Nitrogenase activity in soil and litter of a tropical lowland rain forest and an adjacent fernland in Sri Lanka
Nitrogenase activity in soil and litter of a tropical lowland rain forest and an adjacent fernland in Sri Lanka
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DOI：
10.1017/s026646740000451x
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发表时间：
1990-08
影响因子：
1.4
通讯作者：
J. Maheswaran;I. Gunatilleke
中科院分区：
文献类型：
--
作者：
J. Maheswaran;I. Gunatilleke
摘要：通过乙炔还原法测量了斯里兰卡热带低地雨林和邻近蕨类植物的表层土壤和枯落物层中的固氮酶活性。蕨类植物中减少的乙炔总量（生物固氮量为 38.4 µmol m−2 h−1）高于森林中的乙炔总量（15.3–29.2 µmol m−2 h−1）。在这两个生态系统中，土壤中的固氮酶活性（59-85%）都高于枯落物层。土壤和凋落物中的乙炔还原率与混合凋落物的衰减常数呈反比关系，而乙炔还原率与土壤的C：可提取氮比之间呈正相关。蕨类植物中硝基酶活性相对较高的速率加上凋落物分解速率较慢，表明氮的积累可能会导致森林砍伐地区的土壤和凋落物层在其退化阶段。
ABSTRACT Nitrogenase activity in the surface soil and litter layers from a tropical lowland rain forest and an adjacent fernland in Sri Lanka was measured by the acetylene reduction method. The total amount of acetylene reduced, a measure of biological nitrogen fixation, was greater in the fernland (38.4 µmol m−2 h−1) than in the forest (15.3–29.2 µmol m−2 h−1). In both ecosystems the nitrogenase activity was greater (59–85%) in the soil than in the litter layer. The rates of acetylene reduction in soil and litter showed an inverse relationship with the decay constants of mixed litter and a positive relationship was found between the rate of acetylene reduction and the C:extractable nitrogen ratio of the soil. The relatively greater rate of nitro genase activity coupled with the slower rate of litter decomposition in the fernland indicates that accumulation of nitrogen may result in the soil and litter layers of the deforested areas during their aggrading phases.