CROP COEFFICIENT, DRY MATTER PARTITION AND SEEDLINGS QUALITY OF Hymenaea courbaril L. IN CONTAINERS SIZES UNDER WATER DEFICIT IRRIGATION1

ABSTRACT Native species seedlings are commonly used in the degraded areas reforestation, riparian forests and legal reserve. Among the factors that influence the seedlings quality, are the container size and the substrate water availability. Thus, the objective of this paper was to evaluate Hymenaea courbaril L. seedlings response in function of irrigation levels and container sizes. The experiment was carried out in greenhouse, in randomized blocks design, with three replications in split plots, in 2 x 5 scheme. Rigid pots of 3.1 L and stiff plastic tubes of 4.0 L were used in the plots, while irrigation levels equals to 20%, 40%, 60%, 80% and 100% of the maximum evapotranspiration (ETm) were used in the subplots. The stiff plastic tube provided larger ETm and increased seedlings quality and, consequently, larger crop coefficient (Kc) in comparison with rigid pot, in the phase from 80 to 200 days after the sowing (DAS). The Kc of the seedlings in citrovase varired from 0.54 to 1.12, of the planting at 200 DAS, according the Penman-Monteith methodology. Irrigation levels between ETm 86.8% and 100% propitiated larger seedlings quality index. To the 200 DAS, the roots dry matter was larger than the leaves dry matter, unlike the initial phases.

摘要
乡土树种幼苗广泛应用于退化区域造林、河岸林营建及法定保留林植被恢复。影响幼苗质量的关键因素包括容器规格与基质水分有效性。为此，本研究旨在探究孪叶豆（Hymenaea courbaril L.）幼苗对灌溉梯度与容器规格的响应规律。
本试验于温室环境中开展，采用裂区随机区组设计，设置3次重复，处理组合为2×5因子设计。主区分别使用容积3.1L的硬质花盆与4.0L的硬质塑料管容器，副区则设置为最大蒸散量（ETm）20%、40%、60%、80%及100%的5个灌溉梯度。
在播种后80~200天（DAS）阶段，相较于硬质花盆，硬质塑料管容器可实现更高的ETm水平，改善幼苗质量，进而提升作物系数（Kc）。采用Penman-Monteith方法计算得出，播种后200天（DAS）时，citrovase容器内培育的幼苗Kc值介于0.54~1.12之间。灌溉水平介于ETm的86.8%~100%时，可获得最优的幼苗质量指数。与育苗初始阶段不同，播种后200天（DAS）时，幼苗的根系干物质重量显著高于叶片干物质重量。