The Latest

Flint on Crops: Late Cotton Needs More Summer – Commentary

Ernst Undesser
By Ernie Flint, Mississippi State University September 4, 2017

Flint on Crops: Late Cotton Needs More Summer – Commentary

Cotton field in bloom, Chattanooga, Oklahoma. Photo: Michele Kinder

One of the statements that I have made many times through the years to cotton growers is “The cotton plant knows more about producing cotton than any of us ever will”. I still believe that today as we endure one of the coolest and most fall-like Augusts I can recall.

We have cotton that was planted all the way from the first week of April to the first week of July. That’s right, I said July. Yesterday I saw a field that had been defoliated while others are far from that point.

Thankfully those acres that were planted latest are located in the far southern portion of the state and will have more time to mature than in the central or northern areas. Quite a lot of our crop was planted in late May or in the first ten days of June, so these fields and especially those few planted even later need at least another two to three weeks of summer type weather.

In the days when we were working with the prediction models we were able to estimate maturation to a fairly good degree. The problem was that those models attempted to understand one of the most complex crops in the world. The input data was the issue that influenced how well the models were able to anticipate plant development and yield.

During those early days of computing models were complex, requiring an operator who not only understood but enjoyed the challenge of making it “fly”. Variations in temperature, solar radiation, and several other factors were loaded into the program before it could crunch out a solution.

One set of inaccurate data could throw the whole thing out of kilter. Computer technologists have coined an appropriate phrase that says “Garbage in, Garbage out”.

Those early attempts at understanding how the cotton plant develops gave us some very fundamental insight into the way environment and soils influence the development of a cotton crop. This year all of that came back to my mind during the coolest August I have experienced.

I feel that all is not lost because we have at least maintained daytime temps in the high eighties with low to mid-seventies at night. Without boring you with the math I will say that DD60 units have been accumulating at a rate of around 17 to 20 per day, and at that rate a bloom can become a mature boll in between 45 and 60 days.

This suggests that a white bloom on August 10 should be a mature boll about September 20 to 30 depending upon the weather. Later white blooms are subject to being pushed even later if they can avoid an early freeze.

The sunny days following hurricane Harvey are an indicator that we may still have a good shot. Just don’t get in a hurry about the defoliant on those later fields. I know that is tough but yield can be affected significantly by defoliating only a few days too soon in those later planted fields.

For early planted cotton this may be academic since the plant should have a decent load of bolls and will not work hard at maturing the late ones as it finishes the main crop.  However for the late and very late planted fields this is important stuff. How the weather including temperature and solar radiation arrive will determine both quality and yield.

In areas where early planted fields are defoliated early, there may be enough chemical in the air to nudge those late fields into senescence, but thankfully most of the very late fields are isolated and can take advantage of every degree of temperature and every minute of good sunlight. They will need all of it.

Thanks for your time.

Ernst Undesser
By Ernie Flint, Mississippi State University September 4, 2017