Title: Contours of Contemporary Research: Perspectives Across Disciplines
Chief Editors: Dr. S. Durga, Dr. S. Sathyapriya, and Dr. V. A. Jane
ISBN: 978-81-17787-25-0
Chapter: 15
DOI: https://doi.org/10.59646/880/15
Authors: Mithilesh Khandwala*, Devansh Desai
Abstract
Evapotranspiration (ET), the combined transfer of water to the atmosphere through evaporation from soil and other surfaces and transpiration by plants, is a central component of agricultural water management. In India, where farming systems range from intensively irrigated alluvial plains to semi-arid and arid landscapes, reliable estimates of crop water use are essential for irrigation scheduling, drought assessment, water budgeting and agricultural planning. Satellite remote sensing and ET models—including SEBAL, METRIC, SSEB-type approaches and remotely sensed ET products—make it possible to estimate spatial patterns of water use over fields, irrigation commands and larger regions. This chapter discusses the scientific basis of ET modelling, its practical roles in Indian agriculture, its potential economic pathways and its relevance to the United Nations Sustainable Development Goals (SDGs). Agriculture and allied activities represented about 18.0% of India’s Gross Value Added (GVA) at current prices in 2024–25 according to the Government of India’s second advance estimates; this figure describes the sector’s economic share and must not be interpreted as the contribution of ET models. Rather, ET models can potentially support economic performance indirectly by improving irrigation decisions, reducing avoidable water and energy use, identifying crop water stress and strengthening drought resilience. The chapter also considers applications relevant to Western India, particularly irrigated agricultural systems in Gujarat and water-limited environments in Rajasthan. It concludes that ET products are most useful when combined with field observations, crop yield, rainfall, soil moisture, irrigation and groundwater data and when uncertainty is communicated clearly (FAO, 1998; Allen et al., 2007; Bastiaanssen et al., 1998; Senay et al., 2013).
Keywords: Evapotranspiration; remote sensing; Indian agriculture; irrigation scheduling; SEBAL; METRIC; SSEB; water productivity; Gross Value Added; Sustainable Development Goals; Gujarat; Rajasthan