Nitrogen availability in disturbed, rehabilitated and mature forests of tropical China.
Nitrogen availability in disturbed, rehabilitated and mature forests of tropical China.
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DOI：
10.1016/s0378-1127(02)00220-7
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发表时间：
2003-03-03
影响因子：
3.7
通讯作者：
Kong, Guohui
中科院分区：
文献类型：
--
作者：
Mo, Jiangming;Brown, Sandra;Kong, Guohui
为了研究人类干扰和随后的恢复对土壤氮过程的影响，使用离子交换树脂（IER）袋法估算了中国热带地区受干扰、恢复和成熟森林不同季节和两个土壤深度的氮有效性。土壤总矿物质氮（NH4+-N+NO3--N）随森林和季节的不同而变化很大。总体而言，总矿质氮浓度排序为：恢复>成熟>扰动（森林）；和春季>秋季>冬季>夏季（季节）。在所有森林的矿物质氮总量中，NH4+-N 是主要形式（约占 50-95%），其比例随森林和季节的不同而变化。 NH4+-N 和 NO3--N 之间的相关性在成熟森林中最强，其次是恢复的森林和受干扰的森林。采伐林下和凋落物对土壤氮有显着影响，处理地块中的矿物质氮（干扰较多）高于对照地块（干扰相对较少）。尽管产生了矿质氮，但植物较少和微生物活性较低，导致吸收和固定化程度较低，从而导致处理地块的氮淋失量更大。这项研究的结果表明，在 50 年左右的时间内，严重退化土地上的土壤氮素可用性的成功恢复是可能的，然而，只要继续在退化森林中砍伐林下和枯落物，这种恢复速度和水平就不太可能实现。
To investigate the impact of human disturbance and subsequent recovery on soil nitrogen processes, nitrogen availability during different seasons and at two soil depths in disturbed, rehabilitated and mature forests in tropical China was estimated using the ion exchange resin (IER) bag method. Soil total mineral N (NH4+-N+NO3--N) varied significantly depending on forest and season. Overall, total mineral N concentrations ranked as follows: rehabilitated>mature>disturbed (forest); and spring>fall>winter>summer (season). Of the total mineral N, NH4+-N was the major form in all forests (about 50-95%) with its proportion varying depending on forest and season. The correlation between NH4+-N and NO3--N was strongest in the mature forest, followed by the rehabilitated forest and by the disturbed forest. Harvesting understory and litter had significant effects on soil N-mineral N was higher in treatment plots (more disturbed) than in control plots (relatively less disturbed). Although mineral nitrogen is produced, fewer plants and low microbial activity lead to low uptake and low immobilization resulting in greater N leaching losses in treatment plots. The results of this study suggest that over the period of 50 year or so, successful rehabilitation of soil N availability on severely degraded lands is possible, however, as long as harvesting of understory and litter continues in the degraded forest, this rate and level of recovery is unlikely to be realized.