Determination of Optimum Irrigation Time in Days by Using Plant Based Measurements

Indicators based on plants used extensively in recent years for the purpose of determining irrigation time.In this study leaf water potential (LWP) and crop water stress index (CWSI) was used that method of determination of irrigation time based on plant. Surface drip (DI) and subsurface drip systems (SDI); two irrigation frequencies (IF3: 3-day; IF6: 6-day) and four irrigation regimes (Full irrigation, FI; deficit irrigations, DI50; DI75; and Partial Root-zone Drying PRD50, hich received, respectively 50, 75 and 50% of FI) were tested in a split-split plot design. LWP measurement using the pressure chamber and CWSI values, plant canopy temperature (Tc) and air temperature (Ta) measurements were made with infrared thermometer. At the same time measurements of wet and dry air temperatures were made with a psychrometer thermometer. Both methods were measurement between 08.00 and 17.00 hours during the day. the CWSI values in the middle of the day in both irrigation methods were found to rise towards the middle of the low day in the early hours of the day and tended to fall again towards the evening hours. However, contrary to CWSI values, LWP values were found to be high in early hours of day, falling in mid-day and tending again in the evening. Compared with surface drip irrigation subsurface drip irrigation methods, CWSI and LWP values lower than subsurface drip irrigation method