ET Portioning using isotopes

Abstract

1. Design of lysimeter for seepage measurement: A lysimeter specifically designed to measure seepage losses, particularly during the rice-growing season, should be developed to improve water balance estimations. 2. Development of a Peltier element-based autosampler: A sampling system utilizing a Peltier element-based autosampler can be designed to collect atmospheric water vapor more efficiently for isotope analysis. Since it is very difficult to collect water vapor at remote location using liquid nitrogen based cold traps. 3. Exploration of in-situ methods for soil and plant water collection: Since cryogenic vacuum distillation is a destructive method, alternative in-situ techniques should be investigated for non destructive isotope sampling of soil and plant water. 4. Direct analysis of water vapor using a water vapor isotope analyzer: The current approach relies on Keeling plots for isotope analysis, but these can be improved by directly analyzing water vapor using a field-deployable Water Vapor Isotope Analyzer. 5. Investigation of non-steady-state transpiration: The study assumed a steady-state transpiration, but in real-world conditions, this assumption may not always hold. Future research should focus on quantifying non-steady-state transpiration fraction dynamics for improved ET partitioning. 6. The data generated from both hydrometric and isotopic methods can be utilized for developing and testing hydrological models at plot and field scales, thereby improving future water conservation and agricultural planning strategies 7. Knowledge of isotopic compositions of different components of hydrological cycles and their temporal variations, as studied in this project, can be useful in understanding the complexities of hydrological processes in the Ganga basin. A long-term isotopic record can be helpful in deciphering the response of the hydrological cycle to climatic and anthropogenic changes.