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Quantification of emissions of N2O and N2 by isotopic method (15N) in soils cultivated with sugar cane

Abstract

The N2 and N2O emissions from nitrogen fertilizers reduce fertilization efficiency and can cause environmental damage. The quantification of these gases is complex, mainly due to difficulty of measuring N2 against the high background of 78% in the atmosphere. One of the methods used for simultaneous measurement of N2O and N2 is the 15N tracer method, but despite its indication for determinations in the laboratory and in the field, it has not been used in Brazil. The sugarcane is of great economic importance for the country and demands a large consumption of nitrogenous fertilizers. Currently the management practices used in sugarcane agriculture in Brazil include maintenance of straw and application of vinasse that can potentiate N losses in the form of N2 and N2O. Thus, the aim of this study is to adapt to the Brazilian method of measurement emissions in laboratory and field of N2O and N2 originated from 15N labeled fertilizer applied in sugarcane soils. Two experiments will be conducted. Under laboratory conditions, in a factorial 3x3x2, will be tested three soils cultivated with sugarcane, with different textural classes, in three moisture conditions (40, 60 and 80% of the maximum water retention), and with and without the addition of a source of labile C (500 mg kg-1). The 15N source will be KNO3 labeled (30 at.% - 100 mg N kg-1 soil). In field experiments, in a factorial 2x2x2, will be tested two doses of N (100 and 150 kg ha-1), two doses of vinasse (75 and 150 m3 ha-1) and with and without straw cover (15 Mg ha-1). The NH4NO3 labeled (98 at.% 15N) will be the source of N. The results of the fluxes of N2 and N2O from fertilizer will be subjected to analysis of variance (ANOVA), followed by comparison of means by Tukey test (P < 0.05). Will be held, also, statistical correlations between N2 and N2O fluxes and related variables such as temperature and soil moisture and N-mineral and C-labile. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MILAGRES, J. J. M.; SANT ANA FILHO, C. R.; SCHONINGER, E. L.; TRIVELIN, P. C. O.; BENDASSOLLI, J. A. Soil N Losses by Denitrification Evaluated Using the N-15 Tracer Method. Communications in Soil Science and Plant Analysis, v. 47, n. 13-14, p. 1709-1719, 2016. Web of Science Citations: 0.

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