Department of Agronomy, Federal Institute of Education, Science and Technology of Minas Gerais /IFMG, São João Evangelista, Minas Gerais, Brazil.
Department of Forestry, Forest Institute, Federal Rural University of Rio de Janeiro /UFRRJ, Seropédica, Rio de Janeiro, Brazil.
PLoS One. 2020 Nov 2;15(11):e0238677. doi: 10.1371/journal.pone.0238677. eCollection 2020.
The lack of information regarding the water requirement of tree species results in water waste in the seedlings production in nurseries. Water requirement, the growth plant factors and water efficiencies for height and diameter were determined for Schizolobium parahyba (Vell.) Blake, Cytharexylum myrianthum Cham. and Ceiba speciosa Ravenna seedlings, under automated irrigation management and greenhouse conditions, located at 22o45'53" S and 43o41'50" W. We used sewage sludge biosolids as substrate in the seedling phase (280 cm-3 tube), and sandy soil material in the initial pot growth phase (18 dm-3 pot). In the seedlings phase, four water replacement levels were applied to the substrate, by drip irrigation, corresponding to average replacement ranging from 40 (V1) to 100% (V4) of the species water requirement. Seedlings developed properly and 80 days after emergence, S. parahyba, C. myrianthum and C. speciosa seedlings received, respectively, 2.40, 1.08 and 0.85 L per plant, for V4. After growth phase (230 DAE), the total water volumes were, respectively, 70.0, 50.3 and 52.7 L per plant. Under adequate water supply, there were rapid recovery and growth of the species, even for the seedlings which showed different height and diameter in the tube phase. The growth plant factors values found were below 0.5 for all species indicating low sensitivity to growth, both in height and in diameter, in response to water deficit. Water efficiency indicators point to distinct trends between the two phases, and C. speciosa has higher values of water efficiencies for height (80.7 and 17.0 cm L-1) and diameter (2.1 and 0.5 mm L-1) in both phases.
由于缺乏有关树种需水量的信息，导致苗圃在生产苗木时浪费了大量水资源。本研究采用自动灌溉管理和温室条件，在南纬 22°45'53"，西经 43°41'50" 的位置，以污水处理厂污泥生物固体为基质（280cm-3 管），沙质土壤为初始盆栽生长基质（18dm-3 盆），对巴拉圭苏木（Schizolobium parahyba（Vell.）Blake）、毛叶千屈菜（Cytharexylum myrianthum Cham.）和美丽异木棉（Ceiba speciosa Ravenna）的需水量、生长因子和水分效率进行了研究。在幼苗阶段，通过滴灌对基质进行了四个水平的水分替代，平均替代率从物种需水量的 40%（V1）到 100%（V4）不等。幼苗生长正常，在出苗后 80 天，V4 处理下的 S. parahyba、C. myrianthum 和 C. speciosa 幼苗每株分别获得 2.40、1.08 和 0.85L 水。生长阶段（230DAE）后，每株幼苗分别获得 70.0、50.3 和 52.7L 水。在充足的供水条件下，各树种均能迅速恢复和生长，即使是在管内阶段表现出不同高度和直径的幼苗也是如此。所有树种的生长因子值均低于 0.5，表明在高度和直径方面对水分亏缺的生长敏感性较低。水分效率指标表明，两个阶段之间存在明显的趋势，且 C. speciosa 在两个阶段的高度（80.7 和 17.0cm L-1）和直径（2.1 和 0.5mm L-1）水分效率均较高。
