EVALUATION OF IN-FIELD MONITORING METHODS TO REDUCE NEPS (IN AUSTRALIAN COTTON)

For Australian cotton issues that have been highlighted as concerns by spinners including: neps (small entanglements of cotton fibers), short fiber (fibers shorter than 12.5 mm), rising contamination and micronaire greater than 4.5. Significant research efforts are being undertaken seeking to optimize cotton fiber quality and enhance the value of Australian cotton through research into direct influences of on-farm agronomic management and climate on fiber development and post-harvest research that investigate the degree of these influences on textile performance in the mill. This paper presents research which is developing in-field monitoring techniques to identify circumstances when crops may have increased levels of neps so these instances maybe avoided. Field experiments were conducted that measured neps in harvested cotton taken from treatments that had harvest aids systematically applied to force bolls open from 1.6% open bolls to full harvest maturity (100% open bolls). The amount of neps (count/g) was significantly related the proportion of bolls open (%), nodes above cracked boll (NACB), and % immature bolls (as defined by the color of the seed coats in cut bolls). The most reliable relationship in predicting change in the amount of neps was % open bolls followed by % immature bolls then NACB. Application of harvest aids after 60% open bolls reduced chances of increasing neps and lowering yield. Substantial increases in neps were avoided despite crops being harvested with 20% immature bolls present. Current research is investigating the feasibility of these monitoring techniques to predict neps in crops that have plants variable in their maturity, and how these treatments impact on textile performance (yarn strength and dye uptake). Introduction In recent years in the Australian cotton industry there have been concerns relating to high micronaire (a measure of fiber fineness and maturity), short fiber content and high incidence of neps (small entanglements of cotton fibers) in Australian cotton (Gordon et al. 2004). Practices aimed at increasing yield or attempts to reduce micronaire by forcing open the last few immature bolls growing at the end of the season to include in the harvest may lead to less mature fibers and increased neps. These issues will be especially exaggerated when crops remain actively growing at the end of a season and then experience an abrupt end caused by a cold finish. Premature application of harvest aids will also cause the same effect. Immature bolls may contain immature cotton fibers which can lower micronaire and make the fibers more prone to the incidence of neps (Gordon 2007). Specifically neps are small entanglements of cotton fibers resulting from dead or immature fibers exaggerated by mechanical processing (Hebert 1988). They are undesirable as they decrease mill processing efficiency and typically absorb less dye and reflect light differently and appear as ‘flecks’ on finished fabrics (Goynes et al. 1997; Anthony et al. 1988). Many studies have shown reductions in micronaire (an indirect measurement of both fiber fineness and maturity) with premature applications of harvest aids (Faircloth et al. 2004a; Bednarz et al. 2002). This study uses timing of harvest aids to explicitly attempt to vary the amount of immature fiber to generate different levels of neps and relate this to various measure of crop status. In identifying these relationships it is anticipated that this information be used to develop crop monitoring strategies that aim to optimize yield and fiber quality (including reduction in neps). 87 2009 Beltwide Cotton Conferences, San Antonio, Texas, January 5-8, 2009