褐土上不同氮、钾比例对烟叶化学成分的影响

采用田间随机区组设计，测定不同施氮量和氮、钾比例的褐土和烟叶样品中化学成分含量，经统计分析得出：①N：K2O为1：2的施肥处理可以提高叶重，在施氮量较高的情况下，N：K2O为1：2的处理可以略降低烟叶中的烟碱。N：K2O为1：1的处理烟叶烟碱含量较高，其处理在生育后期总氮处于相对较高的水平。②不施钾的情况下，低氮处理烟叶钾含量略高于高氮处理；施钾情况下，相同氮、钾比例，高氮处理的烟叶钾含量和钾累积量分别高于相应的低氮处理。在褐土上，氮素可以促进烟株对钾的吸收。③施钾量提高，烟叶含钾量增加，烟叶含钙量和含镁量降低。④烟叶中的钾含量与钙、镁含量呈显著负相关，钙和镁对烟株吸收钾有强烈的拮抗作用。烟叶钾含量与土壤速效钾含量呈极显著正相关。

Effect of nitrogen and potassium ratio on chemical components in tobacco leaves grown in cinnamon soil

Experiments to address the effect of N:K ratio on chemical components in tobacco leaf were carried out. Results showed that 1) Treatment with N:K_2O ratio of 1:2 can increase weight of tobacco leaves and reduce nicotine level under condition of abundant nitrogen application, whereas treatment with N:K_2O ratio of 1:1 can result in high level of nicotine and total nitrogen. 2) Under condition 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, higher nitrogen fertilization can result in higher K accumulation. N can promote K absorption for tobacco grown in cinnamon soil. 3) An increasing potassium content and decreasing Ca and Mg contents were observed with increase in potash application. 4) Potassium content in tobacco leaves was significantly negatively correlated with Ca and Mg contents, and there existed intensive antagonism of Ca and Mg to K. Potassium content in tobacco leaves was positively correlated with active potassium content in soil and the correlation was highly significant.