Regional model for nitrogen fertilization of site-specific rainfed corn in haplustolls of the central Pampas,Argentina |
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Authors: | M C Gregoret M Díaz Zorita J Dardanelli R G Bongiovanni |
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Institution: | 1.Technical Area,AACREA Cordoba Norte,Ciudad autonoma de Buenos Aires,Argentina;2.CONICET-FAUBA and Merck Crop Bioscience Argentina,Pilar,Argentina;3.INTA Manfredi,Córdoba,Argentina |
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Abstract: | In semi-arid regions, soil water and nitrogen (N) are generally limiting factors for corn (Zea mays L.) production; hence, implementation of appropriate N fertilization strategies is needed. The use of precision agriculture
practices based on specific site and crop properties may contribute to a better allocation of fertilizer among management
zones (MZ). The aim of this study was to develop a model for diagnosis of N availability and recommendation of N fertilizer
rates adjusted to MZ for dryland corn crops growing in Haplustolls. The model considered variability between MZ by including
site-specific variables soil available water content at sowing (SAW) and Available Nitrogen (soil available N-NO3 at planting + applied N, Nd)] using spatial statistical analysis. The study was conducted in Córdoba, Argentina in Haplustolls
and consisted in four field trials of N fertilizer (range 0–161 kg N ha−1) in each MZ. The MZ were selected based on elevation maps analysis. Grain yields varied between MZ and increased with larger
SAW and Nd at sowing. Grain responses to Nd and SAW in any MZ were not different between sites, allowing to fit a regional
model whose parameters (Nd, Nd2, SAW, SAW2) contributed significantly (p < 0.001) to yield prediction. Agronomical and economically optimum N rates varied among MZs. However, the spatial variability
of optimum N rates among MZs within sites was not enough to recommend variable N fertilizer rates instead of a uniform rate.
Variable N fertilizer rates should be recommended only if variability in SAW and soil N among MZ is greater than that found
in this work. |
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