All posts by Tyson Raper, Cotton & Small Grains Specialist

22 Sep 2015

2015 Defoliation Strip Trial in Gibson County

22 Sep 2015
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IMG_1835Mr. Philip Shelby (Gibson County AG Extension Agent) and I put a defoliation strip trial out on Mr. Jason Luckey’s farm last Thursday (9/17).  This plot is flagged on all four corners with large red bicycle flags. The southwest corner is located near coordinates: 35.797906°, -88.835526°.  Navigating to 36 Esquire Peek Rd in Humboldt, TN 38343 and looking north will put you roughly 100 yards south of the plot.  Treatments target a one-shot approach to defoliation with Continue reading →


14 Sep 2015

2015 Mid-South Cotton Defoliation Guide now available

14 Sep 2015
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Tennessee’s 2015 cotton c2015_defol_guiderop has taken advantage of the hot summer and many of our acres will receive the first shot of defoliant in the next two weeks.  Fortunately, this puts the average acre 10-14 days ahead of last year.  With a favorable 10 day forecast on this the 14th day of Sept., the first part of our defoliation window looks very good!   Keep in mind that warmer temperatures generally reduce rates and increase the predictability of the application.  Also, we will likely need less ethephon (especially in the earlier planted acres) compared to last year.  Given the crop is mature and ready to defoliate, making these applications in warmer conditions can result in higher quality at a lower price. Win-win. Continue reading →


12 Aug 2015

Last Effective Bloom Date: how is it calculated and what does it mean?

12 Aug 2015
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IMG_1876By definition, the last effective bloom date is the day in which the probability of a new flower developing into a boll and making its way into the basket declines to below 50%.  Since it is unlikely (probability less than 50%) that fruiting positions which develop after this date will contribute to yield, end-of-season insecticide termination and defoliation recommendations for our area are based upon protecting/managing  those positions which will be flowering Continue reading →


03 Aug 2015

Sulfur Deficiencies in Cotton

03 Aug 2015
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Tyson Raper (Cotton and Small Grains Specialist) and Frank Yin (Systems Agronomist)

Figure 1: Sulfur deficiencies in the upper canopy of blooming cotton during the 2015 season. Photo courtesy Mr. Bob Sharp.
Figure 1: Sulfur deficiencies in the upper canopy of blooming cotton during the 2015 season. Photo courtesy Mr. Bob Sharp.

Sulfur (S) deficiencies have been becoming more common in cotton fields in recent years.  This is in part due to a reduction in sulfur emissions from manufacturing plants and diesel fuels.  Nitrogen (N) and S deficiencies are commonly confused- particularly late in the season.  Although both cause chlorosis of leaf tissue, the mobile nature of N within the plant results in deficiency symptoms first appearing low in the canopy.  In contrast, S is very immobile in the plant and, as a result, S deficiency symptoms first appear in new growth near the top of the plant.  Continue reading →


28 Jul 2015

Cotton Progress/Heat Unit Accumulation for 2015

28 Jul 2015
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IMG_1344
A rough start for many of TN’s cotton acres has turned into a decent summer for the majority of our acreage.  This is very evident when looking at accumulated heat units noted at the West Tennessee Research and Education Center in Jackson, TN.  As you can see in the below graph, we are quite a bit ahead of the last two years on accumulated heat units.  Warm temperatures in mid/late June and timely rains have Continue reading →


03 Jul 2015

New publication: Guide to Earliness Management in Short-season Cotton Production

03 Jul 2015
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Tennessee cotton is finally ‘growing off’.  Still, here on the 3rd day of July, it appears few farms will reach the coveted ‘bloom by the 4th’.  Although the environment has played a dominate role in maturity up to this point, management decisions emphasizing earliness have been particularly useful in 2015.  This marks the third consecutive year in which managing for earliness has a marked effect on crop maturity by early July. earliness_2015_TN

On the heels of last year’s delayed crop, Dr. Owen Gwathmey and I began discussing potential benefits of managing a cotton crop for earliness and the management practices which encourage timely maturity and harvest with colleagues both within and beyond the University of Tennessee.  We have summarized these thoughts in the attached Guide to Earliness Management in Short-season Cotton Production (PB1830).  Continue reading →