It has been and still is extremely hot (looks like it will continue into next week). Cotton has a relatively lower requirement for water before bloom than during bloom. These extreme temperatures are causing stress and wilting to occur on a lot of the cotton that is currently setting squares. I have been receiving many calls about irrigating cotton before first bloom. Please look at the information below from Dr. Whitaker about irrigating cotton during this critical time.
Cotton requires less water prior to bloom than during bloom. However, shorting water during squaring can have significant impacts on yield. We suggest that the crop receive around 1” of water prior to bloom.
Maintaining optimum soil moisture prior to bloom allows the plant to grow and produce more fruiting nodes prior to bloom initiation. If the crop starts to bloom with at least 8 fruiting main-stem nodes, then the plant can use a greater portion of its energy in setting and developing bolls on the already developed fruiting sites.
If the crop starts blooming with fewer fruiting nodes, then the plant has to both grow vegetatively and set/grow bolls. This situation doesn’t always negatively impact yields, as our growing season has enough time to make good yields, while producing fruiting sites and setting bolls. However, if adverse conditions occur during bloom, then the crop will be more susceptible to cutting out early or having poorer fruit retention.
Again, the three or four weeks prior to bloom are extremely important to cotton growth and development. A study conducted in 2012 which examined the impact of pre-bloom irrigation showed that as little as 1” properly timed irrigation during squaring improved cotton lint yields by over 500 pounds. I will repeat this statement, we made 500 pounds of lint with one 1” irrigation during the second week of squaring (we watered the two treatments exactly the same the rest of the year).