USE OF CHLOROPHYLL METER SPAD-502 IN THE MANAGEMENT OF NITROGEN CORN FERTILIZATION. AZUERO, PANAMA. 2000-2002.
A study was carried out to determine corn nutritional stage regarding nitrogen, through the use of Chlorophyll meter SPAD-502 before the first and second urea spreading on the crop, in order to recommend nitrogen fertilization adjustment. A second objective was determining the necessity to increase o decrease nitrogen rates applied on the field according to chlorophyll meter lecture made 65 days after planting (dap) on the current crop. We used the database of 15 experiment of nitrogen rates carried out in some localities of Azuero Region during 2000, 2001 and 2002. The nitrogen rates of this experiment varied between 0 to 350 kg N/ha. The yield grain was calculated and chlorophyll meter lectures were read to 21, 37 and 65 dap. The two first lectures were achieved on the last true leaf and the last one was achieved on the ear leaf with a chlorophyll meter SPAD-502 by Minolta. The rates what optimized the grain yield, like as the plateau by locality were calculated by Quadratic-Plateau model. The relative yield was calculated by locality and correlated with the 21, 37 and 65 lectures of the SPAD-502 with the use of Linear-Plateau model. We correlated the 65 dap lecture with the additional nitrogen needed to achieved the plateau by localities. We found low correlation between SPAD-502 lecture and relative yield at 21, but this correlation improved with the 37 and 65 dap lectures. According to equation at 21 dap the critical value (joint) to take a decision is around to 39 SPAD-502 unities, in the mean time at the 37 dap this value oscillated around 45 unities. In relation to equation for determining the necessity to increase or not the N rates the next year, lectures below 56.2 indicated nitrogen deficiencies, in the meantime up stairs lectures of this value indicate nitrogen excess.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Instituto de Innovación Agropecuaria de Panamá
2004
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| Online Access: | http://www.revistacienciaagropecuaria.ac.pa/index.php/ciencia-agropecuaria/article/view/322 |
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