Assessing water doses, water use efficiency and tomato quality under greenhouse conditions in Natabuela-Ecuador

In Ecuador, tomato (Solanum lycopersicum L.) is a main crop which production has been increase in the latest decade. The crop is grown throughout the country, although it is in the Sierra region where locate the greenhouse production areas. Tomato manufacturers face the water scarcity problems and in addition, the small and medium producers have little knowledge regarding the amount of water they should apply to the crop, and how they should manage. Considering this framework, this study first is aimed at determining the optimal water doses for tomato crop cultivated under greenhouse conditions in the Sierra region and second, it is aimed at establishing the best irrigation frequency. The experimental study was carried out from June to December 2020, in a metallic greenhouse with plastic cover, located in the Natabuela’s parish which belong to the city of Antonio Ante in the Imbabura province. The variables studied were:  two water doses (100% and 120% of the of the evapotraspiration, ET) and four irrigation frequencies (two irrigations and one irrigation a day, one irrigation every other day and one irrigation every two days). In total, eight treatments were evaluated in an 2 x 4 factorial design, under a completely random block distribution, with four repetitions. The results show that the 120% ET irrigation dose produces the highest plant vigor and total and commercial production, while the 100% ET irrigation dose presents a higher citric acid percentage and total soluble solids content. Likewise, both doses do not showed significant differences in their water use efficiency and pH. Therefore, if the increase in production is searching then, it would be advisable to apply the 120% ET dose, although if the search is for the production quality it would be better to apply 100% ET. Regarding the irrigation frequency, one or two irrigations a day produced higher plant vigor as well as higher production and water use efficiency. None of the irrigation frequencies studied had significant differences in plant height and fruit quality variables.