Abstract:

In order to reveal the elevation patterns of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and their stoichiometric characteristics of different soil depths in mature Cunninghamia lanceolata plantations, an elevation gradient (750, 850, 1000, 1150 m a.s.l.) was designed in Tianma National Nature Reserve, Anhui Province. At each site, three replicate plots were set up and soil samples from different depths were collected for analysis of SOC, TN and TP. The results showed that SOC and TN at different soil depths initially decreased and then increased along the elevation gradient, while TP increased initially and then decreased. In each soil layer, the C/N ratios increased firstly and then decreased, the ratios of C/P and N/P decreased first and then increased with the increase of elevation. At each site, SOC, TN, TP, and ratios of C/P and N/P decreased with oil depth, while soil C/N ratio appeared no significant change. There was a positive significant correlation between SOC and TN. However, SOC and TP, TN and TP were negatively correlated. The changes of C/N, C/P and N/P ratios were irrelevant to elevation, while were significantly correlated to soil pH, water content and soil bulk density.

Key words: Elevation gradient, Cunninghamia lanceolata plantation, soil nutrient, ecological stoichiometry

摘要：

为探究不同海拔梯度上杉木（Cunninghamia lanceolata）人工林土壤化学计量特征,阐明其对海拔的响应规律,从而有效指导杉木人工林的生产。在安徽省金寨县天马国家自然保护区选取了4个海拔梯度（750、850、1000、1150 m）,测定杉木人工林土壤有机碳（SOC）、全氮（TN）、全磷（TP）含量,并分析化学计量特征。研究结果表明：土壤0—10 cm有机碳、全氮、全磷质量分数为42.15、2.51、0.92 g∙kg^-1,均高于我国平均土壤有机碳、全氮、全磷质量分数;土壤C/N比为17.01,高于全国土壤平均值,土壤C/P比为43.59,N/P比为2.63,两者均低于全国平均水平。随着海拔升高不同土层土壤有机碳、全氮均呈先降低后增加的趋势,而土壤全磷呈现先升高后减低的趋势;随海拔增加不同土层土壤碳氮比呈先升高后降低的趋势,碳磷比和氮磷比呈现先降低后升高的趋势;随着土壤深度的增加,不同海拔土壤有机碳、全氮、全磷、碳磷比和氮磷比均呈降低趋势,而土壤碳氮比在不同海拔间变化趋势不一致;土壤有机碳和全氮呈极显著正相关,有机碳和全磷、全氮和全磷显著负相关;土壤碳氮比、碳磷比和氮磷比与海拔不相关,与土壤pH、含水率、容重显著相关。

关键词: 海拔梯度, 杉木人工林, 土壤养分, 生态化学计量