THE EFFECT OF DIFFERENT IRRIGATION WATER AMOUNTS ON COTTON (GOSSYPIUM HIRSUTUM L.) YIELD AND QUALITY

In the study, it was aimed to figure out the relationship between irrigation and cotton plant yield (Gossypium hirsutum L.) under different conditions created by applying different irrigation water levels by using Subsurface Drip Irrigation System in the area of Harran University, representing the conditions of the Harran Plain in Sanliurfa, Turkiye in 2019 and 2020. The irrigation issues; 125% (v/v), 100% (v/v), 75% (v/v), 50% (v/v), and 25% (v/v) were created according to the amount of evaporation obtained from Class A Pan for both years but, the issue of 150% (v/v) as over-irrigation issue was added in the study belonging to 2020 for understanding the statistical reliability of the optimum irrigation issue obtained. While amount of irrigation water used was 933.75-196.75 mm in 2019, it was 1138.5189.75 mm in 2020. The other parameters of irrigation such as Class A-Pan coefficient (Kcp), plant water consumption (ET), soil water change in the effective root zone (Delta S, mm), water use efficiency (WUE), and irrigation water use efficiency (IWUE) were determined. The yield parameters such as seed cotton yield (kg ha-1), ginning out turn (%), 100 grain weight (g), cotton boll weight (g), number of bolls per plant, plant height (cm) were obtained. Fiber quality parameters such as fiber index (%), fiber length (mm), fiber uniformity index (%), fiber strength (g tex-1), fiber fineness (mic), fiber elongation at break (Elg) were studied. In conclusion, the Kcp value for both years was determined as 1.25. The results obtained in the study will support further studies in the field.