| 氮添加与凋落物处理对橡胶林砖红壤有机碳组分及酶活性的影响 |
| 摘要点击 635 全文点击 170 投稿时间：2023-01-30 修订日期：2023-03-30 |
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| 中文关键词 凋落物 氮添加 橡胶林 有机碳组分 酶活性 |
| 英文关键词 litter N addition rubber plantation organic carbon components enzyme activity |
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| 中文摘要 |
| 研究氮添加与凋落物处理对土壤有机碳组分及酶活性的影响对调控人工林生态系统恢复具有重要意义.于海南岛西部橡胶林地开展野外微区模拟试验,采用二因素完全随机设计,设置4个氮水平[不施氮（CK,0 kg·hm-2·a-1,以N计,下同）,低氮（LN,50 kg·hm-2·a-1）,中氮（MN,100 kg·hm-2·a-1）和高氮（HN,200 kg·hm-2·a-1）]以及2种凋落物处理[凋落物去除（LR）,凋落物保留（L）],分析0~10 cm和10~20cm土层的土壤理化性质、总有机碳（SOC）及其组分、酶活性等指标.结果表明,土壤pH随N添加量增加以及凋落物的去除呈显著降低的趋势（P<0.05）.土壤NO3--N和NH4+-N含量随N添加的增加显著增加,N添加和凋落物处理对NO3--N和NH4+-N含量有显著的交互效应.与L处理相比,LR降低了土壤SOC及其各组分含量,其中轻组有机碳（LFOC）含量降幅最大,在0~10 cm和10~20 cm土层降幅分别为29.0%~81.4%和23.5%~58.4%.不同凋落物处理条件下,SOC及其各组分含量随N添加量的增加均呈先增加后降低的趋势,LN处理显著高于HN处理.N添加和凋落物处理对SOC、LFOC（0~10 cm）和重组有机碳（HFOC）含量有极显著的交互作用（P<0.01）.与L处理相比,LR处理在CK和LN处理条件下的土壤多酚氧化酶（PPO）活性显著降低,而在MN和HN条件下,LR处理的PPO含量显著增加；方差分析显示,N添加和凋落物处理对PPO和0~10 cm土层的纤维素酶（CBH）活性有极显著影响的交互作用,土壤酶活性[β-葡萄糖苷酶（BG）、PPO、CBH]对N添加处理的响应程度均大于对凋落物处理的响应.相关性分析表明,SOC含量与微生物生物量碳（MBC）、颗粒态有机碳（POC）、LFOC以及HFOC含量之间呈极显著正相关关系.总体来看,凋落物保留与低N输入对橡胶林地土壤碳库以及酶活性具有较好的协同作用. |
| 英文摘要 |
| It is of great scientific significance in regulating plantation ecosystem restoration to investigate the effects of the nitrogen (N) deposition and litter manipulation on soil organic carbon components and enzyme activities. A micro-plot experiment was conducted with four nitrogen additions[CK (0 kg·hm-2·a-1, calculated by N), LN (50 kg·hm-2·a-1), MN (100 kg·hm-2·a-1), and HN (200 kg·hm-2·a-1)] and two litter treatments[LR (litter removal) and L (litter retained)] for tropical rubber plantations in western Hainan Island. The soil physico-chemical properties, soil organic carbon components, and enzyme activities in 0-10 cm and 10-20 cm depths were analyzed. The results showed that soil pH significantly decreased with elevated N addition and litter removal. The contents of NO3--N and NH4+-N significantly increased with elevated N addition. Moreover, there was a significant interaction between N addition and litter treatment on the contents of NO3--N and NH4+-N (P < 0.05). Compared to that with L, LR reduced SOC and its component contents; particularly, the largest decrease was in LFOC by 29.0%-81.4% in the 0-10 cm depth and 23.5%-58.4% in 10-20 cm, respectively. The contents of SOC and its components presented a trend of increasing first and then decreasing with elevated N addition irrespective of litter treatment, and those contents were significantly higher at LN than those at HN. There was a significant interaction between N addition and litter treatment on SOC, LFOC (0-10 cm), and HFOC contents. Compared with that under L, PPO activity was significantly reduced at LR under CK and LN but was significantly increased at LR under MN and HN, respectively. Variance analysis showed significant interactive effects between N addition and litter treatment on PPO and CBH (0-10 cm) activities, and the soil enzyme activity (BG, PPO, and CBH) responding to N addition was greater than that to the litter treatment. Pearson correlation analysis showed that SOC content was extremely positively correlated with MBC, POC, LFOC, and HFOC contents. To summarize, litter retained combined with low N deposition played an important synergistic role of improving SOC pool and soil enzyme activities for tropical rubber plantation systems. |
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