Effect of deficit and partial root zone drying irrigation techniques on water-yield relations of cotton under Aydin Plain conditions

Objective: This study was carried out to determine seed cotton yield, yield components and water use efficiency of the May 505 cotton cultivar under traditional deficit irrigation and partial root zone drying (PRD) under Aydın conditions in year 2021 at the Research and Application Farm of the Agriculture Faculty of Aydın Adnan Menderes University. Material and Methods: The trial was designated in randomized complete block design with two factors and three replications. In the study, three different irrigation levels (100, 67 and 33%) and two different (traditional deficit irrigation and partial root zone drying (PRD)) applications were investigated. Irrigation water quantity based on cumulative evaporation from class A pan at 8 day irrigation interval was applied through drip system to full irrigation (TS100), deficit irrigation (KS67 and KS33) and partial root zone drying (PRD)- PRD100, PRD67 and PRD67. Results: A total of 575 mm irrigation water was applied to TS100 treatment, while KS67 and KS33 treatment plots received 383 and 189 mm; PRD100 treatment plots received 290 mm, PRD67 received 193 mm and PRD33 treatment received 97 mm of irrigation water. The highest seed cotton yield was obtained from the TS100 treatments as 511 kg/da, while KS67 and PRD100 treatments resulted in yields of 445 kg/ da ve 415 kg/da respectively. There was significant difference among the treatment with respect to seed cotton yields. Average water use efficiency (WUE) values varied between 0.76-1.29 kg/m3. Yield response factor (ky) was found to be 0.59 for traditional deficit irrigation and 0.67 partial root zone drying-PRD). Conclusion: It may be concluded that the treatment which gave the best performance was treatment TS100 (traditional deficit irrigation) when the water was abundant. In the case of water scarcity KS67 and PRD67 (traditional deficit irrigation and partial root zone drying-PRD) treatments resulted in reasonable yield, WUE and fibre quality. Key Words: Aydın, partial root zone drying, cotton, drip irrigation, yield response factor