Different Under Hydrothermal Conditions Rapeseed Organic Nitrogen Mineralization In The Tobacco Planting Soil Characteristics Study

The use of rapeseed cake as a souce of nutrients is widespread among the tobacco planting soil.Beneficts of rapeseed cake on the yield and quality of flue-cured tobacco depend on the N release patterns and uptake by the flue-cured tobacco.This study was conduct to estimate N mineralization in soils amended with rapeseed cake.Soil monisture adjusted to 50%,70%,90% field capacity water content and amended respectively with rapeseed cake ,fermented rapeseed cake with 2 kind of leavening agent were incubated at 15℃, 25℃, 35℃ for 56 days under the simulated indoor experiment.. A non-amended control was also included. At 7, 14, 21 , 28, 35, 45, 56d after the start of decomposition,soil NO^-₃,and soil NH⁺₄ were measured. The relation between N mineralization, lose from soil, rapeseed cake and temperature,moisture and the effect of ferment on the N mineralization of rapeseed cake was discussed. It will provide scientific basis of applying rapeseed cake and N fertilizer to tobacco planting soils.The results obtained were as follows:Temperature and moisture have effect on N mineralization of the tobacco planting soil.The higher the temperature ,the higher the content of NH⁺₄, NO^-₃ ,N_min and the mean of nitrification rate.0¹4d, the content of NH⁺₄, NO^-₃, N_min increased with the soil water content. In the later period of incubation, moisture has little effect on these.Temperature affected on the N mineralization of rapeseed cake. In the early days, content and the rate of N mineralization of rapeseed cake increased with increasing temperature.; But in the later period of incubation, inorganic N content decreased with increasing temperature under all the control because the lose of inorganic increased with increasing temperature.Moisture affected on the N mineralization of soil and rapeseed cake. In the early days,inorganic N content and the rate of N mineralization increased with increasing soil water content,But in the later period of incubation .inorganic N content decreased with increasing soil moisture under all the control because the lose of inorganic increased with increasing soil moisture. The higher the moisture of the soil, the earlier the largest value of the inorganic N content showed up.Fermenting affected on the N mineralization of rapeseed cake. 0¹4d, the content of inorganic in soil with unfermented rapeseed cake is lower than other two fermented rapeseed cake,but the two later control have little difference. In the later period of incubation,the inorganic content of the first control is higher than the two later control.In all control with rapeseed cake,0¹4d,inorganic N content rapid ascent;14-45d ,it increased or decreased gradully;it decreased during 45⁵6 d. It indicated that the rapeseed cake released N manily in the 45 days and it meet with uptake by the flue-cured tobacco.