In order to study the spatial and temporal variations of nitrogen( N) and phosphorous( P) nutrition in artificial wetlands after a single exogenous nutrient input,6 mosaic communities of 7 plant species were set up in a cement channel in the greenhouse. After the addition of N and P nutritional solutions,the concentrations of dissolved total nitrogen( DTN),dissolved total phosphorous( DTP),ammonia nitrogen( NH+ 4-N) 、nitrate nitrogen( NO-3-N) and nitrite nitrogen( NO-2-N) in the surface,middle,and bottom la...