Effect Of Root-cutting And Slow-release Fertilizer On The Late Growth Stage's Potassium Uptake And Utilization Of Flue-cured Tobacco

Potassium is the most amoumt of nutrients absorption and one of the important indicators of the quality of flue-cured tobacco. But there has a certain gap between our country and foreign on potassium content. Root and potassium fertilizer are the main factors influencing the potassium content of flue-cured tobacco. So the paper studied the effect of root cutting and application slow-release potassium fertilizer on potassium content. The main results are as follows:1. Root-cutting has bigger effect on root growth, biomass and potassium content.Root-cutting was advantaged to root weight and volume's accumulation. The best treatment was 10 d before topping and depth5 cm.The root activity increased with the cut dept increased; The treatment of root-cutting earlier's dry weight increased with the cut dept increased increased of cutting depth of root cutting treatment early time, but root-cuting at topping, cut dept is not conducive to the accumulation of dry matter; the K uptake, root-cutting at topping is the best to potassium accumulation, potassium content was 2.53 g/strains.But the cutting depth should not be too deep, the conditions of this experiment in a 5 cm well.2. There has smaller effect of slow-release potassium fertilizer on biomass of flue-cured tobacco, and there was no significant difference between the treatment with potassium sulfate. The two season of tobacco potassium content all increased with potassium fertilizer increased, besiades,slow-release fertilizer can improve the potassium content and utilization rate of potassium, especially 75% citric acid soluble,25% water-soluble slow-release potassium fertilizer,in two season the total potassium content and utilization rate reached 18.54 g/strains,80.07%.3.The field experiment results showed that the application of potassium fertilizer was beneficial to the increasing of potassium content in tobacco leaves, the potassium content in different parts of tobacco leaves showed that bottom leaves>lower leaves>middle leaves> stem>upper leaf. Compared with application of K2SO4,the application of high slow-released potassium could significantly increase(p<0.05) potassium content in upper leaves, which reached 27.44g/kg.With the increasing of the application of slow-released potassium fertilizer, total sugar content, reducing sugar content,the ratio of sugar to nicotine and the ratio of potassium to chlorine improved to various extent in different parts of tobacco leaves.However, the total nitrogen and nicotine content decreased and the quality of tobacco leaves improved.4.The field experiment which combined root-cutting with slow-released potassium showed that root-cutting could enhance the biomass of tobacco plants and the potassium in tobacco leaves and was conducive to the accumulation of total sugar and reducing sugar, increased the content of nitrogen, potassium and other mineral elements in tobacco leaves, improved the ratio of sugar to nicotine,nitrogen to nicotine and potassium to chlorine,reduced the nicotine content, improved coordination of the chemical composition of tobacco leaves and the quality of tobacco leaves. In particular,the highest potassium absorbability and optimal chemical composition was the treatment of combining the application of slow-released with root-cutting.