Abstract

GILETTO, CLAUDIA MARCELA et al. Caracterización del estrés de nitrógeno en papa para industria usando el NDVI. Cienc. suelo [online]. 2016, vol.34, n.2, pp.221-229. ISSN 1850-2067.

Measuring the reflectance with optical sensors has the potential to provide information about the nitrogen (N) status during the potato growing season and it could predict the N rate. The objectives were to evaluate the N status using optical sensors, GreenSeeker 506 (GS) and CropCircle ACS 210 (CC), compare them and provide algorithms to define N sufficiency thresholds. Three field experiences with variable N rate were carried out during the 2009/10, 2010/11 and 2012/13 growing seasons. Potato yield increased with N fertilization and this varied from one growing season to the other. The relationship between normalized difference vegetation index (NDVI) of the two sensors was significant along the growing season with large determination coefficient values (R² = 0.74 to 0.99). Measured NDVI values by CC was lower than by GS from 60 days after plantation (dap). The relationship between relative NDVI with the available N (N at planting + N rate) were significantly associated from 60 dap for CC (R² = 0.85 and 0.91 0.65; for 60, 80 and 100 dap, respectively) and from 80 dap for the GS (R² = 0.72 and 0.76 for the 80 and 100 dap, respectively). The average sufficiency N threshold was 99.4% and 99.7% for the GS and CC; respectively. In general, predictive models of the N stress varied according to the used sensor, and it was determined that the CC was more sensitive than the GS to determine N stress.

Keywords : GreenSeeker 506; CropCircle ACS 210; Optimum N rate.

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