Comparative Evaluation of Naturally Ventilated Polyhouse and Rainshelter on the Performance of Tomato

Abstract

A study was conducted in the Instructional Farm of KCAET, Tavanur, Kerala, during the period from December 2016 to April 2017 to compare the performance of tomato grown under polyhouse and rainshelter cultivation. Tomato variety Akshaya, released by KAU, was used for the study. Drip irrigation system using venturi assembly was used for fertilizer application. The variation of weather parameters such as maximum and minimum temperature, relative humidity and soil temperature during the crop growth period was studied. Mean monthly values of temperature, relative humidity and soil temperature inside the polyhouse was higher than that in rainshelter throughout the growth period. The maximum temperature (36.4 0C) was recorded inside the naturally ventilated polyhouse during the month April and minimum temperature (22.3 0C) was observed in the rainshelter during month of January. The maximum relative humidity (83.82 per cent) was observed in the month of December in the polyhouse and the minimum relative humidity (70.2 per cent) was observed in the month of April in the rainshelter in the morning. The maximum soil temperature (37.8 0C) was observed under the polyhouse in the month of March at the morning and minimum soil temperature (25 0C) was observed inside the rainshelter in the month of February. Crop growth parameters such as plant height, inter-nodal length, number of branches, stem girth, number of leaves and time taken for flower initiation were noted during various crop growth stages for all the treatments. During all growth stages, the plant height and inter-nodal length were significantly higher inside the polyhouse than rainshelter. Stem girth of the plant was higher under rainshelter than the rainshelter. The higher numbers of leaves per plant were observed under rainshelter structure than polyhouse. Among the different treatments, early flower initiation (45 days) was observed in the polyhouse and late flower initiation (49 days) in rainshelter. Yield parameters such as number of fruits per plant and total yield per plant for each treatment were noted during various crop growth stages. Number of fruits per plant was maximum under rainshelter than naturally ventilated polyhouse at all the growing stages of the plant growth. The fruit diameters, average weight per fruit are significantly higher in polyhouse compare to rainshelter. The total yield of tomato observed from polyhouse and rainshelter were 1.31 kg/m 2 and 4.15 kg/m 2 respectively. Quality parameter of tomato like TSS content of tomato under the polyhouse system was found 4.56 0 B and rainshelter was found 4.0 0 B. Water use efficiency was observed higher under rainshelter (165.41 kg/ha.mm) than the polyhouse (52.12 kg/ ha.mm). Cost Benefit (B:C) ratio for each treatment was calculated. The maximum benefit cost ratio of 2.00 was observed in rainshelter than the 0.46 under polyhouse cultivation. From the results of the study it was evident that growing of tomato inside the rainshelter is more profitable than growing it inside naturally ventilated polyhouse.