So, after picking the best cotton varieties for your farm, what are some of these practices that can help capture high yield potential? It may sound extremely “old hat” but getting good soil samples and following the recommendations closely is a great start.
There seems to be more and more “precision ag” grid or zone soil sampling happening and more variable rate lime and preplant fertilizer applications conducted. If lime is called for to raise a pH and you get delayed, say, due to wet weather, it is still “better late than never.”
Apply The Lime
Think about it. If you have a low pH, the only way you can bring it up is to lime. We used to say go ahead and lime fields six months in advance. Now we say three months. What if you get delayed and you only have one month? Put it out! I have actually seen cases where lime was applied soon after planting cotton, and it brought the pH up just high enough and fast enough to avoid a disaster. Nitrogen (N) management is another key to getting a cotton crop off to a good start. The official University of Georgia recommendation is to apply up to one-third of your total N rate at planting and the rest at sidedress between first square and first bloom. This typically equates to around 30 pounds of N per acre at planting and 70 pounds of N per acre at sidedress.
Can I put all of my N out at planting? No. This will likely cause too much vegetative growth early, and then you’ll run out of N later. Can I get all my preplant N in a starter placement? This is tricky since too much N in a traditional “2 x 2” placement can potentially reduce your stand. A common treatment in the Southeast is 10 gallons per acre of 10-34-0 in the “2 x 2” placement. This approach gives roughly 10 pounds of N per acre, which is short of the 30 pounds of N per acre needed.
Proceed With Caution
It is tempting to “spike” the 10-34-0 with an additional 20 pounds of N per acre at something like 28-0-0-5 (S). However, even though you may get away with this under certain conditions (good placement and good soil moisture), it also has the potential under dry conditions.
The phosphorous in 10-34-0 can also be critical since it is very important to early season root seedling root growth. And in the absence of Temik, under certain conditions like early planting when it is cool and/or wet, starter fertilizers can really pay off in terms of avoiding thrips damage.
Contact Glen Harris at the University of Georgia’s Tifton campus at (229) 386-3006 or gharris @uga.edu.