Abstract:

On the basis of seven year fixed position observation in Youxi Ecosystem Experimental Station, the nutrient cycle in Chinese fir young plantation ecosystem was studied and the compartment models of N、P、K cycle were established. The results were as follows:The total quantities of N、P、K accumalated in a 7 year old Chinese fir plantation ecosystem were 7308.46, 2022. 96 and 130290. 14kg/hm² respectively, in which about 99. 73% was stored in the soil compartment. The annual absorption of N、P、K was 52. 2kg/hm² with 22. 62kg/hm² of them ratained, 29. 58kg/hm² of them returned. The input through hydrologic way into the ecosystem and the output through runoff out of the ecosystem were 15. 92kg/hm² and 9. 23kg/hm² respectively. And thus, the net accumulation of ecosystem was 6. 69kg/hm².The transformations of N、P、K and results of fertilization in four compartments of ecosystem within 0-10 years were diseribed quantitatively and the balance points at the time when they reach a stable state were calculated.

Key words: Chinese fir young plantation, Nutrient cycle, Compartment model, Simulation