| The content of potassium in tobacco leaves is commonly low in China, notably in north China. The difference in soil serve as the primary factor contributing to the lower potassium content in tobacco leaves in North than in South. 50% of the tobacco planting soils in Shandong Province, and 70% in Huanghuai Area are cinnamon soil, with high pH and carbonate content. The potassium absorption of tobacco plants in cinnamon soil was often restrained by the antagonism between Ca and K. Pot experiments in greenhouse and field experiments were carried out to study the soil moisture conditions, the fertilization at different ratio of N/K, and the translocation and distribution of potassium in ridge. The main results are showed as the follows.1 Maintaining the soil moisture at different level and in different stages could definitely affect the tobacco leaf yields and potassium content. The pot experiment revealed that a high leaf yield could be got when maintaining soil moisture at 80% in the middle stage of tobacco growth, while high K content when maintaining this water condition in the latter stage. The experiments also indicated high leaf yields and potassium content in the treatment of soil moisture at the level of 60% in middle stage and 80% in latter stage respectively.2 The treatment with the N:K2O ratio of 1:2 could increase the weight of tobacco leaves, while decrease the nicotine level under the conditions of abundant nitrogen application. Whereas the treatment with the N:K2O ratio of 1:1 could yield high level of nicotine and total nitrogen.3 Under the conditions of zero potash application, the potassium level in tobacco leaves with less nitrogen fertilization was higher than that with more nitrogen fertilization. With potash application and the same ratio of N and K, the higher nitrogen fertilization could result in higher K content and accumulation. N could promote the K absorption of tobacco plants in cinnamon soil.4 The increasing potassium content and the decreasing Ca and Mg content were observed with increase in potash application rates.5 Potassium content in tobacco leaves was significantly negatively correlated to Ca and Mg content, and there was intensive antagonism of Ca and Mg to K. Potassium content in tobacco leaves was positively correlated to active potassium content in soil highly significantly.6 With the application at 10 and 20 cm depth, potassium transferred upper definitely more than sideways or downwards. In all treatments, potassium in soil above fertilization site reached the peak level at topping time.7 In the treatment of 20 cm deep application, the available potassium content in 15-25 cm deep soil layer was considerably higher than that in the other two treatments. The level of available potassium increased after rosette stage and reached its peak level at topping time, in accordance with the potassium absorption rule of tobacco plants. In the early stage of growth, the roots of tobacco under plastic film mulching developed mainly among the 0-20 cm soil layers, where abundant nutrition would promote the tobacco growth, whereas too deeper placement of fertilization would affect the growth and development of tobacco plants with less nutrition absorption by tobacco root mass. The...
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