Biological nitrogen fixation in tree legumes of the Brazilian semi-arid caatinga
Biological nitrogen fixation in tree legumes of the Brazilian semi-arid caatinga
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DOI：
10.1016/j.jaridenv.2009.09.018
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发表时间：
2010-03-01
影响因子：
2.7
通讯作者：
Fernandes, A. R.
中科院分区：
文献类型：
--
作者：
Freitas, A. D. S.;Sampaio, E. V. S. B.;Fernandes, A. R.
尽管生物固氮（BNF）对干旱森林系统中的氮循环非常重要，但有关这一过程的信息却很少。它可用于改进管理和选择用于重新植被和农林系统的物种。采用N-15自然丰度方法，对巴西干旱森林（caatinga）的四个地区的豆科树种的生物固氮系数进行了估算，分析了潜在固定物种（目标物种）和非固定物种（参考物种）。目标和参考物种的同位素信号之间的差异允许的N-2固定植物的安全识别和合理精确的计算来自空气中的N的比例（%Ndfa）。结果表明，在本实验条件下，植物固氮能力最强的是细花含羞草、砂含羞草和托叶木。对植物的平均生物固定贡献很高，从27%到68%不等。然而，由于植被群落中固定植物的比例较低，系统中每年增加到叶生物量中的N的估计量较低（2.5和11.2 kg ha（-1）年（-1））。在原生植被再生的情况下，当演替以固定物种为主时，固定可达130 kg ha（-1）年（-1）。(C)2009爱思唯尔有限公司保留所有权利。
Information on biological nitrogen fixation (BNF) in dry forests is scarce, in spite of the importance of the process to nitrogen cycling in these systems. it can be used to improve management and to select species for revegetation and agroforestry systems. The BNF of tree legumes was estimated in four areas of the Brazilian dry forest (caatinga), analyzing potentially fixing species (target species) and non fixing species (reference species), using the N-15 natural abundance methodology. The differences between the isotopic signals of target and reference species permit the safe identification of N-2-fixing plants and reasonably precise calculations of proportions of N derived from the air (%Ndfa). Species with great N-2 fixation capacity were identified, notably Mimosa tenuiflora, Mimosa arenosa and Piptadenia stipulacea. The mean biological fixation contributions to the plants were high, varying from 27 to 68%. However, the estimated quantities of N added annually to the leaf biomass in the systems were low (2.5 and 11.2 kg ha(-1) year(-1)), due to low proportions of fixing plants in the vegetation communities. In situations of native vegetation regeneration, when the succession is dominated by fixing species, fixation could reach up to 130 kg ha(-1) year(-1). (C) 2009 Elsevier Ltd. All rights reserved.