石灰性土壤烤烟含钾量及其累积分布的研究

Study on heightening the potassium content of flue-cured tobacco in calcareous soil areas

通过不同钾水平处理的盆栽试验,采用定位叶片,分析了石灰性土壤上烤烟钾素累积、转移及分配规律,探讨了影响该区烟叶含钾量的主要原因及解决途径。结果表明,烤烟成熟期,根、茎中钾向烟叶中大量转移,烟叶钾的分配率远大于根、茎之和;增施钾肥可减少根、茎钾的转移率,但对各器官中钾的分配比例影响不大。钾素营养不足时,成熟期下部叶片中钾大量向上转移,从而造成下部烟叶含钾量大幅度下降。烤烟生育后期干物质累积速度超过钾吸收速度而引起钾的“稀释效应”,施钾对烟叶含钾量的提高作用在生育后期最为显著。烟叶在成熟期所累积的钾中,约有60%以上分配于上部叶。

Pot experiment treated with different potassium levels is conducted in this paper to study the potassium distribution and accumulation of flue cured tobacco in calcareous soil.The major reason for the lower potassium content in this area is discussed and the possible solution is also posed.The study demonstrated that potassium in root and stem is largely translocated to the leaves.The translocation ratio can be diminished by increasing potassium fertilizer.During mature period,much more potassium in lower leaves translocates to upper leaves if there is a shortage of potassium nutrition,which leads to a significant decrease of the potassium content in lower leaves.In the later period of grows,dry material accumulation velocity is much quicker than that of potassium,which may be the main reason for lower potassium content in leaves in mature period.The effect on heighting the potassium content of leaves is especially significant in the later period of growth after increasing potassium fertilizer.60% of the potassium accumulated in mature period is distributed to upper leaves.This distribution can provide a theory basis for potassium fertilizer topdressing.