| 植茶年限降低土壤团聚体稳定性并促进大团聚体中钾素释放 |
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| 引用本文： | 李露露,李婷,郎山鑫,魏巍,缪利,李智平,席铫.植茶年限降低土壤团聚体稳定性并促进大团聚体中钾素释放[J].植物营养与肥料学报,2020,26(7):1188-1197. |
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| 作者姓名： | 李露露 李婷 郎山鑫 魏巍 缪利 李智平 席铫 |
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| 作者单位： | 四川农业大学资源学院，成都 611130 |
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| 基金项目： | 四川农业大学科研兴趣培养计划（2019332）。 |
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| 摘 要： | 【目的】 研究植茶年限对土壤团聚体稳定性以及供钾和释钾能力的影响，以期为指导茶园土壤施肥、促进茶园生态系统可持续发展提供科学依据。 【方法】 采集四川省雅安市草坝镇茶园农业生态区植茶年限分别为5 a、10 a、15 a和30 a的原状土 (0—15和15—30 cm)，利用湿筛法分离出粒径> 2 mm、0.25～2 mm、0.053～0.25 mm和 < 0.053 mm的土壤样品，分析其稳定性、各粒级土壤速效钾和缓效钾含量，并采用四苯硼钠 (NaTPB) 浸提法探讨了其有效钾释放特征。 【结果】 各植茶年限土壤均以大团聚体 (粒径> 0.25 mm) 为主，质量占比为75.87%～95.75%，但随植茶年限增加，土壤大团聚体比例显著减少 (P < 0.05)，且各土层土壤团聚体平均重量直径 (MWD) 均明显减小。15 a和30 a的茶园土壤中同一粒级团聚体的土壤速效钾和缓效钾含量均高于5 a和10 a茶园。5 a和10 a茶园土壤中各粒级团聚体中速效钾含量分布较为均匀，15 a和30 a的茶园土壤速效钾含量随大粒级团聚体的增加而增高。土壤缓效钾在各年限茶园均表现为微团聚体 (粒径< 0.25 mm) 高于其他团聚体组分。各茶龄土壤不同粒级团聚体有效钾累积释放量在102.3～236.5 mg/kg，且呈现前期快、后期较稳定的趋势，释放过程均以扩散模型拟合程度最好。进一步比较表明，植茶15 a和30 a的土壤团聚体有效钾累积释放量明显高于植茶5 a和10 a时的土壤。 【结论】 茶园土壤中以大团聚体 (粒径> 0.25 mm) 的比例最高，但随植茶年限的增加，微团聚体 (粒径< 0.25 mm) 比例增加，土壤结构稳定性降低，特别是15—30 cm土层土壤。大团聚体的减少促进了土壤速效钾、缓效钾的释放，因而，植茶15 a和30 a的土壤速效钾含量较5 a和10 a的茶园高，但是会耗竭土壤钾库，不利于茶园的可持续利用。
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| 关 键 词： | 植茶年限 土壤团聚体 钾含量 释放特征 |
| 收稿时间： | 2019-11-14 |
Tea plantation ages decrease the stability of soil aggregates and increase the release of potassium from large aggregates |
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| LI Lu-lu,LI Ting,LANG Shan-xin,WEI Wei,MIAO Li,LI Zhi-ping,XI Yao.Tea plantation ages decrease the stability of soil aggregates and increase the release of potassium from large aggregates[J].Plant Nutrition and Fertilizer Science,2020,26(7):1188-1197. |
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| Authors: | LI Lu-lu LI Ting LANG Shan-xin WEI Wei MIAO Li LI Zhi-ping XI Yao |
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| Institution: | College of Resources, Sichuan Agricultural University, Chengdu 611130, China |
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| Abstract: | 【Objectives】 The stability of soil aggregates and the related potassium (K) release were studied, in an attempt to provide scientific basis for guiding the soil fertilization in the tea garden and promoting the sustainable development of the tea garden ecosystem. 【Methods】 Soil samples were collected in 0–15 and 15–30 cm deep of undisturbed soil layers in the tea garden of 5, 10, 15 and 30 years old in Ya'an City, Sichuan Province. Each soil sample was separated into four particle sizes of > 2 mm, 0.25–2 mm, 0.053–0.25 mm and < 0.053 mm by wet screen method. The stability of the four sizes of aggregates and the contents of soil readily available potassium (RAK) and slow available potassium (SAK) inside were analyzed. Meanwhile, the sodium tetracenyl borate (NaTPB) method was utilized to explore the release characteristics of available potassium. 【Results】 The soils in all the investigated tea plantations were mainly composed of large aggregates (size > 0.25 mm), with the mass ratio of 75.87%–95.75%, however, the mass ratio tended to decrease with the increase of plantation ages significantly (P < 0.05), and the mean weight diameter (MWD) of soil aggregates in the two soil layers decreased obviously. The contents of RAK and SAK in different sizes of aggregates at 15 and 30 years after tea planting were higher than those at 5 and 10 years. The content of soil RAK in different sizes of aggregate was similar at tea plantation age of 5 and 10 years, while that was affected by the content of large aggregate at tea plantation age of 15 and 30 years. On the contrary, the content of SAK was higher in microaggregates (size < 0.25 mm) than that in larger aggregates. The cumulative release amount of available potassium from different aggregates varied in the range of 102.3–236.5 mg/kg. Furthermore, the release of available potassium from soil showed a trend of rapid release in the younger tea gardens and stable release in the elder ones, and the release process could be well described using the parabolic diffusion model. Specifically, the cumulative release of available potassium from soil aggregate at 15 and 30 years old tea plantations was significantly higher than those at 5 and 10 years old tea plantations. 【Conclusions】 Large aggregates (size > 0.25 mm) are dominant in all the tested tea plantations, but the stability of large soil aggregates tends to decrease with the increase of tea plantation age, leading to the release of the RAK and SAK contained in the large aggregates, especially in the 15–30 cm soil layers. So, the high soil K levels in tea plantation at 15 a and 30 a reflect the consumption of soil K pool, which is not good for the sustainable use of tea plantation. |
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