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Descripción
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| Including cover crops (CCs) in crop rotations is an agricultural technique that reduces N losses thus minimizing N fertilizer application. Changes in soil moisture, N and C pools may occur in the CC period, thus influencing the processes leading to the emission of N2O.A set of field experiments were carried out in a 3.5-years field study in a maize-fallow rotation placed in Central Spain (350 mm 30-years average annual precipitation). Firstly, we tried to determine the effect of replacing fallow by a CC on N uptake, fate of labeled fertilizer, soil mineral N accumulation, maize yield, nitrate (NO3-) leaching and water balance(Exp. I; 3.5 years duration). The last year of the study (Exp.II) was focused on evaluating the effect of CCs over direct N2O emissions of the rotation. The CCs used during the intercropping period of maize (Zea mays L.) were: barley (Hordeumvulgare L.), vetch (Viciavillosa L.), rape (Brassica napus L., only in Exp.II) and fallow. All treatments were equally irrigated and fertilized according to standard farming practices in the region (~700mm and 210 kg N ha?1). The CC residues were left over the surface in Exp.I, and left in half plot and incorporated in other half for Exp.II. Results showed that there were no differences between CCs in the N recovered from fertilizer, averaging 46%. However, barley recovered more 15N during the autumn-winter following the first plantation. Fertilizer recovered in the barley residue comprised 19% of total N content in aerial biomass, while only 4% in vetch. Vetch increased N supplied by residues after 2 years and N content in grain after three. Replacing fallow with CCs did not affect maize yield, but N uptake. Cumulative NO3- leaching in fallow, vetch and barley was 346, 245, and 129 kg N-NO3- ha-1, respectively; occurring ~80% during the intercrop period. Vetch was the only CC that significantly enhanced N2O losses in the autumn-winter period. Incorporation of rape and barley residue had a significant influence over N2O fluxes in the 2-4 month period following application. This was associated to the interaction between CC residue and N fertilizer application. | |
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Internacional
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Si |
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Nombre congreso
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6th International Nitrogen Conference |
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Tipo de participación
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960 |
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Lugar del congreso
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Kampala, Uganda |
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Revisores
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Si |
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ISBN o ISSN
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1-84170-588-8 |
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DOI
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Fecha inicio congreso
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18/11/2013 |
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Fecha fin congreso
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22/11/2013 |
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Desde la página
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122 |
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Hasta la página
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122 |
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Título de las actas
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6tjINTERNATIONAL NITROGEN CONFERENCE |