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Applied and Environmental Soil Science
Volume 2011, Article ID 847940, 10 pages
Research Article

Biological and Physicochemical Parameters Related to the Nitrogen Cycle in the Rhizospheric Soil of Native Potato (Solanum phureja) Crops of Colombia

Laboratorio de Microbiología Agrícola, Instituto de Biotecnología, Universidad Nacional de Colombia, Avenida carrera 30 no 45-03, A.A 14-490, Bogotá D.C., Colombia

Received 24 November 2010; Accepted 19 May 2011

Academic Editor: Paul Voroney

Copyright © 2011 Nathalia Flórez-Zapata and Daniel Uribe-Vélez. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Nitrogen (N) plays an important role in agricultural production. This study was designed to evaluate the presence of cultivable N cycle-associated microorganisms (nitrogen-fixing bacteria—NFB, proteolytic bacteria—PR, ammonifiers—AMO, ammonium-oxidizing bacteria—AOB, nitrite-oxidizing bacteria—NOB, and denitrifiers—DEN), and their relationship with physical-chemical and agronomic soil descriptors, in Solanum phureja rhizospheric soil samples, from traditional and organic crop management farms. A cluster analysis with the physical and chemical properties of soil, allowed to identify the organic matter content as an important factor that determines the outcome of that grouping. Significant differences ( 𝑃 < 0 . 0 5 ) between farms were found in the abundance of this groups, but correlation analysis showed that proteolytic and nitrogen fixing bacteria were the main nitrogen associated functional groups affected by soils' physical-chemical characteristics. The amount of ammonia available is affected by the agricultural management strategy, which consequently affects the NFB abundance. Finally the results showed that PR, protease activity and soil properties related with organic matter transformation has a positive relationship with productivity, which given the high organic matter content of the Andean soils being studied, we conclude that nitrogen mineralization process has an important role in the nitrogen cycle and its bioavailability in this ecosystem.