摘要:以黄土高原10个典型样点的20年刺槐人工林为研究对象，测定了样地中刺槐叶片碳（C）、氮（N）、磷（P）含量，以及0-10 cm和10-20 cm土层土壤的主要理化指标，探讨了黄土高原刺槐叶片-土壤生态化学计量特征参数随水分梯度的变化规律。研究结果发现：①随着降水量增加，刺槐叶C、N含量呈增加趋势，叶片P含量无一致性规律。② 0-10 cm土层中土壤SOC、TN、TP、铵态氮含量以及C ∶ P和N ∶ P均随降雨量增加呈逐渐增加趋势，而C ∶ N比变化不明显。③刺槐叶片C、N、P及其化学计量比与土壤化学计量比相关性较弱，但叶片N、P与土壤铵态氮、速效磷等速效养分含量呈显著正相关（P<0.05）。本研究叶片N ∶ P>16，说明黄土高原刺槐生长主要受P元素限制，且随着降水的增加，土壤P养分的限制加强。



Abstract:This study sampled 20-year-old Robinia pseudoacacia plantations at 10 typical sites on the Loess Plateau. We determined the C, N and P concentrations in Robinia pseudoacacia leaves and various physical and chemical indexes of 0-10 cm and 10-20 cm soil layers, and further explored the variations in the ecological stoichiometric parameters of the leaf-soil system along a water gradient on the Loess Plateau. The results showed that: ① leaf C and N concentrations increased with increasing rainfall, but there was no clear trend for leaf P concentration along a rainfall gradient. ② Soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and ammonium nitrogen concentrations and soil C:P and N:P ratios increased with increasing rainfall in 0-10 cm soil layer, but soil C:N has no obvious change. ③ There were no significant correlations between plant and soil C, N, P concentrations and C:N, C:P, N:P ratios, but leaf N and P concentrations were significantly positively correlated with soil available phosphorus and ammonium concentrations. The result of leaf N:P>16 indicated that the plant was under P limitation on the Loess Plateau. Additionally, the soil P limitation increased with increasing rainfall.





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