REMOTE SENSING AS AN INDIRECT WAY TO ESTIMATE BIOPHYSICAL AND BIOCHEMICAL PROPERTIES OF BEANS CROP

Abstract

Non-destructive monitoring of agricultural crops becomes more important to improve crop productivity. In site specific management, in-situ remotely sensed data is of significant importance for quantifying nitrogen deficiency and salinity stress effects on crops. In the reported research, the visible and near infrared portions of the electromagnetic spectrum were used to derive vegetation indices sensitive to nitrogen deficiency and salinity stress in beans (Phaseolus Vulgaris, L). Four nitrogen fertilization rates (0, 30, 60 and 100 kg/ha) and three water salinity levels (1.5, 3 and 5 dS/m) were used to subject plants to both stressors. Reflectance measurements were collected from beans plants under artificial illumination conditions at different growth stages and used to calculate 45 commonly used vegetation indices for predicting beans properties. Strong significant correlations between beans properties and different vegetation indices were observed. Crededge and R750/R700 ratio were found to be the optimum indices for predicting beans chlorophyll content (r = 0.657). R710/R760 ratio was also found to be the optimum index for predicting beans biomass (r = -0.582). PSNDb was found to be sensitive to beans grain yield (r > 0.595). The correlations with grain yield were found to be strongest at the R6 growth stage.