Nitrogen fertilization on ornamental ginger under fertigation in protected cultivation

ABSTRACT Tropical floriculture has increased significantly in the last decade due to a growing worldwide market trend of consuming exotic, colorful, beautiful and durable flowers. Among the tropical floriculture products, ornamental gingers, species belonging to the families Zingiberaceae and Costaceae, have high potential for ornamental use, both for landscaping, for cut and potted flower and foliage. However, little information can be found in literature when it comes to crop fertilization, mainly concerning nitrogen fertilization, quite important to tropical soils which are poor in organic matter resource. Thus, this study aimed to evaluate application of nitrogen doses, using fertigation for growing ornamental ginger under protected cultivation. The experiment was carried out from 2012 to 2016, using seedlings produced in vitro multiplication. Plantlets remained for a period of acclimatization in a nursery and, then were planted in pits spaced 1x1 m in a greenhouse. The agronomic parameters and recommendation of nitrogen using SPAD were evaluated from the beginning 2013 until 2016. The experimental arrangement was in randomized blocks with five nitrogen doses (0, 100, 200, 300 and 400 kg ha-1) and 4 replicates. The increase of nitrogen doses, up to 400 kg ha-1 via fertigation, produces 77 100-cm-height commercial flowers/tussock/year, favoring the commercial production and standardization of ornamental ginger.摘要：近十年来，受全球市场对异域、艳丽、美观且耐用花卉的消费需求增长驱动，热带花卉栽培产业规模显著扩张。在热带花卉栽培产品中，隶属于姜科（Zingiberaceae）与闭鞘姜科（Costaceae）的观赏姜类，具备极高的观赏应用潜力，可用于园林绿化、鲜切花生产、盆花栽培及观叶产业。然而，现有文献中针对该类作物施肥技术的研究较为匮乏，尤以氮肥施肥相关研究为甚；而热带土壤普遍有机质匮乏，氮肥对这类土壤的作物生长至关重要。为此，本研究旨在评估设施栽培（protected cultivation）条件下，采用水肥一体化施肥（fertigation）方式施加不同剂量氮肥对观赏姜生长的影响。本实验于2012至2016年间开展，供试材料为离体繁殖（in vitro multiplication）培育的幼苗。组培苗先在苗圃完成一段时期的炼苗驯化，随后定植于温室中株行距为1×1米的种植穴内。2013年初至2016年间，本研究对农艺性状参数以及基于SPAD叶绿素仪（SPAD）的氮肥推荐方案进行了评估。实验采用随机区组设计，设置5个氮肥剂量梯度（0、100、200、300及400 kg·ha⁻¹），共4次重复。结果显示，通过水肥一体化施肥施加最高至400 kg·ha⁻¹的氮肥剂量，可使每丛每年产出77株株高100厘米的商品花，有利于观赏姜类的商业化生产与品质标准化。