I remember doing meetings when fertilizer prices spiked in 2008 and fielding the popular questions “how are we going to deal with these fertilizer prices?” And “where can we cut?” The answers are not easy, as you might remember. And some of the same “strategies” or ideas for how to deal with high fertilizer prices have come up again. Things like legume cover crops for nitrogen, using chicken litter and banding phosphorous and potassium at reduced rates. While these ideas may have some merit, in my opinion there are no “silver bullets”.
For example, legume cover crops do fix nitrogen from the air for free…but the seed isn’t free nor is the cost of establishment. And if you plant too early you may aggravate a nematode problem and if you plant too late you may not get enough growth from the cover crop. Ultimately, you hope to get around a 50 lb N/a nitrogen credit.
Chicken litter is similar in respect that you need to look at the cost or value. When fertilizer prices increase, so does the value of the litter. So if you can purchase chicken litter in 2022 at 2020 prices than it should be a good deal. Even then, chicken litter is best used on cotton as a preplant fertilizer to provide most (if not all) of your P &K and enough N to get started. Two tons of chicken litter per acre at planting followed by 50-60 lb N/a commercial fertilizer N at side dress is a good basic strategy.
“If you band your P&K at planting then you can reduce your rate by ¼ to ¼”. While this sounds like a great strategy and is a great way to sell a fertilizer banding machine, this statement may or may not be true. Current UGA research shows there is no yield advantage to banding P&K at planting if your soil test P&P levels are medium or higher. Yes, sometime when you band P&K you can reduce the rate and not reduce yield…but you could have reduced the rate and broadcasted the fertilizer and not reduced yield as well. And there is a possibility that if you reduce your rate and band P&K you can reduce yield. In other words, yield had more to do with rate of application rather than application method.
So lets talk about some basic practices that should definitely help weather these high fertilizer prices…like soil testing. You might think, I’ll skip soil testing this year and save that money. Bad idea. It’s more critical this year than ever to get your soil pH and nutrient recommendations right to achieve optimum economic yields. Sure in the Midwest they can don’t have to soil sample every year. But their soils are more fertile and more buffered. Soil pH and potassium levels can drop quickly on our south Georgia sands and lead to poor utilization of fertilizer nutrients and poor yields.
“But I’ve been grid soil sampling every year, can I skip a year?” That’s a tough question that I will answer by saying “maybe”. If you have also been variable rate applying lime and P & K and have eliminated your trouble spots in your field then I’ll say “yes, probably”. Looking at this form the opposite viewpoint, what if you have never grid soil sampled or variable rate applied lime and fertilizer, should I use these precision ag tools this year? I will say “yes”. For the simple reason that you will more than likely fix some problem areas in your fields that are holding you back from making optimum economic yields.
Once you soil test and variable rate lime to correct pH problems I would say fertilizing with N-P-K by yield goal is the most important thing you can do to survive the current high fertilizer prices. Forget about the unproven products (some call them snake oils). Let’s face it, when it comes to fertilization, N-P-K make the yields. And on Georgia cotton, I would say it’s probably N then K and then P in that order. But they are all important. These are the “big three “. And finally, timing of application of the Big3 is important also. Phosphorous needs to be applied at planting since it is important to early season root growth. Potassium also needs to be applied at planting since recent UGA research shows there is little advantage to “split applications” of K in most situations. Nitrogen is the nutrient that needs to be split applied on Georgia cotton, ¼ to 1/3 at planting and the remainder at side dress between first square and first bloom. This will assure that you have enough N to get started but not too much to interfere with early fruiting, and also assure you have enough N later in the season to finish to the top crop.
Glen Harris