Mitigating Risks with a Late-Maturing Cotton Crop

by Bill Robertson, Cotton Agronomist and Ray Benson, Cooperative Extension Agent Staff Chair for Mississippi County - June 29, 2021

Management considerations for cotton do not change significantly because of late-planting or a late-maturing cotton crop, but the attention to detail and timing do become more critical. Below is a list of important considerations for profitable cotton production to consider the remainder of the 2021 season.

1. Do not over fertilize, especially nitrogen. Follow the 4-Rs and target season long nitrogen rates to not exceed 100 to 110 #N/A.
   
   
2. Do not over irrigate. Utilize well-timed irrigation.
   
   
3. Maintain balance between vegetative and reproductive growth to promote earliness.
   
   
4. Know the point in time that a new square has little chance to make you money. Greatly reduce new plant growth beyond that point and help direct energy to fruit that will contribute to yield and profit.
   
   
5. Determine cutout dates (ie. the date the crop reaches NAWF = 5 or the last calendar date that a flower has a reasonable chance to mature into a harvestable boll) and follow termination guidelines to optimize yield and earliness.
   
   
6. Expect to see plant response to stress at seasons end. A good boll load is a stress to the plant. End of season stress with a good boll load is an indicator that we did not spend too much money on the crop.
   
   
7. Use a knife to determine maturity of your uppermost harvestable boll to avoid unnecessary delays in harvest aid applications and harvest completion.

2021 Season Overview

We continue to experience challenges to our cotton crop in 2021, most of which are centered around weather. Planting was complicated by narrow planting windows scattered through late-April and the first half of May. Slightly less than half our cotton was planted before the middle of May. While our cotton was planted late in 2021, it did not differ greatly from 2020. According to the weekly Arkansas Crop Progress and Condition reports released by USDA-NASS (https://www.nass.usda.gov/Statistics_by_State/Arkansas/Publications/Crop_Progress_&_Condition/2021/index.php) planting progress in 2021 never fell below 5% from 2020 levels for any reporting period. Planting progress the last half of May exceeded that reported for 2020 approximately 3% the last half of May. However, USDA-NASS reports for 2021 documenting squaring has our crop as much as 10 days behind the progress reported for the 2020 crop.

The major reason for our delay in squaring compared to 2020 was the record-breaking cold temperatures experienced during Memorial Day weekend. It was estimated by some that the lack of plant growth during this time would cost us 7 to 10 days. The USDA-NASS reports are confirming this estimate of loss of maturity. While we cannot realistically speed up development and maturity of a cotton crop, we can make it later if we are not careful.

Cotton Plant Growth

The time from first square to first flower is generally 25 days and does not vary a great deal. Approximately 66% of our cotton in 2021 was planted by May 20 using USDA-NASS estimates. Cotton planted May 20 should be squaring this week. If we assume first square today (6/29), first flower should occur July 24. Latest possible cutout dates range from August 9 in northeast to as late as August 24 in far southeast Arkansas. The latest possible cutout date is the last calendar date that in 50% of previous years we can accumulate the 850 heat units (DD60s) needed to mature a field at cutout to a field we can apply harvest aids without a negative impact on yield or fiber quality in Arkansas.

Most in central Arkansas assume a latest possible cutout date or the last date they can count on a white flower contributing to yield and profit on August 15.  If our first white flower occurs on July 24, we have the potential of having an effective flowering interval of 3 weeks which is adequate to set a very good crop. This is fine for one late field. Our challenge is that it often takes over a month to harvest what we have the potential to plant in one week. When the whole farm is late, any delays cut deep into yield and quality.

Summary

The last thing we need to do in 2021 is to push this crop hard with fertility and irrigation to try and make up for a slow start. This will likely have no positive effects on yield and will effectively further delay termination of an already late crop.

Maintaining a balance between vegetative and reproductive growth can help promote earliness. Directing plant resources toward fruit that has potential to contribute to yield and profit is critical especially in a late-maturing crop.

Determining cutout dates and following termination guidelines will help producers better manage inputs and their costs without having a negative impact on yield and quality. Managing costs will be even more critical in a year that yields may be closer to average as compared to record breaking that we have experienced the last few years.

November 1 is our target harvest completion date. Getting harvest aid applications initiated in a timely fashion is key to getting the pickers in the field and harvest completed to help preserve yield and fiber quality potential. Nothing about harvest works good in the mud and the last thing any of us want is to still be harvesting cotton in December.