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：乡土树种幼苗常被应用于退化地区造林、河岸林营建及法定保留林植被恢复。影响幼苗质量的核心因素包括容器规格与基质水分可利用性。本研究旨在探究孪叶豆（Hymenaea courbaril L.）幼苗对灌溉水平与容器规格的响应规律。试验于温室中开展，采用2×5因子组合的裂区随机区组设计，设置3次重复。主区处理为容积3.1 L的硬质花盆与4.0 L的硬质塑料管容器；副区处理为分别施加相当于最大蒸散量（maximum evapotranspiration, ETm）20%、40%、60%、80%与100%的灌溉水平。在播种后80~200天（DAS）阶段，硬质塑料管容器相较于硬质花盆，可提升植株实际蒸散量，改善幼苗质量，同时获得更高的作物系数（crop coefficient, Kc）。采用Penman-Monteith方法测算，播种后200天时，citrovase培育的幼苗作物系数介于0.54至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。播种后200天时，幼苗根系干物质重量高于叶片干物质重量，这与幼苗生长初期的情况截然相反。