HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Plant, R. A. J. Articles by Bouman, B. A. M. Search for Related Content PubMed Articles by Plant, R. A. J. Articles by Bouman, B. A. M. Agricola Articles by Plant, R. A. J. Articles by Bouman, B. A. M.

Modeling Nitrogen Oxide Emissions from Current and Alternative Pastures in Costa Rica

Lab. of Soil Science and Geology, Wageningen Agricultural Univ., P.O. Box 37, 6700 AA Wageningen, the Netherlands;

Bas A. M. Bouman

Wageningen Agricultural Univ., REPOSA, Apartado 224, 7210 Guápiles, Costa Rica, and DLO-Research Institute for Agrobiology and Soil Fertility, Wageningen, the Netherlands.

^* Corresponding author (rplant{at}gissrv.iend.wau.nl).

ABSTRACT

Emissions of nitrogen (N) oxide were simulated for one current, unsustainable pasture management system (Natural) and two alternative, sustainable systems (Grass-Legume and Fertilized Improved) relevant to the Northern Atlantic Zone (NAZ) of Costa Rica. To produce frequency distributions of N oxide emissions, an expert system for generating technical coefficients of pastures was linked with a process-based simulation model. The expert model generated parameter sets representing different options for the three management systems. The simulation model was rerun for each parameter set. Simulated nitrous oxide (N₂O)-N losses 25 yr after pasture establishment were 3 to 5 kg ha^–1 yr^–1 for natural pastures, 12 to 15 for grass-legume mixtures, and 7 to 28 for fertilized grasses. Losses of nitric oxide (NO)-N were 1 to 2 kg ha^–1 yr^–1 for natural pastures, 7 to 8 for grass-legume mixtures, and 3 to 16 for fertilized grasses. Stepwise multiple regression showed that N₂O-N losses were explained by annual C input to the soil (R² = 0.997), and NO-N losses by attainable dry matter production (R² = 0.972). Carbon input and dry matter production were controlled by stocking rate and fertilizer level. Soil-atmosphere N oxide emissions from pastures may increase by a factor 3 to 5 when natural pastures are converted to improved pastures. Such conversion may increase the sustainability of the pasture by stopping the decline of soil N. However, the change is not necessarily sustainable from a global perspective because it increases the emission of N oxide greenhouse gases.