Effects of N Application Rates and NO_3-N to NH_4-N Ratios on Yield and Quality of Flue-cured Tobacco Planted in Black Soil

摘要

A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a black soil was conducted from 2004 to 2005 in Heilongjiang Province. The results showed that the nitrogen application rates at 45 kg·hm-2 with the ratio of 75% NO3-N to 25% NH4-N resulted in the highest potassium and reducing sugar contents in the flue-cured tobacco leaving with the highest quality grade and value. It is recommended that this nitrogen application rate and NO3-N to NH4-N ratio should be widely applied on flue-cured tobacco grown in the black soil in Heilongjiang Province.