Nitrification in tropical soils linked to microbial competition: a model based on Lotka-Volterra theory

Abstract

Montaño, N.M., Sánchez-Yañez, J.M. 2014. Nitrification in tropical soils linked to microbial competition: a model based on Lotka-Volterra theory. Ecosistemas 23(3): 98-104. Doi.: 10.7818/ECOS.2014.23-3.13

The availability of organic carbon (C) affects microbial processes and nitrogen (N) dynamics in the soil. The microbial theory suggests that depending on C and N availability, microbial populations affect N transformations in the soil. However, other chemical and physical factors may be regulating the interaction between heterotrophic and nitrifying microbial populations, but is completely unknown if high nitrification rates are explained by bacterial competition by C and N in tropical soils. This paper shows how population ecology can address and propose hypotheses to explain the role of bacterial competition by C and N on the nitrification. Two models were here proposed: the first explains how bacterial intraspecific competition by C between heterotrophic microorganisms, determines N availability for nitrifying chemolitotrophic bacteria; whereas the second explains the interspecific competition between nitrifying bacteria that do not compete with heterotrophic by available C, but if by ammonium. The hypotheses are based on the competition model of Lotka-Volterra to explain how the two types of competition determine the dominance of heterotrophic bacterial populations on nitrifiers, which could explain the high nitrification rates in tropical soils. Finally, we exposed the perspectives and limitations on conceptual hypothetical model proposed for understanding the processes linked to soil N availability.