Effects of nitrogen levels on dry matter distribution in different position leaves and yields of flue-cure tobacco on an upland and a paddy field

Two field experiments were conducted to determine effects of nitrogen levels on dry matter distribution of different position leaves and yields of flue-cure tobacco on an upland and a paddy field.The results showed that total dry matter of flue-cure tobacco increased with increase of N rates up to 105 and 120 kg/hm2 on an upland and a paddy field,respectively.However,when nitrogen rates exceed these amounts,total dry matter of tobacco would be reduced.Although total dry matter of tobacco on the paddy field was higher than that on the upland,ratio of dry matter to total dry matter of the leaves for the paddy field(46%) was less than that for the upland(50%),which resulting in higher yield of tobacco on the upland.Furthermore,dry matter yields of lower and middle position leaves accounted for about 34%,whereas dry matter yields of upper position of leaves accounted for about 15% for the upland.For rice field,the ratios were 26% and 20%,respectively,which resulted in higher production value of tobacco on the upland.Besides,appropriate nitrogen rate could improve tobacco quality.The optimum nitrogen levels for upland and paddy field were 105 and 120 kg/hm2,respectively.