TRANSFORMATION AND DISTRIBUTION OF ￣(15)N-LABELED RICE STRAW AND INORGANIC NITROGEN FERTILIZER IN HEAD LETTUCE-GREENHOUSE FIELD SYSTEM
Zhou Pisheng; Wang Lide (Dept. of Landscape & Environmental Science, Shanghai Agricultural College,Shanghai 201101; Dept. of Natural Resources & Environmental Science, Nanjing Agricultural University, Naming 210095)
The pot experiments with 15N-labeled ammonium sulfate and rice straw applied alone,ammonium sulfate plus rice straw applied in combination were carried out. Results showed that the C/N ratio of materials applied,the amount of rice straw were in inverse correlation to mineralization rate and utilizational rate, and in direct correlation to residual rate of rice straw-15N. With increasing of C/N ratio in the materials applied and the amount of rice straw,immobilization rate and residual rate correspondingly increased, but utilizational rate of ammonium sulfate- 15N decreased. The application of rice straw 0. 31%-0. 46% weight of soil could increase the total N of the greenhouse field.