*2.4. NDVI (Normalized Difference Vegetation Index)*

NDVI is a spectral calculation of the density of the green vegetations on a specific area. For NDVI, data was recorded from the three replicates, where a GreenSeekerTM Handheld Optical Sensor Unit (NTech Industries, Inc., Ukiah, CA, USA) was used, kept one meter above the plants during measurement [49].
