成都东部“城–郊–乡”梯度绿地土壤碳氮磷化学计量特征

选取成都东部5个不同交通环线区域(一环内、一环至二环、二环至三环、三环至绕城、绕城外)的绿地土壤为研究对象,采集0~20 cm和20~40 cm土层的土壤样品,测定其总有机碳(C)、全氮(N)、全磷(P)的含量并分析其化学计量特征。结果表明:成都东部绿地土壤C、P含量在沿"城–郊–乡"梯度上总体有降低趋势。各环线区域绿地土壤C、N、P含量基本随着土层的加深而降低,其中以C、P降低最为明显。绿地土壤C:P和N:P在成都东部"城–郊–乡"梯度下有升高趋势,但均低于国内平均水平;绿地土壤C:N在"城–郊–乡"梯度变化不明显。快速的城市化进程导致了C、N、P化学计量比的空间分异。

Stoichiometric Characteristics of Soil C,N and P of Green Space Along Urban–Suburb-Rural Gradient in Eastern Chengdu

The study selected five different traffic circle areas( within the first ring road, between the first and the second ring road, between the second and the third ring road, between the third ring road and the beltway and outside the beltway) in east of Chengdu and sampled Green Space soils at the depth of 0-20 cm and 20-40 cm. Then the contents of soil organic carbon, total nitrogen and total phosphorus and their ecological stoichiometry were analyzed. The results showed that soil carbon and nitrogen concentrations of Green Space generally had a decreasing tendency along urban-suburb-rural gradient. In every area, soil organic carbon, total nitrogen and total phosphorus concentrations of Green Space were decreased with increasing soil depth, and the trend is more significant to carbon and phosphorus. Soil C:N of Green Space was not significantly different along urban-suburb-rural gradient. And both of the C:P and N:P of Green Space tended to increase along urban-suburb-rural gradient in Chengdu, but which were lower than national average. In all, the spatial differentiation of soil C:N:P stoichiometry is caused by the rapid urbanization.