Computation of evapotranspiration using crop simulation models and comparison with leaf area index from multiple sources

The study demonstrated the computation of evapotranspiration (ET) in cultivation of groundnut (Arachis hypogaea) through the application of crop simulation models, alongside a comparative analysis with leaf area index (LAI) from various sources. The cultivation period for groundnut was conducted during the calendar year 2023, during which 2 distinct growth patterns were noted, attributed to variations in environmental conditions. The study analyses the estimated evapotranspiration from AquaCrop model, utilizing crop coefficient (Kc) values in comparison with evapotranspiration data derived from satellite observations provided by the MOD16A2v061 product. Furthermore, LAI was measured through 3 methodologies: an empirical equation based on field data, the Li-Cor 2200 plant canopy analyzer and LAI calculations derived from cloud-free normalized difference vegetation index (NDVI). LAI obtained from Li-Cor 2200 instrument exhibited a higher degree of consistency in correlation with empirical LAI derived from ground observations. Conversely, LAI values calculated using the normalized difference vegetation index (NDVI) demonstrated a greater degree of variability, especially during times of cloud cover. The study emphasizes the relationship between LAI and ET and magnitude of LAI in amount of total evapotranspiration.