FRESENIUS ENVIRONMENTAL BULLETIN, cilt.27, sa.5A, ss.3624-3632, 2018 (SCI-Expanded)
The spectral reflections of plants, chlorophyll a-b and plant nutrient contents vary throughout the growing period. The aim of this study was to examine the relationship between the spectral reflectance (RF) and nutrients, chlorophyll (Chl) a-b content in the visible near infrared (VNIR) region of the electromagnetic spectrum (EMS) during the maturitiy and harvest periods of the lettuce plant. The treatments were solid fertilizers applied before planting at two different rates (0, 300 and 600 kg.da(-1)), and liquid organic fertilizer applied by drip (20-40 It da(-1)) throughout the growing period. Within this period, spectroradiometric measurements were taken with a hand spectroradiometer (plant probe and leaf clips) in the range of 330-1075 nm wavelength of the electromagnetic spectrum. In addition to the relevant measurement, Normalized Difference Vegetation Index (NDVI) calculations were made, and plant nutrient and chlorophyll a-b analyzes were performed. According to the results, at the maturity stage there was a statistically significant relationship at 1% level between blue band and Fe (-0.710**), chlorophyll a (-0.754**), green band and N (-0.779**), Mg (-0.774**), Ca (-0.727**), chlorophyll b (-0.664**), Fe (0.578**), red band and Ca (-0.782**), Mg (-0.668**), NDVI and Ca (0.776**), Mg (0.659**), and at harvest stage, between blue band and P (-0.667**), green band and chlorophyll a (-0.779**), NIR band and chlorophyll a (0.772**), Mn (-0.599**), N (0.593**), Zn (-0.574**) and Cu (-0.571**).