred a lot in 2021. In fact, I wrote an article similar to this one in 2021..but it was in August.  Hopefully we will not get into that situation again in 2023. But if we do… the crop is going to look significantly worse than it is now, it will be taller and more yellow and basically starving for N. Should you soil apply nitrogen sidedress or try to just foliar feed with N.  Foliar feeding nitrogen should be seen as a way to supplement a good soil applied but it cannot replace sidedressing. You just can’t foliar feed enough N to carry the whole crop to a decent yield if you don’t have any sidedress N out. Or I should say the odds are not in your favor.

And finally, you may have noticed I have not mentioned sidedressing with potassium (K), or leaching of potassium with these “red rains” and having to replacing it.  The reason is that I still firmly believe in applying all my recommended potassium at planting and then foliar feeding with K if needed.  This eliminates the problem of getting delayed with your sidedress K. And K is not the same as N. It does not leach as readily as N and I think it foliar feeds a little better. That’s the good news. It’s not too late yet. It’s not time to panic. We want it to stop raining but not stop too much right? Be careful what you wish for. I wish the weather would cooperate so we can make the best Georgia cotton crop ever in 2023!

Glen Harris
Professor and Extension Agronomist – Cotton Soil Fertility
University of Georgia

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