Enhancing Wheat (Triticum aestivum L.) Crop Yield and Water Use Efficiency: A Study on Canopy Air Temperature Difference-Based Drip Irrigation Scheduling in a Semi-Arid Region of Western India

Abstract This study addresses efficient water usage in wheat cultivation in a semi-arid region of India with clay loam soil and an increasing water supply-demand gap. It focuses on optimizing drip irrigation (DI) scheduling, of wheat crops, based on canopy air temperature difference (CATD) using the crop water stress index (CWSI). The field experiments were conducted for two winter seasons, employing high-discharge drip irrigation (DI) on wheat crop (variety - GW 366) at Junagadh Agricultural University (JAU), Gujarat, India. The experiment had nine treatments, each replicated three times in randomized blocks. The DI treatments labeled as T 1 to T 6 , were irrigated at CATD values of -4, -3, -2, -1, 0, and 1 °C, respectively.. While T 7 were irrigated by border irrigation. In order to define upper and lower baselines of CWSI, well watered treatments (T 8 ) and extreme dry treatment (T 9 ) DI were considered. The drip irrigation system (DIS) had an application rate of 7.78 mm/h with a uniformity coefficient of 90.40%. Compared to surface irrigation, DI resulted in water savings ranging from 3.52% (T 1 ) to 43.24% (T 6 ). Using real-time CATD data, the theoretical CWSI (CWSI Th ) and the vapor pressure deficit (VPD) based semi-empirical CWSI (CWSI VPD ) were calculated as 0.3351 and 0.3668, respectively. CATD values showed significant variation in CWSI across treatments. The CWSI demonstrated sensitivity to water stress during critical growth stages. The study identified an optimal CATD of -1 °C, yielding 36.48% higher crop yield (4744 kg/ha), 30.23% water savings (388.42 mm), and notable 95.67% more water use efficiency (12.21 kg/ha-mm,), surpassing the outcomes of border irrigation (3476 kg/ha, 556.74 mm and 6.24 kg/ha-mm). These findings hold significant implications for farmers and policymakers, effectively addressing food and water security concerns. The study underscores the efficiency of DI combined with CATD-based irrigation scheduling in optimizing wheat crop performance. In the context of critical water management, this research provides essential insights for sustainable agricultural practices.