September 2, 2010
Cotton has made good progress this month with generally plus 90 degree temperatures and clear skies. In fact, we have averaged 18.6 heat units per day for the last 30 days, the same average heat units as 2009.
As I have stated before “we make cotton in August.” Scattered rains have been received this month but it was very dry for most everyone. There is a chance this week for rain and temperatures have already begun to moderate some.
I mention this only because of my nervousness as we go into September. Pray for open sunny weather with an occasional gentle rain. We all know we can have weather events which can undo all the hard work applied to our crops. I do not mean a hail-out; I’m talking regrowth, delayed maturity etc. So be careful irrigating into September unless it is through a drip system.
Cotton bollworms have decreased considerably the past couple of weeks. Small and medium worms (less than ½ inch) range from zero to 2500 per acre. Late and/or growthy conventional cotton fields with three and more nodes above white flower, scattered throughout both Hockley and Cochran counties should be checked for another week or so. I am using a 10,000 worms per acre threshold at this time.
Lygus have not been much of a concern. Watch closely fields near alfalfa.
Cotton fields that reached physiological cut-out (5 nodes above white flower) before August 10 have accumulated more than 400 heat units and are safe from most insects other than cotton aphids. I plan on continuing to watch scouting program fields through September 10.
Final thoughts
This time of year I’m often asked to estimate cotton yields for producers for reasons of curiosity, a bankers request for further funding, or just to see how wrong the silly agent is. So I count bolls, establish a plant population and boll size for number of bolls to make a pound of lint, and crunch the numbers.
Then I apply the art of realism into the final number. An example: a field has a plant population of 43,500 plants per acre; after counting a minimum of 50 plants I establish that there is an average of 8.2 bolls per plant; and I estimate that this decent irrigated cotton field has a medium to large bolls size of 320 bolls to make a pound of lint; so (43500 X 8.2) /320 = 1115 pounds of cotton lint yield. I look at the field, consider the producers ability to take this crop to the gin and say “yes this is 2.2-bale cotton.”
That is a realistic scenario. How can we use this to better our management?
Okay, let’s go through another scenario. We will plant to a stand 3 plants per foot or 39,208 plants per acre on every acre, consistently. We water, fertilize, control weeds, manage insects, utilize PGRs, etc., consistently and timely across the whole field.
We use a variety which will set fruit at node seven and quit at node 14. It will have 2 bolls on node 7, 3 bolls on nodes 8 and 9, 2 bolls on nodes 10 through 12, and finally 1 boll on nodes 13 and 14. This is a total of 16 bolls. Now that seems like a lot, but it is very possible if managed properly and consistently.
These bolls are also of a good size, taking 300 bolls to make a pound of lint. Let’s calculate the yield: (39,208 X 16) / 300 = 2091 pounds of lint per acre. Wow. That is plus 4 bale cotton. Ladies and gentlemen we are producing that right now. Sure it is on mostly drip, but it is also being done on pivot irrigation. Okay do not think for a moment that I am saying that you need to be producing 4- to 5-bale cotton. In fact, some who may be doing this have reached a point of diminishing returns when their primary goal is just high yield.
My point is that excellent, profitable yields are achieved by consistency—consistent stand, consistent and necessary inputs, and finally achieving a consistent fruit load. What kills my calculations when a producer asks me to calculate yield for them are the inconsistent stand and inconsistent boll load. If you want to better your profit margin through production, be consistent, timely, and precise.
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