Growth of pitaya seedlings according to the type of substrate and the frequency of irrigation

ABSTRACT The objective of this study was to evaluate the development of pitaya cuttings in different substrates under different frequencies of irrigation. The experiment was conducted from January to May 2017 in a greenhouse at Universidade Federal Rural da Amazônia, Capitao Poço, Pará, Brazil. A completely randomized 3 × 7 factorial design with four replicates was used. Pitaya plants were grown from cuttings in three types of substrates (S1: potting soil; S2: potting soil + cattle manure + wood shavings; and S3: washed sand) under seven irrigation frequencies (24, 48, 72, 96, 120, 144, and 168 h). There was interaction between treatments for root dry matter production, root length variables, the other variables showed no interaction between treatments. The greater development of new and vigorous tissues of the aerial part, the substrates with composition black earth and black earth + manure + sawdust are indicated, and the adoption of the irrigation frequency of 72 h or 96 h. The use of substrate based on black earth + manure + sawdust, allows savings in the rational use of water and energy with the application of the 96 h irrigation frequencies, maintaining satisfactory levels of development to the plant. The washed sand substrate can be used for propagation when this material is abundant, however, greater attention should be paid to the supply of water and nutrients to the plant.摘要 本研究旨在探究不同灌溉频率下，不同基质对火龙果插穗生长发育的影响。实验于2017年1月至5月在巴西帕拉州卡皮唐波苏的亚马逊联邦农村大学（Universidade Federal Rural da Amazônia）温室中开展。本实验采用完全随机3×7因子设计，设置4次重复。以火龙果插穗为试材，设置3种基质（S1：盆栽土；S2：盆栽土+牛粪+木刨花；S3：水洗砂）与7种灌溉频率（24、48、72、96、120、144、168 h）开展栽培试验。结果表明，各处理对根系干物质积累、根长性状存在显著交互效应，其余观测性状则无显著交互作用。若要促进火龙果地上部新生组织健壮生长，宜选用黑土基质以及黑土+牛粪+木刨花复合基质，并采用72 h或96 h的灌溉频率。采用黑土+牛粪+木刨花复合基质并辅以96 h的灌溉频率，可实现水资源与能源的合理节约，同时保障植株生长处于良好水平。水洗砂基质在货源充足时可用于火龙果扦插繁殖，但需格外注意为植株补充水分与养分。