Impact of Climate Change on Groundwater Recharge in Cotton Irrigated Fields under Agronomical Practices

<title>Abstract</title> Cotton crop is one of the major water consumers in the Indus basin region. Accurate groundwater recharge estimation is a provoking duty due to hydrologic and environmental applications under climate change in the agricultural sector. An utmost region that is vulnerable to climate change and cotton production is declining, consequently. Here, historical trends (1975–2005) and future variability (2021-50 and 2051-80) of climate parameters were analyzed and predicted by SDSM for three emission scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) for the semi-arid region Faisalabad, Pakistan. Results revealed a rise in maximum (minimum) temperature and a decline in rainfall, relative humidity, and wind speed for both 2021-50 and 2051-80 using different NCEP parameters (<italic>p &lt; 0.05</italic>). The groundwater recharge was simulated using the Hydrus-1D unsaturated flow model. Hydrus-1D unsaturated flow model simulated the groundwater recharge under six treatments. A 41 cm reduction of groundwater recharge was observed under all scenarios. The highest recharge was observed 71 cm under RCP 2.6, and the lowest recharge was 30 cm under RCP 8.5, a maximum of 23% groundwater recharge controlled by climate variables with the weak relationship among them. Cotton sowing method T₆(bed planting without mulch) showed the highest yield (1,066 kg.ha^{− 1}). It further indicates that rather than climate change, the agronomical practice may have a more significant impact on groundwater recharge and cotton yield. Findings highlight the significance of both climate change and the cotton sowing method while accessing future water resources in irrigated Indus basin agriculture.