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

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 Pu’an 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, espectively. 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.

Abstract

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%, 新叶匚含量较5、15和40年分别显著高21.12%、8.79%和25.63%#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。茶同土壤的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、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同土壤环 境, 利于其可持续开发利用。