Substrates and irrigation levels for growing desert rose in pots

ABSTRACT In the past decades, desert rose has become a very popular ornamental plant, especially among collectors, due to its exotic and sculptural forms. However, it has been grown on a commercial scale only recently, and little is known about how to best manage it as a container-grown plant, or even which potting medium (substrate) to recommend. Therefore, the aim of this study was to investigate the interactions between potting media and irrigation levels for growing desert rose as a potted ornamental plant. The experiment was conducted in a greenhouse using a 6 x 2 factorial arrangement with six replications, six potting media and two irrigation levels. The mixes were characterized by measuring their physical properties, specifically the density and water retention capacity (WRC), as well as chemical properties, such as the pH and electrical conductivity (EC). After 210 days, plant growth and plant water consumption were evaluated and measured. A lower dry density for the vermiculite mixes was observed in comparison to that for the sand mixes. However, WRC ranged from 428 to 528 mL L-1 among the mixes, values considered close to ideal. In general, plant growth exhibited higher increases in mixes consisting of coconut fiber + sand or vermiculite, regardless of the irrigation level. Mixes of vermiculite + coconut fiber and sand + coconut fiber can be used to grow desert rose in pots, as long as irrigation is used to maintain the moisture content of the potting medium (mix) between 60-70% and 80-90% of the WRC.摘要 过去数十年间，沙漠玫瑰（desert rose）凭借其奇异别致的造型与独特形态，成为广受青睐的观赏植物，尤其受到植物收藏爱好者的追捧。然而其商业化规模化种植仅在近年才得以实现，目前对于如何最优管理盆栽沙漠玫瑰，乃至应当推荐何种栽培基质（substrate），相关研究仍较为匮乏。因此，本研究旨在探究盆栽沙漠玫瑰种植过程中，栽培基质与灌溉水平之间的交互效应。本试验于温室中开展，采用6×2因子试验设计，设置6次重复，包含6种栽培基质与2种灌溉水平。研究人员通过测定各基质配比的物理属性（包括密度与持水能力（water retention capacity, WRC））以及化学属性（包括pH值与电导率（electrical conductivity, EC）），完成了基质的表征工作。试验周期为210天，结束后对植株生长状况与耗水量进行了评估与测定。结果显示，蛭石基质配比的干密度显著低于砂质基质配比。不过，各基质配比的持水能力介于428~528 mL·L⁻¹之间，该范围被认为接近理想水平。总体而言，无论灌溉水平如何，椰糠+砂或蛭石基质配比下的植株生长增幅均更为显著。蛭石+椰糠以及砂+椰糠的基质配比可用于盆栽沙漠玫瑰种植，只需通过灌溉将栽培基质的含水率维持在其持水能力的60%~70%与80%~90%区间即可。