ISHS Acta Horticulturae 627: XXVI International Horticultural Congress: Toward Ecologically Sound Fertilization Strategies for Field Vegetable Production
MAPPING SPATIAL VARIATION IN POTATO NITROGEN STATUS USING THE N SENSOR |
| Authors: | B.J. Zebarth, H. Rees, N. Tremblay, P. Fournier, B. Leblon |
| Keywords: | Solanum tuberosum, leaf chlorophyll index, petiole nitrate concentration |
| Abstract:
Variable rate fertilizer N application may be required to optimize N management in fields with variable soil properties. The purpose of this study was to evaluate the N Sensor for mapping N status in potato fields. Different fertilizer N treatments were applied in a field scale trial in two years to induce variable potato N status. Potato N status was measured using the N Sensor (NSI), petiole nitrate concentration (PNIT), and leaf chlorophyll index measured using a SPAD-502 meter (LCI-S) and using a Fieldscout chlorophyll meter (LCI-F). NSI measured early in the growing season was well correlated to relative tuber yield, and NSI measured early or later in the growing season was well correlated with tuber total yield. In addition, NSI was correlated with tuber size distribution and tuber specific gravity, but the correlations were not strong in all cases. This suggests that NSI is an effective measure of potato N status. NSI was generally comparable to PNIT, and superior to LCI-S and LCI-F, as an indicator of potato N status, however of these, only NSI is well suited for mapping spatial variation in potato N status. It is proposed that the N Sensor would be best used in a system where fertilizer N application at planting is close to optimal based on some type of soil test system, and where the N Sensor is used to "fine-tune" fertilizer N application based on potato N requirement. | |
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