Document Type : Research Paper
Department of Irrigation and Reclamation Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Water Engineering, Faculty of Agriculture & Natural Recourses, Imam Khomeini International University, Qazvin, Iran
Leaf area index is an important parameter in controlling different processes between atmosphere-plant-soil and due to its importance in various modeling, its rapid measurement at different scales has been considered. The use of vegetation indices (VIs) is one of the common methods for estimation leaf area index and each of these indices shows different sensitivities in various values of leaf area index during plant growth period. The aim of this study was to estimate leaf area index using Normalized Difference Vegetation Index (NDVI), Simple Ratio (SR), Soil Adjusted Vegetation Index (SAVI), Optimized Soil Adjusted Vegetation Index (OSAVI), Weighted Difference Vegetation Index (WDVI) and Wide Dynamic Range Vegetation Index (WDRVI) and comparison with measured leaf area index during the growth period of maize under different crop densities and the application straw mulching during 2020 growing season in the Karaj. Based on the results, the sensitivity of vegetation indices to leaf area index at different growth stage weren't same and based on coefficient of determination (R2) and root mean square error (RMSE) and equivalent noise (NE), OSAVI index With R2 and RMSE of 0.91 and 0.98, respectively, and high sensitivity as the best index and SR index with the values of R2 and RMSE of 0.69 and 2.19, respectively, and NE of 2.19 as the weakest index for leaf area index prediction.. Also, a similar trend was observed between measured leaf area index and predicted LAI using OSAVI index.