تخمين ميزان تبخير - تعرق در گلخانه

چكيده انگليسي :

Estimation Evapotranspiration in Greenhouse Mohammad Javad Amiri Email address amiriboogar@yahoo com Date of Submission 2008 9 24 Department of Irrigation and Drainage Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor s Name and Email address Jahangir Abedi Koupai koupai@cc iut ac irSaeid Eslamian saeid@cc iut ac irAbstractEvapotranspiration is one of the major components of hydrologic cycle Accurate estimation of thisparameter is essential for the studies such as water balance irrigation system design and management and water resources management A lysimeter study was conducted to determine the evapotranspiration ET rates for grass crop under outdoor and indoor condition from 23 September 2007 to 22 September2008 in Isfahan University of Technology In this research three drainage lysimeter indoor and threeweighing microlysimeters for indoor and outdoor the glasshouse were used to determine the referenceevapotranspiration With the objective of evaluating the performance of pan evaporation in estimating thewater consumption in greenhouse class A pan and reduced pan installed inside the glasshouse andanother class A pan was installed outside The results showed that the mean monthly ET0 value measuredby the microlysimeters installed outside and inside the glasshouse were 139 mm and 103 8 mmrespectively and 108 22 mm for the drainage lysimeter inside the glasshouse Because of the large areaoccupied by a drainage lysimeter and similar accuracy with weighing microlysimeter in the greenhouse microlysimeter has been suggested to determine reference evapotranspiration inside the greenhouses Inthe present work incoming radiation for greenhouse was found to be 39 percent of the incoming radiationoutdoor As a result of this ET0 in the glasshouse was found to be 69 percent of outdoor ET0 Thus greenhouse agriculture provides a way of increasing crop water use efficiency The daily and meanmonthly output from Stanghellini and Solar radiation based method have been tested against referenceevapotranspiration data computed by the lysimeter to assess the accuracy of each model in estimatinggrass reference evapotranspiration in greenhouse The accuracy of Stanghellini equation is the best but theaccuracy of the solar radiation equation is the worse for estimating daily and mean monthlyevapotranspiration The Stanghellini model underestimated the measured ET rates by 7 percent with R2value of 0 96 In order to evaluate the individual and combined effects of climate factors on the measuredET linear multiple regression analyses were done in order to determine empirically based ET models The results revealed it appeared that the empirical models did at least as well if not better than theStanghellini model This study showed that empirical ET models could be used to predict ET rates if thereis a difficulty in running the Stanghellini model due to a lack of input parameters With regard to thecomparisons between the monthly evaporation values measured by the class A pan and reduced pan bothinside the glasshouse with the data of the lysimeters coefficient of pans was obtained 1 148 for the classA pan method and 0 94 for the reduced pan method Also comparing between the monthly evaporationvalues measured by the class A pan outside the glasshouse and the data of the lysimeters inside coefficient of pan was obtained 0 486 Considering the high coefficients of correlation inside theglasshouse it is possible to replace the class A pan outside with the class A pan and reduced pan insideto estimate ET0 Reduced pan has a low cost and is easy to use and also occupied a small area in theglasshouse therefore it is recommend to replace instead of class A pan inside the glasshouse REF ETprogram was used in greenhouse condition but statistical analysis showed that this program can notpredict the reference evapotranspiration with a high accuracy in greenhouse Key WordsEvapotranspiration lysimeters microlysimeter Stanghellini mode

اميري، محمدجواد

تخمين ميزان تبخير - تعرق در گلخانه

چرخه هيدرولوژي , لايستيمرها