Pumice Effect on Yield and Quality of Tomato.

Pumice is a volcanic porous rock used for hydroponics, but their properties are unique for each region. The objective of this study was to evaluate physical properties of pumice and its effect on the yield and quality of tomato hybrid Sun 7705 (Solanum lycopersicum L.) under greenhouse conditions. The research was conducted in Montecillo, Texcoco, state of Mexico, Mexico, from July 11 to December 11, 2013. The substrates were collected from different mines (State of Mexico, Veracruz, and Jalisco); with (Æ <12 mm) and without sieving and an additional red porous volcanic gravel from state of Mexico known as “tezontle” sieved and it was used as a control. Treatements were accommodated in a randomized block design with six replications. Physical characterization for all substrates included determination of bulk density, moisture retention capacity, total porosity, aeration space, easily and hardly available water, reserve water and total available water. We also conducted a tomato assay and evaluated stem diameter, polar and equatorial fruit diameter, yield per plant, color CIEL and chroma, total soluble solids, and ascorbic acid concentration. Data were exposed to analysys of variance and means comparison test (Tukey, P ≤ 0.05). In general, it was observed that the sieved pumice from a mine of State of Mexico provided the best relationships for  water and air capacity and it allowed us to obtain  greater stem diameter, polar and equatorial fruit diameter, as well as higher yield per plant. There were no significant differences for fruit quality variables due to substrate.

Keywords: hydroponics, physical properties, Solanum lycopersicum L.,substrates.