Adaptation to Climate Change in Indian Agriculture: The Role of Water Resources

Sarkar, Nairit (2026) Adaptation to Climate Change in Indian Agriculture: The Role of Water Resources. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Nairit Sarkar (20RS089)) 20RS089.pdf - Submitted Version Restricted to Repository staff only Download (51MB)

Abstract

Anthropogenic inputs, particularly irrigation and fertilizer use, have played a critical role in helping Indian agriculture to adapt to climate change. Most previous assessments regarding Indian agriculture either rely on forecasting or proxy indices or examine climatic and anthropogenic factors in isolation, overlooking their evolving interactions over time. This study investigates how climatic variables (rainfall, maximum and minimum temperatures) and anthropogenic adaptive measures (irrigation and fertilizer use) jointly influenced the yields of four staple crops, rice, wheat, maize, and sorghum, across Indian districts over the last three decades (1990–2019). A multivariate approach using Artificial Neural Networks (ANNs) coupled with Garson’s algorithm helped understand the complex non-linear interactions and the relative importance of these drivers, which conventional bivariate analyses fail to capture. Results indicate that anthropogenic factors, particularly the fraction of irrigated area, dominate rice yields across seasons, whereas minimum temperature is the most influential climatic driver, especially for wheat yields. Across all crops, irrigation and fertilizer exerted sustained influence, whereas the influence of minimum temperatures increased significantly, highlighting a gradual shift from predominantly input-driven production toward climate-sensitive outcomes. Trend analyses using the Modified Mann–Kendall test and Sen’s slope show that rising yields, rather than expansion of gross cropped area, have supported increased production, though yield instability remains moderate to high in over half of Indian districts, as quantified by the Cuddy– Della Valle Instability Index (CDVI). Climatic factors also showed significant changes, and irrigation often buffered yields against these stresses. Integrating CDVI with long-term yield and climate trends into a composite Level of Concern (LOC) index identifies crop- and regionspecific vulnerability hotspots, with maize and sorghum exhibiting the largest areas of concern. To assess the hydroclimatic sustainability of irrigation-based adaptation, a basin-scale case study in the intensively cultivated Nanoor region of the lower Ajay River basin was conducted. Analysis of long-term pre- and post-monsoon groundwater levels revealed declining net monsoonal recharge despite continued rainfall. Stable isotope compositions of groundwater, surface water, and rainwater indicate a limited recharge from contemporary rainfall, suggesting a decoupling between meteoric inputs and aquifer replenishment. Rainfall–runoff analyses using moving averages, anomalies, Quantile Perturbation Method (QPM), and elasticity estimates demonstrate that runoff is highly responsive to rainfall inputs, and land-use changes, particularly agricultural intensification and increased built-up areas, amplify rapid surface flows while reducing infiltration. Overall, this study demonstrates that while anthropogenic measures have successfully buffered crop yields against climate variability, their long-term sustainability is increasingly constrained by groundwater stress and reduced recharge. By linking national-scale crop dynamics with basin-scale hydrological processes, the study highlights the need for water-sensitive, regionspecific adaptation strategies that simultaneously sustain yields and safeguard critical water resources under a warming climate.

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