Wrapping Up Harvest Aid Applications In 2016
DR. TYSON RAPER
JACKSON, TENN.
We have been blessed with another great harvest season and it appears we may be able to finish harvest with little rain. Here on the 5th day of Oct, I would guess the average cotton acre within the state has already received the first application of harvest aids and is very close to seeing a picker. Even so, several acres have not been defoliated. This has led many to call with concerns about the cooler temperatures in the forecast over the weekend and several have asked if it is simply time to defoliate based on calendar date.
Since the second week of October is upon us, I do believe defoliation timing should now begin to lean more heavily on the forecast and historical temperature norms associated with the current date than our maturity measurements (NACBs, percent open, uppermost harvestable boll maturity as determined by the sharp-knife technique, etc.). The 5 day forecast here on the 5th day of Oct. for West TN indicates the next few days appear to be favorable for harvest aid applications but conditions degrade over the weekend. The long-term forecast does indicate the weekend dip may be followed by low temperatures back into the mid to high 50s but 2016 has proven that planning on a 10 day forecast is risky; instead, we have to start focusing on seasonal temperature norms for our area. For those who have not applied the first shot of defoliant, I would consider applying as soon as possible and I would definitely make sure it goes out before the end of next week.
Remember that if we do wait on that last boll to mature we are increasing the time those lower position bolls are open and exposed to Mother Nature. Gambling on higher yields by delaying defoliation may payout but the wager is both the quality and the ability to pick those bolls that contribute the most to the bottom line. Risking those ‘money’ bolls for the ‘top crop’ – which generally contributes the least amount to our bottom line – is a risk that I do not like to take.
Additionally, keep in mind that several of our harvest aids are very dependent upon temperature and as our low temperatures move into the low 50s we begin to see a substantial decline in effectiveness. Much of what I mentioned in last week’s post on Defoliation and boll opening under cooler conditions will apply in the coming days. ∆
DR. TYSON RAPER: Cotton & Small Grains Specialist, University of Tennessee