Glycine betaine application improved seed cotton yield and economic returns under deficit irrigation

Background Deficit irrigation exerts devastating effects on the productivity and economic returns of cotton crop, as well as carbon dioxide (CO2) emission from soil. Osmolytes play a significant role in facilitating the adaptation of cotton plants to abiotic stresses and improve productivity. Methods This study investigated the effects of different osmolytes (glycine betaine, ascorbic acid, salicylic acid 100 mg L−1 each) and deficit irrigation (50 %-I50, 75 %-I75, and 100 %-I100) on seed cotton yield, greenhouse gas emission (CO2-C), emission factor (EFs) and economic returns of cotton in Southern Anatolia, Türkiye. Results Deficit irrigation and osmolyte treatment, both separately and in combination, had a substantial impact on seed cotton yield, CO2-C emission and EFs. The lowest (3800 kg ha−1) and the highest (4746 kg ha−1) seed cotton yield was noted under I50, and I100 treatments, respectively. Similarly, no osmolyte application and application of glycine betaine resulted in the lowest (4097 kg ha−1) and the highest (4545 kg ha−1) seed cotton yield, respectively. The interactive effect indicated that application of glycine betaine and salicylic acid produced better yield than control treatment under all irrigation treatments. The lowest (1.55) and the highest (1.94 mg) CO2-C emission (mg CO2-C m−2 h−1) was recorded for I50, and I100 treatments respectively. Likewise, the lowest (1.52) and the highest (2.19) daily carbon emission were recorded for salicylic acid and glycine betaine application, respectively. The lowest and the highest EFs values were observed for glycine betaine and ascorbic acid application, respectively. Application of glycine betaine resulted in the highest economic returns under all irrigation treatments which was comparable to salicylic acid, whereas the lower economic returns were recorded for control treatment. Conclusion It is concluded that application of glycine betaine can be used to improve seed cotton yield and economic returns under deficit irrigation. Similarly, glycine betaine proved helpful in reducing CO2-C emission under deficit irrigation compared to normal irrigation.