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HighlightsWater availability challenges have increased interest in cotton production in Oklahoma.An attempt was made to understand the feasibility of growing cotton in all counties of Oklahoma.Many areas in Oklahoma have sufficient thermal conditions for cotton production.Potential cotton lint yields generally increase from northern to southern areas of the state.Abstract. With the expansion of planted area, Oklahoma is increasingly becoming a major cotton producing state in the United States (U.S.). However, the feasibility of growing cotton in all counties of Oklahoma has not been determined. In this study, a heat unit based model was used to estimate the potential cotton lint yields (PCLYs) for all 77 counties of Oklahoma using 38 years (1981-2018) of air temperature data. PCLYs were estimated for optimal (no stress) conditions. The long-term total heat units (THUs) were more than 1000°C·d in 99% of counties, an indication that many areas in Oklahoma may have conducive thermal conditions for cotton production in most years. Similar to the THUs, the PCLYs generally increased from the northern to the southern counties of the state, and long-term averages ranged from 407 to 2472 kg ha-1. About 97% of the counties achieved long-term average PCLYs of at least 1000 kg ha-1. However, the results showed significant interannual variability of the estimated PCLYs in each county over the 38-year period. Low and high PCLYs mostly coincided with years characterized by cool and warm growing seasons, respectively. Reductions of PCLY ranging from 6% to 29% were observed when planting was delayed by just one week from the optimized planting date. This indicates that cotton producers need to carefully consider planting date to maximize cotton lint yield. As THUs were the only factor considered for calculating PCLYs in this study, future research should incorporate other variables such as rainfall and heat stress to improve PCLY estimations. Keywords: Air temperature, Planting date, Soil temperature, Yield gap, Yield variability.

Testing was conducted at a western commercial cotton gin to evaluate the effect of humid air moisture addition on fiber quality, bale value, and operating costs; when applied at the gin stand feeder conditioning hopper and battery condenser lint slide. Two tests each with 19 conventional modules of upland cotton were conducted over two consecutive days. The moisture treatments included feeder hopper moisture on or off and lint slide moisture on or off, resulting in four treatment combinations: 1) no moisture added (No Addition), 2) moisture added at the feeder hopper only (Hopper Only), 3) moisture added at the lint slide only (Slide Only), and 4) moisture added at the both the feeder hopper and lint slide moisture (Hopper+Slide). Results showed that seed cotton moisture content at the gin stand was about 0.1 percentage points higher when moisture was added at the feeder hopper and lint moisture content in the bale was about 0.9 percentage points higher when moisture was added at the lint slide. Adding moisture at the feeder hopper resulted in small, but significant (p-value = 0.05), improvements in HVI length [+0.21 mm (0.008 in.)], uniformity (+0.16 percentage points), and strength (+0.25 g/tex), and AFIS length [+0.4 mm (0.016 in.)] and short fiber content (-0.52 percentage points). However, fiber yellowness also increased (+0.12 +b) when moisture was added at the feeder hopper. Adding moisture at the lint slide had very little effect on fiber quality. Moisture addition at either location did not significantly affect spinning performance or yarn quality. Lint produced with moisture added only at the feeder hopper had the highest average value [$1.254/kg (56.88 ¢/lb)] and lint with moisture added only at the lint slide had the lowest value [$1.234/kg (55.98 ¢/lb)]. Bales produced with added moisture were heavier, 9 kg (20 lb) heavier on average for the Hopper+Slide moisture addition than for No Addition. Bales produced using moisture addition not only contained more moisture, but also more lint. This could be due to easier bale pressing, which was supported by measurements which showed that about 2 kW less press power was required to press bales with moisture added at the lint slide. Moisture added at the feeder hopper resulted in the greatest overall increase in value over the value of cotton ginned with no moisture addition, more than $32,000 when extrapolated over 10,000 bales. The moisture addition treatments required more energy to produce bales, mainly due to the additional natural gas required for air humidifying equipment. However, since bales with added moisture contained more dry lint resulting in fewer bales pressed for the same amount of dry lint in bales produced with no moisture addition, savings in bale packaging materials and labor costs made operating the moisture systems slightly less expensive than not, up to about $1400 less for 10,000 bales with the Hopper+Slide moisture addition. Although the results showed little impact on cotton quality by adding moisture, the subtle differences and heavier bales containing more lint could have a significant effect on the value to a producer over an entire cotton crop or to a gin over an entire season. Keywords: Cost benefit analysis, Cotton ginning, Energy, Fiber quality, Humid air, Moisture addition.

The pneumatic fractionator has long been used to determine foreign matter content of seed cotton at the USDA-ARS cotton ginning laboratories. An experiment was conducted to evaluate the pneumatic fractionator as a device to remove foreign matter from ginned lint. No modifications were made to the standard device, except that air pressure to internal jets was reduced to 276 kPa (40 psi) from 517 kPa (70 psi). Three lint cleaning treatments after normal saw ginning were used: no lint cleaning, one standard controlled-batt saw lint cleaner, and cleaning with the pneumatic fractionator. Process times in the pneumatic fractionator were varied from 5 to 30 s. Foreign matter content (2.0 leaf grade and 253 counts g -1 AFIS total foreign matter) and color measurements (78.69 Rd and 10.20 +b) for the pneumatic fractionator were not statistically different from the saw lint cleaner (2.0 leaf grade, 257 counts g -1 AFIS total foreign matter, 79.08 Rd, and 10.18 +b). Length measurements of pneumatic fractionator cleaned lint were similar to or better than those of lint with no lint cleaning and, in most cases, better than lint cleaned with a saw lint cleaner. For example, upper- half mean length for pneumatic fractionator cleaned, no lint cleaning, and saw lint cleaner fiber was 29.7, 30.0, and 29.2 mm (1.17, 1.18, and 1.15 in), respectively. Also, the pneumatic fractionator produced about the same number of fiber entanglements as the saw lint cleaner. Processing time in the pneumatic fractionator had very little effect on fiber quality parameters with the exception that the 5 s processing time had the highest levels of foreign matter. These results showed that the pneumatic fractionator cleaned lint about as well as a saw lint cleaner, but maintained fiber length better.

Cotton production practices have changed in the Southern High Plains of the United States over the last decade resulting in increased yields and improved fiber quality. Moreover, the majority of U.S. cotton now competes in a global fiber market that demands higher quality fiber for ring spun yarn than the former domestic open-end market. The brush-roll stripper harvester is the predominate machine used to harvest the Southern High Plains cotton crop, but interest in spindle pickers has increased recently in efforts to better preserve fiber quality, enhance profitability, and maintain the market share of U.S. cotton in the global fiber market. This work was conducted to compare yields, fiber quality, and agronomic parameters between picker and stripper-based harvest systems under commercial production and ginning conditions. Large-scale harvest system comparison tests were conducted at seven sub-surface drip irrigated sites across the Texas High Plains during the 2008-2010 crop years using brush-roll strippers with field cleaners and spindle pickers. Four cotton modules harvested from each site under each harvest method were ginned by a commercial gin. Compared to picker-harvested cotton, stripper-harvested cotton had 1096 kg ha -1 higher seed cotton yield which increased ginning charges by $72.40 ha -1 . Seed and lint yields were 217 and 108 kg ha -1 higher, respectively, for stripper-harvested cotton resulting in $88.78 ha -1 higher total production revenue. Notwithstanding higher lint yield for the stripper system, custom harvesting was $51.38 ha -1 more expensive for the picker system due to the custom harvesting rates used (picking: $0.22 per lint kg; stripping: $0.18 per lint kg). Except for strength and reflectance that showed no difference by harvest method, all High Volume Instrument (HVI) fiber quality parameters were improved for picker-harvested cotton. Due to improved HVI fiber quality and a substantial decrease in the number of bark contaminated bales, lint value was higher for picker-harvested cotton. However, increased lint value was offset by decreased yield such that net revenue was $66.76 ha -1 higher for stripper-harvested cotton across all sites.

Southern High Plains cotton has improved over the last ten years with regard to yield and fiber length and strength. In light of increased adoption of picker harvesting to preserve fiber quality and improve harvest productivity, ginning practices are needed which preserve fiber quality and maximize return to the producer. The objective of this work was to investigate the influence of harvest method, number of seed-cotton extractor cleaners (e.g. stick machines), and seed-cotton cleaning rate on foreign matter content, lint value, and fiber and yarn quality of cotton produced in the Southern High Plains. Compared to using only one stick machine, the use of two stick machines in the seed-cotton cleaning system removed more foreign material from both picker- and stripper-harvested cotton, but more foreign material was removed by the stick machines from stripper-harvested cotton because it had higher initial foreign matter content. Seed-cotton cleaning rate had no influence on stick machine cleaning performance for picked cotton but higher cleaning rates reduced stick machine cleaning performance for stripper-harvested cotton. Picker-harvested cotton exhibited improved HVI and AFIS fiber quality and higher bale values compared to stripper-harvested cotton. The use of two stick machines improved fiber color properties and reduced lint foreign matter content. Seed-cotton cleaning rate had a minimal effect on fiber quality and bale value was not influenced by the number of stick machines or seed-cotton cleaning rate. Total lint value, on a production area basis, was higher for stripper-harvested cotton after both lint cleaners compared to picker-harvested cotton due to yield differences. Yarn imperfections were reduced for ring spun yarn produced from picker-harvested cotton processed through one stick machine at the high cleaning rate. The findings of this work support a recommendation for using one stick machine in seed-cotton cleaning systems processing picker-harvested cotton and two stick machines in systems processing stripper-harvested cotton.

Cotton gin energy costs have risen more than other operating costs. Energy audits were conducted in 20 U.S. cotton gins representing a range of capacities in six states. The average participating saw gin used 39.5 kWh to process a bale. The average roller gin used 62.6 kWh. Gins have become larger, from a connected power of 570 kW (764 hp) in 1962 to over 2237 kW (3000 hp) today. Energy costs are a larger proportion, 20% of the total cost of ginning, compared to 6% to 10% of the total in the 1970s, even though energy consumed per bale processed is less, approximately 73% of the electricity consumed in 1982. Connected power and energy consumption were allocated to five categories: seed cotton cleaning, ginning, lint cleaning, bale packaging, and materials handling. Materials handling accounted for the largest portion, over half of the electricity consumed by a gin, as it has since the 1960s. Since the 1980s, the power and energy allocated to ginning has decreased slightly, and that allocated to lint cleaning has decreased significantly. Best practices still include: operating at full capacity, avoiding down time, minimizing materials handling, and improving electric motor efficiency.

Cotton fiber quality and textile yarn quality can be affected by ginning processes and cotton cultivars. The overall goals of this study were to utilize a microgin to evaluate the effect of seed cotton cleaner and lint cleaner on fiber and yarn quality, and to benchmark FiberMax 1740 and Phyto Gen 370 against Deltapine 555 grown in Georgia. Six cleaning treatments in a microgin were arranged by varying seed cotton cleaners (stick machine, cylinder cleaner, and Trashmaster®) and one saw-type lint cleaner. Cotton fiber quality and cotton trash content were measured via High Volume Instrument (HVI), Advanced Fiber Information System (AFIS), and Shirley trash analyzer. Ring yarn quality was measured in terms of spinning efficiency, tensile strength and elongation, hairiness, defects, and waste. Fiber quality measured by HVI showed significant differences between the six cleaning treatments in both trash content and fiber length properties. Specifically, the saw-type lint cleaner was more effective in reducing trash content but was more likely to create short fiber content than the seed cotton cleaner. Deltapine 555 demonstrated lower upper half mean length and lower length uniformity than FiberMax 1740. A similar pattern was observed in AFIS data, although cleaning treatments only showed impact on total trash count, visible foreign matter, and neps. The three cotton cultivars exhibited significant differences in cotton length properties. Deltapine 555 had the highest short fiber content (by weight) and lowest length uniformity among the three cultivars. Results from Shirley analyzer revealed that the cleaning treatments without the saw-type lint cleaner had both higher visible and invisible trash content. As for the ring yarn quality, cotton lint with less cleaning processes exhibited lower defects, lower hairiness (irregular CV), but more waste than that with more cleaning processes. Given the waste can be cleaned during the carding process and easily manageable, the less ginning options could be beneficial to spinning process. Among the three cultivars, Phyto Gen 370 generated the highest quality yarn suggesting that Deltapine 555 can be replaced by other cultivars with improved yarn quality. This study sheds light on the effect of cleaning and cotton cultivar on lint fiber quality and the spinning performance of the fiber. The information could be useful to improve the profitability for cotton growers, ginners, and spinners alike.

Seed cotton drying is an important and costly part of cotton ginning. Seed cotton having a moisture content above 7% cannot be cleaned or ginned properly. In this study, 73 dryers were surveyed by on-site visits in 23 gins located in the southwestern United States during the 2007 to 2010 ginning seasons. Drying systems surveyed included: standard tower, short tower, hot shelf, hi-volume tower, belt, big reel, vertical, hot air cleaner, pipe, cross-flow, hot box, hi-slip, jet, fountain, and collider systems. Forty-eight percent of dryers had the recommended dual temperature controls, while 26% had only a primary temperature control and 26% had only a maximum temperature control. Belt and big reel dryers had the lowest specific airflow rates (0.34 to 0.72 m3/kg of seed cotton) and also had the lowest energy in the conveying air (1.7 kJ/kg of lint or less). Collider, fountain, and hi-volume tower dryers had the highest specific airflow rates (1.9 to 2.8 m3/kg) and hi-slip, hi-volume tower, and standard tower dryers had the highest energy in the conveying air (7.7 kJ/kg or more). Belt, cross-flow, and hot air cleaner dryers had the lowest pressure drop across the dryer (0.5 kPa or less), while hi-slip, pipe, and standard tower dryers had the highest pressure drop (1.8 kPa or more). Fuel use was positively correlated with airflow (r=0.58) and temperature rise (r=0.59). Systems with fountain, collider, belt, big reel, jet, and hot air cleaner dryers had favorable, low values for fuel use (13.7 kJ/kg of lint or less), while systems with crossflow and hi-volume tower dryers had high values for fuel use (30.0 kJ/kg or more).

The recent increase in the use of subsurface drip irrigation (SDI) for cotton production in the Texas High Plains has resulted in questions concerning drip lateral position and orientation relative to crop rows. Field experiments were conducted at Halfway, Texas to evaluate traditional SDI installations with crop rows spaced at 0.76 and 1.02 m; crop row to lateral offsets of 0.0, 0.13, 0.25, and 0.38 m; and crop rows perpendicularly crossing SDI laterals spaced at 0.76, 1.02, and 1.52 m. Traditionally installed SDI with cotton rows spaced at 0.76 m resulted in generally higher yield than those spaced at 1.02 m; however, differences were not significant over the 5-year period. Yields were significantly different between individual rows of adjacent row pairs irrigated with single SDI laterals when row offsets were greater than 0.25 m on 0.76-m row spacing. However, cotton plants from rows closest to the SDI lateral largely compensated for yield losses of rows farthest from the lateral. When considering perpendicularly crossing 1.52-m spaced laterals with 0.76-m wide crop rows, only modest declines in cotton lint yield (1.5% and 3.3%) occurred compared to traditional parallel row-lateral orientation with the same lateral and row spacing. With crop rows perpendicular to laterals, SDI lateral spacings resulted in average yields of 1802, 1869, and 1903 kg ha-1 at distances of 1.52, 1.02, and 0.76 m, respectively. Orienting rows perpendicular to drip laterals using 0.76-m crop row widths resulted in significantly higher yields and irrigation water use efficiencies than 1.02-m row widths at high irrigation capacity. As water availability declines, these results will provide producers additional information on SDI installation and management.

Saw-type lint cleaners are now the most common lint cleaners used at gins because of their higher cleaning efficiency. Saw-type lint cleaning improves the grade of the fiber and increases the market value for the farmer. However, during the cleaning process the saw-type lint cleaners damage fiber in creating short fibers and neps. An innovative air-bar lint cleaner (ABLC) was designed and built. The ABLC used pressurized air to clean non-lint materials from cotton fiber while the cotton fiber batt was on a rotating saw cylinder. Thus, non-lint materials attached to the fiber were removed by the interaction of blowing force of compressed airflow and centrifugal force created by the rotating cylinder without the fiber making mechanical contact with a solid object, such as a grid bar. The fiber quality could be preserved by reducing the damage from mechanical impact of the fiber against the grid bar during the lint cleaning process. Preliminary testing of the ABLC prototype was conducted. Compared with cotton cleaned using the conventional saw-type lint cleaner, cotton cleaned using the ABLC had better fiber quality properties, including less short fiber content, less trash content, longer fiber length by number, less immature fiber content, lower yellowness, and less lint content in the lint waste.

In 2001, the Arizona Department of Water Resources implemented an agricultural Best Management Practice (BMP) program. The program was designed to encourage the use of BMPs in irrigation with the goal of increasing the efficient use of water resources on the farm. Several BMPs were identified through meetings with stakeholders, researchers, and scientists. One of the BMPs identified was alternate furrow irrigation. This three-year study was designed to determine the impact of alternate furrow irrigation on surface irrigation water applications and cotton yield. There were two treatments, every furrow (EF) and every other furrow (EOF). Lint yields were 1794 and 1694 kg/ha in 2006; 1795 and 1902 kg/ha in 2007; and 1365 and 1237 kg/ha in 2008 for the EF and EOF treatments, respectively. Seasonal irrigation water applications were 187.7 and 162.3 cm in 2006; 151.4 and 137.2 cm in 2007; and 184.1 and 132.6 cm in 2008 for EF and EOF treatments, respectively. The results indicate that an average of 30.5 cm of water can be saved by the implementation of an alternate furrow irrigation scheme without significantly reducing lint yield.

Picker and stripper harvest systems were evaluated on production-scale irrigated cotton on the High Plains of Texas over three harvest seasons. Observations on fiber quality using High Volume Instrument (HVI) and Advanced Fiber Information Systems (AFIS) were made on multiple cultivars harvested from six locations. When fibers were relatively immature, micronaire, length, and length uniformity as measured by HVI were better for picker harvested cotton than for stripped cotton leading to a higher loan value and average sale price for the producer. In cases where fibers were more mature, differences in fiber quality parameters between picked and stripped cottons were less pronounced leading to less discrepancy in the value of cotton harvested. However, differences in nep counts, short fiber content, and visible foreign matter between harvest treatments were still distinguishable. The results of this study indicate that producers may realize greater fiber quality and lint value by using picker harvesters, but the magnitude of those differences are a function of growing conditions and/or fiber maturity. Differences in cultivars also played a large role in determining fiber properties.

A microgin is built to simulate the performance of commercial gins and to gin cotton samples from whole research plots. This study compared a modern microgin located in the southeast United States, a lab gin stand, and five commercial gins in terms of fiber quality properties and lint turnout. Results showed that the lint turnout from the laboratory gin was consistently higher (0.8-2.3%) than that from the commercial gins, while the microgin and commercial gins had similar gin turnout (0.1-1.6% differences). The HVI trash and leaf grade from the lab gin stand were 0.98 (units) and 3 (grades) higher than that from the commercial gins, respectively; the differences between the microgin and commercial gins were only 0.16 and 1, respectively. Color reflectance from the lab gin was 5.92% less than that from the commercial gins; the difference between the microgin and commercial gins in reflectance was only 0.68%. Length and uniformity from the lab gin were 1.02 mm and 1.7% higher than those from the commercial gins, respectively; the differences between the microgin and commercial gins were only 0.25 mm and 0.58%, respectively. Linear regression analyses showed that the microgin had a consistently lower bias than the lab gin stand in estimating commercial gin values in most fiber quality properties except for micronaire. The data confirmed that the microgin outperforms the lab gin stand in estimating the lint turnout and most fiber quality properties and it should be a valuable tool for cotton research.

There are over 1.0 million ha of cultivated land in the Southern High Plains of Texas, with about 40% in dryland production. Strategies that couple dryland production methods with very low levels of supplemental irrigation in contrast to current irrigated practices could stabilize crop output for an extended period at the expense of reduced agricultural productivity. An eight-year field experiment was conducted from 2001 to 2008 to develop cropping data for economic analysis. The principle goal was to compare a cotton (Gossypium hirsute L.) - sorghum [Sorghum bicolor (L.) Moench] (2:1) rotation system to a continuous cotton system, both efficiently irrigated at levels well below the evapotranspiration rate of these crops. Seasonal irrigation capacities were approximately 0%, 20%, and 40% of peak evapotranspiration rates. The rotation strategy from 2003 to 2005 allowed the movement of limited irrigation between crops based on relative water needs at critical growth periods, and from 2006 to 2008, based on water needs of the crop with the higher economic value. The results showed that in years of below average rain, cotton following sorghum resulted in 18% to 44% higher lint yields compared to continuous cotton. In years of average rain, cotton lint yields following grain sorghum were generally higher than those of continuous cotton, averaging 21%, with a portion of the increase due to higher irrigation. And, in years of above average rain, significant yield differences due to rotation were minimal, particularly at the highest irrigation capacity. Directing available irrigation to the crop of higher value (cotton) at the expense of the lower value crop (sorghum) appeared to be a major factor in elevating seasonal irrigation water use efficiency (0.448 to 0.513 kg lint m-3) compared to irrigating the most water stressed crop (0.200 to 0.35 kg lint m-3). Although cotton lint yield tended to be higher in the rotation than the continuous cotton treatments, the rotation resulted in significantly lower gross irrigation value than the continuous cotton cropping system in most years.

Traditionally, bagging used for cotton bales has been permeable to moisture, but more recently relatively impermeable material has been adopted by the industry. This impermeable bagging has significantly affected the moisture changes that occur during storage. In many cases holes have been punched in the bagging in an effort to increase the permeability. To better understand the effect of different bagging materials on bale weight changes, Universal Density cotton bales were formed with relatively dry lint and covered with different types of bale bagging materials. The bales were stored in a humid environment and weighed periodically for between 63 days, for high permeability bagging, to 155 days, for low permeability bagging. The bale coverings studied included coated woven polypropylene with micro-perf holes, linear low density polyethylene film with different hole patterns, woven cotton, woven burlap, and no bale bagging. The bale weights were modeled temporally using a nonlinear exponential model. Different bales stored in the same bagging type changed weight consistently. A mathematical model was developed for polyethylene bagging that accurately related the rate of bale weight change with the percentage of bag surface removed as holes. The rate of bale weight change obtained from the regression was used to calculate a half-time to equilibrium, in days, for each bagging type. This weight change half-time will simplify communication of the effect bale bagging has on cotton bale weight change during storage.

Seven commercially available portable cotton bale moisture content (mc) meter-probe combinations were purchased by each of the three Agricultural Research Service Cotton Ginning Research Units and examined for precision and accuracy when used with commercially ginned cotton. The devices were used to measure the mc at the same six locations on a total of 96 cotton bales. Lint samples were obtained from the same locations in the bales for mc determination by the oven method resulting in more than 7000 meter readings with corresponding reference mc values. Based on oven-mc, the lint samples had mc in the range 2.3% to 9.4% wet basis. The oven-mc wet basis for the different samples in the same bale had a standard error from 0.15% to 0.42% wet basis. The different meters produced significantly different readings from each other, and these were significantly different from the oven-based mc. Most of the meters were found to have a significant offset from the oven-based mc ranging from -3.3 to 3.3 percentage points. However, the standard deviation of the difference between the individual readings of the meters and the oven-based mc resulted in estimates of precision of plus or minus one percentage point for most of the individual meters.

Universal Density cotton bales were formed with relatively dry lint, covered with different types of bagging materials, and the bales stored in a humid environment for more than 3 months. The bale coverings included coated woven polypropylene with and without holes, linear low-density polyethylene film with different hole patterns, and no bale bagging. The bales were weighed periodically during storage. Some bales were then exposed to drier conditions and the weight change over time again recorded. Theoretical diffusion models were considered and the bale weight changes modeled with a single-term decaying exponential. Different bales in the same bagging type changed weight consistent with the models. The rate of bale weight change from the models was used to calculate a half-time to equilibrium, in days, for each bagging type. The half-time for bales with no bagging was 10 days, for bales in coated woven polypropylene bagging with holes punched in it was 34 days, and for bales with a bagging made of polyethylene film with holes was 102 days. This half-time number will allow simplified communication of the effect bale bagging has on the rate of change of cotton bale weight during storage.

Tests were conducted using a rotor spray system to apply moisture in the form of fine water droplets to cotton lint at the lint slide just before bale packaging. Two studies were conducted, one in which bales were stored for 6 months and another in which bales were stored for 15 months. For the first study, initial cotton lint moisture content averaged 5.1% and ranged from 4.4% to 5.7%, wet basis, and for the second study the initial moisture content averaged 5.5% and ranged from 5.1% to 5.9%. For the 6-month storage test, five levels of moisture addition were studied, including average moisture levels of 6.3%, 6.5%, 7.0%, 7.7%, and 7.9% moisture (just after rewetting), in addition to bales with no additional moisture added. For the 15-month storage test, three levels of moisture addition were studied, including 8.0%, 8.4%, and 10.0% moisture (just after rewetting). In both studies, cotton quality degradation was determined after each of the respective storage periods. No significant changes were found in HVI micronaire, strength, length, or uniformity or any properties measured with the Advanced Fiber Information System. At moistures of 7.5% and greater, the color +b value decreased slightly and the decrease was statistically significant. When considering the moisture range used in this study, results are consistent with earlier studies using atomizing spray nozzles, therefore recommendations for using a rotor spray system for adding moisture to cotton fiber at the lint slide should be the same as those for using an atomizing spray nozzle system. Thus, in order to minimize color degradation during storage, cotton lint moisture should be less than 7.5% wet basis (8.0% dry basis) when the bale is formed.

Ginning seed cotton which is drier than ideal has been shown to result in increased fiber damage measured by an increased percentage of short fiber and reduced fiber length. Previous work has shown that adding moisture to seed cotton (before fiber removal from the seed) will result in improved fiber length properties. Commercially available atomizing nozzles were installed in a commercial cotton gin to apply unheated tap water to seed cotton between the dropper after seed cotton cleaning and above the auger in the conveyer-distributor situated before ginning. The moisture content (mc) of lint samples collected between the gin stand and the first lint cleaner was increased by between 0.2 and 1.1 percentage points with the system. The lint samples which had been ginned at higher mc had higher Advanced Fiber Information System (AFIS) length by weight and upper quartile length with lower short fiber content. The AFIS non-lint content was higher for higher mc lint and the AFIS nep content was lower but the differences were related to the lint mc, not the spray treatment. A small number of High Volume Instrument measurements were obtained for bales with and without moisture restoration from the same module and no statistically significant differences were observed in the measurements of fiber length, strength, leaf, and uniformity. The seed cotton moisture restoration resulted in a small improvement in fiber length for the commercial gin in which it was installed verifying that previous laboratory scale studies are applicable in commercial settings.

The powered roll gin stand is a new saw-type ginning technology that has undergone numerous studies evaluating its use for ginning seed cotton. Past results have shown increased production and turnout without adversely affecting fiber properties. In some cases, improvements in fiber properties over a conventional gin stand were demonstrated. This article reports High Volume Instrument and Advanced Fiber Information System fiber property results from three field tests evaluating the technology on three different makes of gin stands. Results indicate the powered roll gin stand performed equal to or better than some of the conventional gin stands in processing rate, lint turnout, and/or some fiber properties. However, work remains to refine the technology so that it performs consistently on different makes of gin stands.

An experiment was conducted to determine if upland cotton could be roller ginned at a considerably higher than normal rate without compromising fiber properties and at a rate comparable to saw ginning. A conventional roller gin stand was modified to run at high speed by increasing the frequency of the ginning roller and rotary knife, and increasing the force between the ginning roller and stationary knife. Other changes included adding a spray system to cool the ginning roller, enlarging the lint-flue transition, and modifying the seed-cotton feeder for increased throughput. When ginning upland cotton, the high-speed roller gin stand ginned at a rate comparable to saw ginning. The high-speed roller gin stand had the same horsepower requirement of a saw gin stand. Roller ginning, when compared to saw ginning, produced upland fiber that was about one staple length longer, had less short fiber and neps, had higher turnout, but contained more foreign matter in the lint and cottonseed. Although roller ginning did not increase bale value, the improvement in fiber properties may open up new markets for upland cotton, especially in export markets that value the significance of increased staple length and decreased short fiber contents.

The saw-type lint cleaner is the primary method of lint cleaning at gins. Two one-year studies were conducted to examine fiber quality properties produced by a saw-type lint cleaner in response to variations in feed rate, saw speed, combing ratio, variety and lint moisture. One hairy-leaf and two smooth-leaf varieties were used in the studies. Lint moisture and variety were the dominant factors that affected fiber quality. The smooth-leaf variety cleaned under low lint moisture conditions had shorter fiber with higher reflectance. When operated at low saw speed conditions, the cleaner increased turnout, lowered cleaning efficiency, and decreased cleaner waste. At high combing ratio conditions, the cleaner increased cleaning efficiency and short fiber content.

Subsurface drip irrigation (SDI) has expanded dramatically in cotton producing areas of the southwest United States, especially where furrow irrigation was practiced. There is ancillary evidence that cotton may experience shortages of phosphorus (P) and other nutrients more readily under SDI compared with furrow irrigation. This may be related to the smaller wetted volume of soil and hence smaller root volume under SDI. Some cotton producers using SDI in the Trans Pecos region of Texas have observed large increases in cotton lint yield by the addition of small amounts of P; however, cotton response to different P rates under SDI has not been documented in this region. This article presents results of a field experiment repeated during the 2003, 2004, and 2005 growing seasons where cotton lint yield, quality characteristics, and lint gross return were evaluated for different P application rates. The experiment was completely randomized with four treatments and three replications. Treatments were: 1) no phosphorus applications; 2) injection of 4.6 kg ha-1 y-1 P contained in Miller Solugro® (12-48-8); 3) injection of 32.9 kg ha-1 y-1 P contained in phosphoric acid; 4) injection of 65.7 kg ha-1 y-1 P contained in phosphoric acid. The cost of P treatments ranged from $21.10 to $42.20 ha-1 y-1, but marginal gross returns for lint were $520 to $1,252 ha-1 y-1 more from phosphoric acid and $233 to $872 ha-1 y-1 more from Miller Solugro®. In 2003 and 2004, lint yields and gross returns were greatest for the 65.7-kg ha-1 y-1 P rate, which was similar to recommended rates based on a 2004 soil fertility analysis. In 2005, lint yields and gross returns were greatest for the 32.9-kg ha-1 y-1 P rate, which was slightly below recommended rates based on pre-plant 2005 soil fertility analysis. These results support injecting P at rates based on soil fertility analyses. Both phosphoric acid and Miller Solugro® were suitable for injecting P into SDI systems. The P2O5 application rates increased the productivity per unit of water applied during the three years of the study. Plant petiole analysis in 2004 correlated with P application rates, suggesting a qualitative method to detect P deficiencies during the growing season.

Knowledge and proper control of moisture in cotton lint is crucial to optimal operation of cotton gins. Currently available portable meters have a standard error of 0.5 to 1.0 percentage point, which is not as accurate as desired. A battery powered, portable, resistance-based cotton lint moisture meter was designed and two units constructed using a sensing grid, which has been used in non-portable applications in gins. The entire weight of the meter, 5.8 kg (12.8 lb), consistently pressed the electrodes against the sample. The meters used a toggle switch for commands from the operator and displayed results on a liquid crystal display. The meter readings of well conditioned lint compared to the oven-based moisture content were used in calibration. A separate data set was used to verify the calibration and the standard error was found to be 0.26 percentage point for both units over the 4.3% to 10.2% range.

Although the boll weevil (Anthonomus grandis grandis Boheman) has been eradicated over much of the U.S. cotton production area, there are still cotton production areas that are infested. As a result, USDA, Animal and Plant Health Inspection Service (APHIS) has procedures in place to keep the weevil from being reintroduced into eradicated areas as well as being transported overseas to cotton growing areas in other countries. Included in the procedure is the fumigation of baled cotton with methyl bromide prior to shipment. Methyl bromide may not be available as a fumigant in the near future and the fumigation process is expensive. Research was done at the USDA, ARS, Southwestern Cotton Ginning Research Laboratory to determine the actual re-infestation risk from live boll weevils processed through the normal cotton ginning and baling systems in the United States. Two tests were done: 1) a gin process survival test, and 2) a bale compression survival test. No weevils survived processing through a saw gin stand and one saw-type lint cleaner. In addition, most weevils were immediately killed at compressions of 352.4 kg/m3 (22 lb/ft3) and higher in the bale press. There were also no survivors after six days at the specified UD bale density of 448.5 kg/m3 (28 lb/ft3). Test results showed it was extremely unlikely that a live boll weevil could survive both gin processing and bale compression.

Seed flax stalks are usually considered a waste product but they can be separated into marketable fiber and shive. The fiber can be used for applications such as composites and paper. Separation of traditional long line fiber from fiber flax stalks is a rigorous and expensive process that requires the stalk to be biologically degraded (retted) before processing. This process is not economically feasible for seed flax stalks. This study evaluated the potential of several machines traditionally used to remove foreign matter from cotton in terms of their capability to remove flax fiber from chopped seed flax straw. The successful mechanical principles of several machines were then incorporated into a single machine and used to separate the fiber and shive from the straw. The new machine consists of components of a modified gin cleaner typically used for cleaning seed cotton and components of a machine typically used for cleaning lint. The initial version of the machine did not yield the desired 80% fiber purity, so more saw cylinders were added. The most effective version produced 13.8% yield out of a possible 20% fiber with a purity of 81.4%. The yield can be improved with additional modifications to the machine.

An experiment was conducted to determine the performance of experimental stationary knives when ginning upland cotton. Pima cotton was also used for comparison. Three knives were modified to allow an opening between the knife and the ginning roller of 2.4-, 4.0-, and 5.6-mm (0.095-, 0.158-, and 0.221-in.) depth, respectively. (A standard stationary knife has practically no opening.) The hypothesis is that linters (short fibers) cannot be pulled from the seed if the distance between the seed and the gripping point is increased beyond their length. As it is now, linters have a tendency to be scalped from the seed at the ginning point and allow shorter fibers (linters) to be included with the lint. If there is less scalping, there should be fewer short fibers. As expected, most of the fiber and cottonseed properties were affected by variety and were at acceptable levels. The only fiber and cottonseed properties that were affected by stationary-knife design included color reflectance, color yellowness, foreign matter content in the lint, and cottonseed linters content. Foreign matter content in the lint, measured by the Shirley Analyzer, increased as the opening between the stationary knives and ginning roller increased. The foreign matter content may have contributed to the fiber appearing different, and hence the differences in color reflectance and color yellowness. There were obvious differences, both visually and statistically, in cottonseed linters; the lowest linters content occurred when using the stationary knife with the 2.4-mm (0.095-in.) deep opening between the knife and ginning roller. Short fiber content was not affected by stationary-knife design as hypothesized. Ginning rate was affected by knife design; the highest rate was obtained with a 2.4-mm (0.095-in.) deep opening between the stationary knife and ginning roller.

The requirements of precision crop management or limited water supply requires that either plant water status be varied during the growing season to optimize crop performance or a continuous level of limited irrigation must be practiced to match irrigation water availability. Canopy temperature (TC) has been successfully used to time irrigation applications for well-watered crop growing conditions. The cumulative daily time that TC exceeds a crop-specific temperature threshold, designated as stress time (ST), is used to indicate the need for irrigation. Manipulation of the ST value required to indicate the need for irrigation changes irrigation frequency and seasonal irrigation. The ST value that generates the irrigation signal is the time threshold (TT). This study developed a procedure for estimating the relationship between TT for cotton and seasonal irrigation rates. Data were analyzed from irrigation studies that measured the water application and cotton yield response to a range of average daily ST. All irrigation studies included a common control TT of 330 min/d above a canopy temperature threshold of 28°C as the criteria for the irrigation signal that maintained cotton in a well-watered status. In order to develop relationships between daily ST and final yield, or water input during the season, daily ST values were calculated and averaged over the irrigation season. The same procedure was used to calculate the average TC. The procedure for identifying control TT to establish different crop water status levels included the following steps. First, a linear relationship was defined between average daily ST and lint yield. Second, separate linear relationships were established between average daily ST and total water or irrigation input. Third, based on the slope of the trend line between average daily ST and yield, 1-h differences in average daily ST were selected to produce sufficiently large differences in total water and irrigation input to affect yield. These average ST values were 408, 468, and 528 min/d, and corresponded with control TT values of 330, 390, and 450 min/d. These control TT should result in different amounts of water application during the growing season and produce differences in cotton yield.

Nitrogen is typically applied to cotton (Gossypium hirsutum L.) in two or three split applications, however, with subsurface drip irrigation (SDI), nitrogen can be applied daily. The major objective was to show yield and grade response of cotton where nitrogen was applied daily through a SDI system at two nitrogen application strategies compared with overhead sprinkler (SP) and non-irrigated (DRY) regimens. The SDI system provided daily irrigation and nitrogen to a randomized block design with three irrigation levels (100%, IL1; 75%, IL2; and 50%, IL3); two nitrogen levels, N1 and N2, (67 and 101 kg ha -1); two drip tube lateral spacings, IR and AM (individual row = IR, alternate row middles = AM), with three replications per treatment. Nitrogen was applied in split applications to the SP and DRY areas in a randomized block design. Cotton was planted following peanuts during the 1999 and 2000 growing seasons on a Tifton sandy loam soil (fine -loamy, kaolinitic, thermic Plinthic Kandiudults). In 1999, there was a 6% lint yield increase for N2 (total lint: 1484 kg ha -1), but there was no lint yield difference with nitrogen levels in 2000 (total lint: 1280 kg/ha). There was no yield difference with drip tube lateral spacing or irrigation level except at IL3 (50%) in 1999. Lint yield was higher in both the SDI and SP compared with the DRY regime. Differences within grade parameters were not consistent across years for micronaire, fiber strength, or fiber uniformity with respect to nitrogen applied or irrigation system. Overall, the application of nitrogen on a daily basis with SDI had the same lint yield and grade compared with SP and higher lint yield than the DRY. The lower nitrogen rate (N1) had the same yield as the higher nitrogen rate (N2) which suggests that lower nitrogen rates may be appropriate when using SDI.

The purpose of this research was to determine if moisture applied before packaging caused cotton fiber degradation during subsequent storage. Fiber quality characteristics of universal density cotton bales were determined before and after extended storage (months) in three separate studies. For the test bales, water was sprayed over the top of the fiber as it came down the lint slide after ginning and cleaning. The bales were then packaged at universal density and placed in either tripled polyethylene bags, woven polypropylene bags, or fully coated woven polypropylene bags, and then stored at atmospheric conditions. Bale moisture content after the water was added ranged from less than 5% to over 15% w.b. The bales changed weight and moisture content substantially during storage depending on the type of bale covering and the initial bale moisture content. Most fiber quality characteristics except color remained about the same. The HVI color decreased from Middling (31) before storage to as low as Strict Low Middling Spotted (43) after storage depending on moisture content. Other HVI data changed slightly during storage regardless of the moisture level. The higher initial bale moisture contents resulted in greater degradation in color. Based on these studies, cotton bales should not be stored at moisture contents above 7.3% w.b. regardless of bale covering materials.

“Quart-size” (0.95-L) metal cans with metal lids have been used for transportation and storage of cotton lint samples intended for moisture content analysis by the oven method for many years. In some cases, particularly when the samples are collected at a distance from the analysis lab, the transportation of the empty cans can be inconvenient. This study examined the use of zipper-closed plastic bags, which are widely available, for sample transportation and storage. Cotton lint samples were pretreated with higher and lower humidity, placed in containers, and stored in an environment maintained at a constant relative humidity and temperature. The samples and containers were weighed periodically. After a period of between 2 to 3 weeks the cotton was tested for moisture content by the oven method. This moisture content was used with the weight data to calculate the moisture content over the storage period. Statistical analysis was used to estimate the moisture content/time slope based on the different containers. The metal cans proved to be the best of the containers tested. Double bagging using freezer bags was the best of the plastic bag containers. Therefore, metal cans should be used when available; however, if the samples are promptly shipped and analyzed then the double-bagged freezer bags can be used.

Proper assessment of the moisture content (mc) of cotton lint is critical to all phases of cotton processing. Traditional methods of mc determination require multiple 20-g specimens of lint, which is more than is available on many occasions. Thus, the use of smaller specimens was considered. Cotton lint specimens of 1, 5, 10, and 20 g were taken from lots conditioned to different moisture content levels and mc determined by the oven method. Results indicated that the mean mc based on 1-g specimens was the same as that based on 20-g specimens. Based on the variance of the mc data separated by specimen size and drying time, seven 1-g specimens produced the same variance as three 20-g specimens after 1 h of oven drying. Therefore, 1-g specimens can be used for oven-based mc determination instead of 20-g specimens, consuming considerably less lint material. The procedure to determine mc based on 1-g specimens required more time and effort as well as more specimens to achieve a similar variance, so the 1-g sample procedure should only be used when material is limited.

Three studies were conducted to ascertain the impact of number of bale ties, density, and climatic storage conditions on bale tie forces. One study using six or eight ties per bale and platen separations of 48.3 or 53.3 cm (19 or 21 in.), bale tie lengths of 215.9 or 226.1 cm (85 or 89 in.), and storage at high humidity and normal humidity indicated that the average force on the six-tie pattern was about 22% higher than for the eight-tie pattern. Tie five was located in about the same position for both patterns and exerted about 20% more force for the six-tie pattern. The force exerted on individual restraint ties on a gin universal density cotton bale differed dramatically for different tie locations. Bale tie forces increased dramatically immediately after the bale was released from the press and tended to stabilize after 60 days. Cotton bales gained moisture at a declining rate until they reached equilibrium with the moisture in the air after about 100 days of storage. In a second study, different force levels were required to compress cotton bales at different tie locations suggesting a different amount of lint near each tie. In a third study which compared eight bale ties to five ties at the same locations on both bales, tie forces averaged about 36% higher for the bale with five ties.

This study examined simulated net returns to gin lint cleaning in the Southern High Plains of Texas during the 1993, 1994, and 1995 crop years to determine the number of lint cleaners required to maximize producer net returns. Net returns for five stripper harvested cotton varieties with different management practices, including the use of irrigation and field cleaners, were evaluated in this study. Results indicated that net returns were consistently higher for one stage of lint cleaning for all of the management practices evaluated. It was found that producers could have saved approximately $4.00/bale by lint cleaning cotton once.

The objective of this study was to determine whether the Shirley Trash Separator (STS) could be used to measure fine trash not captured by the standard Shirley Analyzer (SSA) and if the STS could be used to predict waste content expected using the SSA. Three experiments were conducted to compare waste quantities from the two machines. Visible waste contents were significantly lower with the STS in the first and second tests, but invisible and total waste contents were higher in the second test. All waste contents were significantly lower with the STS in the third test. This is more in line with what was expected because the STS was designed to catch what previously went out as invisible waste in the SSA. These tests have shown that the STS can be used to measure fine trash not collected by the SSA and that the STS can predict visible waste from the SSA satisfactorily.

This analysis simulated net returns for six stripper harvested cotton cultivars to determine the number of lint cleanings that maximizes producer net returns. The study found that net returns were consistently higher for one lint cleaning in the gin plant for all cultivars regardless of time of harvest. One lint cleaning gave higher net revenue by an average of $4.54/bale, with a range of $7.35 to $1.92/bale, in comparison to two lint cleanings.

Cleaning, drying, and ginning cotton cultivars on conventional ginning equipment produces commercially useful information for comparative purposes. Evaluation of numerous cultivars grown in Mississippi in two years on different soil types indicated substantial differences between the cultivars in terms of monetary returns to the farmer and fiber properties important to the textile industry. In 1994, gross monetary returns averaged $1,097.71 per hectare and ranged from about $957.92 to $1,258.19; classers’ color was generally Middling grade but leaf ranged from 1.3 to 3.3; the number of neps averaged 289 and ranged from 209 to 381 per gram of lint; seed-coat fragments (SCFs) averaged 59.6 and ranged from 44 to 116 per 3 g of lint; and short fiber content (SFC) by weight averaged 8.0% and ranged from 5.4% to 11.2%. Similar results occurred in 1993, unfortunately, the “best” characteristics were not all present in the cultivars that yielded the highest monetary return. These results show the potential for improving cotton fiber quality parameters but care must be exercised to ensure that all growth conditions are considered.

Selective breeding has improved upland cotton fiber properties. New high-speed roller ginning technology has advanced to the point that processing capacities have approached that of saw ginning. Producers seeking a better price for their upland cotton are interested in fiber property and textile mill performance data comparing cultivars processed by both saw and roller ginning. Three diverse cultivars, one of them stripper-harvested, were processed by saw ginning, conventional roller ginning, and high-speed roller ginning, with different levels of lint cleaning appropriate to each treatment. Samples were submitted for HVI and AFIS fiber property analysis. Ring-spun yarn from each treatment was tested. Results showed that the roller gin (conventional and high speed) produced fiber that was longer, more uniform, had less short fiber, and fewer neps than the saw gin stand. Turnout, color grade, and leaf were not different among gin stand type. With respect to yarn properties, the conventional/high-speed roller gin had fewer thick places, but was higher in vegetable and foreign dark matter (contaminants), seed coats, and neps. The composition of neps changed as fiber was processed into yarn. The conventional/high-speed roller gin had fewer raw stock and card mat neps than the saw gin stand, but more neps in finished yarn. Differences among cultivar were prevalent throughout the study. In addition to differences in length, strength, and immature fiber content, the cultivar that was stripper harvested had double the trash content at harvest. There were differences in most fiber properties, but not yarn properties, among lint cleaner type. Roller gin lint cleaning was less aggressive than saw-type lint cleaning and had longer fiber, better uniformity, and fewer neps. Saw-type lint cleaning had better color and leaf grades, and less lint trash. There was no appreciable difference between the two types of roller gin lint cleaning used, but one saw-type lint cleaner as opposed to two was less damaging to the fiber. Although roller ginned upland cotton is a niche market, textile mills value the higher quality obtained from roller ginning. Newer upland cultivars may make roller ginning a viable option in parts of the Unites States where roller ginning has not been available previously.

Studies involving moisture levels, trash levels, gin machines, and types of cotton were conducted to assess their impact on market value and fiber properties after processing with various gin machinery sequences. Selecting the optimum machine sequences increased monetary values for Study 1 from $12.22 to $20.85 per bale and averaged $16.72 per bale. Bale values ranged from $357.13 for the standard machine sequence for DPL 50 to $404.10 for the extractor-feeder gin stand only sequence with DPL 50. Monetary returns for Study 2 ranged from $312.63 for DES 119 at medium moisture to $425.92 for Stoneville 132 at medium moisture for the same optimum machine sequence. Monetary increases ranged from $10.58 to $46.70 and averaged $29.06 per bale. The predominate optimum sequence for the hairy-leaf cottons was stick machine, extractor-feeder and gin stand, and two lint cleaners. The smooth-leaf cottons required fewer cleaning machines to maximize monetary returns and also provided higher returns than did hairy-leaf cottons. For both studies, fewer machines than are currently recommended were the most profitable and most of the other fiber quality factors were more desirable. Since different sequences were required to optimize monetary returns, process monitoring and control systems must be used to maximize profits.

Respiratory diseases occur in some textile mill workers who are exposed to cotton dust for long periods. Research has shown that endotoxins are present in cotton dust. Correlations between endotoxin content of cotton dust and pulmonary function of human volunteers exposed to the dust have been found. It has been shown that short-duration, high-temperature treatments of cotton can reduce the amount of endotoxin present in cotton dust. This report describes development and evaluation of a device to provide rapid, high-temperature treatment of cotton as it comes out of a gin. The device is based partially on the principle of the belt dryer, which employs a conveyor belt to transport cotton, and uses hot air for drying. The device recirculates heated air that can be controlled at temperatures up to 260° C (500° F). Regulating belt speed controls exposure time of the cotton batt flowing through the device. The device’s ability to regulate air temperature and duration of exposure allowed large-scale pseudo-duplication of experimental procedures used previously in destroying endotoxin in cotton. The device performed very well in a three-day test, successfully treating 179 kg (394 lb) of cotton lint for examinations of endotoxin content, guinea pig pulmonary response, cotton quality, and textile processing performance. Related research on the cotton and dust from this work showed that endotoxin content was reduced about the amount expected, guinea pig responses to dust were partially ameliorated, but cotton quality and processing performance were reduced.

Various components of a computerized process control system, such as infrared moisture meters, video cameras, computers, paddle samplers, pneumatic cylinders, etc., were installed in a phased approach over a five-year period at two commercial cotton gins. The systems are not yet fully automated or fully implemented, but all of the components that have been evaluated functioned well for extended periods of time. Analyses indicate that reducing the number of lint cleaners from two to one on cotton selected by the computerized system could increase the bale value by about $3 to $6 each. Controlling moisture correctly could have a similar impact and a savings of about $6 per bale. Total additional profits for cotton grown in the United States could exceed $135 million annually.

Too much foreign matter in cotton lint lowers the value of the harvested crop, while overcleaning can damage the cotton fibers and reduce the total amount of material sold. Removal of foreign matter is usually accompanied by removal of saleable lint. This study attempts to determine the optimum number of lint cleaners for stripper harvested cotton, based on net returns to the farmer, by using a previously developed simulation model, GINQUAL. Findings indicate two lint cleanings most of the time, although three are required 25% of the time and one is best 20% of the time.

Cotton by-products produced during ginning such as cotton gin waste (CGW) have been utilized or disposed of by several methods such as spreading on soil, composting, feeding to livestock, dumping, and incineration. The CGW includes gin-cleaned lint cleaner waste (commonly referred to as motes), lint-cleaned motes, first- and second-cut linters from an oil mill, hulls, ginned lint, and waste from the seed cotton cleaners. The potential for CGW as well as other gin by-products for cleaning up oil spills was considered in this study. In addition, the components of Kenaf (core and bast) were also examined. Results indicated that ginned lint absorbed 80 times its weight in oil, whereas fibrous waste such as cleaned lint cleaner waste absorbed 67 times its weight in oil. Waste collected in the seed cotton cleaning process was much less efficient as an oil absorbent at about 9 to 1. Kenaf core and bast absorbed about 35 times its weight of oil, respectively, before cleaning which was about equal the sorption of raw lint cleaner waste. Gin by-products and Kenaf can be utilized to efficiently remove oil from water surfaces; however, reuse of the sorption material after removing the excess oil from the sorption material was not feasible.

Saw-cylinder lint cleaners at cotton gins improve the grade and market value of cotton but can reduce some of the quality factors desired at the textile mill. A four-year study was conducted to update lint cleaner recommendations for spindle-harvested cotton in response to new quality demands of spinners and new cotton varieties. The effects of none, one, two, and three stages of saw-cylinder lint cleaning on foreign matter content, length and short fiber content, strength, nep count, and seed-coat fragment level of ginned lint were developed. Smooth- and hairy-leaf variety cottons of various trash levels were used in the experiments. One or two stages of lint cleaning produced the highest monetary returns depending on the initial trash level and type of cotton. The information and guidelines should aid ginners in selecting levels of lint cleaning that preserve fiber quality while producing acceptable market returns for the grower.

The equipment and instrumentation necessary to continuously measure the color, trash, and moisture levels of seed cotton and lint have been developed, tested in the laboratory, and field tested in commercial gin plants for two years. A complete computerized gin process control system including routing valves, sensors, sample collection devices, and computer software has been installed and tested in both a small-scale and a full-scale ginning system. A uniform density of the surface of the cotton sample was required in order to ensure that measurements were within acceptable accuracies. The system relies heavily on the density enhancing equipment which was developed and patented to improve the accuracy of the sensor measurements.

Two laboratory-type video color/trash meters were installed and evaluated in a commercial gin during the 1989 and 1990 ginning seasons. Calibration of the meters was accomplished using manufacturer-supplied reference standards. During the 12-week ginning season each year, in which about 18,000 bales were ginned, the meters performed without any maintenance problems. Samples were collected from the cotton during gin processing throughout the ginning seasons in order to verify the accuracy of the meters. Comparison of measurements made by the meters during ginning to those made on representa-tive samples by the USDA, Agricultural Marketing Service, Cotton Division produced acceptable repeatabilities 72%, 49%, and 79% of the time for trash, reflectance (Rd), and yellowness (plus b), respectively. Acceptable values for similar measurements with two laboratory meters were 75%, 81%, and 75%. Thus, reflectance measurements had a lower repeatability for the gin measurements than for the laboratory measurements. If twice the allowable laboratory deviations are assumed to be acceptable for gin process control, then the repeatability percentages increase to 84%, 73%, and 87% for trash, reflectance, and yellowness, respectively. Color grades, which are a combination of reflectance and plus b measurements, were estimated correctly about 55% of the time, whereas 94% were estimated correctly within one grade. Video color/trash meters can be utilized in commercial ginning systems to estimate the color and trash components of cotton.

Pima cotton is roller ginned to preserve its length and to minimize neps. Since Pima has recently experienced a substantial increase in production and an increased emphasis on quality, operators of roller-ginning plants are seeking ways to improve the performance of their plants while maintaining the quality of Pima cotton. A survey was conducted to determine the type and effectiveness of seed-cotton and lint-cleaning equipment currently used in United States roller ginning plants. The survey clearly shows that guidelines for an optimum lint-cleaning sequence is needed for roller gins.

The simulation model, GINQUAL, was used to estimate the effects of processing rate, moisture, initial trash content, and machinery sequence on seed cotton cleaning efficiency for stripper-harvested cotton. The machinery sequences included various combinations of an airline cleaner, an inclined cleaner, a stick machine, and a combination bur and stick machine. Initial seed cotton moisture varied from 5 to 15%, ginning rate from 3.28 to 8.20 bales/m-width-h (218 kg or 480 lbs per bale), and input trash from 25.5 to 46%. Simulated total seed cotton cleaning efficiency decreased with increasing moisture, input trash levels, and ginning rate. However, the decrease in total seed cotton cleaning efficiency corresponding to increased input trash levels was probably a result of the increased effective processing rate. Increasing the input trash and moisture levels increased the effective processing rate (total mass flow rate) through the overhead cleaning equipment for each selected ginning rate. For instance, it takes 915 and 1439 kg (2017 and 3172 lbs), respectively, of raw material to produce a bale of lint when the cotton contains 25.5% trash and 5% moisture compared to 46% trash and 15% moisture (assuming 33% of the clean seed cotton is lint). Stick removal efficiency was the component most affected by initial moisture content. The model produced results consistent with previous research and is useable as a technology transfer tool to aid in optimizing existing and future ginning systems.

Three trash meters designed for measurement of foreign matter content (trash) in ginned lint were installed in a small-scale cotton ginning system and evaluated as tools for trash measurements on seed cotton and lint cotton. Regression analyses of seed cotton and lint foreign matter as a function of the area and count (number) of trash particles indicated by the trash meter produced high correlations. Results indicated that the trash meters were sufficiently accurate to continuously assess the foreign matter of cotton in a gin process control system.

A dynamic programming model that optimizes farmer profits and minimizes gin processing and energy consumption provides the basis for computer selection of gin machinery sequences. The model utilizes the cotton market price and the performance characteristics of gin machinery to determine the optimum machinery sequence. Cotton moisture, color, and foreign matter measurements are made with electronic devices at three stations in the gin system and are used to monitor and control the gin process. Special routing valves are used to bypass or select any combination of four seed cotton cleaners, two multi-path driers, and three lint cleaners as directed by computer process control software. A PC-compatible2 microcomputer and C-language form the basis for the control system. The gin process control system operates successfully and has the potential to minimize fiber damage and machinery usage while optimizing profits.