Growth of cactus pear cv. Miúda under different salinity levels and irrigation frequencies

Abstract Soil and water salinity are considered the main limiting factors of plant production. This work aimed to evaluate the influences of irrigation frequency and soil salinity on the development of cactus pear cv. Miúda (Nopalea cochenillifera Salm Dyck). The experiment was conducted in factorial arrangement of four salinity levels: 0.3 (control), 0.5 (low), 1.5 (medium) and 3.6 (high salinity) (ds m-1), associated with four irrigation frequencies (each 7, 14, 21 and 28 days) and two soil textures (sandy and sandy loam) in a randomized block design with four replicates. One cladode was planted in each polyethylene pot containing 10 kg of soil. The soil texture influenced some of the morphological characteristics of the cactus pear, so that plants grown in sandy loam soil yielded higher number of cladodes (9.47) and higher productivity (62.1 g plant-1). The sandy soil produced plants with fewer cladodes (4.50). Irrigation water with a salinity level of 3.6 ds m-1 and an irrigation frequency of 7 days showed higher soil electrical conductivity (48.65 dS m-1) and plants with a higher damage (5.0) and lower productivity (32.51 g plant-1), indicating a low tolerance of the cv. Miúda to salt stress.摘要 土壤与水盐度被视为制约植物生产的主要限制因素。本研究旨在探究灌溉频率与土壤盐度对‘Miúda’梨果仙人掌（Nopalea cochenillifera Salm Dyck）生长发育的影响。本实验采用因子设计，设置4个盐度水平：0.3（对照）、0.5（低盐）、1.5（中盐）与3.6（高盐）（dS·m⁻¹），搭配4种灌溉频率（每7、14、21、28天一次）以及2种土壤质地（砂质土与砂壤土），采用随机区组设计并设置4次重复。每个装有10 kg土壤的聚乙烯盆中种植1片茎节。土壤质地对梨果仙人掌的部分形态性状存在显著影响：砂壤土种植的植株茎节数量更多（9.47片），单株生产力更高（62.1 g·plant⁻¹）；而砂质土种植的植株茎节数量更少（4.50片）。当灌溉水盐度为3.6 dS·m⁻¹且灌溉频率为7天时，土壤电导率更高（48.65 dS·m⁻¹），植株受胁迫损伤程度更严重（评分5.0），单株生产力更低（32.51 g·plant⁻¹），表明‘Miúda’梨果仙人掌对盐胁迫的耐受性较低。