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。
其他摘要
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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