Assessing the spectral separability of flue cured tobacco varieties established on different planting dates and under varying fertilizer management levels

Abstract

The NDVI was used to discriminate tobacco variety, assess fertilizer levels, and determine the impact of planting date on separating crops. A split plot design with four planting dates, September, October, November, and December, as main plots, variety as subplot, and fertilizer treatments as sub-subplots was used. Radiometric measurements were taken from 5 m × 5 m sampling plots, using a multispectral radiometer. The September, October, and November crops had significant variety x fertilizer treatment differences (F < 0.05) from the age of 10 weeks. T 66 and KRK26 varieties had similar (F > 0.05) NDVI values and these were greater (F < 0.5) than those for K E1. The 100% and the 150% fertilizer treatments were similar (F > 0.05) and both were greater (F < 0.05) than the 50% fertilizer treatments. All of the fertilizer and variety treatments at the December planting dates had similar reflectance characteristics (P > 0.05), which were lower (P < 0.05) than the September and October planting dates. The results showed that planting dates, varieties, and fertilizer levels could be distinguished using spectral data. Weeks 10-11 and 15 after the start of the experiment were optimal for separating the planting date effect.