何季 卢青 吴传美 杨谨铭 黄春艳 甘正刚 姚斌

摘要：【目的】研究贵州省普安县特有珍稀四球茶茶树和土壤生态化学计量特征的差异及其内在关联性，为四球茶的合理栽培及可持续开发利用提供科学依据。【方法】以四球茶为研究对象，选择植茶年限分别为5、15、25和40年的健康茶树种群，测定茶树和土壤的碳（C）、氮（N）、磷（P）含量，分析不同植茶年限下茶树和土壤生态化学计量特征之间的内在关系及元素限制情况。【结果】随着植茶年限的增加，0～20 cm层土壤和叶片C含量呈先上升后下降的变化趋势，25年时达最大值，土壤C含量较5和15年分别显著高27.33%和23.33%（P<0.05，下同），老叶C含量较5、15和40年分别显著高13.75%、13.07%和10.78%，新叶C含量较5、15和40年分别显著高21.12%、8.79%和25.63%;N含量呈先下降后上升的变化趋势，P含量则逐渐增加。随着植茶年限的增加，土壤、新叶和老叶的C∶N均呈先上升后下降的变化趋势（25年时最大），C∶P和N∶P逐渐降低，其中，15、25和40年土壤的N∶P显著低于5年，分别低27.95%、29.01%和33.25%;植茶40年时，其养分吸收利用效率和生长速率明显降低。茶园土壤的P素回归水平较高，N素回归水平较低，随着植茶年限的增加，老叶生长一直受N素限制，新叶生长逐渐由P素限制转变为N素限制。茶树叶片的P、C∶P、 N∶P与表层土壤的C、P含量有显著的相关性，老叶与新叶的N含量间、P含量间呈极显著正相关（P<0.01，下同），叶片的C∶P、N∶P与叶片P含量呈显著或极显著负相关。【结论】适当的植茶年限（≤25年）有利于有机质的积累和土壤生态环境的改善，植茶年限过长（≥40年），土壤养分水平降低，养分循环过程受限，应采取增施N肥、补充有机质等措施以改善茶园土壤环境，利于其可持续开发利用。

关键词： C、N、P;生态化学计量;四球茶;养分循环;元素限制;土壤—植物

中图分类号： S154.4                             文獻标志码： A 文章编号：2095-1191（2021）03-0682-11

Stoichiometric characteristics of plants and carbon， nitrogen and phosphorus in soils of precious tea species Camellia tetracocca Zhang in Guizhou Province

HE Ji1， LU Qing1， WU Chuan-mei1， YANG Jin-ming1， HUANG Chun-yan1，

GAN Zheng-gang2， YAO Bin3*

（1College of Agriculture，Guizhou University， Guiyang  550025， China; 2Tea Industry Development Center of Puan County in Guizhou Province，Southwest Guizhou， Guizhou  561500， China; 3Institute of Desertification Studies，

Chinese Academy of Forestry， Beijing  100091， China）

Abstract：【Objective】In order to provide scientific basis for the rational cultivation and sustainable development and utilization of precious tea species Camellia tetracocca Zhang in Puan County，Guizhou Province， the differences and internal correlations of ecological stoichiometric characteristics between the tea plant and the soil were studied. 【Method】The tea population of C. tetracocca with 5，15，25 and 40 planting years were taken as the research objects. The contents of carbon （C）， nitrogen （N） and phosphorus（P） in tea plant and soil were determined. The relationship between the ecological stoichiometric characteristics of tea planting years and soil was analyzed，and the circumstances of element limitation was studied under different tea planting years. 【Result】With the increase of planting years，the C content in the 0-20 cm soil and leaves increased first and then decreased，and 25-year cultivation of the tea tree reached the highest level. The C content of soil at 25 years was 27.33% and 23.33% significantly higher than that of 5 and 15 years（P<0.05， the same below），the C content of old leaves was 13.75%，13.07% and 10.78% significantly higher than that of 5，15 and 40 years，and the C content of new leaves was 21.12%，8.79% and 25.63% significantly higher than that of 5，15 and 40 years，respectively. The N content decreased first and then increased，and the P content gradually increased. With the increase of planting years，the C∶N of soil，new leaves and old leaves increased first and then decreased（25-year cultivation of the tea tree reached the highest level）. With the increase of planting years，the C∶P and N∶P decreased gradually. The N∶P of soil at 15，25 and 40 years were 27.95%、29.01% and 33.25% lower than that of 5 years，respectively. The nutrient absorption efficiency and growth rate of C. tetracocca were decreased greatly in planting 40 years. The P regression level of tea garden soil was higher，but the N regression level was lower. With the increase of planting years，the growth of old leaves were restricted by N element，and the growth of new leaves gradually changed from P-limitation to N-limitation. There were significant correlations between P，C∶P，N∶P of leaves and C，P content of surface soil. The N and P contents of old leaves were extremely positively correlated with those of new leaves（P<0.01， the same below）. The C∶P and N∶P of leaves were significantly or extremely negatively correlated with P content of leaves. 【Conclusion】Appropriate planting ages（≤25 years） is conducive to the accumulation of organic matter and the improvement of the soil ecological environment. If the planting ages is too long（≥40 years），the soil quality would be reduced，and the nutrient cycling process would be limited. Measures such as increasing N fertilizer and supplementing organic matter should be taken to improve the soil environment of the tea orchards，so as to facilitate its sustainable development and utilization.

Key words： C， N， P; stoichiometry; Camellia tetracocca Zhang; nutrient cycle; element limitation; soil-plant

Foundation item：Joint Project of National Natural Science Foundation of China and Guizhou Provincial Peoples Government（U1612442）; Re-establishment Project of Surplus Funds of National Natural Science Foundation of China （IDS2019JY-5）; Science and Technology Planning Project of Guizhou（QKHJC〔2019〕1106， QKHHBZ〔2020〕3001）

0 引言

【研究意义】生态化学计量学是一门将生物学、物理学和化学等基本原理结合在一起，研究生态过程中多重化学元素平衡关系的学科（Elser et al.，2000;曾德慧和陈广生，2005）。土壤养分供应量及植物养分利用量的差异，使植物和土壤中的养分含量具有明显的时空变异，因此，碳（C）、氮（N）、磷（P）生态化学计量特征在生物系统物质循环和元素平衡中发挥着重要的指示作用（胡培雷等，2017）。茶樹作为一种多年生植物，由于种植年限及代谢能力的变化，必然会导致叶片和土壤中C、N、P含量及其比值发生变化，进而影响茶树养分利用效率和生长速率，最终影响茶叶的产量和品质。因此，研究植物—土壤系统中C、N、P的动态平衡及其相互关系，对于理解茶树养分循环与环境之间的耦合关系具有重要意义。……