After Beijing implemented plain afforestation projects in the riparian zones of major rivers

the vegetation types and soils in the riparian zones have been affected to varying degrees. The study of soil ecological stoichiometry characteristics of the original and reconstructed vegetation types in the riparian zone provides scientific basis for the soil carbon (C)

nitrogen (N) and phosphorus (P) balance and the improvement of the C sequestration potential of the riparian ecosystem. Total 3 original vegetation types (arbor forest

arbor-shrub mixed forest and grassland) and 2 reconstructed vegetation types (arbor forest and shrub forest) were selected as experimental samples at 15 sites of Beijing Wenyu River Changping riparian zone. Soils were sampled at 3 layers (0-10

10-20

20-30 cm)

and analyzed for the contents and measurement ratios of C

N and P. The results showed that the ranges of soil organic carbon (SOC)

total nitrogen (TN)

and total phosphorus (TP) of the original and reconstructed vegetation types were 3.810~10.320

0.223~0.700

0.551~0.692 g/kg respectively

C/N

N/P

and C/P were 11.592~25.373

0.373~1.022

5.662~15.493 respectively. Both SOC and TN were concentrated in the surface layer

and like N/P and C/P

they decreased with the increases of soil depth

while the C/N was on the contrary. TP was less affected by the change of soil depth. The SOC and TN in the original vegetation types (arbor forest) were higher than the others. The C/N and C/P at 10-20 and 20-30 cm soil layers were significantly lower than the others (P< 0.05). The N/P of original vegetation types (grassland) was the lowest at 0-10 cm soil layer. The soil TP content of reconstructed vegetation type (arbor forest) was significantly lower than those of the other vegetation types. The C/N of reconstructed vegetation types (shrub forest)was significantly higher than the others. The study revealed that the soil N was the limiting factor for plant growth. Arbor and arbor-shrub mixed forest released more soil organic matter

had the higher levels of P availability

and had strong carbon sequestration potential. The re-vegetation types had the slower organic matter mineralization and stronger phosphorus fixation capacity. Thus

it's recommended that the mixed mode of pure forest and arbor-shrub mixed could accumulate soil organic matter and improve the soil quality and carbon sequestration potential of riparian ecosystems in the Wenyu River riparian zone.