A field experiment on spectrometry of crop response to soil salinity

A field experiment was carried out to assess the effects of irrigation with highly saline (T1 treatment), moderately saline (T0.5) and non saline (T0) water on soil and eggplant (Solanum melongena) properties and spectral response. The investigated soil was a clay-loam Alfic Xerarent, with swelling clay minerals (smectites). After 5 years of irrigation, T1 and T0.5 treatments resulted in soils that were saline-sodic and sodic, respectively. The soil salinity/sodicity status noticeably affected dry biomass, leaf area index (LAI), plant water content, leaf water potential (ψl) and spectral properties of eggplant. Significant relationships were obtained between plant characteristics and normalised difference vegetation index (NDVI) and water index (WI). Soil salinity conditions had significant impacts on NDVI and WI, but not on the red-edge position in the spectral response. Therefore spectral response was considered a useful criterion for discriminating salt-affected soils from non salt-affected soils.