Search

Studies on the effect of nitrogen (N) application rates on lint yield and fiber quality in irrigated and rainfed cotton were conducted for two years. In 2013, cotton was planted in 48 plots. Twenty-four plots were irrigated and the other 24 pots were rainfed. Six N application rates (0, 39, 67, 101, 135, and 168 kg/ha) with four replicates were randomly assigned to the irrigated and rainfed plots. In 2014, five N treatments (0, 56, 112, 168, and 224 kg/ha) with four replicates were assigned to 20 irrigated plots. Effect of N application rates on cotton lint yield was significant in 2014 (p = 0.0196), but not in 2013. Yield showed a quadratic relationship with leaf N content in irrigated cotton in both 2013 (p = 0.0268) and 2014 (p = 0.0099). Correlation between leaf N and yield of rainfed cotton was not significant in 2013. Leaf N of irrigated cotton in 2014 had significant correlation with fiber length (p = 0.0037), UQL (p = 0.0001), and UHML (p < 0.0001). Yellowness was linearly related with leaf N content. Fiber strength showed a linear relationship with leaf N in 2013 rainfed cotton (p = 0.0495), a quadratic relationship with irrigated cotton in 2013 (p = 0.0231) and 2014 (p = 0.0365). Overuse of nitrogen fertilizer in cotton could result in loss of yield and fiber quality. When the fiber quality from irrigated cotton was compared with rainfed cotton, irrigation increased lint yield by 26% and fiber length by 2%.

Understanding seed coat fragment (SCF) spiking results in advanced fiber information systems (AFIS) analysis of seed coat neps (SCN) in ginned cottons is confounded by the opening of entangled fibers in the instrument’s fiber individualizer. This may influence seed coat tissue fragmentation and recovery since a high degree of machine-fiber interaction is required to individualize entities for sensing. In this paper, slivers were pre-opened in the AFIS followed by manual cleaning, spiking, and AFIS analysis. A protocol was developed to spike the pre-opened slivers. The percent recovery of the spiked entity was dependent on the species and cultivar of the cotton used to prepare the slivers. The lowest recovery was with Pima fibers. Also, the recovery improved with the increase in length of the fibers biologically attached to the SCF surface. Delinted seed coat fragments produced the lowest recovery. Seed coat fragments carefully removed from ginned lint and added to the processed slivers gave the highest recovery. Averaged SCN recoveries from two AFIS units ranged from 26 to 100% (theoretical). These results helped to explain why the AFIS analysis of SCN counts in processed cotton is lower than by the microscopic analysis.

U.S.-produced cotton is among the cleanest available in the world; however, pieces of sheet plastic are found occasionally in cotton bales produced in the U.S. Standard cotton ginning equipment is not efficient in removing plastic contaminating seed cotton. The purpose of this work was to examine how selected operating conditions affect the sheet-plastic removal efficiency and fiber loss of one type of gin cleaning machine, the cylinder cleaner. In the first part, two sources of plastic were each tested in a central composite design, varying air flow rate through the machine, seed cotton processing rate, and size of plastic contaminant. In the second part, only one plastic source was used, but two cotton cultivars were tested in a central composite design. An additional response surface variable, cylinder rotation speed, was evaluated. Plastic removal increased linearly with increasing air flow rate and decreasing size of the plastic pieces. The effect of seed cotton processing rate on plastic removal was less significant than the effect of air flow rate or plastic size in the first part and was not statistically significant in the second part. The plastic from shopping bag material was removed more effectively than module wrap material. More plastic was removed at lower cylinder rotation speeds. Fiber loss increased with higher air flow rates or cylinder rotation speeds and lower seed cotton processing rates. Lower cylinder rotation speeds increased plastic removal and decreased fiber loss; selecting the optimum air flow rate was a compromise between plastic removal and fiber loss.

A total of seven source fiber types were selected for use in the manufacturing of nonwoven roll goods: polyester; polypropylene; rayon; greige cotton from two sources; mechanically cleaned greige cotton; and scoured and bleached cotton. The microbial burden of each source fiber was measured as a preliminary assessment of microbial contamination using heterotrophic spread plate counts. Greige cotton fibers exhibited the highest levels of total microbial contamination, which were reduced by both storage time and trash removal in the form of mechanical cleaning. Changes in microbial burden levels were measured at each step in the nonwoven manufacturing process. The hydroentanglement process resulted in the greatest overall reduction in microbial burden with no detectable levels of aerobic microbial contamination present on any of the final hydroentangled roll goods regardless of the source fiber. No detectable levels of aerobic microbial regrowth were observed on any fabrics despite storage time or ambient storage conditions. Analysis of suspended solids present in hydroentanglement effluents collected during fabric production revealed significantly less suspended solids from synthetic fibers compared to all cotton fiber types. The study provided insight and potential guidelines that could be incorporated into a nonwoven processing line to ensure specific sterility requirements are met for various converters in end-uses such as hygiene and medical applications.

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.

Effects of supplemental irrigation and graded levels of nitrogen (N) on cotton yield and fiber quality were investigated in the Mississippi Delta in 2011 and 2012. Cotton was planted in 48 experimental plots with irrigation as main treatment unit and N application rate (0, 39, 67, 101, 135, and 168 kg ha -1 ) as subunit. Supplemental irrigation was conducted based on soil-water sensor measurements. Cotton yield was determined using a boll buggy equipped with load cells. Cotton samples were collected and ginned, and the fiber quality was evaluated. Statistical analyses on the effects of irrigation and leaf N on the yield and fiber quality indicated that compared with non-irrigated cotton, the irrigated cotton increased seed cotton yield by 14%. Leaf N content varied in a range of 3.27% to 5.86% with an average of 4.34%. Leaf N of irrigated plants was 9.0% and 3.6% higher than that of the non-irrigated plants in 2011 and 2012, respectively. Soil water stress had a negative effect on N uptake of cotton plants. Yield showed a positive linear correlation with leaf N content in both irrigated and non-irrigated plots. Irrigation improved fiber quality, including all fiber length parameters. Upper half mean length (UHML) of cotton fiber in irrigated treatment was 2.7% and 1.8% greater than that in the non-irrigated treatment in 2011 and 2012, respectively. Micronaire decreased, and neps and yellowness increased with the increase of leaf N under irrigated and non-irrigated conditions. Excessive application of N would not be beneficial to fiber quality and could possibly create negative impact on some properties of cotton fibers.

Increased prices for greige cotton paired with an increase in domestic consumption of cotton and a push to increase sustainability requires a means to reduce costs for domestic textile mills while increasing the availability of raw materials to be processed and reducing the environmental impact of cotton production. Gin motes, and other cotton byproducts, are often viewed as waste materials which must be disposed of at a cost to the ginner. It is understood that some percentage of mote material is of sufficient quality to be used in textile processing. However, it is not known what amount of mote material is actually fiber of sufficient quality, nor is it understood how to best assess the mote material for determination of lint quality. Motes of various quality were collected and subjected to a battery of tests in an effort to assess both the lint quality and quantity as well as the test methods themselves. Motes were used in various combinations, up to 40% by weight, with greige cotton to produce medium count open end rotor spun yarns. The yarns were subjected to a battery of tests to assess the quality of the blended yarns. The goal of this research is to assess the potential for gin motes to be used in textile processing without reducing the overall quality of textile goods.

Four cotton cultivars were ginned with a saw-gin equipment line and also with a high-speed roller-gin line. The saw-gin line using an air-jet and controlled-batt saw-type lint cleaner was compared to the high-speed roller-gin line using two versions of an experimental lint cleaner, of a basic design not used with commercial roller ginning, one design with a lint reclaimer and the other without the lint reclaimer. The high-speed roller-gin processed the seed cotton at the same rate as the saw-type gin stand per m of machine width; however, the roller-gin stand is narrower than the saw gin stand. The roller-gin line produced lint with better fiber length properties than the saw gin line. The roller-gin stand did less damage to the fiber than the saw-gin stand and the experimental lint cleaner, with or without the reclaimer, did less damage to the lint than the controlled-batt saw-type lint cleaner. Fewer neps were created in the roller-gin line than the saw-gin line. The experimental lint cleaner did not remove as much non-lint as the traditional controlled-batt lint cleaner, about ¾ as much, but cleaned well and the measurements of the negative effects of the lint cleaner were not statistically significant for the experimental cleaner but were significant for the traditional cleaner. The fiber processed with the lint cleaner with the reclaimer had somewhat lower quality than the fiber processed with the same lint cleaner without the reclaimer. Also, the lint cleaner with the reclaimer removed nearly as much material as without the reclaimer. Therefore, the reclaimer will not be included in further testing.

Cotton strippers have used extractor type cleaners for many years to remove large foreign material from harvested seed cotton. These machines are commonly referred to as “field cleaners” and are similar in design and operation to stick machines used in cotton gins. The field cleaners used on modern cotton strippers are capable of processing burr cotton at the harvesting rate of four row strippers but are overloaded when used on strippers with six- and eight-row-wide headers. The objective of this work is to report on the design and optimization of a new field cleaner with improved cleaning performance and processing capacity. A 0.305 m (1 ft) wide prototype machine was constructed and used in a response surface experiment to optimize cleaning performance and lint loss. Predictive equations were developed using five configuration factors: loading rate per unit width, primary saw cylinder speed, reclaiming saw cylinder speed, primary saw grid spacing, and reclaiming saw grid spacing. As observed in previous work, the results indicate that a balance must be reached in the trade-off between maximizing cleaning performance and minimizing lint loss. The results also indicate that the experimental machine is capable of reaching 60% cleaning efficiency but that additional design modifications and testing are necessary for the machine to reach the lint loss design goal of less than or equal to 1%.

Traditionally seed cotton has been stored in modules from the time it was harvested until it was ginned. These modules have been formed using additional equipment and operators. In an effort to improve the efficiency of cotton production by reducing the number of operators and equipment, two newer harvesters have been introduced which form modules on the harvester. These modules are smaller than the traditional modules, one being an approximately half-sized rectangular module and the other having a round cross section holding approximately one fourth the seed cotton of a traditional module. Data and samples were obtained at seven gins located in four states to determine if significant problems in ginning were related to the newer modules. Cotton degradation was observed when loose seed cotton was placed at the ends of modules and when modules were

Traditionally bale 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 which occurred 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 the different bagging materials on bale weight changes, Universal Density cotton bales were formed with relatively dry lint. They were then covered with different types of bale bagging materials, and the bales stored in a humid environment for more than two months. The bale coverings 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 bales were weighed periodically during storage. The bale weights were modeled with a nonlinear model exponential temporally. Different bales in the same bagging type changed weight at the same rate. 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 allow simplified communication of the effect bale bagging has on the rate of change of cotton bale weight during storage.