Flax (Linum usitatissimum L.) is a potential winter crop for the Southeast USA that can be grown for both seed and fiber. The objective of this research was to evaluate the effect of irrigation on flax straw, fiber, and seed yield of fiber-type and seed-type cultivars at different flax growth stages. The study was conducted during the winter growing seasons of 2010/2011, 2011/2012, and 2012/2013 near Florence, SC. Four fiber-type cultivars and one seed-type cultivar were grown with and without irrigation for two years. The four fiber-types were evaluated for straw and fiber yield in the third year. Soil water was monitored to trigger irrigations. Irrigation was applied before all four harvests in 2010/2011, before only the last harvest in 2011/2012, and was not applied in 2012/2013. Straw harvests were made at the onset of flowering, 10 days past the onset of flowering, 20 days past the onset of flowering, and when seeds were mature. Seed harvests were made at the end of the 2011/2012 and 2012/2013 growing seasons. In 2010/2011, plots had to be replanted in February so crop development was delayed. Irrigation increased straw yield at the last three harvests in that year. In the other two years, when planting occurred at normal times in the fall, irrigation did not influence straw or fiber yield. Irrigation had no significant effect on seed yield. The fiber-type cultivars did not differ for straw or fiber yield. At the onset of flowering harvest, the seed-type cultivar had similar fiber content to the fiber-type cultivars. The fiber-type cultivars had higher fiber content in later harvests. The results support previous research in that fiber-type cultivars appear viable for production as fiber winter crops in the region. The results also suggest that high straw yielding seed-type cultivars could be used, especially in systems with early straw harvests.

Flax (Linum usitatissimum L.) is a winter crop in the southeastern United States that has potential in double cropping systems. This research was conducted to provide estimates of N, P, K, Ca, Mg, and Zn removal in the harvested portions of the crop (straw and grain). Four fiber‐type cultivars and one seed‐type cultivar were grown with and without irrigation for 2 years. The four fiber‐types were grown without irrigation in the third year. Nutrient concentrations were determined on the straw and grain in the first 2 years when the crop was harvested at seed maturity. In the third year, only nutrient concentrations in the straw were measured. Irrigation had a very limited impact on straw and grain nutrient concentrations. Differences among years were greatest for K concentration in the straw as K concentration in 2011 to 2012 was >1.00% and almost five times greater than in the other two years. Higher K concentration in that year is likely due to differences in the amount of K leached from the straw before it was harvested. Differences occurred between the fiber‐type cultivars and the seed‐type cultivars for both straw and seed nutrient concentration, but these were generally small. Nutrient removal in the flax straw and grain were primarily dependent on biomass. Our results indicate a flax straw crop of 5000 lb per acre will remove 48 lb N, 8 lb P, 13 to 56 lb K, 17 lb Ca, 9 lb Mg, and 0.28 lb Zn per acre.

Natural fibers for many and varied industrial uses are a current area of intense interest. Production of these fibers, furthermore, can add to farmer incomes and promote agricultural sustainability. Flax (Linum usitatissimum L.), which has been used for thousands of years, is unparalleled in supplying natural fibers for industrial applications as diverse as textiles and paper, providing high value linseed and fiber from a single plant, and maintaining sustainable agriculture in temperate and subtropical climates for summer or winter production, respectively. As a value-added replacement for glass fiber from a renewable resource, flax fiber is recyclable, biodegradable, and sustainable for the economy, ecology, and society. To the point, Daintier Chrysler reported that natural fibers for automotive components required 83% less energy and were 40% less expensive than glass fiber components. A better understanding of the fiber characteristics that influence composite performance could lead to the development of additives, coatings, binders, or sizing suitable for natural fiber and a variety of polymeric matrices. Stems of flax require retting to separate fiber from nonfiber components and rigorous mechanical cleaning to obtain industrial-grade fibers. Considerable work has been undertaken to improve the retting process using specific cell-free enzymes, especially pectinases, to control and tailor properties for industrial applications. Fiber processing and use in composites are affected by variables such as length, uniformity, strength, toughness, fineness, surface constituents, surface characteristics, and contaminants. One of the main concerns for the composite and other industries in incorporating natural fibers, such as flax, into production parts is the fiber variability resulting from crop diversity, retting quality, and different processing techniques. Standardized methods to assess flax fiber properties, therefore, are needed to maintain quality from crop to crop and provide a means to grade fibers for processing efficiency and applications. Other parts of the plant stalk, notably the waste shive and dust, can potentially be utilized as coproducts to offset costs for producing the major products of fiber and seed.

Flax (Linum usitatissimum L.) fibers can be blended with other short staple fibers, such as cotton (Gossypium barbadense L. or Gossypium hirsutum L.), processed into a yarn, and then manufactured into a fabric. Enzyme-retting is a new, experimental method that decomposes the pectinaceous and matrix substances to separate cellulose fibers from shives using pectinase-rich enzymes and chelators. Spinning tests were used to determine how well fibers were assembled to form yarn and provided an indirect measurement of fiber properties. Miniature spinning allows expanded predictive strategies for ranking fiber production methods such as enzyme-retting and resultant yarns beyond traditional fiber testing.

Flax (Linum usitatissimum L.) is an agricultural crop that is being considered as cost effective alternative to glass in composites. Flax is nature's composite with strong bast fibers held together in bundles and located in the outer regions of the plant stem between the outermost cuticle-epidermis layer and the innermost, woody tissues. Agricultural production of this crop is environmentally beneficial because it is produced through photosynthesis and considered a naturally renewable and sustainable material. Its use in bio-based composites could help lessen our dependence on fossil fuels today and into the future. Despite the longevity of flax in world markets, particular problems exist to provide flax fiber economically for markets in the US and North America. Barriers to such provisions include consistent, high-quality retting methods, efficient processing of whole steins into cottonized fibers, and development of standards to judge fiber quality. Processability of plant stalks into usable fiber requires retting which selectively removes pectinaceous and matrix substances thus separating cellulose fibers from non-fibrous substances and easing mechanical cleaning. Enzymes have been tested for efficiency of retting, and recommendations are in place for particular fiber properties. Before this work began, no processing facilities existed in North America for producing high value fibers. To facilitate research on bast fiber retting and subsequent processing, the Flax Fiber Pilot Plant (Flax-PP), was designed and modified after the 'Unified Line'; it is the only research facility of this type in the US and effectively processes and extracts bast fibers from plant stalks. A separate cottonizing unit has been installed to complete processing of fibers for various applications. Each processing step creates a fiber product and byproduct both with potential uses in composites. The development of standards through ASTM International is a continuing project. Currently, emphasis is on new equipment to quantify properties of particular usefulness such as cleanliness, fineness, and color. The Flax-PP becomes a valuable tool for improving fiber processing and quality, and thus integrates all activities for a flax fiber industry in North America.

Enzymes have the potential to provide an improved method to ret flax for textile fibers. Retting is the separation or loosening of fiber bundles from the cuticularized epidermis and the woody core cells. New commercial pectinase products were evaluated both with and without ethylenediaminetetraacetic acid (EDTA) for retting efficiency. The Fried Test identified the most efficient enzymes and best retting conditions. All enzymes retted flax stems better in the presence of 18 mM EDTA. Pectinases that also contained cellulases reduced fiber strength, whereas those without cellulases effectively retted flax without substantial strength loss. Viscozyme, which has been used extensively in our enzyme-retting research, and several pectinolytic enzymes were compared in pilot plant scale tests. Texazym BFE and Bioprep 3000 L retted flax as well as Viscozyme in this system, and the fibers had higher tenacity. The monocomponent nature, commercial availability and price, and ability to ret flax in combination with EDTA at high pH indicated a potential advantage for Bioprep 3000 L in these tests. Retting with different enzymes and formulations resulted in fibers with different properties, thereby leading to protocols for tailored fiber characteristics.

There currently are no data on using reduced tillage for flax (Linum usitatissimum L.) production when double-cropped after cotton (Gossypium hirsutum L.) in the southeastern USA. This study evaluated how tillage and subsoiling influenced double-cropped flax and cotton productivity and quality under conditions in the southeastern USA. An irrigated study on a loamy sand soil (Eunola loamy sand) was conducted beginning in spring 2001 through spring 2003. Treatments evaluated in both crops were subsoiling (subsoiled to 30-cm or none) and tillage (chisel plow to 20-cm plus disking, disking only, and no tillage). Standard fiber test methods were used to evaluate treatment effects on fiber properties. Subsoiling increased the cotton and flax yield. Cotton yields were not influenced by tillage treatment while flax dry plant matter yields were greater for chisel and disk treatments compared with the no-tillage treatments. Fiber properties, cotton micronaire, fiber length, and fiber length uniformity, and flax fiber strength were impacted by tillage. Our results indicate that for this double-crop system, no tillage with subsoiling is a viable practice for cotton but further research is needed to improve flax productivity with this management practice.

Flax (Linum usitatissimum L.) is an important commercial crop that supplies both linseed and bast fibers for multiple applications. Retting, which is a microbial process, separates industrially useful bast fibers from non-fiber stem tissues. While several methods (i.e., water- and dew-retting) are used to ret flax, more recently enzymes have been evaluated to replace methods used currently. Alkaline pectate lyase (PL) from the commercial product BioPrep 3000 and ethylenediaminetetraacetic acid (EDTA) from Mayoquest 200 as a calcium chelator were used in various formulations to ret flax stems. Retted stems were then mechanically cleaned through the USDA Flax Fiber Pilot Plant and passed through the Shirley Analyzer. The PL and chelator effectively retted flax from both fiber flax and linseed stems, and the use of enzyme plus chelator retted flax stems better than either component alone. Fiber yield and strength were greater than retting with a mixed-enzyme product that contained cellulases. Retting with PL and chelator was optimized based on fine-fiber yield, remaining shive content, and fiber properties. PL at levels of about 2% of the commercial product for 1h at 55°C followed by treatment with 18mM EDTA for 23–24h at 55°C provided the best fibers based on these criteria. Yield and fiber properties determined by these tests were not improved with PL levels of 5% of the commercial product.

Development of a flax (Linum usitatissimum L.) industry in North America is desired to supply a domestic source of clean, consistent quality textile fiber for blending with cotton. The objective of this work was to evaluate portions of traditional cotton gin equipment (extractor feeder and lint cleaner) and the “50-g cotton-spinning test (CST)” for flax. Dust was collected on an area sampler in an isolated card room to evaluate dust potential during textile pilot plant processing. Fibers retted by diverse means were cleaned on two separate portions of Continental Eagle's pilot plant cotton gin stand, the Super 96 Feeder and the 24D lint cleaner. Fibers separated and removed from flax stalks by these gin sections were compared against the standard ‘unified line’ processing technique of the USDA Flax Pilot Plant. Test yarns were then made in a CST with cotton and flax blends to provide an indirect measurement of fiber properties that can be related to the retting and gin cleaning processes. The yarns were tested for strength and evenness. Flax fibers that displayed the most favorable properties in the CST were then spun in 23kg lots in the pilot plant at the following cotton/flax blend ratios: 100/0, 75/25, 50/50, 25/75, and 20/80. With modifications, it appears that portions of a cotton gin stand are able to process adequately small samples of properly retted flax stalks. The CST with minor adjustments provides useful data for ranking and further large-scale flax processing. As expected, it appears that flax fiber can be successfully cleaned on a cotton processing line and that increasing the amount of flax generates additional dust.

United States is pursuing natural fibers as sustainable, environmentally friendly sources for a variety of industrial applications. Flax (Linum usitatissimum L.) fiber offers many possibilities towards this goal. Specific United States Department of Agriculture (USDA) research objectives are to: (1) evaluate traditional farm equipment for flax production, (2) improve retting, especially through use of enzymes, (3) develop objective standards for fiber quality testing, and (4) test fibers for manufacturing performance and/or aesthetic properties. Fiber flax for short staple uses can be rapidly harvested by equipment readily available on US farms. Warm southern climates allow this crop to be grown in the winter to produce flax on traditionally dormant fields. Enzymes to extract fibers provide an environmentally friendly method for reliable and sustainable agriculture. Commercial enzymes and calcium chelating agents provide a key step in the economic development of a controlled and scientific approach to efficiently produce fibers of high and consistent quality. A USDA Flax Pilot Plant based on commercially available equipment provides better understandings of fiber quality parameters, fiber standards, processing costs, and eliminates uncertainties of raw material supply. ASTM International standards are being developed to judge flax fiber for quality related to processing and marketing decisions. Flax fiber blended with cotton and spun by vortex, rotor, and ring-spinning equipment at the Cotton Quality Research Station (CQRS), ARS-USDA, provide a final stage of evaluation.

对纤用亚麻(阿里安)与北达科他州油用亚麻茎进行酶法脱胶实验。脱胶酶制剂含Viscozyme L(富含果胶酶的成品酶)和乙二胺四乙酸(螯合剂EDTA)。碾压破裂后的亚麻茎浸吸不同比例的Viscozyme L-EDTA溶液,脱胶后纤维进行梳纺。供测纱样为Shirley机清理的原亚麻纤维与棉花纤维按不同比例混纺而成的纱。处理不同,清理后的纤维性质有所不同。不同配比的酶溶液脱胶后的纤维性质不同,不考虑EDTA的因素,0.3%(v/v)的酶浓度比0.05%的酶浓度脱胶效果好,但纤维强力低。麻样与酶制剂不同,混纺纱的质量变异系数、单纱强力与粒结数存在差异。以成本、纤维和纱的质量为依据,本实验结果确立了脱胶酶制剂的组分含量范围,可作为进一步研究优化亚麻脱胶酶制剂的基础。本实验中,0.3%v(v/)Viscozyme L与25m MEDTA配制的酶溶液脱胶制成的纱最好。因此,可以此为基础进一步研究开发工业级纺织用亚麻短纤维。

Manufacturing composites with polymers and natural fibers has traditionally been performed using chopped fibers or a non-woven mat for reinforcement. Fibers from flax (Linum usitatissimum L.) are stiff and strong and can be processed into a yarn and then manufactured into a fabric for composite formation. Fabric directly impacts the composite because it contains various fiber types via fiber or yarn blending, fiber length is often longer due to requirements in yarn formation, and it controls the fiber alignment via weaving. Composites created with cotton and flax-containing commercial fabrics and recycled high-density polyethylene (HDPE) were evaluated for physical and mechanical properties. Flax fiber/recycled HDPE composites were easily prepared through compression molding using a textile preform. This method takes advantage of maintaining cotton and flax fiber lengths that are formed into a yarn (a continuous package of short fibers) and oriented in a bidirectional woven fabric. Fabrics were treated with maleic anhydride, silane, enzyme, or adding maleic anhydride grafted polyethylene (MAA-PE; MDEX 102-1, Exxelor® VA 1840) to promote interactions between polymer and fibers. Straight and strong flax fibers present problems because they are not bound as tightly within yarns producing weaker and less elastic yarns that contain larger diameter variations. As the blend percentage and mass of flax fibers increases the fabric strength, and elongation generally decrease in value. Compared to recycled HDPE, mechanical properties of composite materials (containing biodegradable and renewable resources) demonstrated significant increases in tensile strength (1.4–3.2 times stronger) and modulus of elasticity (1.4–2.3 times larger). Additional research is needed to improve composite binding characteristics by allowing the stronger flax fibers in fabric to carry the composites load.

SUMMARY Mature Ariane flax was retted with various proportions of the commercial enzyme mixture Viscozyme L (0.05, 0.1, 0.2, and 0.3% of product as supplied) and ethylenediaminetetraacetic acid (4,7, and 18 mM) from Mayoquest 200. Retted material was then cleaned through the USDA Flax Fiber Pilot Plant (Flax-PP) consisting of the following: 9-roller crushing colander, top shaker, scutching wheel, and 5-roller grooved colander. To simulate cottonization of fiber for use in textiles, the Flax-PP-cleaned fiber was passed 1 × through a Shirley Analyzer. Fiber yields and properties (strength, elongation, fineness, and color), which were determined for the various processing stages, were influenced by various formulations and by processing stage. For this flax sample, 0.05% Viscozyme plus 18 mM EDTA produced the highest yield of Flax-PP and Shirley-cleaned fibers, strong fine fibers of light color, and the strongest coarse fibers from Shirley by-product material. Key Words: FlaxviscozymeMayoquest 200EDTAFlax-PPpilot plantrettingcleaning

The purpose of this study was to determine if various tillage and sub-soiling techniques were detrimental or beneficial to winter flax (Linum usitatissimum L.) yields under South Carolina conditions. Flax was double-cropped with cotton. Subsoiling increased the cotton and flax yield which is similar to findings for other crops on southeastern USA Coastal Plain soils. Cotton yields were not influenced by tillage treatment while flax dry plant matter yields were significantly greater for chisel and disk treatments than for no tillage. For the fiber properties studied, micronaire, fiber length, and fiber length uniformity of cotton along with flax fiber strength were impacted by the tillage management studied. Cotton fiber properties are such that conservation systems appear to be a viable option for growers due to fiber property improvements. Fiber flax yield and fiber properties indicate additional field preparation may be required to produce increased yields with improved fiber properties. Our results indicate that conservation tillage practices can be beneficial for cotton production under Florence, SC growing conditions but additional research on improved techniques is needed for the production of fiber flax with this management practice.

Municipal solid wastes generated each year contain potentially useful and recyclable materials for composites. Simultaneously, interest is high for the use of natural fibers, such as flax (Linum usitatissimum L.), in composites thus providing cost and environmental benefits. To investigate the utility of these materials, composites containing flax fibers with recycled high density polyethylene (HDPE) were created and compared with similar products made with wood pulp, glass, and carbon fibers. Flax was either enzyme- or dew-retted to observe composite property differences between diverse levels of enzyme formulations and retting techniques. Coupling agents would strengthen binding between fibers and HDPE but in this study fibers were not modified in anyway to observe mechanical property differences between natural fiber composites. Composites with flax fibers from various retting methods, i.e., dew- vs. enzyme-retting, behaved differently; dew-retted fiber composites resulted in both lower strength and percent elongation. The lowest level of enzyme-retting and the most economical process produces composites that do not appear to differ from the highest level of enzyme-retting. Flax fibers improved the modulus of elasticity over wood pulp and HDPE alone and were less dense than glass or carbon fiber composites. Likely, differences in surface properties of the various flax fibers, while poorly defined and requiring further research, caused various interactions with the resin that influenced composite properties.

Abstract New methods for retting flax are sought to overcome problems in the current method of dew-retting of flax. Published data are reviewed and new data presented on the development and testing of a method to ret flax using pectinase-rich enzyme mixtures plus chelators based on cost and fiber yield and properties. In spray enzyme retting (SER), flax stems are crimped to physically disrupt the plant's protective barrier and then sprayed until soaked with, or briefly immersed in, an enzyme/chelator formulation. Flax is then incubated at temperatures optimal for enzyme activity, washed, and dried. Pilot scale tests, conducted with 10 kg samples of flax retted with a series of formulations, showed that this method effectively retted flax stems from a variety of sources, including fiber flax, mature fiber flax, and linseed straw. Fiber yield, strength, and fineness were significantly influenced by variations in enzyme-chelator amounts. Cellulases inpectinase mixtures appeared to preferentially attack dislocations in fibers and fiber bundles resulting in loss of fiber strength. Polygalacturonases alone effectively separated fiber from non-fiber components. The SER method proved to be an effective framework for further tests on enzyme-chelator formulations that now must be integrated with physical processing to optimize the extraction of flax fibers based on cost and fiber yield and properties. Key Words: Pectinaseschelatorsfiber yieldstrengthfinenessfibernodesmicroscopy

Flax fiber and oilseed use is increasing in textiles, composites, paper/pulp and industrial/nutritional oil sectors in the U.S. As a winter crop, flax fits well into double-cropping systems in the southeastern U.S. Flax can be harvested as an early crop for fiber, with attached immature seeds, or harvested as a late, mature crop, for both seed and fiber production. Flax can be grown and harvested for fiber using equipment that is readily available and well understood by U.S. farmers.

SUMMARY Although traditional linen in Europe is constructed with long-line fibers, many industry analysts indicatethat the largest use for US textiles will be as short staple flax fibers blended with cotton or other fibers. Thelow load-bearing cost of flax fibers in composites might predict its potential use in composites and otherindustrial products. Agricultural operation of flax is currently feasible with available US equipment. Cropyields are acceptable and may lead to the establishment of a flax industry in the US. US grown flax stems aresuitable for dew- or enzyme-retting to be utilized in the textile, composite, or paper/pulp industries. ASTMtest methods and practices are currently being developed to grade flax fibers for length, strength, fineness,color, fineness, and trash to aid in marketing. Results suggest that enzymes-retting could produce fibers withparticular properties, thus providing diversity in fiber characteristics for various applications. This retting canbe performed utilizing commercial enzyme and chelator products. Enzyme-retting and processing can cur-rently be performed at the USDA Flax Pilot Plant with a large scale industrial process coming on-line inKingstree.