| 摘要: |
| 桉树（Eucalyptus）作为世界三大速生树种之一，其长期不当经营引发的土壤地力下降问题已引起广泛关注。因此，探究桉树人工林土壤碳与养分储量及其分布特征，对于评价桉树人工林生产与生态效益具有重要意义。本研究以广东东莞市国营大岭山林场23年生桉树过熟人工林为研究对象，通过在林地内建立固定、标准样地，采集并测定0~100 cm土壤不同土层pH值、土壤有机碳含量、土壤全量养分含量（土壤全氮、土壤全磷、土壤全钾）和速效养分含量（碱解氮、有效磷和有效钾），探究该典型桉树人工林土壤有机碳、全量与速效养分储量及其化学计量特征。该桉树人工林土壤（0-100 cm）整体呈强酸性（pH=4.13±0.02）。土壤有机碳与全氮含量随土层深度的增加而下降，呈明显的表聚现象，0-20 cm土壤有机碳与全氮含量分别为：12.85±1.21 g?kg-1和0.98±0.08 g?kg-1；土壤全磷和全钾各土层之间的差异不显著（P>0.05）。速效养分碱解氮、有效磷和有效钾含量均随土层的增加而下降。土壤化学计量特征除C:N（12.83±0.29）达到全国陆地土壤C:N的平均值水平外，C:P、N:P均未达到全国的相应平均水平。该23年生桉树人工林土壤碳与各养分储量大小表现为：C>K>N>P，其值分别为143.28 t·hm-2、85.81 t·hm-2、10.90 t·hm-2和3.54 t·hm-2。土壤C储量达到全国人工林土壤C储量的平均水平（107.1 t·hm-2），其中0~40 cm土壤碳储量占整体的57.6%。土壤C、N储量均随土壤深度的增加而下降，0~40 cm N储量占土壤整个剖面储量的55.3%。本研究表明了桉树人工林0~40 cm土壤层较好地扮演着碳库与氮库的角色，但整体上土壤磷、钾含量相对不高，因此建议后期经营管理中一方面注意过熟林地表层土壤养分的保护，另一方面可针对性的开展林分的综合改造，以期有效提升桉树人工林的生态与社会功能。 |
| 关键词: 桉树 碳储量 土壤养分 垂直分布 人工林 |
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| 基金项目:广东省林业科技创新平台项目（2021-KYXM-09-02）；广东省林业科技创新项目（2022KJCX015; 2021KJCX003）。 |
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| Soil organic carbon and nutrient storage in a typical overmature Eucalyptus forest in Dalingshan Forest Farm in Dongguan |
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shendecai1, Feng Yingjie2, Liu Xiaodong2, liu ting3, zhao xinyu4, long fengling4
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1.Dongguan Research Institute of Forestrya;2.South China Agricultural University;3.Dongguan Research Institute of Forestrya/Forest Ecosystem Research Station in City Cluster of the Pearl River Estuary,;4.College of Forestry and Landscape Architecture, South China Agricultural University
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| Abstract: |
| Eucalyptus, which is one of the three fastest growing trees in the world, has attracted widespread attention due to the problem of soil fertility degradation caused by long-term improper management. Therefore, it is of great significance to explore the soil carbon and nutrient storage characteristics of Eucalyptus plantation to evaluate the production and ecological benefits of Eucalyptus plantation. In this study, a 23-year-old Eucalyptus overripe plantation in Dalingshan Forest Farm was selected as the research object. Collection and determination of 0 ~ 100 cm soil layers pH, soil organic carbon (SOC), total nutrient content (total nitrogen (TN), total phosphorus (TP) and total kalium (TK)) and available nutrient content (available nitrogen (AN), available phosphorus (AP) and available kalium (AK)), explore the changes of SOC storage, total nutrient storage and stoichiometric in different soil layers. The results showed that the soil (0-100 cm) was strongly acidic (pH=4.13±0.02). The SOC and TN contents decreased with the increase of soil depth, presenting obvious surface aggregation. The SOC and TN contents in 0-20 cm soil were 12.85±1.21 g?kg-1 and 0.98±0.08 g?kg-1, respectively. There was no significant difference in TP and TK among different soil layers (P>0.05). The contents of AN, AP and AK decreased with the increase of soil layer. Soil stoichiometric characteristics of C:N (12.83±0.29) reached the national average of C:N, but C:P and N:P did not reach the corresponding national average. The order of soil carbon and nutrient storage was: C>K>N>P, and the values were 143.28 t·hm-2, 85.81 t·hm-2, 10.90 t·hm-2 and 3.54 t·hm-2, respectively. Soil C storage reached the average level of 107.1 t·hm-2 in China, and the carbon storage in 0-40 cm soil accounted for 57.6% of the whole. Soil C and N storage decreased with the increase of soil depth, and N storage of 0~40 cm accounted for 55.3% of the whole soil profile. This study showed that 0-40 cm soil layer of eucalyptus plantation plays the role of carbon and nitrogen reservoir well, but the content of P and K in the soil is relatively low. Therefore, it is suggested to pay attention to the protection of soil nutrients in the surface layer of overripe forest and carry out targeted comprehensive stand transformation in the later management. In order to effectively improve the ecological and social functions of Eucalyptus plantation. |
| Key words: Eucalyptus Carbon storage Soil nutrient vertical distribution plantation |
