The large and rapidly expanding body ofliterature related to nitrogen cycling in both managed and native terrestrial ecosystems reflects the importance accorded to the behaviour of this vital and often limiting nutrient. Research at the organism, ecosystem and landscape levels commonly addresses questions concerning nitrogen acquisition, internal cycling and retention. Goals for this research include increased agricultural productivity and a better understanding of human impact on local, regional and global nitrogen cycles. Nitrogen cycle research in tropical regions has a long and distinguished history. Research on different aspects of nitrogen cycling in ecosystems of the tropics has been carried out in many regions. In relatively few instances has there, however, been a focus on the biogeochemical cycles at the ecosystem level. The meeting resulting in this volume was an attempt to bring together existing information on nitrogen cycling in ecosystems of Latin America and the Caribbean and discuss this in an ecosystem context.

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Plant assimilation and nitrogen cycling.- Microbiological regulation of the biogeochemical nitrogen cycle.- Simulation of nitrogen in agro-ecosystems: Criteria for model selection and use.- Nitrogen supply and crop yield: The global scene.- The role of the atmosphere in nitrogen cycling.- Regional nitrogen budgets: Approaches and problems.- Some priority research areas in nitrogen studies.- Nitrogen in shifting cultivation systems of Latin America.- Nitrogen distribution in several traditional agro-ecosystems in the humid tropical lowlands of south-eastern Mexico.- Nitrogen distribution in hybrid and local corn varieties and its possible relationship to a declining soil nitrogen pool under shifting agriculture at Indian Church, Belize.- 15N-urea transport and transformation in two deforested Amazonian soils under laboratory conditions.- Nitrogen cycling in sugarcane.- Nitrogen gains and losses in sugarcane (Saccharum sp.) agro-ecosystems on the coast of Peru.- Potential growth of alfalfa (Medicago sativa L.) in the desert of Southern Peru and its response to high NPK fertilization.- Crop utilization and fixation of added ammonium in soils of the West Indies.- Distribution of 15N fertilizer in field-lysimeters sown with garlic (Allium sativum) and foxtail millet (Setaria italica).- Nitrogen cycling in a 15N-fertilized bean (Phaseolus vulgaris L.) crop.- Nitrogen cycling in a flooded-soil ecosystem planted to rice (Oryza sativa L.).- The nitrogen balance of vegetable crops irrigated with untreated effluent.- Research into the Rhizobium/Leguminosae symbiosis in Latin America.- Nitrogen cycling in coffee plantations.- Nitrogen cycle of tropical perennial crops under shade trees: I. Coffee.- Nitrogen cycle of tropical perennial crops under shade trees: II. Cacao.- Dynamics of nitrogen in a shaded cacao plantation.- Nitrogen fixation in a Mexican coffee plantation.- Nitrogen cycling in South American savannas.- Nitrogen balance in the Trachypogon grasslands of Central Venezuela.- Net primary productivity and nitrogen and carbon distribution in two xerophytic communities of central-west Argentina.- The nitrogen cycle in a 'Terra Firme' rainforest on oxisol in the Amazon territory of Venezuela.- Nitrogen cycling in the seasonally dry forest zone of Belize, Central America.- Seasonal dynamics of nitrogen cycling for a Prosopis woodland in the Sonoran Desert.- Litterfall and nitrogen turnover in an Amazonian blackwater inundation forest.- Nitrogen in litterfall and precipitation and its release during litter decomposition in the Chilean piedmont matorral.- Regional gains and losses of nitrogen in the Amazon basin.- Eutrophy in Lake Aculeo, Chile.- Work group reports Shifting cultivation and traditional agriculture.- Sugarcane.- Cereal and grain crops.- Coffee and cacao plantations.- Savannas and shrublands.- Latin American forests.- Wetlands (including rice) and aquatic systems.- List of participants.