the economical assessment of irrigation interval on water productivity and quality of tea

abstract in this research we studied the economical effects of rainfed irrigation and 4, 8, 12 and 16 day sprinkler irrigation intervals as well as their effects on water productivity and tea quality. the study was done in fouman tea research station, northern part of iran where tea is a major crop, during growing season of 2002-2004. the results showed that during dry season of 2002 and 2003 yield quality traits e.g. water soluble solid materials and polyphenols of made tea and dry mater of green leaf and water productivity were decreased with increasing in irrigation interval. mean comparison test showed that 4, 8, 12 and 16 day irrigation intervals raised the yield by 74.5, 71.5, 67.4, and 59.4 present comparing to the rainfed treatment, respectively. economical evaluation of different irrigation regime showed that the mean benefit/cost ratio for 4, 8, 12 and 16 day and control were 2, 1.74, 1.64, 1.43 and 1.5, respectively. although lower interval caused in cost increasing, higher quality of the situation resulted a higher amount of income. in years with moderate rain it is recommended to increase the irrigation interval.