Abstract

HOYOS GARCIA, Dubián et al. Growing Degree Days Accumulation in a Cucumber (Cucumis sativus L.) Crop Grown in an Aeroponic Production Model. Rev. Fac. Nac. Agron. Medellín [online]. 2012, vol.65, n.1, pp.6389-6398. ISSN 0304-2847.

Abstract. Plant growth and development is determined largely by weather which is composed by several factors. Temperature is one of such key factors which is very important for deciding sowing and harvest time and production. The Growing Degree Days (GDD) or Heat Units (HU) are indexes commonly used for growth and harvest time estimation. In cucumber crops (Cucumis sativus L.), the number of days from sowing until harvest significantly changes according to genotype and temperature. In this work we studied some variables which may affect the efficiency and crop production under an aeroponic system. We determined that 726 and 660 GGD corresponding to 73 and 64 days were requires for the commercial matherials Dasher II and Poinsset 76 respectively. The effect of two aspersion time periods of 30 and 60 seconds followed by a four minutes interval during the day, were evaluated over leaf area and stem and leaves dry weight, using the hybrid Dasher. No statistical significant differences were found suggesting that the 30 s time period is the best choice since it reduces electric energy costs. The effect of three different nutrient solutions: Hoagland and Arnon, Aeroponicos 100% and Aeroponicos 50%, was tested for leaf area, dry weight, fruit weight and number. We found a significant reduction in the variables leaf area, leaf and stem dry weight, average fruit weight (up to 43.3%) and fruit number, using the solution named Aeroponicos at 50% of the commercial concentration. Together our results allowed implementing variables to increase efficiency on a cucumber aeroponic crop system, some of which may improve the economic and environmental performance of cucumber crop using this technology.

Keywords : Phenology; base temperature; physiological time; climate.

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