滦河口湿地植物-土壤生态化学计量相关性研究

Correlation Between the Stoichiometric Characteristics of Plants and Soils in Luanhe Estuary Wetland

河口湿地是河海交汇地带,环境变化剧烈,土壤碳氮磷变化显著影响着湿地生态系统的生产力。为了解滦河口植物与土壤碳氮磷计量特征关系,在滦河口湿地设置4个采样区选取典型植物群落采集土壤及植物,并对样品养分含量进行了分析。结果表明:不同植物群落地上部分和地下部分养分含量均表现为C>N>P,氮磷均呈正相关,植物氮含量呈现出地上部分大于地下部分的规律;土壤则表现为C>P>N,碳与氮、磷均呈现显著正相关。不同植物群落之间土壤养分含量存在一定差异,土壤碳、氮、磷含量的变化范围分别为(3.8±0.44)～(10.52±0.6) g/kg,(0.29±0.12)～(0.11±0.21) g/kg,(0.99±0.27)～(2.24±0.51) g/kg,研究区土壤养分含量低于全国湿地养分平均水平。不同植被—土壤之间的C∶N,C∶P,N∶P存在一定的差异性,植物地上部分、地下部分生态化学计量比由大到小为:C∶P>C∶N>N∶P,土壤生态化学计量比由大到小为:C∶N>C∶P>N∶P,植物群落碳氮磷及其化学计量比与土壤化学计量比相关性较弱,植物与土壤养分表现出不完全同步的变化形式。

The changes of soil carbon, nitrogen and phosphorus in estuarine wetland significantly affect the productivity of wetland ecosystem. A typical plant community was selected to take soil and plant samples in the estuary of Luanhe River. The nutrient contents of samples were determined and analyzed. The results showed that the nutrient contents of the above-ground parts and underground parts of different plant communities decreased in the order: C>N>P;there was a certain difference in soil nutrient contents between different plant communities. The variation ranges of soil carbon, nitrogen and phosphorus contents were(3.8±0.44)^(10.52±0.6) g/kg,(0.99±0.27)^(2.24±0.51) g/kg,(0.99±0.27)^(2.24±0.51) g/kg, respectively. The soil nutrient contents in the study area were lower than those of the national average values. Stoichiometric ratios of plants decreased in the order: C∶P>C∶N >N∶P;stoichiometric ratios of soils decreased in the order: C∶N>C∶P>N∶P, which indicated that the soil organic matter decomposition rate was fast, nitrate leaching risk and nitrogen mineralization degree were high. Therefore, increasing the content of soil organic matter and nitrogen fertilizer can improve the productivity of wetland ecosystem in this area.