As the cotton-growing season winds down and final irrigations have been made, we begin to look at decisions for harvest preparation and harvest aids application. There are two main components of this decision, and each can be influenced by a variety of factors.
The two components are timing and material. Both can be influenced by many factors including crop maturity, crop and soil water status, crop fertility status, and weather conditions around the time of defoliation. The choice of harvest aid material can be complex since there are different types on the market including herbicidal defoliants, desiccants and hormonal stimulants.
In Arizona, a lot of work has been done evaluating appropriate timing and material selection in a wide variety of production scenarios. As general guidelines, it is best to use some crop evaluation techniques to determine crop readiness for defoliation.
If the late-season irrigation interval is 12 days, then it is estimated in about two times that late season irrigation interval beyond the final irrigation (24 days) the crop would be ready for a defoliant application. This interval may vary depending on soil water-holding capacity and weather conditions. Under hot and dry conditions, this interval may be shorter. Cooler and wetter conditions may lead to a longer time between final irrigation and defoliation.
Another good indicator for crop readiness is percent open boll. This can be estimated by counting the number of nodes above the uppermost first position cracked boll to the uppermost harvestable boll. Nodes above cracked boll (NACB) is easy to evaluate and provides a fairly accurate measurement of percent open boll. When NACB drops below four, the crop is at approximately 60 percent open boll, which is the trigger point for most herbicidal-type defoliants. If desiccants, such as sodium chlorate, are to be used, it is important to wait until you approach 80 percent open boll before application.
For more information on harvest aid application timing and material selections, go to the “cotton” section of cals.arizona.edu/crops.
The National Agricultural Statistics Service August Crop Production Report projects Arkansas producers to harvest 1,103 pounds of lint per acre. This estimate is 28 lbs lint/A greater than last year and slightly above our five-year average of 1,101 lbs lint/A.
Cooler temperatures in August generally translate into higher yields. Lower-than-average temperatures we experienced through the first half of the month can help give some optimism for continued improvement of our yield estimates. Temperatures in the last half of August and September can go a long way toward making or breaking a crop.
Oftentimes, yield drives profit, but there is a point of diminishing returns that can lead to losses for even the most needed inputs. We don’t have the luxury of having a cushion in our cotton budget to gamble on feel-good or look-good treatments that don’t provide a return to the producer. Tracking heat unit accumulation beyond cutout to effectively terminate inputs without affecting yield is critical in managing costs and preserving profit potential.
As harvest approaches, we must remember to preserve yield and fiber quality potential through well-developed and well-timed cultural practices for harvest aids and harvest management. Avoiding discounts is paramount. An effective lint contamination prevention program that starts in the field benefits everyone.
We need to improve our overall efficiency for cotton to be sustainable.
As we end the 2017 fruiting and growing season, it has been interesting to see that once rains began in early June, there was very little window for management on most of the Florida cotton acres. Some growers were not able to apply side-dress nitrogen in a timely manner or at all along with growth regulators. There should not be much nitrogen left in the root zone for cotton to continue vegetative growth, which helps with defoliation and preparing the crop for harvest.
Some producers flew on nitrogen because soils were too wet for field equipment. Most of these applications had minimal rates of nitrogen due to the expense of flying on material. Some farmers who routinely apply potassium as a side-dress on sandy soils were not able to make those applications, which created concern about potassium deficiencies.
However, most cotton looks good even with reduced inputs and should produce an average crop or better if the remainder of the season goes well. Cotton is a hardy crop and often suffers more from dry weather than wet during the growing season. Our farmers always seem to adapt to changing conditions. We will look back on this year as being wet unless something more catastrophic happens during harvest.
Yield potential for the 2017 cotton crop has improved during the past month. Current estimates are about 1,000 pounds of lint per acre. Target spot is prevalent across the state in many fields due to rainfall, cloudy, and humid conditions. Defoliation began in the latter part of August, and harvest will begin in the earlier planted fields during early September.
As we prepare the 2017 crop for harvest, we should review some of the basic defoliation timing principles. There is always a balancing act between yield and fiber quality when defoliating cotton. There are several accepted methods to time defoliation, and all of them have strengths and weaknesses. Here is a review of some of the more common defoliating-timing techniques. These three methods or options for timing cotton defoliation are at 60 percent open boll, four nodes above cracked boll, or 1,050 heat units beyond cutout (NAWF=4).
Most importantly, whatever method is employed farmers should include inspecting the uppermost harvestable boll prior to defoliation by cutting a cross-section of the selected bolls. A boll is considered mature if it is difficult to slice with a knife, and seeds have begun to form a tan/brown or black seed coat. Once a dark seed coat has formed, defoliation will not adversely affect the yield of those bolls.
Our Louisiana cotton defoliation guide can be found at lsuagcenter.com>crops>cotton>agronomy.
The 2017 roller coaster ride continues in Mississippi. Over the past six weeks, we have seen a tremendous amount of bollworm pressure that has necessitated insecticide applications on all commercial Bt technologies. Everyone is aware cotton varieties have different susceptibility levels to worms, depending on which Bt technology is planted.
However, researchers at Texas A&M have confirmed bollworm populations collected in Mississippi are resistant to Cry1ac and/or Cry2ab toxins. These Bt toxins comprise some, if not all, of the current commercially available Bt trait packages. Trait composition within a given variety, particularly with respect to the Bt component, should be considered when selecting a variety in 2018. In addition, do not rely solely on Bt traits for bollworm control next year as subsequent sprays may be necessary.
Cracked and open bolls appeared in early August in our earliest planted cotton. However, large-scale harvest aid applications will likely not take place until the end of September. A small portion of our cotton will be harvested at that time and then move into full swing in October. A repeat of 2016 fall weather is sorely needed to finish this crop and get it out of the field.
According to the Aug. 7 Crop Progress and Condition Report, cotton squaring had reached 97 percent. Cotton-setting bolls reached 69 percent. We are ahead of last year’s pace and the five-year average. Cotton condition was rated 1 percent very poor, 9 percent poor, 33 percent fair, 47 percent good and 10 percent excellent. Our last effective bloom date is near, and at this time, the over-all crop looks good.
However, there are concerns for the rest of the season. Last year, the U.S. Department of Agriculture had projected a near-record yield. I knew this was unrealistic because we had so many days of rainfall and cloudy weather during July and August. At the Cardwell weather station, we had more than 9 inches of rain during this period. Therefore, the projected yield was off by about 100 pounds per acre.
This year, we have rainfall forecast for 10 of the next 15 days. Wet soils and cloudy days are not good this time of the year. In 2016, many of our irrigated fields yielded less than non-irrigated fields due to boll rot and target spot.
As of Aug. 2, the Missouri Department of Agriculture had received 240 alleged dicamba complaints. Since then, Section 24(c) labels are in effect with more restrictions, including on-line registration prior to use. It will be interesting to see how the rest of the season plays out.
The North Carolina crop is late overall, which could delay defoliation and harvest. Because of this, it’s important we initiate defoliation and harvest as soon as the crop is ready. The average hours suitable for harvest per day or week decrease as we move later into the year with shorter days and lower solar radiation.
Gaining a week in early to mid-October by starting on time can save you several weeks in November or December. Defoliation delays may also push some of your defoliation into cooler weather where the results may be less than desired.
Nodes above cracked boll is a good tool to use to help time defoliation. We normally see that we can defoliate cotton at four nodes above cracked boll. Sometimes we can defoliate a little earlier if the crop is compact and the plant population is not low.
The best way to know when it is safe to defoliate is to use nodes above cracked boll as a guide and start cutting some of the least mature bolls you intend to harvest to check maturity. The least mature bolls will normally be on the top of the plant and on vegetative branches. It is important to consider the fruit on vegetative branches, especially with skippy stands or low plant populations.
This year, the U.S. Department of Agriculture-National Agricultural Statistics Service is estimating we planted 470,000 acres and will harvest 450,000. We likely have more than 500,000 acres planted, the most in the state since 1982.
The 2016 crop yielded 617,000 bales, which was an all-time record high per-acre yield — an astounding 1,021 pounds per acre — for the state for all practices. The cotton varieties and technologies our farmers planted are producing record yield and quality when environmental factors align. Although we don’t necessarily expect a record state per-acre yield in 2017 from this much larger planted acreage, we are still anticipating another huge crop in terms of bale volume due to this substantial acreage increase.
The recent NASS report estimated the statewide yield at 768 lbs/acre, which results in a 720,000-bale production number. Even if the crop finishes in a less-than-desirable manner and the statewide average is 600 lbs/acre, this still results in a 625,000-bale crop, which would be similar to last year’s production.
The crop has made good to excellent progress in the past several weeks. Irrigation in most areas was adequate to meet crop demands. Soil moisture got somewhat short in early August in certain areas, but later rainfall has been excellent in many counties. It appears we have good dryland and irrigated yield potential in many places.
Harvesting and ginning another anticipated large crop will be a challenge for both producers and ginners. Harvesting as early as possible is critical with respect to fiber quality. And farmers should be on point with respect to monitoring crop maturity, applying harvest aids, and getting the crop harvested as quickly as possible.
The quality of a cotton boll is never greater than on the day it opens. It only goes down after that, so time is of the essence with respect fiber quality. The value of a properly executed early harvest cannot be overstated. And in our area, proper harvest aid selection, crop maturity assessment, application timing and harvesting must all be integrated for success.
On Aug. 14, I’d rate the average cotton acre in Tennessee at near exceptional. Plant bug pressure has been light, and fruit retention is very good. Leaf spots of almost every type have appeared across our acreage, but treatable levels of target spot have only developed on very few acres.
Many acres reached physiological cutout the first week of August close to our last effective bloom date. At this point, we only need several good rains and a warm, dry fall to finish the crop. Rains today and over the past weekend helped, but we are still several inches away from set. Furthermore, much of July and August have been cooler than normal and we are behind on heat units. I’m still concerned about the number of acres we have planted to varieties with high mic potential. However, the season is not progressing in a manner that would suggest high mic will be a major issue for us during 2017.
I’ll be updating our news.utcrops.com blog with defoliation information near the middle of September and will get into variety-specific defoliation management at our Cotton Tour in Jackson on Sept. 6. Hope to see you there!
As of mid-August, cotton harvest is wrapping up in the Rio Grande Valley. Irrigated cotton yields and quality are quite good while yields on some dryland areas reflect the lack of rainfall received all year. Harvest conditions in the Coastal Bend have been good with many reports of 2.5-plus bales dryland yields. This likely will exceed 2016’s high yields.
The Upper Gulf Coast began harvesting Aug. 1 but had a scare with a week of wet weather. After resuming harvest in mid-August, yields of 3-plus bales are common. Dryland cotton harvest in the Southern Blacklands will begin in early September. Average yields are expected, while irrigated cotton should exceed 3 bales.
The Northern Blacklands and all the Rolling Plains (dryland and irrigated) have a lot of potential to make a great crop, especially if the Rolling Plains has a warm fall. Aphid problems have been widespread through much of that area with higher numbers than usual. Weed control has been good, and reports of off-target movement have remained low.
On Aug. 15, we were coming out of the latest string of storms that brought most of the High Plains several rain showers since the end of July. With the last effective bloom date historically in mid- to late August across the region, most of the crop received at least an inch of rain to help finish out the flowering period and contribute to filling bolls.
As the crop matures over the next several weeks, the next major step will be harvest-aid applications. Although it’s too early to tell what kind of weather the fall will bring, this will have a tremendous influence on what products will be needed. However, there are some things we do know that will influence end-of-season decisions. Most of the crop is behind, either due to harsh conditions early in the season or because of delayed planting.
Tracking plant development late in the effective blooming window will be key. If our first frost date is close to the Oct. 31 average, there may be some late fruit set that won’t have a chance to fully mature. It will be key to take this into account when monitoring the plant to schedule harvest aid applications, as both the 60 percent open boll and four nodes above cracked boll (NACB) methods should only take into account harvestable bolls. This means we should focus only on bolls that will be open and contain fully mature fiber, as well as contribute the most to yield.
We can leave out immature bolls that contribute very little to lint yield and contain poor quality fiber. Most field cleaners can dispose of green bolls or immature bolls frozen shut by a frost with only small amounts of immature fiber making it into the basket. This is a more desirable scenario than attempting to wait until all bolls are open, exposing the largest proportion of our yield to detrimental weathering effects. Although bolls at the top of the plant are tempting, factoring them into our end-of-season decisions often does more harm than good.
While writing this blog, I looked outside and observed the fifth rainy day in a row. This is a good sign as the past two Augusts have been dry for Virginia cotton producers. Yields, as I type this, appear to be above average.
However, we need to get through tropical storm season to be sure.
In 2016, we lost an estimated 500-600 pounds of lint per acre from two tropical systems, resulting in the lowest lint yields in my tenure as Virginia’s cotton specialist. Let’s hope Mother Nature is kind during boll opening this year.
Once the time comes to defoliate, producers need to consult local Extension defoliation guides to make sure the proper combinations of defoliants and boll openers with current weather are applied to limit the negative effects on fiber quality.
So far, so good in Virginia, let’s keep our fingers crossed and hope tropical storms do not materialize.
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