Abstract: The ecological effect and economic return of the P.communis multistage utility technique was studied. P.communis residue was firstly used to culture mushroom,and then mushroom residue was used as medium of vegetable cultivation,and finally the medium residue with vegetable root was applied to farmland as organic matter.The result showed that the assistant energy efficient is 8.1% in the mushroom culture and 8.4% in the vegetable culture.N transformation efficiency is about 40%both in mushroom and vegetable culture.The yield of both mushroom and vegetable with P.communis residue as medium are equal to the yield with conventional medium culture.For the cost of P.communis residue is much less than conventional medium,the economic return is much higher as well.

Key words: Dongting Lake wetland, Carex brevicuspis, soil environmental factor, principal component analysis.