Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, BP 5005, Dakar, Senegal.
J Environ Manage. 2012 Mar;95 Suppl:S260-4. doi: 10.1016/j.jenvman.2011.03.038. Epub 2011 Apr 22.
The relations between plants and soil biota involve positive and negative feedbacks between soil organisms, their chemical environment, and plants. Then, characterization of microbial community functioning is important to understand these relations. An experiment was conducted in a field system in the north of Senegal for two years (2005 and 2006) in order to investigate the effect of depth and distance from Acacia senegal tree stem on soil microbial biomass and inorganic-N content. Soils were sampled during dry season (April, T(0)) and wet season (August, T(1)) along transects (R(0), foot tree; R(/2,) approximately 0.50 m distance from the stem; and R, approximately 1 m distance from the stem) and at different layers: 0-25 cm, 25-50 cm and 50-75 cm of A. senegal trees rhizosphere. Total microbial biomass and inorganic-N content were negatively correlated to the distance from tree stem and the depth. The highest values of microbial biomass and mineral nitrogen were found at the foot tree (R(0)) and at 0-25 cm layer. Inorganic-N was mostly in nitrate form (NO(3)(-)) during the dry season. In contrast, during the wet season, inorganic-N was dominated by ammoniac form (NH(4)(+)). Soil total microbial biomass and inorganic-N (NH(4)(+)+NO(3)(-)) were negatively correlated. Our results suggest a positive influence of A. senegal rhizosphere on soil microbial biomass and inorganic-N content.
植物与土壤生物群之间的关系涉及土壤生物、其化学环境与植物之间的正反馈和负反馈。因此，微生物群落功能的特征化对于理解这些关系非常重要。本研究在塞内加尔北部的一个田间系统中进行了为期两年（2005 年和 2006 年）的实验，以调查深度和距塞内加尔相思树树干的距离对土壤微生物生物量和无机氮含量的影响。在旱季（4 月，T(0)）和雨季（8 月，T(1)）沿样带（R(0)，脚树；R(/2,)，距树干约 0.50 m；和 R，距树干约 1 m）并在不同层（0-25 cm、25-50 cm 和 50-75 cm 的 A. senegal 树根际）采集土壤样品。总微生物生物量和无机氮含量与距树干的距离和深度呈负相关。微生物生物量和矿质氮的最高值出现在脚树（R(0)）和 0-25 cm 层。在旱季，无机氮主要以硝酸盐形式（NO(3)(-))存在。相比之下，在雨季，无机氮主要以氨形式（NH(4)(+))为主。土壤总微生物生物量和无机氮（NH(4)(+)+NO(3)(-))呈负相关。我们的结果表明，A. senegal 根际对土壤微生物生物量和无机氮含量有积极的影响。
