B M V V M H VJD VC *2 lint cleaners were used for all modules

Transcription

1 Sala Especializada 1:Incidência da colheita e do beneficiamento na preservação da qualidade da fibra EFFECT OF HARVESTING METHODS ON FIBER AND YARN QUALITY Eric F. Hequet 1,2 ; Randal K. Boman 3 ; John Wanjura 4 1 Fiber and Biopolymer Research Institute Texas Tech University, Lubbock, Texas (eric.hequet@ttu.edu) 2 AgriLife Research, Lubbock, Texas 3 Oklahoma State University, Altus, Oklahoma 4 USDA-ARS, Lubbock, Texas Large-scale tests undertaken by Texas A&M AgriLife Extension Service in Lubbock were the basis for our investigations. The tests were conducted at eight locations in the Southern High Plains over a three-year period. Each test consisted of 4 large plots. Each large plot was divided into two blocks. Each block corresponded to one module. Half of the blocks were harvested with a brush-roll stripper with field cleaner and half with a spindle picker. The stripped cotton was commercially ginned with the usual industrial sequence for stripper harvested cotton. The commercial gins used a less aggressive ginning sequence for the picker harvested cotton (bypassing some seedcotton cleaners and one lint cleaner). A total of 64 modules were generated across all sites and years. From each module, one bale was purchased. Then, the lint was processed through our short staple ring spinning facility according to the protocol delineated in Faulkner et al. (2011). Prior to processing, the lint was tested on both High Volume Instrument (HVI - 4 micronaire readings 4 colors 10 length/strength) and Advanced Fiber Information System (AFIS - 5 replications of 3,000 fibers). The yarns produced (RS 30Ne carded with a knitting twist) was tested on the Scott Tester (10 bobbins tested), the UT3 (400 meters per bobbin and 10 bobbins), and the UTR3 (10 breaks per bobbin and 10 bobbins). The location codes are shown Table 1. Table 1. codes Year Producer Code B M V V M H VJD VC *2 lint cleaners were used for all modules * 1-Fiber results Figures 1 shows a significant improvement in micronaire for picker harvested cottons when the micronaire is relatively low, while for higher micronaires the differences between harvesting methods tend to be negligible. For HVI Upper Half Mean Length (UHML), picker harvested cottons show improved length compared to stripper harvested cottons (Figure 2). Nevertheless, the improvement in length is quite small (about one hundredth of an inch on average). This slight

2 HVI UI, % HVI UHML, inch HVI Micronaire length improvement goes together with a better length uniformity index (Figure 3) revealing a better fiber length distribution for picker harvested cottons (+0.5% UI). HVI tensile properties (strength and elongation) are about the same for picker and stripper harvested cottons (data not shown) Harv. * Figure 1. HVI micronaire Harv. ** Harv. * Loc. NS Figure 2. HVI Upper Half Mean Length Harv. * Loc. NS Figure 3. HVI Uniformity Index

3 Neps, count/g HVI +b HVI Reflectance, % Cotton lint color (Figures 4 and 5) also tends to be better for picker harvested cottons with higher reflectance and lower yellowness (+0.6 and -0.3 respectively) Harv. ** Harv. * Loc. ** Figure 4. HVI Reflectance Harv. * Loc. * Figure 5. HVI Yellowness For HVI fiber properties, picker harvested cottons tend to have slightly better fiber quality than stripper harvested cottons especially for lower micronaire cottons. However, this improvement is relatively small. The situation is quite different with AFIS fiber properties. The number of neps for picker harvested cottons is drastically reduced (-130 neps/gram, Figure 6) and the mean length by number is significantly improved (+0.03 inch, Figure 7) especially for lower micronaire cottons. As expected, this goes together with a significant decrease in visible foreign matter content (-0.8%, Figure 8) Harv. * Figure 6. AFIS Nep count

4 Fineness, mtex VFM, % L(n), inch Harv. * Figure 7. AFIS Mean Length by number Harv. * Figure 8. AFIS Visible Foreign Matter Content Finally, AFIS fineness, immature fiber content, and maturity ratio are all improved with picker harvesting (Figure 9 through 11) Harv. * Loc. * Figure 9. AFIS Fineness

5 Maturity ratio IFC, % Harv. * Loc. ** Figure 10. AFIS Immature Fiber Content Harv. * Loc. NS Figure 11. AFIS Maturity Ratio These findings could be summarized as follows: harvested cottons have on average better fiber properties especially for AFIS fiber properties: Micronaire: (+4.3%)* UHML: inch (+0.7%) UI: +0.5 % (+0.6%) Reflectance: 0.6 % (+0.8%) and Yellowness: -0.3 (-3.2%) Neps: -130 count/g (-29.0%) UQL: inch (+1.4%) L(n): inch (+3.3%) L(n)CV: -2.3 % (-4.3%) SFC(n): -2.5% (-8.6%) VFM: -0.8% (-35.9%) Fineness: +2.9 mtex (+1.9%) IFC: -0.7 % (-7.3%) MR: (+1.2%) *100 x (picker )/

6 CVm, % Total waste, % 2- Carded yarn results As anticipated, the amount of waste during opening and carding (Figure 12) is lower for picker harvested cottons. For yarn evenness, carded ring spun yarn quality also shows a clear advantage for picker harvested cottons (Figures 13 through 17). For yarn tensile properties (data not shown) there is no advantage for picker harvesting Harv. * Figure 12. Total waste (opening waste + card waste) Harv. * Figure 13. RS yarn 30Ne carded: Coefficient of variation (CVm) Uster 50%

7 Neps 200%, count/km Thick places, count/km Thin places, count/km Harv. * Loc. ** Uster 50% Figure 14. RS yarn 30Ne carded: Thin places Harv. * Uster 50% Figure 15. RS yarn 30Ne carded: Thick places Harv. * Uster 50% Figure 16. RS yarn 30Ne carded: Neps (200%)

8 Hairiness Harv. * Uster 50% Figure 17. RS yarn 30Ne carded: Hairiness These findings could be summarized as follows: harvested cottons have on average better yarn quality: Opening waste: -0.5% (-15.5%) Card waste: -0.7% (-16.5%) CVm: -0.39% (-2.4%) Thin places: -4 count/km (-18.8%) Thick places: -49 count/km (-18.4%) Neps 200%: -99 count/km (-24.4%) Total yarn imperfections (IPI): -151 count/km (-21.9%) Hairiness: (-2.9%) In conclusion, for lower micronaire cottons, picker harvesting is clearly beneficial. It results in better fiber quality; more importantly, it results in better yarn quality for all evenness-related parameters. However, in micronaire readings ( 4.0) were much higher than in and In these conditions, it appears that picker harvesting benefits only marginally yarn quality. Acknowledgments The authors acknowledge support of this work by the Plains Cotton Improvement Committee, Cotton Incorporated, the Texas Department of Agriculture, and the International Cotton Research Center Literature Faulkner W.B., J.D. Wanjura, E.F. Hequet, R.K. Boman, B.W. Shaw, and C.B. Parnell Evaluation of Modern Cotton Harvest Systems on Irrigated Cotton: Yarn Quality. Applied Engineering in Agriculture. 27(4)