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棉 花 学 报 Cotton Science 2008，20(1)：45-50
Effect of Cultivation Approach on Fiber Quality of High Quality Cotton Abstract：The 2-year field trial about planting densities, nitrogen fertilization and chemical regulation was conducted on Kemian 3, a excellent high fiber quality cotton cultivar, to analyze the effect of cultivation approach on fiber quality of high quality cotton in Nanjing city, in 2005 and 2006. The result showed that there were significant difference of fiber quality traits among rot bolls and bolls setting in different growth stages. The rot boll ratio and boll temporal distribution were altered with cultivation approaches, thus the fiber quality was affected. The rot boll ratio of bolls setting before August 15th was increased 5 to 10 times or more with the treatments of over nitrogen fertilization and non-chemical regulation. This indicated that over nitrogen fertilization and deficient chemical regulation were key cultivation approaches to increasing rot boll ratio. The total nitrogen content of plant and different organs at later-stage had significant positive correlations with the mean rot boll ratio. So reducing the nitrogen fertilization at later-stage was in favor of decreasing the rot boll ratio. With increasing nitrogen fertilization, the boll temporal distribution was deferred; and with increasing planting density, the ratio of bolls setting from July 21th to Augustt 15th was decreased and that before July 20th and after August 25th was increased; and with increasing chemical regulation, the ratio of bolls setting in early-and mid-stage was increased and that mid-and later-stage was decreased. The results suggest that to realize the purposes of improving fiber quality by means of decreasing the ratio of rot bolls and increasing that of finer fiber quality bolls, the cultivation approaches was to maintain optimal planting densities, nitrogen fertilization and chemical regulation. The strategy of nitrogen fertilization was to increase in early-stage, to maintain in mid-stage, and to reduce in later-stage, respectively; and that of chemical regulation was to increase slightly in whole grouth period, that was to reduce before flowering, maintain in flowering, and increase in budding termination.
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