太湖流域河岸带不同土地利用下草本植物叶片和土壤C、N、P化学计量特征

Carbon,nitrogen,and phosphorous stoichiometry of herbaceous plant leaf and soil in ripa-rian zone of Taihu Lake basin,East China under effects of different land use types.

以太湖流域典型河岸带草本植物叶片及土壤为研究对象，通过比较邻近3种土地利用类型（林地、农田、村镇）植物叶片及土壤的C、N、P元素，探讨不同土地利用下河岸带植物叶片与土壤C、N、P含量和化学计量特征的变化规律。结果表明：农田河岸带土壤全磷（TP）含量显著低于林地与村镇，林地表层土壤（0～10cm）土壤有机碳（SOC）、土壤全氮（TN）含量最高；农田植物叶片全碳（TC）、TN、TP含量显著高于林地和村镇，与土壤含量变化不一致；农田植物叶片全氮含量高，其C：N显著低于村镇土地利用类型；农田土壤N：P和C：P明显高于林地和村镇，而土壤C：N相对稳定，林地表层土壤C：N明显高于村镇与农田。以上表明，人为干扰强度影响地表凋落物积累及表层土壤对营养元素滞留能力：植物叶片与土壤元素含量高低不一致，这与农肥中元素形态及植物、土壤对元素滞留能力有关；不同土地利用类型河岸带植物养分限制状况一致；林地表层土壤C：N结果说明其土壤碳分解速率及氮素矿化能力偏低。

Taking the herbaceous plant leaf and soil in the typical riparian zone in Taihu Lake basin as the objects, this paper studied the plant and soil carbon （ C）, nitrogen （ N）, and phos- phorus （P） in three adjacent land use types （forest land, cropland, and village）, and ap- proached the variation patterns of the plant and soil C, N, and P and their stoichiometry. In the cropland of the riparian zone, the soil total phosphorus （TP） content was significantly lower than that in the forest land and village, while the 0-10 cm soil organic carbon （SOC） and total nitro- gen （TN） contents in the forest land were the highest. The plant leaf total carbon （TC）, TN, and TP contents in cropland were significantly higher than those in forest land and village, with a variation pattern different from the that of soil TC, TN, and TP contents. The plant leaf TN con- tent was the highest in cropland, but the plant leaf C ： N ratio was significantly lower than that in village. Cropland soil had the highest C：P and N：P ratios, but its C：N ratio was relatively sta- ble. The C ：N ratio in 0-10 cm soil layer was significantly higher in forest land than in cropland and village. It was suggested that human disturbance strongly affected the accumulation of litter and the nutrient retention capacity of surface soil. The plant leaf and soil showed different pat- terns of the nutrient contents among the three land use types, which could be related to the nutri- ents speciation in manure and the nutrient retention capacity of plant and soil. The plant nutrient limitation status was in consistency among these land use types. The higher surface soil layer C： N ratio in forest land indicated its lower decomposition rate of soil carbon and lower mineralization rate of soil nitrogen.