Document Type : Original Article
Authors
Department of Production Engineering and Plant Genetic,Faculty of Agriculture,Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Abstract
Roselle (Hibiscus sabdariffa L.) is an annual herbaceous shrub belonging to the Malvaceae family, commonly grown in tropical and subtropical countries. The pharmacobotanical and phytochemical studies of this plant have contributed to the understanding of its pharmacological effects and the development of new natural products with applications in medicine and the pharmaceutical industry. To investigate the effects of planting arrangement and integrated nutrient management on some traits of roselle, a field experiment was conducted during the 2023-2024 growing season at the Educational Farm No. 1 of the Department of Plant Genetics and Production Engineering, Shahid Chamran University of Ahvaz, Iran. This study was conducted as a split-plot experiment arranged in a randomized complete block design (RCBD) with three replications. The main plot treatment consisted of ridge and furrow planting arrangements at four levels: row spacing of 50 cm (conventional furrow and wide furrow) and row spacing of 75 cm (conventional furrow and wide furrow). The subplot treatment included five levels of integrated nutrient management: 100% chemical fertilization, integrated fertilization A, integrated fertilization B, organic fertilization A, and organic fertilization B. At the end of the experiment, the following traits were measured: chlorophyll a, chlorophyll b, carotenoid content, total antioxidant capacity, pentose and hexose sugars, total calyx carbohydrates, flavonoids, phenols, and calyx anthocyanin. The main effects of planting arrangement treatments, integrated fertilizer management, and their interactions on most of the studied traits were found to be significant. The interaction of the wide furrow treatment at 75 cm with the integrated fertilizer (B) was identified as the optimal treatment for the examined traits. This combination resulted in the highest concentrations of chlorophyll a (1.6 mg/g), chlorophyll b (0.55 mg/g), carotenoids (0.8 mg/g), total antioxidant capacity (82.5%), pentose sugars (1.3%), total sugars (1.26%), calyx phenols (49.9 mg/g), calyx anthocyanin (47.5 µmol/g Fresh Weight) and calyx yield (78 g per plant) in the 75 cm wide furrow planting arrangement with integrated fertilizer (B). The highest flavonoid content (4.9mg/g) was observed in the 75 cm wide furrow arrangement with 100% chemical fertilizer. The optimal interaction between the 75 cm wide ridge planting arrangement and the integrated fertilizer (B) improved growth parameters and increased the concentrations of key phytochemicals such as chlorophylls, carotenoids, phenols, and anthocyanin. This combination can enhance yield and improve the quality of calyxes, contributing to the promotion of sustainable agricultural practices in roselle cultivation. Implementing effective planting patterns and integrated fertilization strategies is essential for maximizing productivity and ensuring the long-term sustainability of this valuable crop.
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