Evapotranspiration Based Micro Irrigation Scheduling of Tomato Crop under Naturally Ventilated Polyhouse

The present study was undertaken to investigate the Evapotranspiration Based Micro Irrigation Scheduling of Tomato Crop under Naturally Ventilated Polyhouse, at experimental field of Department of Irrigation and Drainage Engineering, G. B. Pant University of Agriculture & Technology, Pantnagar, Uttarakhand during 2017-18. The average of mean monthly ET0 estimated under polyhouse by FAO-PM (benchmark) model was 39.44 mm, but that of the FAO Penman, Hargreaves, Stanghellini, Priestley-Taylor and FAO Radiation models were 38.37, 18.18, 37.80, 48.17 and 53.87 mm, respectively. Whereas, the average of mean monthly ET0 estimated under open environment by FAO-PM (benchmark) model was 116.34 mm, but that of the FAO Penman, Hargreaves, Stanghellini, Priestley-Taylor and FAO Radiation models were 119.33, 133, 126.41, 113.17 and 117.37 mm, respectively. The FAO Penman and Hargreaves model are found to be most and least appropriate models for estimating daily ET0 under polyhouse. Whereas, FAO Radiation and Stanghellini model observed to be most and the least appropriate models in open environment for estimating daily ET0 under polyhouse for the Pantnagar tarai condition of Uttarakhand. During the six month growing period, the average water requirement for tomato crop under polyhouse and open environments were 0.2149 and 0.2924 liter per day per plant, respectively, showing that the water requirement in the open environment was estimated as 30% higher than that of polyhouse. The experimental results also revealed that the treatment T2 (100% water application of ETc without mulch under polyhouse) recorded significant yield (18.97 kg/m2), water use efficiency (135.26 kg/m3) and maximum fruit weight (106.66 gm).