Determination of Plant Water Consumption Components and Water-Production Functions under Different Irrigation Methods in Paddy (Oryza sativa L.) Farm

In this study, determination of yield, yield components and water-production functions of paddy plant, irrigated by different irrigation methods, was aimed. For this purpose, the effect of water constraint, applied with different irrigation methods, on paddy yield and yield parameters was compared statistically and economically. The research was carried out according to randomized blocks factorial trial design with three repetitions in 2015, 2016 and 2017 and three different irrigation methods (D: Drip irrigation, Y: Sprinkler irrigation, AWD: Alternate wetting and drying) were used for the irrigation of paddy plant. In every three methods, two different irrigation water levels (I1= The subject in which the 25% of the water between the saturation point and field capacity was applied when the soil moisture was around the field capacity, I2= The subject in which the water was applied until the field capacity when 25% of the usable water holding capacity) were used. Besides, traditional continuously flooded irrigation method, which is intensively used in paddy farming, was carried out with three repetitions besides the trial design and it was compared with other three methods. The applied irrigation water amounts of drip irrigation, sprinkler irrigation and AWD irrigation in I1 and I2 irrigation levels changed between 774-1172 mm in 2015, 930-1372 mm in 2016 and 868-1299 mm in 2017. In traditional continuously flooded application, 1812, 1939 and 1946 mm irrigation water was applied in 2015, 2016 and 2017 years, respectively. As a result of the study, the highest average paddy yield was obtained from traditional continuously flooded method with 7,95 t ha-1. AWD –I1 application with 7,60 t ha-1 and D-I1 application with 6,39 t ha-1 followed this. According to the cumulative variance analysis results, the difference between the methods and irrigation levels and irrigation method * irrigation levels was found statistically significant in 1% confidence level. The highest irrigation water usage yields (IWUE) in all applied irrigation methods and irrigation levels changed between 0,47 – 0,64 kg da-1 mm-1 in the first year, 0,38 – 0,55 kg da-1 mm-1 in the second year and 0,41 – 0,59 kg da-1 mm-1 in the third year of the research. The highest water application efficiency was obtained from AWD-I1 subject in three years. As a result of the economic evaluations, when the different irrigation methods and three-year net incomes obtained from different irrigation methods and irrigation levels were examined, it was determined that the highest net income was obtained from traditional pan irrigation application and AWD-I1 subject and D-I1 subject followed this. According to the other economic analysis results (cost-benefit ratio, internal rate of return), it was concluded that I1 subjects of all the methods were applicable.