wAbstract
@While the amount of reactive nitrogen circulating at the global
level has increased markedly in the last century, the effects
of this increase are largely seen at the regional level due to
interacting ecological and socio-economic factors. In contrast
with most other regions of the world, Latin America and the Caribbean
(LA-Ca) stand out due to the fact that the major input of reactive
nitrogen (Nr) still occurs naturally via biological nitrogen fixation
(BNF) in natural ecosystems as opposed to anthropogenic inputs
of synthetic fertilizer, fossil fuel combustion and cropping with
leguminous species. Largely due to economic reasons, the consumption
of fertilizer N in the LA-Ca region is still low in comparison
with the average consumption of the world. However, the fertilizer
N consumption is increasing at much faster rate than in developed
regions of the world, like USA and Canada. The Nr production through
BNF in cultivated plants that fix nitrogen (C-BNF) is 5 times
lower than that occurring naturally in Latin America, but is still
equivalent to 16 of the world C-BNF. The cultivation of nitrogen-fixing
crop species in the LA-Ca region is also increasing, almost entirely
due to the expansion of soybean fields in the central and northern
regions of Brazil and the Pampa region of Argentina. Other anthropogenic
activities in the region that contribute to an increase in the
circulation of reactive nitrogen include the impact of biomass
burning and urbanization. In the last decade, an average of 47,000
km2 per year of forests was burned in the LA-Ca region.
The environmental impact of urban centers in the LA-Ca region
has become very important, since an intense urbanization process
is occurring in this region, at an intensity that far exceeds
urban development in the northern hemisphere. The consequences
of increased urbanization include increased emissions of NOx to the atmosphere due to the fossil fuel combustion,
and the lack of sewage treatment facilities in most cities of
the LA-Ca result in a large volume of untreated sewage discharged
into surface waters, creating serious environmental problems.
The combination of rapid urbanization and agricultural intensification
in this region suggest that concern is warranted for the potential
for increase in the circulation of reactive nitrogen in the very
near future. At the same time, the opportunity still exists to
mitigate some of the consequences of human impact on the nitrogen
cycle in a region that still maintains a large fraction of its
natural ecosystems intact.
Keywords: Biomass burning; Caribbean; Latin America; Nitrogen;
Reactive agriculture; Urbanizationx
Introduction
The geography and socio-economic aspects of the Latin America
and the Caribbean (LA-Ca) regions
@Geography
@Social and economical indicators
Land use in Latin America and the Caribbean
@Land use
@Fertilizer N consumption in Latin America and the Caribbean
@C-BNF historical trends in Latin America and the Caribbean
@Biomass burning (source of N to the atmosphere)
Urbanization (fossil fuel and sewage)
Conclusion
Acknowledgements
References