OPTIMIZATION OF WATER USE IN ARBOREAL SPECIES SEEDLING PRODUCTION

Abstract

 The quantification of the hydric necessity for production of qualified seedlings is of extremely importance, and the substrate is a mediator of such influence. However, few studies are carried out in this context and, mainly, with native species as Luehea divaricata Mart. et Zucc., which presents elevated wood potential and for restoration of riparian forests. Thus, the work consisted in evaluating different substrates and irrigation schemes, in the survival and growing of seedlings, characterizing the hydric demand of the species, using factorial scheme composed by four formulations of substrate (100T: 100% turf (peat); 80T: 80% peat and 20% carbonized rice husk - CRH; 60T: 60% peat and 40% CRH; 40T: 40% peat and 60% CRH) and six irrigation schemes. Variables of survival, height, stem diameter, production of aerial dry mass, root and total, leaf area and Dickson Quality Index were evaluated. We observed elevated survival, height, stem diameter, aerial dry mass and leaf area in irrigation of 16 mm day^-1, combined with the substrates 100T and 80T. The dry masses and Dickson Quality Index, independent of the irrigation scheme, reflected in a greater carbon accumulation. Thus, we concluded that the substrates based on peat, mixed with until 20% of CRH provide a greater seedling growth, making them available to the hardening and expedition more quickly, when associated to the irrigation scheme of 16 mm day^-1. Luehea divaricata is a native species that can be considered with high hydric demand during the phase of seedling production.