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棉 花 学 报 Cotton Science 2006，18(3)：175-179
Effects of Potassium on Yield of Cotton ( Gossypium hirsutum L.) and Optimal Quantity of Potassium in Huanghuaihai Plain, China Abstract：Recently, premature senescence caused by potassium deficiency has become an important problem in cotton production throughout the Huanghuaihai Plain, China. Therefore, field experiments were conducted in Wuqiao, Hebei Province and Xiajin, Shandong Province in 2004. These were carried out to investigate the effects of K fertilizers on yield and yield components of transgenic insect-resistant cotton and conventional cotton. The content of exchangeable potassium in the soil of Wuqiao and Xiajin were 100 and 130mg·kg-1, respectively. The varieties of transgenic insect-resistant cotton used in Wuqiao included DP99B, Jimian668, CCRI 41 and Handan284, in Xiajin included DP99B, Jimian668, Lumianyan21 and Lumianyan22. The varieties of conventional cotton used at the two sites were all CCRI 12 and CCRI 35. By applying 600kg·hm-2 KCl before sowing, the results showed that seed cotton yield averaged across all varieties was increased 20.4% and 6.4% in Wuqiao site and Xiajin site respectively. The number and weight of bolls located in the top sympodial branches (≥10) and the outer nodes (≥3) were enhanced by potassium fertilizer more greatly than those located in the bottom (1～5) and medium (6～10) sympodial branches and inner nodes (1～2). It's noteworthy that there weren't any significant differences between transgenic insect-resistant cotton varieties and conventional cotton varieties in their sensitivity to potassium fertilizer under conditions of this research. Because the content of exchangeable potassium in the soil of the two sites exceeded 90mg·kg-1，the lowest value of potassium supply normally in general soil, there was a need to study further the sensitivity to potassium fertilizer of transgenic insect- resistant cotton varieties under potassium deficiency conditions. Furthermore, this research screened the optimal quantity of potassium fertilizer in Huanghuaihai Plain, and found that applying 150kg·hm-2 KCl could get a great benefit while the exchangeable potassium in soil was 100～130mg·kg-1.
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