Abstract

MORA RAVELO, Sandra Grisell; SANDOVAL VILLA, Manuel; GAVI REYES, Francisco  and  SANCHEZ GARCIA, Prometeo. EMISIÓN DE N ₂ O CON FERTILIZACIÓN NITROGENADA EN FERTIRRIEGO Y FERTILIZACIÓN CONVENCIONAL. Rev. Int. Contam. Ambient [online]. 2005, vol.21, n.1, pp.23-29. ISSN 0188-4999.

The use of chemical and organic nitrogen fertilizers and its relationship to environmental contamination implies the necessity of implementing alternatives that may reduce nitrogen losses from soil and hence increase nitrogen use efficiency by crops. Fertirrigation is a technique of water and fertilizers application that improves fertilizers use efficiency. There are no reports on fertirrigation effects on nitrous oxide (N2O) emissions or denitrification. The objective of the present work was to study the effect of fertirrigation and conventional fertilization on denitrification and verify if fertirrigation can reduce N2O emissions to the atmosphere. N2O was trapped in situby the method adapted by Grageda (1999) and Vivanco (2000). The samples of N2O were taken at 2, 24, 48, and 72 h after irrigation. Soil temperature was taken with a regular thermometer approximately at 10 cm of soil depth. Soil water (0-12 cm) was monitored by using a DT Delta - T device, type ML2 ThetaProbe. N2O quantification was carried out by gas chromatography. Statistical analysis and figures were developed using the SAS soft ware (SAS 1998). The figures and results obtained demonstrated that soil water strongly affected N2O emission since there were significant differences at 2, 24, 48, and 72 h after irrigation compared to conventional fertilization and irrigation. In spite of the fact that differences between systems were not significant, N2O emission for fertirrigation was 0.69 and 2.82 for conventional fertilization at 48 and 72 h. The temperature registered along crop growing season were lower than optimum temperature for denitrification, and it is believed that low temperature decreases denitrification. Soil pH ranged from 8.0 to 8.4, which is significantly higher than optimum for denitrificacion and this may affect negatively N2O emissions in conventional and fertirrigation nitrogen fertilization.

Keywords : nitrous oxide; denitrification; nitrogen; humidity.

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