Agricultural crop shifts associated with changing water availability in Aligarh District, Uttar Pradesh

Long-term variability in water availability influences agricultural production, particularly in regions dependent on rainfall-derived soil moisture (green water, GW) and irrigation from surface water and groundwater resources (blue water, BW). This study examines long-term associations between precipitation variability, agricultural production, and cropping area in Aligarh District, Uttar Pradesh, using multi-decadal data from 1991 to 2021. Crop production (1991–2021), cropping area (1991–2015), and annual rainfall data were analysed using Pearson correlation analysis to evaluate relationships among crop production, cropping area, and precipitation variability. The results revealed contrasting temporal trends in crop production, cultivated area, and productivity among crop groups. Interpretation using published crop-specific water footprint values suggests that crops such as rice, grown primarily during the monsoon season (GW ~ 2040 m³ t⁻¹; BW ~ 937 m³ t⁻¹), and potato with low BW requirements (GW ~ 244 m³ t⁻¹; BW ~ 28 m³ t⁻¹) generally expanded. In contrast, sugarcane (GW ~ 1107 m³ t⁻¹; BW ~ 455 m³ t⁻¹) requires prolonged water supply throughout the year and has a comparatively greater published BW footprint. Barley, sugarcane, and pulses exhibited declining production and cultivated-area trends, whereas rice, potato, and millet showed increasing trends in both parameters. Strong inverse correlations among these crop groups indicated systematic shifts in cropping patterns over time. These findings demonstrate statistically supported crop–water associations and provide a scientific basis for sustainable agricultural planning and groundwater management under changing hydroclimatic conditions.