Ginning Stripper Harvested Cotton

Moderator:Stanley Anthony, U.S. Cotton Ginning Laboratory
Panelists:Roy Baker, USDA-ARS
 Kenneth Hood, Ginner (MS)
 Curtis Stewart, Ginner (AR)

Stanley Anthony opened the session on ginning with an overview of "Considerations for Ginning Ultra Narrow Row Cotton." He indicated that gins must consider the following factors when preparing to process stripper-harvested cotton:

  • Cotton must be harvested at lower moistures to prevent excessive fiber entanglement and subsequent poor preparation calls at the Classing Office, thus harvesting window is more narrow.
  • Trash contains more moisture than cotton and thus stripper-harvested modules might have a greater potential for fiber degradation.
  • Field cleaners should be used on strippers.
  • Modules have higher trash content and occupy more storage space on gin yard. It takes about 1800-2200 pounds of material to get 500 lb of lint as compared to 1400 for spindle pickers.
  • Gins need more drying, and larger trash removal and handling equipment due to trash moisture
  • Reduced ginning rate with current machines (about 40% with existing equipment) and more wear on equipment and more trash to dispose of at the gin.
  • More trash in cottonseed and motes (lower value).
  • Possible lint grade reductions due to bark and increased short fiber and neps with additional cleaning.
  • Fixed and variable costs of ginning go up.

Mr. Kenneth Hood of Perthshire Plantation near Gunnison, MS is both a farmer and a ginner. Most of his comments were directed toward farmers because he feels that gins can be modified mechanically to handle the UNRC. Mr. Hood warned that UNRC is a major change and requires an entirely different approach to cotton production. He advises farmers to:

  • Change cultural practices. If you are accustomed to conventional rows, banded herbicides, and cultivation in the middles, you have to develop a new mind set.
  • Change your planting habits. When using this system, you must get ready to plant at least 30 to 35 pounds of seed per acre. You can’t skimp on seed if you expect the crop to develop a quick canopy cover. That is necessary for good weed control. When your stand is thin and you can see the ground, you can keep the crop clean – but it will cost you a fortune.
  • Control morning glories, vines, and broadleaf weeds. You will have a mess on your hands at harvest time if weeds and grasses come through the cotton. In spots where heavy weed infestations are breaking through, you have to be willing to give up those areas of the field.
  • Use Pix effectively. When using the ultra-narrow-row system, it is essential to keep plants short and slender. Proper use of a plant growth regulator, coupled with close, high-density plant spacing, is necessary to force the correct plant morphology for efficient harvest.
  • Harvest fast. Once you desiccate or defoliate the crop, you have to be ready to harvest in a hurry. When the leaves are off and the bolls are open, you have to get the crop out of the field immediately.
  • Hood told producers that before they choose UNRC they need to ask themselves several questions. "Are you ready to change your cultural practices?" "Are you ready to change your planting habits? Are you ready for the costs?" He added that producers also need to determine whether their gins are ready.
  • Hood emphasized that with UNRC, precision planting is a must. "Are you ready to plant 30 pounds per acre of cotton seed?" he asked producers. He also noted that the Mid-South poses a particular problem: with the high humidity, it’s difficult to desiccate cotton.
  • Manufacturers must provide good harvesting machines."

According to Curtis Stewart, General Manager of Dumas Cotton Gin, Dumas, AR, Dumas Cotton Gin (DCG) processed 712 bales of Ultra Narrow Row Stripper Harvested Cotton (UNRC) during the 97-98 season. All but 5 bales of these bales were commercially grown, with the exception bales being from the experiment station at Rohwer, Arkansas.

The UNRC contained 640 pounds of trash per bale on average, compared to 180 pounds per bale of conventional picker cotton. This increase in trash is similar to stripper harvested cotton with a burr extractor. Ginning was reduced from 60 bales per hour to 15. This decrease in ginning rate was attributed to the additional trash content of the cotton, as well as the volume of trash going through the trash handling system. The trash handling system at Dumas must be redesigned to prevent this problem; however, ginning rate will still be substantially reduced for UNRC. Grades from the UNRC were comparable with the conventional cotton, but with increased bark, grass and prep calls. There were no differences in cottonseed grades, and no dockage for excess trash.

While the experiences with UNRC were generally negative, all the problems associated with ginning can be resolved with money and experience. Ginners need to know up-front that ginning rate will decrease, and that the equivalent of 3-4 bales of picker trash per bale of UNRC, and extra wear and tear on ginning machinery. DCG remains committed to the advancement of UNRC, but cautions growers that there will be extra charges at the ginning level for the extra wear on equipment and slower ginning rates.

Roy Baker, Research Leader at the Lubbock, TX, Cotton Ginning Laboratory of the Agricultural Research Service of the USDA, discussed "Ginning Stripper Harvested Cotton."

1. Background - Our research at Lubbock has always been focused on stripper harvested cotton, which for the most part is grown in Texas, Oklahoma, and Eastern New Mexico. Today we really have two types of stripper cotton in these areas. We have brushed stripped cotton without field cleaners and brushed stripped cotton with field cleaning. The gins in these stripper areas are setup to handle the typically 700 - 900 lb of trash/bale that is found in regular brush stripped cotton. When they process field cleaned cotton, they only have to deal with 400 lbs of trash per bale, which is real easy if you are setup for the heavier loading but very difficult if you are not.

Stripper gins have higher capacity conveying systems (larger air lines and fans) than do most picker gins, especially for trash handling. They also use at least one more stage of stick extraction than their picker cousins, and in many cases the 1st stage of extraction is a combination bur & stick machine rather than a ordinary stick machine. Stripper gins, however, rely on similar fine trash removal equipment as picker gins. They normally use two stages of cylinder cleaning, a good cleaning/extracting feeder, and one or two stages of saw lint cleaning for this purpose. Stripper gins need double lint cleaning a little more often than a picker gin, but there are still many instances where one lint cleaner is enough to produce maximum bale value for the farmer,

2. Potential Ginning Problems for Picker Gins Handling Stripped Cotton

A: Over loaded trash conveyors, pneumatic conveying lines and trash disposal systems.

B. If an extra stick machine is not available, then a lot more trash will get to the feeder and gin stand. This could overload the feeder's trash auger, put more trash into the gin stand, increase the trash content of the cottonseed and lint, and increase the bark content of the lint.

C. Even with a field cleaner, a stripper will harvest 2 to 3 times more trash than a picker.

D. Increased trash levels can put an extra load on seed cotton drying systems, forcing a slow down in ginning rate.

E. Higher trash levels are normally also associated with higher R&M, leading to higher ginning costs.

F. Current ginning charges for picked cotton may not adequately cover actual ginning costs of stripped cotton if the extra trash in stripped cotton causes the picker gin to slow down, or to have more downtime, or to incur more repair, energy and labor costs per bale.


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