茶树根际土壤氮素组成及其吸收利用效率分析

为了揭示茶树种植年限对土壤氮素组成及茶树氮素吸收利用的影响。以植茶0、4、9和30年的铁观音茶树根际土壤为材料，分析不同树龄茶树根际土壤可溶性有机氮（soluble organic nitrogen，SON）组成及其对茶树氮素吸收利用效率的影响。结果表明，随着茶树树龄的增加，根际土壤氨基酸SON含量从46.83%下降至22.71%，非氨基酸SON含量则从53.17%上升至77.29%。氨基酸含量分析表明，不同树龄茶树根际土壤共检测到14种氨基酸，其中5种疏水氨基酸含量随着茶树树龄的增加显著上升，8种亲水氨基酸含量随着茶树树龄的增加显著下降。茶树氮素吸收利用效率结果表明，随着茶树根际土壤年限的增加，茶树氮素吸收效率、氮素生理利用率、氮素效率、氮素经济效益等均呈现下降趋势。相关性分析表明，土壤年限与土壤氨基酸SON、亲水氨基酸含量、氮素效率、氮素吸收效率、氮素生理利用率、氮素经济效率等呈显著或极显著负相关，其他指标则相反。可见，随着茶树树龄的增加土壤氮素组分及氨基酸含量发生显著变化，进而影响茶树对土壤氮素的吸收与利用。结果为酸化茶园土壤修复提供一定的理论依据。

Analysis of Nitrogen Composition and its Absorption and Utilization Efficiency in Rhizosphere Soil of Tea Tree

In order to explore the effect of tea planting years on soil nitrogen composition, nitrogen absorption and utilization of tea trees, the rhizosphere soils from Tieguanyin tea plantations of 0, 4, 9 and 30 years old were used to analyze the soluble organic nitrogen (SON) composition in rhizosphere soil of different age tea trees, nitrogen absorption and utilization efficiency of tea trees. The results showed that the content of amino acid SON in rhizosphere soil decreased from 46.83% to 22.71%, and the content of non-amino acid SON increased from 53.17% to 77.29%, with the increase of tea tree age. Analysis of the amino acid contents indicated that 14 kinds of amino acids were detected in the rhizosphere soil of tea trees of different ages, among which 5 kinds of hydrophobic amino acids were significantly increased with the increase of tea tree age, and 8 kinds of hydrophilic amino acids were significantly decreased with the increase of tea tree age. The results of nitrogen absorption and utilization efficiency of tea tree showed that the nitrogen absorption efficiency, physiological nitrogen utilization rate, nitrogen efficiency and nitrogen economic benefits of tea tree were all decreased with the increasing of tea tree age. Correlation analysis results showed that soil age was significantly negatively correlated with soil amino acid SON, hydrophilic amino acid content, nitrogen efficiency, nitrogen absorption efficiency, nitrogen physiological utilization efficiency, and nitrogen economic efficiency, etc., while other indexes were the opposite correlated. In conclusion, with the increase of tea tree age, the soil nitrogen components and amino acid contents changed significantly, which further affected the nitrogen absorption and utilization of tea tree. The present research provided some theoretical basis for soil remediation of acidified tea plantation.