| The experimentation was carried out at farm of Yishui country, Linyi tobacco-growing area in Shandong province in 2008.This study set up four planting patterns with wheat intercropping with flue-cured tobacco(T1), tuber intercropping with flue-cured tobacco(T2), green manure application with flue-cured tobacco(T3 ), tobacco single cropping(T4)and non-nitrogen disposa(lT5).All these were used to study the nitrogen absorption and utilization of tobacco. The main research results as follows:1,In different planting pattern, the accumulation of dry matters in tobacco is increasing to the upmost extent at 70 days. Green manure application with flue-cured tobacco accumulated most dry matters in four different planting pattern treatments. Tobacco single cropping accumulated less dry matters, the accumulation of dry matters were less than other treatments 28 days after transplanting.2,In different planting pattern, the accumulation of nitrogen in tobacco were increasing gradually in the tobacco growth period. The accumulation of nitrogen of tobacco single cropping and Green manure application with flue-cured tobacco treatments increased to the upmost extent at 42 days after transplanting. The accumulation of nitrogen of wheat intercropping with flue-cured tobacco and tuber intercropping with flue-cured tobacco treatments increased to the upmost extent at 56days after transplanting.3,The result of isotope experiment showed as follows: The tobacco assimilates soil nitrogen as the main form of nitrogen, which takes 60%～90% of the total nitrogen assimilation. The fertilizer nitrogen only toke a small part of total nitrogen assimilation(10%～40%). Soil nitrogen assimilation was higher than fertilizer nitrogen. The accumulation of nitrogen in tobacco most was soil nitrogen. Tobacco single cropping treatment assimilated much fertilizer nitrogen than other treatments (36.84%)4,The main form of nitrogen supply in tobacco field soil is nitrate nitrogen, and the content of nitrate nitrogen is much higher than ammonium nitrogen. The content of inorganic nitrogen in wheat intercropping with flue-cured tobacco and tuber intercropping with flue-cured tobacco were higher than tobacco single cropping treatment. The content of inorganic nitrogen in the green manure application with flue-cured tobacco is less than other treatments. However, its content increased rapidly at late tobacco growth stage. |
