El GNDVI, por su parte, es un indice de la planta "verde" o de la actividad fotosintetica comunmente utilizado para determinar la absorcion de agua y el nitrogeno en el follaje del cultivo.
El GNDVI sustituye a la banda de color rojo (R) de la recoleccion de datos para NDVI y lo hace con una banda muy especifica de la luz en el rango verde, con lo que puede obtener informacion util adicional.
La obtencion de GNDVI frecuentes permite la optimizacion del riego e indica cuando se produce aislamiento del agua o cuando ella varia a traves del campo.
Vegetation Formula References indices 1 NDVI B7 - B4IB7 + B4  2 EVI G * B7 - B4IB7 + C1 * B4 - C2 * B2 + L  Note: C1 = 6; C2 = 7.5; L =1; G = 2.5 3 MSR (B7IB4 - 1)l((B7 + B4)m + 1)  4 SR B7IB4  5 NDI45 B5 - B4IB5 + B4  6 S2REP 705 + 35 *  ((((B7 + B4)I2) - B4)I(B6 - B5)) 7 GNDVI
B7 - B3IB7 + B3  TABLE 3: Important value index for each species found in private forest.
During the 2014 harvest, significant differences in the calculated indices were observed only during the vegetative period and for NDVI and GNDVI. In terms of NDVI, plots that received the 160kg [ha.sup.-1] treatment performed better than those treated with 80kg [ha.sup.-1].
Of the vegetation indices employed in this study, those most sensitive in terms of ability to detect differences in the canola canopy across nitrogen fertilization treatments were the SR, NDVI, and GNDVI.
The SR, NDVI, and GNDVI vegetation indices are sensitive metrics for detection of changes in the spectral reflectance of canola associated with variation in top dress nitrogen application.
The values of RNDVI, GNDVI, and SR (based on red, green, and near infrared radiation) were similar at the booting and heading stages, while their values decreased during grainfilling.
The indices RNDVI, GNDVI, and SR also showed a strong association between booting and heading, and booting and grainfilling in the years 2002-2003 and 2003-2004, but not in the year 2001-2002.
All indices showed the highest association between years at the grainfilling stage except for PRI and GNDVI between years 2001-2002 and 2002-2003 (Table 5).
In-addition, the mean vegetative index values (GNDVI, GVI, RNDVI, and RVI) were calculated from the three replications of each experimental unit.
Analysis of variance and multiple range testing showed that the GNDVI had smaller reflectance values for the control, with no significant differences consistently demonstrated among the N-sources.