Water use in the growth of atlantic forest tree species seedlings under different shading levels

Abstract

ABSTRACT The increase in the demand for seedlings of native tree species makes it important to determine their water and light requirements, which are important factors in their production, in terms of costs and time. Water use and productivity in the growth of seedlings of Dalbergia nigra (Vell.) Allemão ex Benth., Apuleia leiocarpa (Vogel) J.F. Macbr and Hymenaea courbaril L. were determined under four light levels (three shading levels and control), using a randomized block design with four replicates. Height, stem diameter, leaf area and biomass, as well as Dickson quality index (DQI) were evaluated. The seedlings were transplanted into 280-cm3 plugs, filled with substrate composed of pure biosolids, and irrigated by a drip system with automatic management. The highest total volumes applied were 3.1 L per D. nigra seedling (in 37 and 58% shading), 2.5 L per A. leiocarpa seedling (in 37% shading) and 3.8 L per H. courbaril seedling (in full sun). Growth indices, confirmed by the DQI, indicate that shading levels of 37 and 58% for D. nigra, 37% for A. leiocarpa, and full sun for H. courbaril are the most recommended. The highest volumes of irrigation promoted the greatest development of the species, in general for intermediate shading, which provided the highest values of DQI and irrigation water productivity.