Irrigation regime and water retaining polymer doses in morphological and physiological characteristics of Cordia trichotoma seedlings

Abstract

The objective of this research was to define which irrigation regime, whether or not combined with water retaining polymer doses added to the substrate, is recommended in the production of Cordia trichotoma seedlings. The substrate was used with different dosages of water retaining polymers (0, 1.5, 3.0 and 4.5 g L^-1). After emergence the seedlings were subjected to different irrigation regimes (4-4-4, 4-8-8, 4-8-12, 8-8-8, 8-12-12 and 12-12-12 mm day^-1, alternating them every 60 days). The experiment was conducted in a completely randomized design in a split plot scheme, where the main plot was formed by the different irrigation regimes and subplots by doses of a hidroretentor polymer. After 180 days of applying the irrigation blades, the following morphological and physiological variables were obtained. Seedlings are intolerant to water stress after 180 days under blade 4 or 12 mm constant irrigation. The permanent use of the 4 mm day^-1 blade is possible, since associated with an addition of approximately 2.4 g L^-1 dose of a water retaining polymer to the substrate. A suitable growth of seedlings was obtained with blades of 4-8-8 mm day^-1, alternating every 60 days with the possibility of using a smaller blade at the start of growth, thereby reducing water consumption.