Abstract: The effects of decayed pig manure,rapeseed cake and decayed crop straw application for preceding and present season crops on nitrogen supply and characteristics of soil were studied by field test.The result showed that 35 days after transplanting,the nitrate nitrogen content in soil where organic manure was applied for preceding crop was higher than that the manure was applied for present crop;it was contrary 63 days after transplanting.The rule of nitrogen supply from soil where organic manure was applied for preceding crop better conformed to the rule of nitrogen demand of flue-cured tobacco plant.The results determined after harvest indicated that:volume weight decreased and porosity increased for soil applied with organic manure,compared with CK,with the exception that the soil was applied with decayed pig manure.The soil environment of flue-cured tobacco growth was effectively improved by applying organic manure for preceding crop.