National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
A study was carried out for comparison of reference evapotranspiration by different methods under agro climatic condition of Pusa (North Bihar). Reference evapotranspiration (ETo) values were computed by thirteen different methods using DSS-ET model and the estimates were compared with ETo values of FAO-56 Penman Monteith method by developing relationships between mean daily ETo of each method with FAO-56 Penman Monteith method. Besides, regression analysis and an indicator namely standard error of estimate (SEE) were evaluated. The method resulting lesser values of standard error of estimate (SEE) was considered as the better method after FAO 56-Penman Monteith method for this region. Mean monthly daily ETo computed by different methods ranged from 4.0 mm day-1 (FAO 56-PM) to 5.0 mm day-1 (1972 KP). The results revealed that mean monthly daily ETo values of all the methods, overestimated the ETo values obtained from FAO 56- Penman Monteith ETo except Hargreaves and Turc method. Amongst them, ETo values obtained from Penman Monteith (SEE= 0.06 mm day-1) and Penman 1963 VPD#1 (SEE= 0.07 mm day-1) were strongly correlated to the standard method and thus assigned 2nd and 3rd ranks, respectively whereas Hargreaves method yielded highest value of SEE (0.60 mm day-1) with poorest rank (11th) for this region. Using the developed relationships ETo values of any applicable method can be converted into standard method estimates for this region that will help in irrigation scheduling, crop water modeling and management of water resources.
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